ABSTRACTPurposeA significant barrier to adoption of de-escalated treatment protocols for human papillomavirus-driven oropharyngeal cancer (HPV-OPC) is that few predictors of poor prognosis exist. We conducted the first large whole-genome sequencing (WGS) study to characterize the genetic variation of the HPV16 genome and to evaluate its association with HPV-OPC patient survival.Patients and Methods460 OPCs from 2 large US medical centers (1980-2017) underwent HPV16 WGS. Site-specific variable positions (SNPs) across the HPV16 genome were identified. Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for overall survival by HPV16 SNPs. Harrell C-index and time-dependent positive predictive value (PPV) curves and areas under the PPV curves were used to evaluate the predictive accuracy of HPV16 SNPs for overall survival.Results384 OPCs (83.48%) passed quality control filters with sufficient depth and coverage of HPV16 genome sequencing to be analyzed. 284 HPV16 SNPs with a minor allele frequency >1% were identified. Eight HPV16 SNPs were significantly associated with worse survival after false discovery rate (FDR) correction (individual prevalence:1.0%-5.5%; combined prevalence: 15.10%); E1 gene position 1053 (HR for overall survival [HRos]:3.75,95%CI:1.77-7.95;Pfdr=0.0099); L2 gene positions 4410 (HRos:5.32,95%CI:1.91-14.81;Pfdr=0.0120), 4539 (HRos:6.54,95%CI:2.03-21.08;Pfdr=0.0117); 5050 (HRos:6.53,95%CI:2.34-18.24;Pfdr=0.0030) and 5254 (HRos:7.76,95%CI:2.41-24.98;Pfdr=0.0030); and L1 gene positions 5962 (HRos:4.40,95%CI:1.88-10.31;Pfdr=0.0110) and 6025 (HRos:5.71,95%CI:2.43-13.41;Pfdr=0.0008) and position 7173 within the upstream regulatory region (HRos:9.90,95%CI:3.05-32.12;Pfdr=0.0007). Median survival time for patients with ≥1 high-risk HPV16 SNPs was 3.96 years compared to 18.67 years for patients without a high-risk SNP; log-rank test P<0.001. HPV16 SNPs significantly improved the predictive accuracy for overall survival above traditional factors (age, smoking, stage, treatment): increase in C-index was 0.069 (95% CI: 0.019-0.119, P <0.001); increase in area under the PPV curve for predicting 5-year survival was 0.068 (95%CI: 0.015-0.111, P =0.008).ConclusionsHPV16 genetic variation is associated with HPV-OPC prognosis and can improve prognostic accuracy.
Childhood radioactive iodine exposure from the Chornobyl accident increased papillary thyroid carcinoma (PTC) risk. While cervical lymph node metastases (cLNM) are well-recognized in pediatric PTC, the PTC metastatic process and potential radiation association are poorly understood. Here, we analyze cLNM occurrence among 428 PTC with genomic landscape analyses and known drivers (131I-exposed = 349, unexposed = 79; mean age = 27.9 years). We show that cLNM are more frequent in PTC with fusion (55%) versus mutation (30%) drivers, although the proportion varies by specific driver gene (RET-fusion = 71%, BRAF-mutation = 38%, RAS-mutation = 5%). cLNM frequency is not associated with other characteristics, including radiation dose. cLNM molecular profiling (N = 47) demonstrates 100% driver concordance with matched primary PTCs and highly concordant mutational spectra. Transcriptome analysis reveals 17 differentially expressed genes, particularly in the HOXC cluster and BRINP3; the strongest differentially expressed microRNA also is near HOXC10. Our findings underscore the critical role of driver alterations and provide promising candidates for elucidating the biological underpinnings of PTC cLNM. Childhood radioactive iodine exposure from the Chornobyl accident led to an increased papillary thyroid carcinoma (PTC) risk and potentially higher invasiveness depending on tumour genetic profiles. Here, the authors use genomics to characterise and predict cervical lymph node metastases in PTC patients affected by the Chornobyl accident.
Systemic anaplastic large cell lymphoma (ALCL) is a rare CD30-expressing T-cell non-Hodgkin lymphoma. Risk of systemic ALCL is highly increased among immunosuppressed individuals. Because risk of cancers associated with viruses is increased with immunosuppression, we conducted a metagenomic analysis of systemic ALCL to determine whether a known or novel pathogen is associated with this malignancy. Total RNA was extracted and sequenced from formalin-fixed paraffin-embedded tumor specimens from 19 systemic ALCL cases (including one case from an immunosuppressed individual with human immunodeficiency virus infection), 3 Epstein-Barr virus positive diffuse large B-cell lymphomas (DLBCLs) occurring in solid organ transplant recipients (positive controls), and 3 breast cancers (negative controls). We used a pipeline based on the Genome Analysis Toolkit (GATK)-PathSeq algorithm to subtract out human RNA reads and map the remaining RNA reads to microbes. No microbial association with ALCL was identified, but we found Epstein-Barr virus in the DLBCL positive controls and determined the breast cancers to be negative. In conclusion, we did not find a pathogen associated with systemic ALCL, but because we analyzed only one ALCL tumor from an immunosuppressed person, we cannot exclude the possibility that a pathogen is associated with some cases that arise in the setting of immunosuppression.
Human papillomavirus (HPV) positive oropharyngeal squamous cell carcinoma (HPV + OPSCC) is increasing in prevalence in the USA, as are cases of patients with multiple HPV + OPSCCs (mHPV + OPSCC). mHPV + OPSCCs present a unique opportunity to examine HPV + OPSCC mutation acquisition and evolution. We performed sequencing of the viral genome, somatic exome and somatic transcriptome from 8 patients each with 2 spatially distinct HPV + OPSCCs, and 37 'traditional' HPV + OPSCCs to first address if paired tumors are caused by the same viral isolate and next, if acquired alterations, and the underlying processes driving mutagenesis, are shared within pairs. All tumor pairs contained viral genomes from the same HPV type 16 sublineage and differed by 0-2 clonal single nucleotide polymorphisms (SNPs), suggesting infection with the same viral isolate. Despite this, there was significant discordance in expression profiles, mutational burden and mutational profiles between tumors in a pair, with only two pairs sharing any overlapping mutations (3/3343 variants). Within tumor pairs there was a striking discrepancy of mutational signatures, exemplified by no paired tumors sharing high APOBEC mutational burden. Here, leveraging mHPV + OPSCCs as a model system to study mutation acquisition in virally mediated tumors, in which the germline, environmental exposures, immune surveillance and tissue/organ type were internally controlled, we demonstrate that despite infection by the same viral isolate, paired mHPV + OPSCCs develop drastically different somatic alterations and even more strikingly, appear to be driven by disparate underlying mutational processes. Thus, despite a common starting point, HPV + OPSCCs evolve through variable mutational processes with resultant stochastic mutational profiles.
Abstract The 1986 Chernobyl nuclear power plant accident increased papillary thyroid cancer (PTC) incidence in surrounding regions, particularly for 131I-exposed children. To investigate the contribution of environmental radiation to PTC characteristics and improve understanding of radiation-induced carcinogenesis, we analyzed genomic, transcriptomic, and epigenomic characteristics of 440 pathologically-confirmed fresh-frozen PTCs from Ukraine (359 with estimated childhood or in utero 131I exposure and 81 from unexposed children born after March 1987) and matched normal tissue (non-tumor thyroid tissue and/or blood). Mean age at PTC was 28.0 years (range: 10.0-45.6). Among 131I-exposed individuals, mean radiation dose was 250 mGy (range: 11.0-8,800). In multivariable models adjusted for age at PTC and sex, we observed radiation dose-dependent enrichment of fusion drivers (P=6.6 × 10−8), nearly all occurring in the MAPK pathway, as well as increases in small deletions (P=8.0 × 10−9) and simple/balanced structural variants (P=1.2 × 10−14). Further analyses demonstrated even stronger associations for those small deletions and simple/balanced structural variants that were clonal and bore hallmarks of non-homologous end-joining repair (deletions: P=4.9 × 10−31; simple/balanced structural variants: P=5.5 × 10−19). In contrast, radiation dose was not associated with subclonal small deletions (P=0.82) or subclonal simple/balanced structural variants (P=0.91). Additionally, radiation dose was not associated with TINS (locally templated insertions), which are characteristic of alt-end-joining repair (P=0.69). The effects of radiation on genomic alterations with more pronounced for those younger at exposure. Analyses generally were consistent with a linear radiation dose-response for all molecular characteristics except clonal small deletions. Analyses of transcriptomic and epigenomic features demonstrated strong associations with the PTC driver gene but not radiation dose. Our results point to DNA double-strand breaks as early carcinogenic events that subsequently enable PTC growth following environmental radiation exposure. Citation Format: Lindsay M. Morton, Danielle Karyadi, Chip Stewart, Tetiana Bogdanova, Eric Dawson, Mia Steinberg, Jieqiong Dai, Stephen Hartley, Sara Schonfeld, Joshua Sampson, Yosi Maruvka, Vidushi Kapoor, Dale Ramsden, Juan Carvajal-Garcia, Chuck Perou, Joel Parker, Marko Krznaric, Meredith Yeager, Joseph Boland, Amy Hutchinson, Belynda Hicks, Casey Dagnall, Julie Gastier-Foster, Jay Bowen, Olivia Lee, Mitchell Machiela, Elizabeth Cahoon, Alina Brenner, Kiyohiko Mabuchi, Vladimir Drozdovitch, Sergii Masiuk, Mykola Chepurny, Liudmyla Yu Zurnadzhy, Maureen Hatch, Amy Berrington de Gonzalez, Gerry Thomas, Mykola Tronko, Gad Getz, Stephen Chanock. Molecular characterization of papillary thyroid cancer in relation to ionizing radiation dose following the Chernobyl accident [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-055.
IKZF1 encodes Ikaros, a zinc finger-containing transcription factor crucial to the development of the hematopoietic system. Germline pathogenic variants in IKZF1 have been reported in patients with acute lymphocytic leukemia and immunodeficiency syndromes. Diamond-Blackfan anemia (DBA) is a rare inherited bone marrow failure syndrome characterized by erythroid hypoplasia, associated with a spectrum of congenital anomalies and an elevated risk of certain cancers. DBA is usually caused by heterozygous pathogenic variants in genes that function in ribosomal biogenesis; however, in many cases the genetic etiology is unknown. We identified a germline IKZF1 variant, rs757907717 C > T, in identical twins with DBA-like features and autoimmune gastrointestinal disease. rs757907717 C > T results in a p.R381C amino acid change in the IKZF1 Ik-x isoform (p.R423C on isoform Ik-1), which we show is associated with altered global gene expression and perturbation of transcriptional networks involved in hematopoietic system development. These data suggest that this missense substitution caused a DBA-like syndrome in this family because of alterations in hematopoiesis, including dysregulation of networks essential for normal erythropoiesis and the immune system.
Genomics of radiation-induced damage The potential adverse effects of exposures to radioactivity from nuclear accidents can include acute consequences such as radiation sickness, as well as long-term sequelae such as increased risk of cancer. There have been a few studies examining transgenerational risks of radiation exposure but the results have been inconclusive. Morton et al. analyzed papillary thyroid tumors, normal thyroid tissue, and blood from hundreds of survivors of the Chernobyl nuclear accident and compared them against those of unexposed patients. The findings offer insight into the process of radiation-induced carcinogenesis and characteristic patterns of DNA damage associated with environmental radiation exposure. In a separate study, Yeager et al. analyzed the genomes of 130 children and parents from families in which one or both parents had experienced gonadal radiation exposure related to the Chernobyl accident and the children were conceived between 1987 and 2002. Reassuringly, the authors did not find an increase in new germline mutations in this population. Science , this issue p. eabg2538 , p. 725
APOBEC is a mutagenic source in human papillomavirus (HPV)-mediated malignancies, including HPV+ oropharyngeal squamous cell carcinoma (HPV + OPSCC), and in HPV genomes. It is unknown why APOBEC mutations predominate in HPV + OPSCC, or if the APOBEC-induced mutations observed in both human cancers and HPV genomes are directly linked. We performed sequencing of host somatic exomes, transcriptomes, and HPV16 genomes from 79 HPV + OPSCC samples, quantifying APOBEC mutational burden and activity in both host and virus. APOBEC was the dominant mutational signature in somatic exomes. In viral genomes, there was a mean of five (range 0–29) mutations per genome. The mean of APOBEC mutations in viral genomes was one (range 0–5). Viral APOBEC mutations, compared to non-APOBEC mutations, were more likely to be low-variant allele fraction mutations, suggesting that APOBEC mutagenesis actively occurrs in viral genomes during infection. HPV16 APOBEC-induced mutation patterns in OPSCC were similar to those previously observed in cervical samples. Paired host and viral analyses revealed that APOBEC-enriched tumor samples had higher viral APOBEC mutation rates (p = 0.028), and APOBEC-associated RNA editing (p = 0.008), supporting the concept that APOBEC mutagenesis in host and viral genomes is directly linked and occurrs during infection. Using paired sequencing of host somatic exomes, transcriptomes, and viral genomes, we demonstrated for the first-time definitive evidence of concordance between tumor and viral APOBEC mutagenesis. This finding provides a missing link connecting APOBEC mutagenesis in host and virus and supports a common mechanism driving APOBEC dysregulation.
Human papillomavirus (HPV) type 31 (HPV31) is closely related to the most carcinogenic type, HPV16, but only accounts for 4% of cervical cancer cases worldwide. Viral genetic and epigenetic variations have been associated with carcinogenesis for other high-risk HPV types, but little is known about HPV31. We sequenced 2093 HPV31 viral whole genomes from two large studies, one from the U.S. and one international. In addition, we investigated CpG methylation in a subset of 175 samples. We evaluated the association of HPV31 lineages/sublineages, single nucleotide polymorphisms (SNPs) and viral methylation with cervical carcinogenesis. HPV31 A/B clade was >1.8-fold more associated with cervical intraepithelial neoplasia grade 3 and cancer (CIN3+) compared to the most common C lineage. Lineage/sublineage distribution varied by race/ethnicity and geographic region. A viral genome-wide association analysis identified SNPs within the A/B clade associated with CIN3+, including H23Y (C626T) (odds ratio = 1.60, confidence intervals = 1.17–2.19) located in the pRb CR2 binding-site within the E7 oncogene. Viral CpG methylation was higher in lineage B, compared to the other lineages, and was most elevated in CIN3+. In conclusion, these data support the increased oncogenicity of the A/B lineages and suggest variation of E7 as a contributing risk factor.
HPV35 has been found in only similar to 2% of invasive cervical cancers (ICC) worldwide but up to 10% in Sub-Saharan Africa, warranting further investigation and consideration of impact on preventive strategies. We studied HPV35 and ethnicity, in relation to the known steps in cervical carcinogenesis, using multiple large epidemiologic studies in the U.S. and internationally. Combining five U.S. studies, we measured HPV35 positivity and, in Northern California, observed HPV35 type-specific population prevalence and estimated 5-year risk of developing precancer when HPV35-positive. HPV35 genetic variation was examined for differences in carcinogenicity in 1053 HPV35+ cervical specimens from a U.S. cohort and an international collection. African-American women had more HPV35 (12.1% vs 5.1%, P < .001) and more HPV35-associated precancers (7.4% vs 2.1%, P < .001) compared to other ethnicities. Precancer risks after HPV35 infection did not vary by ethnicity (global P = .52). The HPV35 A2 sublineage showed an increased association with precancer/cancer in African-Americans (OR = 5.6 vs A1, 95% CI = 1.3-24.8) and A2 was more prevalent among ICC in Africa than other world regions (41.9% vs 10.4%, P < .01). Our analyses support a strong link between HPV35 and cervical carcinogenesis in women of African ancestry. Current HPV vaccines cover the majority of cervical precancer/cancer across all ethnic groups; additional analyses are required to determine whether the addition of HPV35 to the already highly effective nine-valent HPV vaccine would provide better protection for women in Africa or of African ancestry.
HPV16 causes half of cervical cancers worldwide; for unknown reasons, most infections resolve within two years. Here, we analyze the viral genomes of 5,328 HPV16-positive case-control samples to investigate mutational signatures and the role of human APOBEC3-induced mutations in viral clearance and cervical carcinogenesis. We identify four de novo mutational signatures, one of which matches the COSMIC APOBEC-associated signature 2. The viral genomes of the precancer/cancer cases are less likely to contain within-host somatic HPV16 APOBEC3-induced mutations (Fisher's exact test, P = 6.2 x 10(-14)), and have a 30% lower nonsynonymous APOBEC3 mutation burden compared to controls. We replicate the low prevalence of HPV16 APOBEC3-induced mutations in 1,749 additional cases. APOBEC3 mutations also historically contribute to the evolution of HPV16 lineages. We demonstrate that cervical infections with a greater burden of somatic HPV16 APOBEC3induced mutations are more likely to be benign or subsequently clear, suggesting they may reduce persistence, and thus progression, within the host.
Abstract Background: Human papillomavirus type 16 (HPV16) is one of the most common and carcinogenic HPV types associated with high risk of anal, vagina, vulva, penis and cervical neoplastic transformations. However, many genetic variants exist within this virus and not all seem to have the same carcinogenic potential. Aim: To determine HPV16 lineages and their association with risk of high-grade anal lesions in African Americans in an inner-city hospital. Methods: We reviewed medical records of 370 African Americans with anal lesions from Jan. 2007 to Dec. 2015. This study was approved by Howard University Institutional Review Board. Demographic, clinical and pathological data including HPV, HIV, HCV (hepatitis C virus), diabetes mellitus, hypertension and body mass index (BMI) were collected. DNA was extracted from a subset of HPV16-positive patients with FFPE tissue samples (72 patients, 111 samples) and used for HPV16 whole-genome sequencing. We assessed HPV16 variant lineages and associations with disease stage. Statistical analyses were performed using Chi-square tests, Student's t-tests, and logistic regression. Odds ratios (OR) and p-values were calculated for comparisons of normal/condyloma/high-grade dysplasia (HGD) vs. squamous cell carcinoma (SCC) and for normal/condyloma vs. HGD. The most common HPV16 A1 sublineage was used as a reference in these comparisons. Results: Males represented 75% of the patients (n=276), with a median age of 44 years and BMI of 25.8 kg/m2. The frequency of condyloma, high-grade dysplasia, SCC and adenocarcinoma was 191 (52%), 26 (7%), 31 (8%) and 8 (2%), respectively. The frequency of HPV, HIV, and HCV was 231 (68%), 147 (43%) and 42 (12%), respectively. HPV and HIV were risk factors for condyloma and dysplasia (P<0.05). All four main lineages of HPV16 (A,B,C,D) were detected in our specimens, with sublineage A1 most common. Lineage B, also named the African-1 HPV16 lineage because it is most common in Africa, had the strongest association with SCC (OR=10.5) whether alone or in combination with lineages A4 and D (OR=10.5), although with a lower statistical significance (0.054 vs. 0.009). As for HGD, lineage B along with A4, C and D only gave an OR of 1.4. Conclusion: We show that the majority of patients with anal lesions are young males with HPV and HIV co-infections. HPV16 lineage B was associated with a high risk of SCC development. Citation Format: Hassan Brim, Lisa Mirabello, Ali Afsari, Muneer Abbas, Meredith Yeager, Joseph Boland, Sara Bass, Mia Steinberg, Michael Cullen, Adeyinka Laiyemo, Tammy Naab, Babak Shokrani, Edward Lee, Mehdi Nouraie, Hassan Ashktorab. Anal cancer among African Americans associate with HPV16 lineage B and HIV [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2027.
AbstractHuman papillomavirus (HPV) 16 displays substantial sequence variation; four HPV16 lineages (A, B, C, and D) have been described as well as multiple sublineages. To identify molecular events associated with HPV16 carcinogenesis, we evaluated viral variation, the integration of HPV16, and somatic mutation in 96 cervical cancer samples from Guatemala. A total of 65% (62/96) of the samples had integrated HPV16 sequences and integration was associated with an earlier age of diagnosis and premenopausal disease. HPV16 integration sites were broadly distributed in the genome, but in one tumor, HPV16 integrated into the promoter of the IFN regulatory factor 4 (IRF4) gene, which plays an important role in the regulation of the IFN response to viral infection. The HPV16 D2 and D3 sublineages were found in 23% and 30% of the tumors, respectively, and were significantly associated with adenocarcinoma. D2-positive tumors had a higher rate of integration, earlier age of diagnosis, and a lower rate of somatic mutation, whereas D3-positive tumors were less likely to integrate, had later age of diagnosis, and exhibited a higher rate of somatic mutation. In conclusion, Guatemalan cervical tumors have a high frequency of very high-risk HPV16 D2 and D3 sublineages harboring distinct histology, which may help guide future therapeutic strategies to target the tumor and reduce recurrence.Significance:This study details the biological and molecular properties of the most pathogenic forms of HPV16, the cause of the majority of cervical cancers.
Background: Human papillomavirus (HPV)16 can be separated into genetic sub-lineages (A1-4, B1-4, C1-4, D1-4) which may have differential cervical cancer risk. Methods: A next-generation sequencing assay was used to whole-genome sequence 7116 HPV16-positive cervical samples from well-characterised international epidemiological studies, including 2076 controls, 1878 squamous cell carcinoma (SCC) and 186 adenocarcinoma/adenosquamous cell carcinoma (ADC), and to assign HPV16 sub-lineage. Logistic regression was used to estimate region-stratified country-adjusted odds ratios (OR) and 95%CI. Results: A1 was the most globally widespread sub-lineage, with others showing stronger regional specificity (A3 and A4 for East Asia, B1-4 and C1-4 for Africa, D2 for the Americas, B4, C4 and D4 for North Africa). Increased cancer risks versus A1 were seen for A3, A4 and D (sub)lineages in regions where they were common: A3 in East Asia (OR = 2.2, 95%CI:1.0-4.7); A4 in East Asia (6.6, 3.1-14.1) and North America (3.8, 1.7-8.3); and D in North (6.2, 4.1-9.3) and South/Central America (2.2, 0.8-5.7), where D lineages were also more frequent in ADC than SCC (3.2, 1.5-6.5; 12.1, 5.7-25.6, respectively). Conclusions: HPV16 genetic variation can strongly influence cervical cancer risk. However, burden of cervical cancer attributable to different sub-lineages worldwide is largely driven by historical HPV16 sub-lineage dispersal.
Thrombocytopenia-absent radii (TAR) syndrome, characterized by neonatal thrombocytopenia and bilateral radial aplasia with thumbs present, is typically caused by the inheritance of a 1q21.1 deletion and a single-nucelotide polymorphism in RBM8A on the nondeleted allele. We evaluated two siblings with TAR-like dysmorphology but lacking thrombocytopenia in infancy. Family NCI-107 participated in an IRB-approved cohort study and underwent comprehensive clinical and genomic evaluations, including aCGH, whole-exome, whole-genome, and targeted sequencing. Gene expression assays and electromobility shift assays (EMSAs) were performed to evaluate the variant of interest. The previously identified TAR-associated 1q21.1 deletion was present in the affected siblings and one healthy parent. Multiple sequencing approaches did not identify previously described TAR-associated SNPs or mutations in relevant genes. We discovered rs61746197 A > G heterozygosity in the parent without the deletion and apparent hemizygosity in both siblings. rs61746197 A > G overlaps a RelA-p65 binding motif, and EMSAs indicate the A allele has higher transcription factor binding efficiency than the G allele. Stimulation of K562 cells to induce megakaryocyte differentiation abrogated the shift of both reference and alternative probes. The 1q21.1 TAR-associated deletion in combination with the G variant of rs61746197 on the nondeleted allele is associated with a TAR-like phenotype. rs61746197 G could be a functional enhancer/repressor element, but more studies are required to identify the specific factor(s) responsible. Overall, our findings suggest a role of rs61746197 A > G and human disease in the setting of a 1q21.1 deletion on the other chromosome.
Navy vessels consist of various metal alloys and biofilm accumulation at the metal surface is thought to play a role in influencing metal deterioration. To develop better strategies to monitor and control metallic biofilms, it is necessary to resolve the bacterial composition within the biofilm. This study aimed to determine if differences in electrochemical current could influence the composition of dominant bacteria in a metallic biofilm, and if so, determine the level of resolution using metagenomic amplicon sequencing. Current was generated by creating galvanic couples between cathodes made from stainless steel and anodes made from carbon steel, aluminum, or copper nickel and exposing them in the Delaware Bay. Stainless steel cathodes (SSCs) coupled to aluminum or carbon steel generated a higher mean current (0.39 mA) than that coupled to copper nickel (0.17 mA). Following 3 months of exposure, the bacterial composition of biofilms collected from the SSCs was determined and compared. Dominant bacterial taxa from the two higher current SSCs were different from that of the low-current SSC as determined by DGGE and verified by Illumina DNA-seq analysis. These results demonstrate that electrochemical current could influence the composition of dominant bacteria in metallic biofilms and that amplicon sequencing is sufficient to complement current methods used to study metallic biofilms in marine environments.
Abstract Human papillomavirus (HPV) is a very common sexually transmitted infection, however only a small proportion of women progress to cervical precancer or cancer. HPV16 is the most carcinogenic type, causing more than half of the cervical cancer globally. The HPV16 genome is 7,906base-pairs coding for 8 genes (E6, E7, E1, E2, E4, E5, L2, L1) and one upstream regulatory region (URR). Within HPV16 there are 4 main lineages (A, B, C, D) that are strongly associated with disease risk. Human APOBEC3A (hA3A) cytidine deaminases have been shown to have antiviral effects. The APOBEC mutational process results in a C to T base change at specific motifs (5’ [C/T]•C>T•W 3’). Previous studies established that there was evidence of APOBEC3 editing on a small number of HPV16 samples. It’s unknown how these mutations are related to infection clearance or the long-term accumulation of genomic mutations that contribute to HPV-associated cancers. We conducted detailed analyses to comprehensively evaluate APOBEC3 editing on HPV16 genomes using HPV16 whole-genome sequencing data from 3,215 HPV16-infected women in the NCI-HPV Persistence and Progression (PaP) cohort. Cases were defined as women with cervical precancer (CIN3, N = 1,093) or cancer (N = 109) and controls were women with no histologic evidence of precancer or cancer (T•W 3’) out of 96 potential motifs of 3 base-pairs. Using logistic regression, we compared the number of APOBEC3-associated variants in cases and controls, among HPV16 variant lineages, and among genome regions of the virus. We discovered that there is evidence of APOBEC3 editing throughout the HPV16 genome. Specifically, we observed that women with precancer or cancer had less APOBEC3-associated variants compared to the controls (OR = 0.84, p-value = 0.06). We further showed that women with an HPV16 A lineage infection have more APOBEC3-associated variants compared to those with a non-A lineage infection (OR = 1.35, p-value = 0.02). After controlling for the number of APOBEC3 vulnerable loci, we observed that the L1 (OR = 0.23, p-value = 0.04) and E7 (OR = 0.29, p-value = 0.07) genes have less APOBEC3 footprints overall, and particularly in the cases compared to the controls in these regions, compared to the viral non-coding upstream regulatory region (URR). Overall, we found that APOBEC3 is not affecting the HPV16 genome in a uniform way, and instead, it appears to be targeting specific regions which could suggest antiviral activity. Importantly, we determined that APOBEC3-associated variants are less prevalent in cases which could be related to disease progression in these individuals. Further evaluation is underway. Citation Format: Yanzi Xiao, Bin Zhu, Meredith Yeager, Michael Cullen, Joseph Boland, Nicolas Wentzensen, Tina Raine-Bennett, Zigui Chen, Kai Yu, Qi Yang, Mia Steinberg, David Roberson, Sara Bass, Laurie Burdette, Thomas Lorey, Philip Castle, Robert Burk, Mark Schiffman, Lisa Mirabello. Evidence of APOBEC3 editing in the HPV16 genome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4249. doi:10.1158/1538-7445.AM2017-4249