BACKGROUND:Hepatocellular carcinoma (HCC) is increasing in the U.S. despite a decline in cancer overall. Latinos have higher rates of HCC than the general population according to the Surveillance, Epidemiology, and End Results (SEER) Program. Not included in SEER, Texas Latinos make up one-fifth of the U.S. Latino population. To determine whether HCC incidence differs among U.S. and Texas Latinos, this descriptive study compares HCC incidence from 1995 through 2006 among three Latino populations: U.S. SEER, Texas overall and a South Texas subset. To identify lines of prevention research, we compare prevalence of known HCC risk factors among these Latino groups. METHODS:Data were collected from the U.S. SEER Program, Texas Cancer Registry and Texas Department of State Health Services (TDSHS). Annual age-specific and age-adjusted HCC incidence rates, annual percent changes (APCs) and 95% confidence intervals were calculated as well as prevalence of obesity, diabetes, heavy alcohol use and cigarette smoking. RESULTS:Of the three Latino groups compared, South Texas Latinos had the highest age-adjusted HCC incidence rates and SEER Latinos had the lowest (10.6/100,000 (10.1-11.1) and 7.5/100,000 (7.2-7.7), respectively). HCC incidence significantly increased over time (APCs>0) among Latinos in all three geographic groups. Between 1995 and 2006, there was an increase in obesity among all three populations, and obesity was highest among South Texas Latinos. Diabetes increased among U.S. Latinos, and Latino women in South Texas had significantly higher diabetes prevalence than U.S. Latino women. Cigarette smoking and heavy alcohol use were similar among groups. CONCLUSIONS:The incidence of HCC among Latinos in South Texas is higher than elsewhere in the United States. Higher rates of HCC among Texas and South Texas Latinos may be associated with greater prevalence of obesity and diabetes, risk factors for HCC that are amenable to intervention.

Abstract Introduction. Hepatocellular carcinoma (HCC) has increased in the U.S. from 1975-2006 while overall cancer has declined. Moreover, HCC among South Texas Latinos is higher than other U.S. Latinos. In recent years a number of risk factors have been associated with HCC including hepatitis-C virus infection, heavy alcohol use, obesity, diabetes and others. Of these, only diabetes exhibits characteristics which make it a candidate for why HCC is increasing in the U.S. Latino population and increasingly higher among South Texas Latinos. This study compares incidence rates of HCC and prevalence rates of diabetes among U.S. Latinos and South Texas Latinos. We hypothesize that these data implicate diabetes in HCC and suggest a clear path to informed HCC prevention. Methods. Data from the U.S. SEER (Surveillance, Epidemiology, and End Results) Program, Texas Cancer Registry, and the Texas Department of State Health Services (TDSHS) were obtained. Age-adjusted HCC incidence rates were calculated using SEER*Stat and SPSS software and aggregated over 3-year periods. Likewise, annual prevalence of diabetes was calculated and aggregated over the same periods. For each measure values for the mutually exclusive U.S. and South Texas populations were compared. Trend slopes for both HCC and diabetes were calculated and displayed graphically. Group differences were assessed at p < .05 if confidence intervals did not overlap. Results. U.S. (SEER) Latino HCC incidence averaged 6.1/100,000 during 1995-1997 and increased to 8.0 during 2004-2006 (slope m = 0.455). South Texas Latino rates averaged 9.2 and 11.7 during the same periods (slope m = 0.625) (incidence rate difference, p < .05). Simultaneously, the prevalence rate of diabetes was 5.9% and 7.7% among U.S. SEER Latinos (slope m = 0.450) and 7.6% and 9.6% among South Texas Latinos (slope m = 0.500) (prevalence rate difference, p < .05). Although slope differences could not be calculated, they indicate a greater rate of increase among South Texas Latinos than U.S. SEER Latinos. Conclusion. Our findings support observations that HCC and diabetes are increasing in the United States. We have described an important relationship between increasing rates of HCC and diabetes in the U.S. SEER and South Texas Latino populations. We suggest this relationship may explain higher rates of HCC among Latinos. There is a need to focus HCC etiological research to account for this relationship while simultaneously on other attributable risks for the disease as well as genetic, cultural and socioeconomic predisposing features. We note that diabetes is preventable or treatable. The potential contribution of this research can firmly establish associations and inform HCC prevention. Acknowledgements. The San Antonio Cancer Institute, San Antonio, Texas (P30-CA54174) and the National Cancer Institute, Redes En Acción (U01-CA86117). Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3595. doi:1538-7445.AM2012-3595

Abstract Introduction: Hepatocellular carcinoma (HCC) incidence is increasing in the U.S. for unknown reasons despite a decline in cancer overall during 1975–2006. Latinos have higher rates of HCC than other groups, and attributable risks for HCC among Latinos have been identified. This study compared HCC incidence and behavioral risk factors associated with it from 1995 through 2006 between U.S. Latinos, Texas Latinos and a South Texas Latino subset. We hypothesized that HCC incidence is higher among South Texas Latinos in conjunction with higher attributable behavioral risk factors during the same period. Methods: Data from the U.S. SEER (Surveillance, Epidemiology, and End Results) Program, Texas Cancer Registry, and the Texas Department of State Health Services (TDSHS) were obtained. Annual age-specific and age-adjusted HCC incidence rates, annual percent changes (APCs) and 95% confidence intervals (CI) were calculated as well as prevalences of obesity, diabetes, heavy alcohol use and smoking. Analyses were performed using SEER*Stat and SPSS Complex Samples software. Groups were compared using Chi-Squared and T-Tests with differences assessed at p < .05 if confidence intervals did not overlap. Results: Latinos accounted for more than a third of HCC in Texas and nearly three-fourths of all HCC in South Texas, significantly greater proportions than SEER. More than 70% of HCC in Latinos occurred in men, with similar percentages observed among SEER, Texas and South Texas groups. HCC in Latinos was highest in South Texas (10.6/100,000) and Texas (9.7/100,000) compared to SEER (7.5/100,000). South Texas Latinos were older than their SEER counterparts (Median = 67 vs. 62). More South Texas and Texas Latinos than SEER resided in rural areas (14.8%, 14.3% vs. 5.2%). Prevalence percentages of HCC-related behavioral risk factors for Latinos in the U.S., Texas and South Texas for two time periods, 1995–1997 and 2004–2006 show that obesity increased among all three groups of Latinos overall from the first to the second time period. Additionally, Texas and South Texas Latinos had higher obesity prevalence than U.S. Latinos during the most recent period (30.2% and 35.0% versus 26.7%). Moreover diabetes prevalence increased among U.S. Latinos. Texas and South Texas Latinos also showed an increasing pattern, although confidence intervals overlapped. For 2004–2006, the prevalence of diabetes was higher in South Texas Latinas than U.S. Latinas (10.3% and 7.8%, respectively). Heavy alcohol and cigarette use did not change significantly over time among any Latino group. Conclusion: Our findings support observations that HCC is alarmingly on the rise in the United States. We have described an important constellation of risks for HCC in this group that may result in higher rates of the disease among Latinos. Most if not all of these risks are modifiable, preventable or treatable. Clearly there is a need to focus on HCC etiological research and intervention that takes into account not only the most significant attributable risks for the disease, but also genetic, cultural and socioeconomic predisposing features. The potential contribution of these to HCC indicates a need for etiologic research to firmly establish associations and inform HCC-related prevention interventions. Acknowledgements: This research was possible by grants from the San Antonio Cancer Institute, San Antonio, Texas (P30-CA54174) and the National Cancer Institute, Redes En Acción (U01-CA86117). Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):PR1.

Germline mutations of FH, the gene that encodes for the tricarboxylic acid TCA (TCA) cycle enzyme fumarate hydratase, are associated with an inherited form of cancer referred to as Hereditary Leiomyomatosis and Renal Cell Cancer (HLRCC). Individuals with HLRCC are predisposed to the development of highly malignant and lethal renal cell carcinoma (RCC). The mechanisms of tumorigenesis proposed have largely focused on the biochemical consequences of loss of FH enzymatic activity. While loss of the tumor suppressor gene von Hippel Lindau (VHL) is thought to be an initiating event for the majority of RCCs, a role for FH in sporadic renal cancer has not been explored. Here we report that FH mRNA and protein expression are reduced in clear cell renal cancer, the most common histologic variant of kidney cancer. Moreover, we demonstrate that reduced FH leads to the accumulation of hypoxia inducible factor- 2α (HIF-2α), a transcription factor known to promote renal carcinogenesis. Finally, we demonstrate that overexpression of FH in renal cancer cells inhibits cellular migration and invasion. These data provide novel insights into the tumor suppressor functions of FH in sporadic kidney cancer.

You have accessJournal of UrologyKidney Cancer: Basic Research1 Apr 2011384 REDUCED EXPRESSION OF FUMARATE HYDRATASE IN CLEAR CELL RENAL CANCER PROMOTES HIF-2α ACCUMULATION, MIGRATION AND INVASION Sunil Sudarshan, Karthigayan Shanmugasundaram, Susan Naylor, Shu Lin, Carolina Livi, Cynthia Galindo, Dipen Parekh, I-Tien Yeh, LuZhe Sun, and Karen Block Sunil SudarshanSunil Sudarshan San Antonio, TX More articles by this author , Karthigayan ShanmugasundaramKarthigayan Shanmugasundaram San Antonio, TX More articles by this author , Susan NaylorSusan Naylor San Antonio, TX More articles by this author , Shu LinShu Lin San Antonio, TX More articles by this author , Carolina LiviCarolina Livi San Antonio, TX More articles by this author , Cynthia GalindoCynthia Galindo San Antonio, TX More articles by this author , Dipen ParekhDipen Parekh San Antonio, TX More articles by this author , I-Tien YehI-Tien Yeh San Antonio, TX More articles by this author , LuZhe SunLuZhe Sun San Antonio, TX More articles by this author , and Karen BlockKaren Block San Antonio, TX More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.472AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Germline mutations of FH, the gene that encodes for the tricarboxylic acid TCA (TCA) cycle enzyme fumarate hydratase, are associated with an inherited form of renal cancer referred to as Hereditary Leiomyomatosis and Renal Cell Cancer (HLRCC). Individuals with HLRCC are predisposed to the development of highly malignant and lethal renal cell carcinoma (RCC). The mechanisms of tumorigenesis proposed have largely focused on the biochemical consequences of loss of FH enzymatic activity. While loss of the tumor suppressor gene von Hippel Lindau (VHL) is thought to be an initiating event for the majority of RCCs, a role for FH in sporadic renal cancer has not been explored. Here we report the reduced expression of FH in clear cell renal cancer, the most common histologic variant of kidney cancer. METHODS Clear cell renal carcinoma samples were evaluated by immunohistochemistry, western blotting, and real time RT-PCR for the expression of FH (fuamrate hydratase). In addition, the effects of modulation of FH, either via knockdown with siRNA or overexpression with a cDNA constrct, were determined in VHL null renal cancer cells. The effect on HIF-2α and AKT signaling were determined via western blotting. Migration and invasion were determined via chamber assays. RESULTS We report the reduced expression of FH in clear cell renal cancer, the most common histologic variant of kidney cancer. Moreover, we demonstrate that reduced FH leads to the accumulation of hypoxia inducible factor- 2α (HIF-2α), a transcription factor known to promote renal carcinogenesis. Finally, we demonstrate that overexpression of FH in renal cancer cells inhibits cellular migration and invasion. CONCLUSIONS These data provide the first evidence that FH is reduced in the most common histological variant of renal cancer and that its expression levels can impact basal HIF-2α levels in renal cancer cells in addition to migratory and invasive behavior. Given the role of FH in the tricarboxylic acid cycle, these findings provide further evidence of aberrant metabolism in renal cancer. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e155 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Sunil Sudarshan San Antonio, TX More articles by this author Karthigayan Shanmugasundaram San Antonio, TX More articles by this author Susan Naylor San Antonio, TX More articles by this author Shu Lin San Antonio, TX More articles by this author Carolina Livi San Antonio, TX More articles by this author Cynthia Galindo San Antonio, TX More articles by this author Dipen Parekh San Antonio, TX More articles by this author I-Tien Yeh San Antonio, TX More articles by this author LuZhe Sun San Antonio, TX More articles by this author Karen Block San Antonio, TX More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Mitochondrial alteration has been long proposed to play a major role in tumorigenesis. Recently, mitochondrial DNA (mtDNA) mutations have been found in a variety of cancer cells. In this study, we examined the contribution of mtDNA mutation and mitochondrial dysfunction in tumorigenesis first using human cell lines carrying a frame-shift at NADH dehydrogenase (respiratory complex I) subunit 5 gene (ND5); the same homoplasmic mutation was also identified in a human colorectal cancer cell line earlier. With increasing mutant ND5 mtDNA content, respiratory function including oxygen consumption and ATP generation through oxidative phosphorylation declined progressively, while lactate production and dependence on glucose increased. Interestingly, the reactive oxygen species (ROS) levels and apoptosis exhibited antagonistic pleiotropy associated with mitochondrial defects. Furthermore, the anchorage-dependence phenotype and tumor-forming capacity of cells carrying wild-type and mutant mtDNA were tested by growth assay in soft agar and subcutaneous implantation of the cells in nude mice. Surprisingly, the cell line carrying the heteroplasmic ND5 mtDNA mutation showed significantly enhanced tumor growth, while cells with homoplasmic form of the same mutation inhibited tumor formation. Similar results were obtained from the analysis of a series of mouse cell lines carrying a nonsense mutation at ND5 gene. Our results indicate that the mtDNA mutations might play an important role in the early stage of cancer development, possibly through alteration of ROS generation and apoptosis.

Chromosomal regions showing homozygous deletion in tumors are not commonly found and are usually the site of genes involved in tumor suppression. We previously identified the homozygous deletion of a discrete region at 18q22.3 in 50% of breast tumors and 58% of prostate tumors. There are no known genes in this region. Our hypothesis for this study was the following: Encoded within this 18q region is a transcript that when lost plays a role in the development of breast and prostate cancer. The objective of this study was to determine whether sequences within the region of deletion are transcribed in primary breast and prostate epithelial cells. A microarray experiment using RNA isolated from primary mammary epithelial cells and primary prostate epithelial cells enabled us to detect an approximately 500 basepair region that is transcribed in normal breast and prostate epithelial cells. This is a novel transcribed sequence that has not been described previously. A quantitative real‐time TaqMan assay verified the existence of the transcript in breast and prostate epithelial cell RNA. The novel transcript was also detected in high abundance in RNA isolated from brain, cervix, spleen, and thymus. Through our experiments, we hope to identify a new molecular pathway in breast and prostate cancer that could provide new targets for developing therapeutics.

PURPOSE:SEMA3B and SEMA3F are 2 closely related genes lying 80 kb apart on chromosome 3 that have been shown to suppress tumor formation in vivo and in vitro. Each gene has a single nucleotide polymorphism that results in a nonsynonymous coding change, rs2071203 (SEMA3B) and rs1046956 (SEMA3F), as well as noncoding single nucleotide polymorphisms. MATERIALS AND METHODS:We performed a case-control study of 789 prostate cancer cases and 907 controls from 3 races/ethnicities to determine possible associations of 10 variants with prostate cancer risk or prognosis. RESULTS:The risk of prostate cancer increased more than 2-fold in Hispanic men with TT alleles at rs2071203 in SEMA3B and with CC alleles for rs2072054 at the 5' end of SEMA3F (OR 2.13, 95% CI 1.12-4.04, p = 0.02 and OR 2.55, 95% CI 1.34-4.84, p = 0.0045, respectively). These 2 single nucleotide polymorphisms were also associated with a poor prognosis in Hispanic men (2.71 and 3.48-fold increased risk). A frequent G-C-G-G-A-T-C-C-T-G haplotype encompassing 10 SNPs was associated with an increased risk of prostate cancer and poor prognosis in Hispanic samples (OR 2.72, 95% CI 1.20-6.12, p = 0.016 and OR 3.32, 95% CI 1.21-9.10, p = 0.02). In nonHispanic white men the T-C-G-A-A-T-C-C haplotype was associated with a high Gleason score (OR 1.44, 95% CI 1.06-1.96, p = 0.021). CONCLUSIONS:These data indicate that polymorphisms in SEMA3B and SEMA3F are associated with prostate cancer risk and poor prognosis in Hispanic and nonHispanic white men.

Purpose: Because of the role of TGFB1 in prostate cancer and progression, we hypothesized that polymorphisms of TGFB1 at C-509T may be associated with prostate cancer risk and/or more aggressive tumors.Materials and Methods: This is a case-control study. Controls consisted of male volunteers 40 years old or older with a normal digital rectal examination and prostate specific antigen 2.5 ng/ml or less. Cases consisted of men with biopsy proven prostate cancer. High grade prostate cancer included all cancers of Gleason sum 7 or greater. Poor prognosis in cases was defined as any stage with Gleason sum 8-10, pT3A (if Gleason sum was greater than 7), pT3B or higher (all Gleason sums), any N1 or higher, any M1 or higher, or any documented PSA recurrence (biochemical failure). Single nucleotide polymorphisms were genotyped using allelic discrimination assays. Logistic regression models were used to estimate the OR with the corresponding 95% CI for individual racial/ethnic groups. Allelic frequency across ethnic/racial groups was compared using Pearson's chi-square test.Results: A total of 653 cases and 1,476 controls were genotyped at C-509T. The TT genotype showed a significant protective effect against high grade prostate cancer (OR 0.482, 95% CI 0.274-0.849). In addition, the TT genotype was associated with a decreased risk of poor prognosis prostate cancer (OR 0.488, 95% CI 0.236-1.009). Limiting analysis to nonHispanic white men showed that the TT genotype had an even more pronounced protective effect for poor prognosis prostate cancer (OR 0.297, 95% CI 0.100-0.887). Finally, there was a significant difference in the distribution of allelic frequency across racial/ethnic groups (p < 0.0001).Conclusions: We observed an association between single nucleotide polymorphisms of TGFB1 at C-509T and a decreased risk of aggressive prostate cancer. The TT genotype of TGFB1 at C-509T demonstrates a protective effect against high grade prostate cancer and cases with poor prognosis.

Studies of the genetic influences on prostate cancer have indicated that there are familial genes that account for only a small fraction of the genetic components of prostate cancer. Many investigators have investigated the association of single nucleotide polymorphisms in candidate genes with an increased risk in prostate cancer. The types of candidates examined include genes in steroid metabolism, oxidative stress, and DNA repair as well as common variants of genes found by family studies. These analyses have identified some SNPs that are associated with prostate cancer risk. A complete genetic snapshot of prosatate cancer risk will only be obtained when all the genetic risk factors are identified and combined with other known markers of risk.

Prostate cancer is the second leading cause of cancer deaths among American men. The loss of Y chromosome has been frequently observed in primary prostate cancer as well as other types of cancer. Earlier, we showed that introduction of the human Y chromosome suppresses the in vivo tumorigenicity of the prostate cancer cell line PC-3. To further characterize the Y chromosome, we have developed a high-density bacterial artificial chromosome (BAC) microarray containing 178 BAC clones from the human Y chromosome. BAC microarray was used for array comparative genomic hybridization on prostate cancer samples and cell lines. The most prominent observation on prostate cancer specimens was a deletion at Yp11.2 containing the TSP.Y tandem gene array. Out of 36 primary prostate tumors analyzed, 16 (44.4%) samples exhibited loss of TSPY gene copies. Notably, we observed association between the number of TSPY copies in the blood and the incidence of prostate cancer. Moreover, PC-3 hybrids with an intact Yp11.2 did not grow tumors in nude mice, whereas PC-3 hybrids with a deletion at Yp11.2 grew tumors in nude mice.

You have accessJournal of UrologyDiscussed Poster, Monday, May 22, 2006, 1:00 - 4:00 pm1 Apr 2006821: The VEGF+405 CC Polymorphism is Associated with Prostate Cancers of Poor Prognosis Edith D. Canby-Hagino, Dawn Garda, lan M. Thompson, Dean Troyer, Jacques Baillargeon, Timothy C. Brand, Robin Leach, and Susan L. Naylor Edith D. Canby-HaginoEdith D. Canby-Hagino More articles by this author , Dawn GardaDawn Garda More articles by this author , lan M. Thompsonlan M. Thompson More articles by this author , Dean TroyerDean Troyer More articles by this author , Jacques BaillargeonJacques Baillargeon More articles by this author , Timothy C. BrandTimothy C. Brand More articles by this author , Robin LeachRobin Leach More articles by this author , and Susan L. NaylorSusan L. Naylor More articles by this author View All Author Informationhttps://doi.org/10.1016/S0022-5347(18)33057-XAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail "821: The VEGF+405 CC Polymorphism is Associated with Prostate Cancers of Poor Prognosis." The Journal of Urology, 175(4S), p. 265 © 2016 by American Urological AssociationFiguresReferencesRelatedDetails Volume 175Issue 4SApril 2006Page: 265 Advertisement Copyright & Permissions© 2016 by American Urological AssociationMetricsAuthor Information Edith D. Canby-Hagino More articles by this author Dawn Garda More articles by this author lan M. Thompson More articles by this author Dean Troyer More articles by this author Jacques Baillargeon More articles by this author Timothy C. Brand More articles by this author Robin Leach More articles by this author Susan L. Naylor More articles by this author Expand All Advertisement PDF DownloadLoading ...

After the completion of a draft human genome sequence1, the International Human Genome Sequencing Consortium has proceeded to finish2 and annotate each of the 24 chromosomes comprising the human genome. Here we describe the sequencing and analysis of human chromosome 3, one of the largest human chromosomes. Chromosome 3 comprises just four contigs, one of which currently represents the longest unbroken stretch of finished DNA sequence known so far. The chromosome is remarkable in having the lowest rate of segmental duplication in the genome. It also includes a chemokine receptor gene cluster as well as numerous loci involved in multiple human cancers such as the gene encoding FHIT, which contains the most common constitutive fragile site in the genome, FRA3B3. Using genomic sequence from chimpanzee and rhesus macaque, we were able to characterize the breakpoints defining a large pericentric inversion that occurred some time after the split of Homininae from Ponginae, and propose an evolutionary history of the inversion.

Abstract : We hypothesize that chromosomal loss of the Y chromosome in prostate cancer is a specific tumorigenic event. Our studies are to prove whether loss of a specific region of the Y chromosome is indicative of a tumor suppressor gene. We transferred the Y chromosome by microcell mediated chromosome transfer into PC-3 cells to determine if it suppressed tumor growth. Of the %5 mice injected with several independent clones only one produced a tumor in nude mice in contrast to control PC-3 cells. Our second approach is to determine the frequency of loss of the Y chromosome in prostate tumors. PCR analysis of Y specific loci on prostate cancer samples and FISH is used to identify the region of loss. Smaller chromosomal fragments are being used in the transfer experiments to define the region. Data from these experiments suggest that a tumor suppressor gene is located near the selectable marker on the short arm. The second approach is to develop a genomic microarray specific for the Y chromosome. BAC clones have been isolated and arrayed. Successful identification of a gene on the Y chromosome will provide a marker that may aid in the diagnosis and prediction of prognosis of prostate cancer.

In the search for a tumour suppressor gene in the 3P21.3 region we isolated two genes, RBM5 and RBM6. Gene RBM5 maps to the region which is homozygously deleted in the small cell lung cancer cell line GLC20; RBM6 crosses the telomeric breakpoint of this deletion, Sequence comparison revealed that at the amino acid level both genes show 30% identity, They contain two zinc finger motifs, a bipartite nuclear signal and two RNA binding motifs, suggesting that the proteins for which RBM5 and RBM6 are coding have a DNA/RNA binding function and are located in the nucleus. Northern and Southern analysis did not reveal any abnormalities. By SSCP analysis of 16 lung cancer cell lines we found only in RBM5 a single presumably neutral mutation, By RT-PCR we demonstrated the existence of two alternative splice variants of RBM6, one including and one excluding exon 5, in both normal lung tissue and lung cancer cell lines, Exclusion of exon 5 results in a frameshift which would cause a truncated protein of 520 amino acids instead of 1123 amino acids. In normal lung tissue, the relative amount of the shorter transcript was much greater than that in the lung tumour cell lines, which raises the question whether some tumour suppressor function may be attributed to the derived shorter protein.

Avian erythroblastosis virus, a retrovirus that causes erythroblastosis and sarcomas in infected birds, possesses two host cell-derived genes [viral (v) erb-A and erbB]. Although v-erb-11 seems to be responsible for oncogenic transformation, v-erb-A might have an enhancing effect on transformation. In chickens, the natural host for avian erythroblastosis virus, cellular (c) erb-A and erb-B genes appear to be unlinked, but their chromosomal locations in other species are unknown. To ascertain the chromosomal location of c-erb genes in man and mouse, we analyzed interspecies somatic cell and microcell hybrids by Southern filter hybridization techniques using specific v-erb-A and v-erb-B probes. We found cerb-A sequences on human chromosome 17 (17pll qter) and located c-erb-B on human chromosome 7 (7pter q22). In contrast, both c-erb-A and c-erb-B reside on mouse chromosome 11. Avian erythroblastosis virus (AEV) is a rapidly transforming retrovirus that induces erythroid leukemias and sarcomas in infected birds and transforms erythroblasts and fibroblasts in vitro (1). AEV requires a helper virus for replication, as portions of its genome have been substituted with two genetic loci [viral (v) erb-A and erb-B] that have been derived from the chicken genome and are responsible for viral oncogenesis (2). Transformation by AEV appears to arrest the development of erythroid precursor cells, and it has been suggested that the chicken cellular (c) erb-A and erb-B genes might function normally in the control of hematopoietic cell differentiation (3). An involvement of chicken c-erb-B in avian leukosis virus-induced erythroblastosis has been found in the form of activation of the proto-oncogene by avian leukosis virus promoter insertion (4). Although recent studies using in vitro mutagenesis techniques apparently indicate that the ability ofAEV to transform both fibroblasts and erythroblasts resides solely in the v-erb-B locus, a role for v-erb-A in leukemogenesis has not been rigorously excluded (5). The v-erb-A gene may, in fact, have an enhancing effect on transformation in these cell systems (6). Inasmuch as AEV is composed of two independent cellderived sequences, it has been of interest to determine the molecular and chromosomal organization of the chicken cerb-A and c-erb-B genes. The chicken c-erb-A and c-erb-B genes are carried on cellular DNA fragments that must be separated by a distance of at least 12 kilobase pairs (kbp), and the genes might be unlinked altogether (2). Recently, isolation of c-erb-A and c-erb-B genes in man and their characterization in man and mouse have been described (7). To analyze the chromosomal organization of cerb genes in man and mouse, we have used molecular probes specific for the v-erb-A and v-erb-B genes and filter hybridization of DNAs isolated from interspecies somatic cell and microcell hybrids. Although we found human c-erb-A and cerb-B genes asyntenic on chromosomes 17 and 7, respectively, both mouse c-erb homologs were assigned to chromosome 11. Thus, in the mouse, c-erb genes are physically linked. Moreover, in humans, c-erb genes reside on chromosomes whose structural or numerical abnormalities are often associated with hematopoietic disorders (8). MATERIALS AND METHODS Somatic Cell Hybrids. The human-mouse somatic cell hybrids were constructed by the fusion of human fibroblasts or leukocytes (with normal karyotype or containing translocation chromosomes) with rodent cell lines (LMTK. 'RAG, or A9). The construction and characterization of these hybrid cell lines (WIL, REW, NSL, TSL, DUA, JSR, ATR, XER, XTR, JWR) have been described extensively elsewhere (9). In addition, hybrid cell lines containing single human chromosomes were used: DUAlCSAZF and DUAlCSAZH (chromosome 7), IT22xWeRi (chromosome 17; originally obtained from A. Bernstein). The mouse-Chinese hamster somatic cell hybrids (EBS) were derived from the fusion of BALB/c mouse spleen cells with Chinese hamster V79 lung fibroblasts (clone E36) (10, 11). Their chromosome content has been described elsewhere (12). Additional hybrids (PBH) were constructed by the fusion of mouse spleen cells (F1 of Peru-B10129) with Dona3 Chinese hamster cells lacking thymidine kinase activity (unpublished observations). By selecting PBH hybrids for retention of moup thymidine kinase (Tk), portions of chromosome 11 encoding Tk were retained. The mouse microcell rat cell hybrid F(11)F constructed by microcell fusion (13) contained an intact mouse chromosome 11. Counterselection of F(11)F with BrdUrd yielded F(11)FR, which lacked both detectable Tk activity and mouse chromosome 11. v-erb-A and v-erb-B Probes. Different domains from the region of AEV-11 efcompassing v-erb-A and v-erb-B were used (2). Plasmid pAEPst contains a 0.5-kbp Pst I fragment originating from the v-erb-A locus, whereas plasmid pAEBamRI contains a Q,5-kbp fragment from the 3' region of the v-erb-B locps. B9tp recombinant plasmids were gifts of J. M. Bishop and Colleagues. Abbreviations: AEV, avian erythroblastosis virus; kbp, kilobase pair(s). tPresent address: Department of Pediatrics, University of Mainz, Langenbeckstrasse 1, D-6500 Mainz, F.R.G. VPresent address: Department of Cellular and Structural Biology, The University of.Texas Health Science Center, San Antonio, TX 78284. IPresent address: Department of Medicine, Division of Endocrinology, The University of Texas Health Science Center, San Antonio, TX 78284. 4874 The publication costs of this article were defrayed jn part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact. Proc. NatL Acadl Sci. USA 81 (1984) 4875 The 0.5-kbp v-erb-A probe was prepared by Pst I digestion of pAEPst. A BamHI-Pvu II digestion of pAEBamRI yielded a 0.4-kbp v-erb-B probe without sequences of the flanking viral envelope region. Both inserts were purified by electroelution from agarose, followed by chromatography on NACS-52 resin (Bethesda Research Laboratories). The 32plabeled probes used for filter hybridization were prepared by nick-translation as described (14). Filter Hybridization, Human and mouse c-erb-A and c-erbB sequences were detected by filter hybridization methods (15) using cell hybrid DNA isolated at the same cell passage used for karyotyping and marker enzyme analysis (12). DNA isolation, restriction enzyme digestion, and agarose electrophoresis were performed as reported (12). Filters were hybridized with probe in a buffer containing 50% formamide, 0.75 M sodium chloride/75 mM sodium citrate, 1 x concentrated Denhardt's solution [0.02% (each) polyvinyl pyrollidone, bovine serum albumin, and Ficoll 400], 20 mM sodium phosphate (pH 6.5), 10% sodium dextran sulfate, 0.1% NaDodSO4, and 200 Mtg of sonicated, denatured salmon sperm DNA per ml for 48 hr at 30'C. Filters were rinsed briefly at 250C in 0.3 M sodium chloride/0.03 M sodium citrate/0.1% NaDodSO4 and then in 15 mM sodium chloride/1.5 mM sodium citrate/0.1% NaDodSO4 for 30 min at 50°C. Filters were then exposed to Kodak XAR film at -70°C with Dupont Cronex intensifying screens.

Of 311 expressed sequenced tags (ESTs) mapped to single human chromosomes by analysis of a monochromosome somatic cell hybrid panel, 29 were localized to chromosome 3. Analysis of somatic cell hybrid lines containing different regions of chromosome 3 has enabled the regional assignment of these 29 ESTs to 13 of 23 intervals covering chromosome 3. Northern analysis of 25 of the EST clones has provided information on the pattern of expression of potential genes represented by these transcripts in 16 human tissue types. Nine of the clones hybridized solely to a transcript(s) in the testis, 12 hybridized to transcripts in testis and other tissues, and 4 hybridized with transcripts in testis and other tissues but in addition have testis-specific transcript sizes. These ESTs will provide useful markers throughout chromosome 3 for the development of physical and transcription maps. In addition, they provide candidate genes for disease loci mapping to the intervals defined by the chromosome 3 deletion panel.