An 8-year-old girl presented with a cerebral tumor and 3 recurrences within 15 months. The primary tumor was a low-grade astrocytoma, but the recurrences showed progressively malignant phenotypes with increasing mitotic activity and MIB-1 labeling indices. Radiotherapy was given between the first and the second recurrences. Cytogenetic analysis of the first and the second recurrences showed abnormal karyotypes. There seemed to be 2 common breakpoints in these 2 recurrences. TP53 gene mutation screening, using comprehensive denaturing gradient gel electrophoresis, revealed among others a possibly causative mutation of exon 5 in 3 of 4 tumor samples. The meaning of TP53 mutations in low-grade astrocytomas is still unclear, but the highly abnormal karyotypes, which are unusual in these tumors, probably provide genetic evidence for the unexpected aggressive behavior of the tumor in this patient.

In adults, the TP53 tumor suppressor gene is frequently mutated in astrocytic brain tumors which is supposed to represent an early event in their development. In juvenile pilocytic and low‐grade astrocytomas, however, TP53 mutations have until now been reported as rare, which has led to the suggestion that these tumors may follow a different molecular pathogenesis with an involvement of genes other than TP53. Our analysis of 20 pilocytic and two lowgrade astrocytomas of childhood, based on a comprehensive denaturing gradient gel electrophoresis (DGGE) mutation detection assay of the entire coding region, including all splice site junctions of TP53 , showed mutations considered as causative in 7 of the 20 (35%) pilocytic astrocytomas and in one of the two low‐grade astrocytomas. Our finding is significantly different from the mutation frequency of 1.3% (2/155) previously reported for these tumor types. This may be attributed to the mutation detection system used, which also detects mutations occurring outside the evolutionary conserved region of TP53. Our results suggest that, contrary to the present notion, TP53 mutations may well play a role in the development of juvenile astrocytomas. Furthermore, no mutations were found in tumors of patients with progression of residual tumor after postoperative follow‐up. This suggests that TP53 mutations may be associated with less aggressive forms of juvenile astrocytomas, analogous to the situation in adult astrocytomas.

We report on the cytogenetics of a primary testicular nonseminoma, a residual mature teratoma after remission-induction chemotherapy, and a late relapse after 9 years of follow-up, in one patient. The late relapse was composed of a mature teratoma and a yolk sac tumor component. Cytogenetic comparison of the different tumors shows that progression of primary testicular nonseminoma to residual mature teratoma and to a late-relapse lesion is accompanied by net loss of chromosomes. In addition, our findings may suggest that transformation to viable cancer in a late-relapse lesion is accompanied by further chromosomal losses.

About 70 to 75% of patients with nonseminomatous testicular germ cell tumors (NSs) present with metastases. When these metastases are treated with chemotherapy, often residual mature teratoma (RMT) is left. RMT is composed of fully differentiated somatic tissue. Untreated metastases of NSs rarely consist exclusively of mature somatic tissue. Apparently, after chemotherapy treatment there is a shift towards higher degrees of differentiation. Investigating tumor progression and the mechanism(s) involved in therapy-related differentiation, we compared the cytogenetically abnormal karyotypes of a series of 70 NSs with those of 31 RMTs. In NSs and RMTs, the modal total chromosome number does not differ and is in the triploid range. Both the frequency and the average copy number of i(12p) are the same, and the pattern of chromosomal over- and underrepresentation and distribution of breakpoints do not differ significantly in these series. So, we found the chromosomal pattern of RMTs as abnormal as those of primary NSs. Based on cytogenetics, we found no indication that specific chromosomal alterations parallel metastasis and therapy-related differentiation of the metastases. The cytogenetic data suggest that both induction of differentiation of (selected) cells or selection of cells with capacity to differentiate are possible mechanisms for the therapy-related differentiation of RMTs.

Renal‐cell cancer comprises a heterogeneous group of tumors, which currently can be sub‐divided into morphologically distinct entities, each characterized by a specific combination of genetic changes. Sarcomatoid transformation might occur in any of the sub‐types, resulting in tumors consisting of both carcinomatous and sarcomatous components. The specific diagnosis of these neoplasms, as to tumor sub‐type, is usually made on the histologic properties of the carcinomatous tissue present. However, this might not reflect the true nature of the sarcomatous component. Since the genetic changes associated with the development of the different sub‐types of renal‐cell cancer are well established, this knowledge might serve as a tool in diagnosing sarcomatoid tumors. Assessing the genetic constitution of the latter may lead to correct diagnosis. It may also provide valuable information about the genetic changes associated with sarcomatoid transformation. Hence we performed a genetic characterization of a case of sarcomatoid renal‐cell cancer, histologically diagnosed as being of the chromophilic type. The observed genetic changes included loss of 3p, 6q, 8p, 9, 13, 14 and 17p, and gain of 5, 12 and 20, as well as a mutation in the coding region of the p53 gene. This combination of genetic changes points to clear‐cell rather than chromophilic origin of the sarcomatoid tumor investigated, indicating that the genetic constitution of sarcomatoid tumors may be a more reliable indicator of tumor sub‐type than histologic appearance. Int. J. Cancer 72:265–269, 1997. © 1997 Wiley‐Liss, Inc.

The most important prognostic factor in soft tissue sarcomas (STS) is tumor grade. Since most grading methods are subject to the interpretation of the individual pathologist, there is a need for objective criteria such as DNA ploidy and karyotype, which are of prognostic value in several types of malignancy. We have analyzed the relationships among tumor grade, DNA ploidy, cytogenetic abnormalities and the clinical outcome of 44 previously untreated patients with 12 different histological types of primary STS. The tumors were graded according to the method of Coindre, which resulted in 9 grade 1 (20%), 18 grade II (41%) and 17 grade III (39%) STS. DNA flow cytometry and chromosomal analysis were performed using standard techniques. After a median follow-up time of 39 (range, 2-124) months, Kaplan-Meier survival analysis was performed. Significant differences in 5-year overall survival were found between patients with grade I or II and grade III STS (p < 0.05), Seventeen STS were aneuploid and 26 were euploid, in 21 of 39 successfully cultured STS an abnormal karyotype was found. There were no significant differences in survival in relation to DNA ploidy or the presence of chromosomal abnormalities. Our results show that grading had higher prognostic value than DNA ploidy or the presence of cytogenetic abnormalities in this heterogeneous group of STS. (C) 1997 Wiley-Liss, Inc.

Testicular germ cell tumors (TGCT) of adolescents and adults are, for clinical and pathological reasons, divided in seminomas (SE) and nonseminomatous germ cell tumors (NS). Whether and to what degree these two entities are pathogenetically related is still controversial and a matter of debate. TGCT may contain both SE and NS components. Cytogenetic studies of the SE and NS components of these mixed TGCT might shed light on the pathogenetic relationship between both components. Separate cytogenetic analysis was performed on both components of three cases of mixed TGCT with both SE and NS components. The karyotypes of both components were compared with each other. In one case, the SE and NS component share eight different structural chromosomal abnormalities, indicating that the SE and NS component are pathogenetically closely related and have a common neoplastic pathway for a considerable length. Both components of the other two cases have, respectively, i(12p) and no structural chromosomal abnormalities in common. Our results, together with data from the literature, indicate that in mixed TGCT with SE and NS components, both components may have either a monoclonal or a polyclonal origin.

A cytogenetic study of two cases of alveolar soft part sarcoma showed near-diploid karyotypes with multiple chromosomal rearrangements. An abnormality of the long arm of chromosome 17, involving band q25, is present in both cases and in 2 of 4 cases in the literature. This recurrent structural abnormality probably plays an important role in the histogenesis of this unusual neoplasm and therefore is important for further molecular investigation.

Many of the reported oncocytomas have different chromosome abnormalities, indicating that they comprise a cytogenetically heterogenous group of tumors consisting of potentially cytogenetic subgroups. We have performed cytogenetic studies on nine renal oncocytomas. Clonal abnormalities were present in eight tumors. The findings most observed were the loss of the Y chromosome, and abnormalities of chromosomes 1 and 22. We also observed telomeric associations (tas) in two tumors and structural aberrations of chromosomes 9p and 19q, as well as monosomy 10. In two cases we found a similar reciprocal t(5;11)(q35;q13) in two cases. Review of the literature disclosed one other oncocytoma with a t(5;11)(q35;q13). This suggests that t(5;11)(q35;q13) defines a (second) subset of oncocytomas apart from the subgroup specifically associated with the loss of chromosomes 1 and Y.

Chondrosarcomas are a heterogeneous group of bone neoplasms of which the basic neoplastic tissue is cartilaginous. Frequently the histologic diagnosis and grading of chondrosarcomas is difficult and the histologic appearance does not always reflect the biologic behavior of these tumors. Therefore, it is important to find other parameters that can be of help in the proper diagnosing and grading of these neoplasms. To this end, we attempted to correlate the chromosomal pattern of chondrosarcomas to their histologic subtypes and grades. The cytogenetic analysis of two intermediate-grade chondrosarcomas of bone, and a review of the literature, are presented.

BACKGROUND:Both DNA flow cytometry and cytogenetic analysis have been used to study soft tissue tumors. With flow cytometry, the DNA content of a relatively large number of cells can be examined, but cytogenetic analysis gives more detailed information about genomic changes.EXPERIMENTAL DESIGN:In order to compare the advantages and drawbacks of DNA flow cytometry versus chromosomal analysis, 92 primary or recurrent malignant, 16 borderline malignant, and 13 benign soft tissue tumors were karyotyped after short-term culture. DNA ploidy was determined by flow cytometry of suspensions prepared from frozen or paraffin-embedded samples. From 97 patients, 121 samples were analyzed.RESULTS:On the basis of the results, four groups were distinguished: DNA-euploid tumors with normal diploid karyotypes (group a) or with abnormal (group b) karyotypes, and DNA-aneuploid tumors with normal (group c) or abnormal (group d) karyotypes. The findings in group b show that structural chromosomal abnormalities or minor numerical aberrations of chromosomes are not detected by DNA flow cytometry. In group c, the finding of tumors with an aneuploid DNA-profile and cells with normal karyotypes is most likely due to overgrowth of fibroblasts during culture and subsequent karyotyping of normal cells.CONCLUSIONS:The findings show that a) DNA flow cytometry has a higher success rate than karyotyping, b) both techniques are complementary, such that DNA flow cytometry gives an "overview", whereas karyotyping gives more detailed information; comparison of both techniques in individual cases leads to a better understanding of the chromosomal events that occurred during oncogenesis, c) histologically low grade tumors are generally DNA-diploid, but may have an abnormal karyotype, and d) histologically high-grade sarcomas tend to have an aneuploid DNA-profile; they are generally more difficult to karyotype.

Nonepithelial malignant renal tumors are very rare, comprising approximately 2-3% of all malignant renal tumors. We were able to culture and subsequently karyotype a leiomyosarcoma (LMS) of the kidney that showed the following representative karyotype: 84,XY,add(X)(q25),-Y,add(1)(p11),dic(1;20) (p34;q13.3),-5,-6,dup(6)(q24),i(7)(p10),add(8)(p11),-9,-11,add(13)(p11), -15,-15 , add(17)(q24)x2,-18,-19,-21,-22,-22, +mar1(?hsr),+mar2,+2mar. A clonal add(1)(q11) was also evident. The DNA index was 1.9. Our results as compared with data from the literature suggest that LMS of the kidney has most cytogenetic aberrations reported to be characteristic of LMS, especially those located in the abdomen, and that different genetic mechanisms of initiation and progression appear to play a role in LMS of similar histology but from different anatomic sites.

Induction of differentiation as a treatment modality for nonseminomatous germ cell tumors (NSGCTs) may promote the development of residual mature teratoma (RMT), which is usually associated with primary tumors that are capable of spontaneous somatic differentiation. Therefore, we studied the combination of a cytotoxic drug and a differentiation-inducing agent in vivo in three murine teratocarcinoma models with different levels of spontaneous somatic differentiation: E86-379 (moderate differentiation); NF-1 (poor differentiation); and MH-15 (no differentiation). We used retinoic acid (RA) as differentiation-inducing agent and cisdiaminodichloroplatinum (CDDP) as cytotoxic drug, plus a combination of both. In four separate experiments, the combination of RA and CDDP gave a significant further reduction of tumor size as compared with treatment with either RA or CDDP alone. Morphologically intact tumor after treatment with combined RA-CDDP contained a smaller proportion of undifferentiated tissue (embryonal carcinoma) than after CDDP alone. However, somatic differentiation was not induced in the tumor model lacking spontaneous somatic differentiation. Toxicity was reflected in loss of body weight and death of some animals and closely paralleled the degree of tumor reduction in all experiments.