Inverse relationship between human papillomavirus-16 infection and disruptive p53 gene mutations in squamous cell carcinoma of the head and neck.

PURPOSE: Squamous cell carcinomas of the head and neck (HNSCC) often harbor p53 mutations, but p53 protein degradation by the viral oncoprotein E6 may supercede p53 mutations in human papillomavirus 16 (HPV16)-positive tumors. The prevalence of p53 mutations in HPV-positive HNSCCs is indeed lower, but in some tumors these alterations coexist. The purpose of this study was to discern whether HNSCCs differ in the type of p53 mutations as a function of HPV16 status. EXPERIMENTAL DESIGN: The study was nested within a prospective multicenter study (ECOGE 4393/RTOG R9614) of patients with HNSCC treated surgically with curative intent. Tumors from one study center were used to construct a tissue microarray. The tumors were well characterized with respect to p53 mutational status. The tissue microarray was evaluated by HPV16 in situ hybridization. HPV16 analysis was also done on a select group of tonsillar carcinomas known to harbor disruptive p53 mutations defined as stop mutations or nonconservative mutations within the DNA binding domain. RESULTS: HPV16 was detected in 12 of 89 (13%) HNSCCs. By tumor site, HPV16 was detected in 12 of 21 (57%) tumors from the palatine/lingual tonsils, but in none of 68 tumors from nontonsillar sites (P < 0.00001). Both HPV16-positive and HPV16-negative HNSCCs harbored p53 mutations (25% versus 52%), but disruptive mutations were only encountered in HPV16-negative carcinomas. Of seven tonsillar carcinomas with disruptive p53 mutations, none were HPV16 positive, in contrast to HPV16-positive tonsillar carcinomas without disruptive p53 mutations (0% versus 57%; P = 0.008). CONCLUSIONS: Although HPV16 and mutated p53 may coexist in a subset of HNSCCs, HPV16 and disruptive p53 mutations seem to be nonoverlapping events. A less calamitous genetic profile, including the absence of disruptive p53 mutations, may underlie the emerging clinical profile of HPV16-positive HNSCC such as improved patient outcome.     

Human papillomavirus and p53 mutations in head and neck squamous cell carcinoma among Japanese population

We aimed to reveal the prevalence and pattern of human papillomavirus (HPV) infection and p53 mutations among Japanese head and neck squamous cell carcinoma (HNSCC) patients in relation to clinicopathological parameters. Human papillomavirus DNA and p53 mutations were examined in 493 HNSCCs and its subset of 283 HNSCCs. Oropharyngeal carcinoma was more frequently HPV‐positive than non‐oropharyngeal carcinoma (34.4% vs 3.6%, P < 0.001), and HPV16 accounted for 91.1% of HPV‐positive tumors. In oropharyngeal carcinoma, which showed an increasing trend of HPV prevalence over time (P < 0.001), HPV infection was inversely correlated with tobacco smoking, alcohol drinking, p53 mutations, and a disruptive mutation (P = 0.003, <0.001, <0.001, and <0.001, respectively). The prevalence of p53 mutations differed significantly between virus‐unrelated HNSCC and virus‐related HNSCC consisting of nasopharyngeal and HPV‐positive oropharyngeal carcinomas (48.3% vs 7.1%, P < 0.001). Although p53 mutations were associated with tobacco smoking and alcohol drinking, this association disappeared in virus‐unrelated HNSCC. A disruptive mutation was never found in virus‐related HNSCC, whereas it was independently associated with primary site, such as the oropharynx and hypopharynx (P = 0.01 and 0.03, respectively), in virus‐unrelated HNSCC. Moreover, in virus‐unrelated HNSCC, G:C to T:A transversions were more frequent in ever‐smokers than in never‐smokers (P = 0.04), whereas G:C to A:T transitions at CpG sites were less frequent in ever‐smokers than in never‐smokers (P = 0.04). In conclusion, HNSCC is etiologically classified into virus‐related and virus‐unrelated subgroups. In virus‐related HNSCC, p53 mutations are uncommon with the absence of a disruptive mutation, whereas in virus‐unrelated HNSCC, p53 mutations are common, and disruptive mutagenesis of p53 is related with oropharyngeal and hypopharyngeal carcinoma.     

CD8+ tumour‐infiltrating lymphocytes in relation to HPV status and clinical outcome in patients with head and neck cancer after postoperative chemoradiotherapy: A multicentre study of the German cancer consortium radiation oncology group (DKTK‐ROG)

We examined the prognostic value of tumour‐infiltrating lymphocytes (TILs) in patients with squamous cell carcinoma of the head and neck (SCCHN) after surgery and postoperative cisplatin‐based chemoradiotherapy. FFPE‐tissue originating from the surgery of 161 patients treated in 8 DKTK partner sites was immunohistochemically stained for CD3 and CD8. Their expression was correlated with clinicopathological characteristics as well as overall survival (OS), local progression‐free survival (LPFS) and distant metastases free‐survival (DMFS), also in the context of the HPV16‐DNA/p16 status. After a median follow‐up of 48 months (range: 4100 months), OS at 4 years was 46.5% for the entire cohort. In multivariate analysis, high CD8 expression was confirmed as an independent prognostic parameter for OS (p = 0.002), LPFS (p = 0.004) and DMFS (p = 0.006), while CD3 expression lacked significance. In multivariate analysis HPV16 DNA positivity was associated with improved OS (p = 0.025) and LPFS (p = 0.013) and p16‐positive patients showed improved DMFS (p = 0.008). Interestingly, high CD8 expression was a prognostic parameter for the clinical outcome in both HPV16 DNA‐positive and HPV16 DNA‐negative patients. Similar findings were observed in the multivariate analysis for the combined HPV16 DNA/p16 status. Altogether, CD8+ TILs constitute an independent prognostic marker in SCCHN patients treated with adjuvant chemoradiotherapy. These data indicate that CD8‐positive TILs have antitumour activity and could be used for treatment stratification. Further validation of the prognostic value of CD8+ TILs as a biomarker and its role in the immune response in SCCHN patients after adjuvant chemoradiotherapy is warranted and will be performed in the prospective DKTK‐ROG study.     

DNA double strand break repair defect and sensitivity to poly ADP-ribose polymerase (PARP) inhibition in human papillomavirus 16-positive head and neck squamous cell carcinoma

Patients with human papillomavirus-positive (HPV+) head and neck squamous cell carcinomas (HNSCCs) have increased response to radio- and chemotherapy and improved overall survival, possibly due to an impaired DNA damage response. Here, we investigated the correlation between HPV status and repair of DNA damage in HNSCC cell lines. We also assessed in vitro and in vivo sensitivity to the PARP inhibitor veliparib (ABT-888) in HNSCC cell lines and an HPV+ patient xenograft. Repair of DNA double strand breaks (DSBs) was significantly delayed in HPV+ compared to HPV− HNSCCs, resulting in persistence of γH2AX foci. Although DNA repair activators 53BP1 and BRCA1 were functional in all HNSCCs, HPV+ cells showed downstream defects in both non-homologous end joining and homologous recombination repair. Specifically, HPV+ cells were deficient in protein recruitment and protein expression of DNA-Pk and BRCA2, key factors for non-homologous end joining and homologous recombination respectively. Importantly, the apparent DNA repair defect in HPV+ HNSCCs was associated with increased sensitivity to the PARP inhibitor veliparib, resulting in decreased cell survival in vitro and a 10–14 day tumor growth delay in vivo. These results support the testing of PARP inhibition in combination with DNA damaging agents as a novel therapeutic strategy for HPV+ HNSCC.     

Trends in incidence rates of head and neck squamous cell carcinomas overall and by potential relatedness to human papillomavirus,Costa Rica 2006 to 2015

In Costa Rica (CR), only one report on head and neck cancer (HNC) incidence trends (1985-2007) has been published and no investigations on the epidemiology of potentially human papillomavirus (HPV)-related and HPV-unrelated HNCs have been done. We examined the age-standardized incidence rates (IRs) and trends of head and neck squamous cell carcinomas (HNSCC) and compared incidence trends of potentially HPV-related and HPV-unrelated HNSCCs. We obtained all available HNC cases for the period 2006-2015 from the Costa Rican National Cancer Registry of Tumors and the population estimates from the Costa Rican National Institute of Statistics and Census. The analysis was restricted to invasive HNSCCs (n = 1577). IRs and incidence rate ratios were calculated using SEER*Stat software and were age-standardized for the 2010 Costa Rican population. Joinpoint regression analysis program was used to calculate trends and annual percent changes (APCs) in rates. For all HNSCCs, the age-standardized IR was 34.0/million person-years; 95% CI 32.4, 35.8. There was a significant decline in the incidence of nasopharyngeal cancer (APC: −5.9% per year; 95% CI −10.8, −0.7) and laryngeal cancer (APC: −5.4% per year; −9.2, 1.5). The incidence trends for hypopharyngeal, oropharyngeal and oral cavity cancers each remained stable over time. HNSCCs were categorized by their potential relatedness to HPV infection. Though the APCs were not statistically significant, IRs of potentially HPV-related HNSCCs trended upward, while HPV-unrelated HNSCCs trended downward. HNSCCs are uncommon in CR and decreased over time. We observed a divergent pattern of decreasing HPV-unrelated with increasing HPV-related HNSCCs that should be further informed by HPV genotyping tumor samples.     

Modeling rectal cancer to advance neoadjuvant precision therapy

Progress in rectal cancer therapy has been hindered by the lack of effective disease-specific preclinical models that account for the unique molecular profile and biology of rectal cancer. Thus, we developed complementary patient-derived xenograft (PDX) and subsequent in vitro tumor organoid (PDTO) platforms established from preneoadjuvant therapy rectal cancer specimens to advance personalized care for rectal cancer patients. Multiple endoscopic samples were obtained from 26 Stages 2 and 3 rectal cancer patients prior to receiving 5FU/RT and implanted subcutaneously into NSG mice to generate 15 subcutaneous PDXs. Second passaged xenografts demonstrated 100% correlation with the corresponding human cancer histology with maintained mutational profiles. Individual rectal cancer PDXs reproduced the 5FU/RT response observed in the corresponding human cancers. Similarly, rectal cancer PDTOs reproduced significant heterogeneity in cellular morphology and architecture. PDTO in vitro 5FU/RT treatment response replicated the clinical 5FU/RT neoadjuvant therapy pathologic response observed in the corresponding patient tumors (p < 0.05). The addition of cetuximab to the 5FU/RT regiment was significantly more sensitive in the rectal cancer PDX and PDTOs with wild-type KRAS compared to mutated KRAS (p < 0.05). Considering the close relationship between the patient's cancer and the corresponding PDX/PDTO, rectal cancer patient-derived research platforms represent powerful translational research resources as population-based tools for biomarker discovery and experimental therapy testing. In addition, our findings suggest that cetuximab may enhance RT effectiveness by improved patient selection based on mutational profile in addition to KRAS or by developing a protocol using PDTOs to identify sensitive patients.     

A prospective study on the natural course of low‐grade squamous intraepithelial lesions and the presence of HPV16 E2‐, E6‐ and E7‐specific T‐cell responses

This study investigates the clinical course of low grade squamous intraepithelial lesions (LSIL), HPV status and HPV16‐specific immune response in a large prospective study of 125 women with LSIL followed cytologically, virologically and histologically. Women with low‐grade abnormal smears were recruited and followed‐up for one year. Colposcopy, cervical biopsy for histology and brushings for HPV typing was performed at recruitment, 6 months (no biopsy) and upon completion of the study at one year. HPV16‐specific T‐cell responses were analysed by interferon‐γ ELISPOT at entry, 6 and 12 months. Infection with multiple HPV types was detected in 70% of all patients, HPV16 was found in 42% of the patients. LSIL lesions progressed to HSIL in 24%, persisted in 60% and regressed to normal in 16% of the patients. No difference was observed in the clearance rate of infections with single or multiple HPV types among the groups with a different histological outcome. HPV16‐specific type 1 T‐cell responses were detected in only half of the patients with an HPV16+ LSIL, and predominantly reactive to HPV16 E2 and E6. Interestingly, the presence of HPV16 E2‐specific T‐cell responses correlated with absence of progression of HPV16+ lesions (p = 0.005) while the detection of HPV16 E6 specific reactivity was associated with persistence (p = 0.05). This large prospective study showed that the majority of LSIL persisted or progressed within the first year.This was paralleled by immune failure as most of the patients with an HPV16+ LSIL failed to react to peptides of HPV16 E2, E6 or E7.     

Circulating tumor DNA and circulating tumor cells in metastatic triple negative breast cancer patients

Circulating tumor DNA (ctDNA) is a new circulating tumor biomarker which might be used as a prognostic biomarker in a way similar to circulating tumor cells (CTCs). Here, we used the high prevalence of TP53 mutations in triple negative breast cancer (TNBC) to compare ctDNA and CTC detection rates and prognostic value in metastatic TNBC patients. Forty patients were enrolled before starting a new line of treatment. TP53 mutations were characterized in archived tumor tissues and in plasma DNA using two next generation sequencing (NGS) platforms in parallel. Archived tumor tissue was sequenced successfully for 31/40 patients. TP53 mutations were found in 26/31 (84%) of tumor samples. The same mutation was detected in the matched plasma of 21/26 (81%) patients with an additional mutation found only in the plasma for one patient. Mutated allele fractions ranged from 2 to 70% (median 5%). The observed correlation between the two NGS approaches (R² = 0.903) suggested that ctDNA levels data were quantitative. Among the 27 patients with TP53 mutations, CTC count was ≥1 in 19 patients (70%) and ≥5 in 14 patients (52%). ctDNA levels had no prognostic impact on time to progression (TTP) or overall survival (OS), whereas CTC numbers were correlated with OS (p = 0.04) and marginally with TTP (p = 0.06). Performance status and elevated LDH also had significant prognostic impact. Here, absence of prognostic impact of baseline ctDNA level suggests that mechanisms of ctDNA release in metastatic TNBC may involve, beyond tumor burden, biological features that do not dramatically affect patient outcome.     

A controlled trial of HNSCC patient-derived xenografts reveals broad efficacy of PI3Kα inhibition in controlling tumor growth

Head and neck squamous cell carcinomas (HNSCCs) frequently harbor alterations in the PI3K/AKT/mTOR signaling axis, particularly in the PIK3CA gene. PI3K-targeted agents have therefore gained considerable preclinical and clinical interest as emerging therapies for HNSCC. Identification of predictive biomarkers of response would advance the clinical application of PI3K-targeted drugs for patients, in order to achieve maximal benefit. To date, studies of drug biomarkers have largely focused on screening cell lines, with much more limited in vivo testing, usually only as validation. This approach has rarely enabled accurate predictions of clinical efficacy. Recently, clinical trials of PDX models (PDX clinical trials) have been introduced as a preclinical approach to interrogate interpatient response heterogeneity. Already, PDX clinical trial responses have been demonstrated to correlate closely with patient outcomes. Here, using both an HNSCC specific, 28-cell line panel and a PDX clinical trial of 80 xenografts derived from 20 unique HNSCC tumors, we systematically examine patterns of response to PI3K inhibition in HNSCC. We find EGFR, AKT1 and CSMD1 copy number aberrations, but not PIK3CA mutations, to be associated with responsiveness to PI3K-targeted drugs. Further, we reveal PI3Kα inhibition to be almost globally tumoristatic in HNSCC xenografts regardless of PIK3CA mutational status, emphasizing its potential as a stabilizing neoadjuvant therapy for HNSCC patients.     

Human papillomavirus infections as a marker to predict overall survival in lung adenocarcinoma

Human papillomavirus (HPV) has been implicated in multiple cancers, but its significance in lung cancer has remained controversial. As the prevalence of HPV 16/18 infection was higher in lung adenocarcinoma among Taiwanese females, the aim of our study was to evaluate the clinical impact of HPV infections in lung adenocarcinoma. Two hundred and ten patients were enrolled to investigate the associations of HPV status in tumors with clinical characteristics as well as its impact on overall survival. The methods to assess HPV status were by immunohistochemistry for HPV L1 capsid protein and E6 protein and by nested polymerase chain reaction for HPV 16 and HPV 18. HPV infections were identified in 35.2% of patients, and associated with localized and smaller sized tumors (p = 0.022 and p = 0.002, respectively). Patients with HPV infections had a significantly better survival (p = 0.023, by log‐rank test) and a significantly reduced mortality risk after adjustments of age, tumor extent, epidermal growth factor receptor (EGFR) mutations status and treatments [adjusted hazard ratio = 0.68, 95% confidence interval (CI) = 0.49–0.96, p = 0.026, by multivariate Cox proportional hazards models]. Specifically, patients with both HPV infections and EGFR mutations had the best survival outcome [1‐year survival rate, 68.5% (95% CI = 52.2–4.8%)]. Our findings indicate that HPV infections represent an independent prognostic factor for overall survival in patients with lung adenocarcinoma.     

Patient-derived xenograft models of breast cancer and their predictive power

Despite advances in the treatment of patients with early and metastatic breast cancer, mortality remains high due to intrinsic or acquired resistance to therapy. Increased understanding of the genomic landscape through massively parallel sequencing has revealed somatic mutations common to specific subtypes of breast cancer, provided new prognostic and predictive markers, and highlighted potential therapeutic targets. Evaluating new targets using established cell lines is limited by the inexact correlation between responsiveness observed in cell lines versus that elicited in the patient. Patient-derived xenografts (PDXs) generated from fresh tumor specimens recapitulate the diversity of breast cancer and reflect histopathology, tumor behavior, and the metastatic properties of the original tumor. The high degree of genomic preservation evident across primary tumors and their matching PDXs over serial passaging validate them as important preclinical tools. Indeed, there is accumulating evidence that PDXs can recapitulate treatment responses of the parental tumor. The finding that tumor engraftment is an independent and poor prognostic indicator of patient outcome represents the first step towards personalized medicine. Here we review the utility of breast cancer PDX models to study the clonal evolution of tumors and to evaluate novel therapies and drug resistance.     

Targeted next-generation sequencing identifies molecular subgroups in squamous cell carcinoma of the head and neck with distinct outcome after concurrent chemoradiation

The value of mutational profiling by targeted next-generation sequencing (NGS) for risk stratification of patients with locally advanced oro-/hypopharyngeal carcinomas treated with concurrent chemoradiation was established. Besides HPV status and clinical factors, somatic mutations in TP53 and NOTCH1, and two germline variants in KDR were identified as independent risk factors for outcome.BackgroundBased on epidemiological (HPV status, smoking habits) and clinical risk factors (T/N stage), three subgroups of patients suffering from locally advanced oropharyngeal carcinoma with significantly different outcome after concurrent chemoradiation (cCRTX) can be distinguished. Mutational profiling by targeted next-generation sequencing (NGS) might further improve risk stratification.Patients and methodsPatients with stage IV squamous cell carcinoma of the oropharynx and hypopharynx who had been enrolled in a randomized phase III trial (ARO-0401) comparing two regimens of cCRTX and from whom archival tumor specimens were available were included. The HPV status was determined by p16 immunostaining and detection of HPV DNA. Targeted NGS covering 45 genes frequently altered in squamous cell carcinoma of the head and neck (SCCHN) was applied for detection of non-synonymous somatic and germline mutations. Interference of mutational profiles with cCRTX efficacy was determined.ResultsThe prognostic value of the ‘Ang’ risk model could be confirmed in the total biomarker study cohort (N = 175) as well as the patient subgroup for which mutational profiles could be established (N = 97). Mutations in genes involved in phosphoinositide 3-kinase (PI3K), receptor tyrosine kinase (RTK), and p53 signaling pathways were significantly enriched in the low- (N = 7), intermediate- (N = 20), and high-risk group (N = 70), respectively. Mutations in TP53 identified a subgroup of high-risk patients with dismal outcome after cCRTX. No prognostic relevance was observed for mutations in PI3K and RTK signaling pathways in the low- and intermediate-risk groups, respectively. Mutated NOTCH1 and two functional KDR germline variants (rs2305948, rs1870377) were associated with improved outcome in all risk groups. All genetic markers (TP53, NOTCH1, KDR) remained independent prognosticators of OS in the multivariate model.ConclusionA potential of targeted NGS for risk classification of SCCHN cases beyond HPV status and clinical factors was demonstrated.     

Patient-derived xenografts effectively capture responses to oncology therapy in a heterogeneous cohort of patients with solid tumors

BackgroundWhile patient-derived xenografts (PDXs) offer a powerful modality for translational cancer research, a precise evaluation of how accurately patient responses correlate with matching PDXs in a large, heterogeneous population is needed for assessing the utility of this platform for preclinical drug-testing and personalized patient cancer treatment.Patients and methodsTumors obtained from surgical or biopsy procedures from 237 cancer patients with a variety of solid tumors were implanted into immunodeficient mice and whole-exome sequencing was carried out. For 92 patients, responses to anticancer therapies were compared with that of their corresponding PDX models.ResultsWe compared whole-exome sequencing of 237 PDX models with equivalent information in The Cancer Genome Atlas database, demonstrating that tumorgrafts faithfully conserve genetic patterns of the primary tumors. We next screened PDXs established for 92 patients with various solid cancers against the same 129 treatments that were administered clinically and correlated patient outcomes with the responses in corresponding models. Our analysis demonstrates that PDXs accurately replicate patients’ clinical outcomes, even as patients undergo several additional cycles of therapy over time, indicating the capacity of these models to correctly guide an oncologist to treatments that are most likely to be of clinical benefit.ConclusionsIntegration of PDX models as a preclinical platform for assessment of drug efficacy may allow a higher success-rate in critical end points of clinical benefit.     

Molecular profile of head and neck squamous cell carcinomas bearing p16 high phenotype

BackgroundWe sought to determine biomarker expression differences in head and neck squamous cell cancers (HNSCCs) based on p16/human papillomavirus (HPV) classification. In addition, our aim was to explore how expression of biomarkers is modulated after E6/E7 repression in HPV16⁺ oropharyngeal cancer cells.MethodsHPV16⁺ and HPV^- HNSCC cells were infected with retroviruses expressing short hairpin RNA targeting HPV16 E6/E7. Components of the epidermal growth factor receptor (EGFR) pathway before and after E6/E7 gene silencing were analyzed by immunoblotting and qRT–PCR. Protein expression of 13 biomarkers was analyzed using AQUA on a tissue microarray (TMA). The HPV16 status was determined using HPV16 in situ hybridization (ISH).ResultsIn HPV16⁺ cells, E6/E7 silencing was associated with PTEN upregulation and reduction of phosphorylated EGFR. Tumors were classified into four categories based on the HPV and p16 status. HPV⁺/p16⁺ tumors expressed significantly higher levels of E-cadherin (P = 0.003), PTEN (P = 0.004), lower levels of PI3Kp110 and β-catenin (P = 0.07). There was a significant difference in overall survival (OS, P = 0.016) among the four subsets. The median OS was 24.83 months for p16^-/HPV^- patients, 11.63 for p16^-/HPV⁺ patients and was not reached for p16⁺/HPV^- and p16⁺/HPV⁺ groups.ConclusionsAberrant EGFR signaling contributes to malignant conversion of HPV16⁺ HNSCC cells. These results validate β-catenin as a distinct biomarker in HPV⁺/p16⁺ HNSCC. Wnt signaling inhibitors merit exploration in HPV⁺/p16⁺ HNSCC.     

Application of the hybrid capture 2 assay to squamous cell carcinomas of the head and neck: a convenient liquid-phase approach for the reliable determination of human papillomavirus status

BACKGROUND:

A growing proportion of head and neck squamous cell carcinoma (HNSCC) is caused by the human papillomavirus (HPV). In light of the unique natural history and prognosis of HPV‐related HNSCCs, routine HPV testing is being incorporated into diagnostic protocols. Accordingly, there is an escalating demand for an optimal detection strategy that is sensitive and specific, transferrable to the diagnostic laboratory, standardized across laboratories, cost‐effective, and amenable to broad application across specimen types including cytologic preparations.

METHODS:

Cytologic preparations (fine‐needle aspirates [FNAs] and brushes) were obtained from surgically resected HNSCCs and evaluated for the presence of high‐risk HPV using the Hybrid Capture 2 assay. HPV analysis was also performed on the corresponding tissue sections using HPV in situ hybridization and p16 immunohistochemistry. In cases in which the immunohistochemical and in situ hybridization results were discordant, HPV status was determined by real‐time polymerase chain reaction detection of E7 expression. HPV status in the tissues and corresponding cytologic samples was compared.

RESULTS:

Based on benchmark HPV testing of the tissue sections, 14 HNSCCs were classified as HPV positive and 10 as HPV negative. All corresponding cytologic preparations were correctly classified using the Hybrid Capture 2 assay.

CONCLUSIONS:

The Hybrid Capture 2 strategy, already widely used for the detection of high‐risk HPV in cervical brushes, is readily transferrable to HNSCCs. Consistent accuracy in cytologic preparation suggests its potential application in FNAs from patients who present with lymph node metastases, and may eliminate the need to obtain tissue solely for the purpose of HPV testing. Cancer (Cancer Cytopathol) 2012. © 2011 American Cancer Society.     

Antibodies against human papillomaviruses as diagnostic and prognostic biomarker in patients with neck squamous cell carcinoma from unknown primary tumor

Treatment of patients with neck lymph node metastasis of squamous cell carcinoma (SCC) from unknown primary tumor (NSCCUP) is challenging due to the risk of missing occult tumors or inducing toxicity to unaffected sites. Human papillomavirus (HPV) is a promising biomarker given its causal link to oropharyngeal SCC and superior survival of patients with HPV‐driven oropharyngeal SCC and NSCCUP. Identification of HPV‐driven NSCCUP could focus diagnostic work‐up and treatment on the oropharynx. For the first time, we assessed HPV antibodies and their prognostic value in NSCCUP patients. Antibodies against E6 and E7 (HPV16/18/31/33/35), E1 and E2 (HPV16/18) were assessed in 46 NSCCUP patients in sera collected at diagnosis, and in follow‐up sera from five patients. In 28 patients, HPV tumor status was determined using molecular markers (HPV DNA, mRNA and cellular p16^INK4a). Thirteen (28%) NSCCUP patients were HPV‐seropositive for HPV16, 18, 31, or 33. Of eleven patients with HPV‐driven NSCCUP, ten were HPV‐seropositive, while all 17 patients with non‐HPV‐driven NSCCUP were HPV‐seronegative, resulting in 91% sensitivity (95% CI: 59–100%) and 100% specificity (95% CI: 80–100%). HPV antibody levels decreased after curative treatment. Recurrence was associated with increasing levels in an individual case. HPV‐seropositive patients had a better overall and progression‐free survival with hazard ratios of 0.09 (95% CI: 0.01–0.42) and 0.03 (95% CI: 0.002–0.18), respectively. For the first time, seropositivity to HPV proteins is described in NSCCUP patients, and high sensitivity and specificity for HPV‐driven NSCCUP are demonstrated. HPV seropositivity appears to be a reliable diagnostic and prognostic biomarker for patients with HPV‐driven NSCCUP.     

Human papillomavirus type 16 E7 oncoprotein causes a delay in repair of DNA damage

Background and purposePatients with human papillomavirus related (HPV+) head and neck cancers (HNCs) demonstrate improved clinical outcomes compared to traditional HPV negative (HPV−) HNC patients. We have recently shown that HPV+ HNC cells are more sensitive to radiation than HPV− HNC cells. However, roles of HPV oncogenes in regulating the response of DNA damage repair remain unknown.Material and methodsUsing immortalized normal oral epithelial cell lines, HPV+ HNC derived cell lines, and HPV16 E7-transgenic mice we assessed the repair of DNA damage using γ-H2AX foci, single and split dose clonogenic survival assays, and immunoblot. The ability of E7 to modulate expression of proteins associated with DNA repair pathways was assessed by immunoblot.ResultsHPV16 E7 increased retention of γ-H2AX nuclear foci and significantly decreased sublethal DNA damage repair. While phospho-ATM, phospho-ATR, Ku70, and Ku80 expressions were not altered by E7, Rad51 was induced by E7. Correspondingly, HPV+ HNC cell lines showed retention of Rad51 after γ-radiation.ConclusionsOur findings provide further understanding as to how HPV16 E7 manipulates cellular DNA damage responses that may underlie its oncogenic potential and influence the altered sensitivity to radiation seen in HPV+ HNC as compared to HPV− HNC.     

Recapitulating the clinical scenario of BRCA‐associated pancreatic cancer in pre‐clinical models

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies. BRCA‐associated PDAC comprises a clinically relevant subtype. A portion of these patients are highly susceptible to DNA damaging therapeutics, however, responses are heterogeneous and clinical resistance evolves. We have developed unique patient‐derived xenograft (PDX) models from metastatic lesions of germline BRCA‐mutated patients obtained at distinct time points; before treatment and at progression. Thus, closely mimicking clinical scenarios, to further investigate treatment naïve and resistant patients. DNA was isolated from six BRCA‐mutated PDXs and classified by whole‐genome sequencing to stable‐genome or homologous recombination deficient (HRD)‐genome. The sensitivity to DNA‐damaging agents was evaluated in vivo in three BRCA‐associated PDAC PDXs models: (1) HRD‐genome naïve to treatments; (2) stable‐genome naïve to treatment; (3) HRD‐genome resistant to treatment. Correlation between disease course at tissue acquisition and response to PARP inhibitor (PARPi)/platinum was demonstrated in PDXs in vivo. Only the HRD‐genome PDX, naïve to treatment, was sensitive to PARP inhibitor/cisplatin treatments. Our results demonstrate heterogeneous responses to DNA damaging agents/PARPi in BRCA‐associated PDX thus reflecting the wide clinical spectrum. An HRD‐genome PDX generated from a naïve to treatment biopsy was sensitive to platinum/PARPi whereas no benefit was observed in treating a HRD‐genome PDXs generated from a patient that had acquired resistance nor stable‐genome PDXs.