TP53 Mutations in Head and Neck Squamous Cell Carcinoma and Their Impact on Disease Progression and Treatment Response

TP53 Mutation in Correlation to Immunohistochemical Expression of P53 Protein in Patients with Hepatocellular Carcinoma

BACKGROUND:

Mutations causing p53 inactivation are among the most common genetic alterations in human malignant tumours including hepatocellular carcinoma. Detection of p53 gene mutations in patients with hepatocellular carcinoma (HCC) should provide relevant data for the patients from the Republic of Macedonia and should allow the survivals additional therapeutic option as is gene therapy.

AIM:

We aimed to detect p53 gene mutations in HCC tissue, and to correlate them with the immunoexpression of p53 protein and multiple clinicopathologic characteristics of a tumour.

MATERIAL AND METHODS:

We analysed thirty patients with HCC for multiple clinic-pathological characteristics. Tumour tissue samples were immunostained for p53 and detection of p53 gene mutations was performed by polymerase chain reaction followed by Sanger sequencing.

RESULTS:

Changes in p53 gene sequence were detected in four patients (13.33%), one of them a polymorphism and the other three were missense point mutations with p53 immunoexpression of 50%, 0%, 0% and 90%, respectively. All patients with p53 mutations had cirrhosis. Two of them had Hepatitis B infection, moderately differentiated tumour and T2 status. There was one case with a well-differentiated tumour and one with T4 status. All of them were with vascular invasion. The size of the tumours was in the range of 2.5 cm to 16 cm. All 3 mutations were located in exon 7.

CONCLUSION:

Mutations in p53 gene are not always associated with obviously altered immunoexpression of p53 protein. Detection of p53 gene mutations is necessary in each case because the new therapeutic modalities offer to apply gene therapy.

Genomic Landscapes of EBV-Associated Nasopharyngeal Carcinoma vs. HPV-Associated Head and Neck Cancer

: Epstein-Barr virus-positive nasopharyngeal carcinoma (EBV(+) NPC), and human papillomavirus-positive head and neck squamous cell carcinoma (HPV(+) HNSCC) are two distinct types of aggressive head and neck cancers with early age onsets. Their recently identified genomic landscapes by whole-exome sequencing (WES) clearly reveal critical roles of: (1) inflammation via NF-kB activation, (2) survival via PI3K aberrations, and perhaps (3) immune evasion via MHC loss in these cancers as summarized in this review. Immediate outcomes of these WES studies include the identification of potential prognostic biomarkers, and druggable events for these cancers. The impact of these genomic findings on the development of precision medicine and immunotherapies will be discussed. For both of these cancers, the main lethality comes from metastases and disease recurrences which may represent therapy resistance. Thus, potential curing of these cancers still relies on future identification of key genomic drivers and likely druggable events in recurrent and metastatic forms of these intrinsically aggressive cancers of the head and neck.

High tRNA Transferase NSUN2 Gene Expression is Associated with Poor Prognosis in Head and Neck Squamous Carcinoma

NSUN2 is a tRNA methyltransferase and plays an important role in cell development via modifying RNA methylation. We aimed to evaluate the expression of NSUN2 and its prognostic value in HNSCC. Random-effects model of meta-analysis shows 1.99-folds (95% CI: 1.89-2.09) upregulation of NSUN2 expression in HNSCC versus normal tissues. Patients with high NSUN2 levels had approximately 22 months shorter overall survival, and had a higher mortality risk than those with low one (p-trend = 0.020). In conclusion, NSUN2 is a potential independent prognostic marker and may be a potential therapeutic target in HNSCC.

Prognostic role of PIK3CA and TP53 in human papillomavirus-negative oropharyngeal cancers

BACKGROUND

Human papilloma virus (HPV)-negative oropharyngeal squamous cell carcinomas (OPCs) have a poorer prognosis and best management is an unmet need. We studied the prognostic role of epidermal growth factor receptor (EGFR) and PIK3CA amplifications and TP53 functional status.

METHODS

Between 1992 and 2000, 90 consecutive patients with OPCs were treated with surgery, followed by radiotherapy in case of high-risk pathologic features. Of those, 73 cases were HPV-negative and therefore were selected for molecular analysis ( PIK3CA and EGFR fluorescent in situ hybridization [FISH] analysis and TP53 mutation analysis).

RESULTS

FISH analyses of EGFR and PIK3CA were successfully conducted on 69 and 63 of 73 tumor samples, respectively. EGFR alterations were detected in 43% of patients but just 7% showed amplification. Seven cases (11%) carried PIK3CA amplification and 18 (29%) gene gain or high polysomy. TP53 was detected as nonfunctional in 24 of 67 (36%) successfully analyzed cases. Both univariable and multivariable analysis showed statistically significantly worse disease-free survival (DFS) for patients with PIK3CA disomy compared to those with gene gain or high polysomy. No differences in overall survival or DFS for EGFR and TP53 alteration were evident. The combined evaluation of PIK3CA and TP53 showed that PIK3CA gene copy number gain separated a population with better outcome, defining an overall worse prognosis population (disomy) now clearly further divided according to TP53 functional status.

CONCLUSION

PIK3CA gene copy number increase is associated with a favorable clinical outcome in HPV-negative OPCs treated with surgery ± postoperative radiotherapy. In patients without PIK3CA alteration, TP53 nonfunctional mutations are associated with poor prognosis.

Precision Therapy of Head and Neck Squamous Cell Carcinoma

Precision medicine is an approach to disease prevention and treatment that takes into account genetic variability and environmental and lifestyle influences that are unique to each patient. It facilitates stratification of patient populations that vary in their susceptibility to disease and response to therapy. Shared databases and the implementation of new technology systems designed to advance the integration of this information will enable health care providers to more accurately predict and customize prevention and treatment strategies for patients. Although precision medicine has had a limited impact in most areas of medicine, it has been shown to be an increasingly successful approach to cancer therapy. Despite early promising results targeting aberrant signaling pathways or inhibitors designed to block tumor-driven processes such as angiogenesis, limited success emphasizes the need to discover new biomarkers and treatment targets that are more reliable in predicting response to therapy and result in better health outcomes. Recent successes in the use of immunity-inducing antibodies have stimulated increased interest in the use of precision immunotherapy of head and neck squamous cell carcinoma. Using next-generation sequencing, the precise profiling of tumor-infiltrating lymphocytes has great promise to identify hypoimmunogenic cancer that would benefit from a rationally designed combinatorial approach. Continued interrogation of tumors will reveal new actionable targets with increasing therapeutic efficacy and fulfill the promise of precision therapy of head and neck cancer.

Alterations in the expression of DNA damage response-related molecules in potentially preneoplastic oral epithelial lesions

OBJECTIVES

The aim of this study was to evaluate the expression levels of DNA damage response (DDR) markers in potentially preneoplastic oral epithelial lesions (PPOELs).

STUDY DESIGN

Immunohistochemical expression of DDR markers (γΗ2 ΑΧ, pChk2, 53 BP1, p53, and phosphorylated at Ser 15 p53) was assessed in 41 oral leukoplakias, ranging from hyperplasia (H) to dysplasia (D) and in comparison with oral squamous cell carcinoma (OSCC) and normal mucosa (NM). Statistical and receiver operating characteristic curve analysis were performed.

RESULTS

γH2 AX immunoexpression demonstrated a gradual increase and upper layer extension from NM to H to higher D degrees to OSCC. pChk2 expression was minimal in NM, relatively low in PPOELs, with an increasing tendency from H to D, and higher in OSCC. 53 BP1 demonstrated higher levels in OSCC than in NM, whereas its expression in PPOELs was heterogeneous, gradually increasing according to D. p53 demonstrated progressively higher levels and upper layer extension from H to D to OSCC. Phosphorylated p53 was absent in NM and relatively low in PPOELs and OSCC.

CONCLUSIONS

DDR markers' expression is variable in PPOELs, showing a tendency to increase along with dysplasia. Activated DDR mechanisms may play an important protective role at early stages of oral carcinogenesis, but probably suffer progressive deregulation, eventually failing to suppress malignant transformation.

Cellular Plasticity-Targeted Therapy in Head and Neck Cancers

Head and neck cancer is one of the most frequent human malignancies worldwide, with a high rate of recurrence and metastasis. Head and neck squamous cell carcinoma (HNSCC) is cellularly and molecularly heterogeneous, with subsets of undifferentiated cancer cells exhibiting stem cell-like properties, called cancer stem cells (CSCs). Epithelial-mesenchymal transition, gene mutation, and epigenetic modification are associated with the formation of cellular plasticity of tumor cells in HNSCC, contributing to the acquisition of invasive, recurrent, and metastatic properties and therapeutic resistance. Tumor microenvironment (TME) plays a supportive role in the initiation, progression, and metastasis of head and neck cancer. Stromal fibroblasts, vasculature, immune cells, cytokines, and hypoxia constitute the main components of TME in HNSCC, which contributes not only to the acquisition of CSC properties but also to the recurrence and therapeutic resistance of the malignancies. In this review, we discuss the potential mechanisms underlying the development of cellular plasticity, especially the emergence of CSCs, in HNSCC. We also highlight recent studies implicating the complex interplays among TME components, plastic CSCs, tumorigenesis, recurrence, and therapeutic resistance of HNSCC. Finally, we summarize the treatment modalities of HNSCC and reinforce the novel concept of therapeutic targeting CSCs in HNSCC.

New therapeutic strategies to treat human cancers expressing mutant p53 proteins

The tumor suppressor p53 plays a critical role to preserve DNA fidelity from diverse insults through the regulation of cell-cycle checkpoints, DNA repair, senescence and apoptosis. The TP53 is the most frequently inactivated gene in human cancers. This leads to the production of mutant p53 proteins that loose wild-type p53 tumor suppression functions and concomitantly acquire new oncogenic properties among which deregulated cell proliferation, increased chemoresistance, disruption of tissue architecture, promotion of migration, invasion and metastasis and several other pro-oncogenic activities. Mouse models show that the genetic reconstitution of the wild type p53 tumor suppression functions rescues tumor growth. This strongly supports the notion that either restoring wt-p53 activity or inhibiting mutant p53 oncogenic activity could provide an efficient strategy to treat human cancers. In this review we briefly summarize recent advances in the study of small molecules and compounds that subvert oncogenic activities of mutant p53 protein into wt-p53 tumor suppressor functions. We highlight inhibitors of signaling pathways aberrantly modulated by oncogenic mutant p53 proteins as promising therapeutic strategies. Finally, we consider the clinical applications of compounds targeting mutant p53 and the use of currently available drugs in the treatment of tumors expressing mutant p53 proteins.

Genomic analysis of head and neck cancer cases from two high incidence regions

We investigated how somatic changes in HNSCC interact with environmental and host risk factors and whether they influence the risk of HNSCC occurrence and outcome. 180-paired samples diagnosed as HNSCC in two high incidence regions of Europe and South America underwent targeted sequencing (14 genes) and evaluation of copy number alterations (SCNAs). TP53, PIK3CA, NOTCH1, TP63 and CDKN2A were the most frequently mutated genes. Cases were characterized by a low copy number burden with recurrent focal amplification in 11q13.3 and deletion in 15q22. Cases with low SCNAs showed an improved overall survival. We found significant correlations with decreased overall survival between focal amplified regions 4p16, 10q22 and 22q11, and losses in 12p12, 15q14 and 15q22. The mutational landscape in our cases showed an association to both environmental exposures and clinical characteristics. We confirmed that somatic copy number alterations are an important predictor of HNSCC overall survival.

PARP-1 inhibitors sensitize HNSCC cells to APR-246 by inactivation of thioredoxin reductase 1 (TrxR1) and promotion of ROS accumulation

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide. Mutations of TP53 may reach 70% - 85% in HNSCC patients without human papillomavirus (HPV) infection. Recurrence rate remains particularly high for HNSCC patients with mutations in the TP53 gene although patients are responsive to surgery, irradiation, and chemotherapy early in the treatment. p53-Reactivation and Induction of Massive Apoptosis-1 (PRIMA-1) and its methylated analogue PRIMA-1Met (also known as APR-246) are quinuclidine compounds that rescue the DNA-binding activity of mutant p53 (mut-p53) and restore the potential of wild-type p53. In the current report, we demonstrated that inhibition of poly (ADP-ribose) polymerase-1 (PARP-1) with 6(5H)-phenanthridinone (PHEN) and N-(6-Oxo-5,6-dihydrophenanthridin-2-yl)-(N, N-dimethylamino) acetamide hydrochloride (PJ34) sensitizes UMSCC1, UMSCC14, and UMSCC17A, three HNSCC cell lines to the treatment of APR-246. PHEN enhances APR-246-induced apoptosis, but not programmed necrosis or autophagic cell death in HNSCC cells. The PARP-1 inhibition-induced sensitization of HNSCC cells to APR-246 is independent of TP53 mutation. Instead, PARP-1 inhibition promotes APR-246-facilitated inactivation of thioredoxin reductase 1 (TrxR1), leading to ROS accumulation and DNA damage. Overexpression of TrxR1 or application of antioxidant N-acetyl-L-cysteine (NAC) depletes the ROS increase, reduces DNA damage, and decreases cell death triggered by APR-246/PHEN in HNSCC cells. Thus, we have characterized a new function of PARP-1 inhibitor in HNSCC cells by inactivation of TrxR1 and elevation of ROS and provide a novel therapeutic strategy for HNSCC by the combination of PARP-1 inhibitors and APR-246.

Gain-of-function mutant p53 promotes the oncogenic potential of head and neck squamous cell carcinoma cells by targeting the transcription factors FOXO3a and FOXM1

Many mutant p53 proteins exert oncogenic gain-of-function (GOF) properties that promote cancer cell invasive growth and metastasis, yet the mechanisms mediating these functions still largely remain elusive. We show here that overexpression of the GOF mutant p53 G245D and other GOF p53 mutants enhances the invasive cell growth of p53-deficient head and neck squamous cell carcinoma (HNSCC) UM-SCC-1 cells both in in vitro three-dimensional culture and in an in vivo orthotopic nude mouse model of HNSCC through a novel transcription-independent mechanism. We demonstrate that the expression of the oncogenic forkhead transcription factor FOXM1 is upregulated by GOF mutant p53s. Moreover, we show that overexpression of GOF mutant p53 G245D decreases the AMP-activated protein kinase (AMPK)-mediated phosphorylation of FOXO3a, a tumor suppressive forkhead transcription factor, leading to its cytoplasmic accumulation. This downregulation of FOXO3a’s activity, in turn, leads to de-repression of FOXM1 expression. Importantly, we show that either overexpression of FOXO3a or downregulation of FOXM1 impairs both GOF mutant p53-mediated cell invasion in vitro and pulmonary metastases of UM-SCC-1 cells in vivo. Finally, not only do oral cancer patients with p53 mutations exhibit higher levels of FOXM1 expression than patients with wild-type p53, but also HNSCC patients with TP53 mutations and high levels of FOXM1 expression have the poorest survival outcomes. Given our prior demonstration that GOF mutant p53s inhibit AMPK, our current study, establishes and demonstrates a novel transcription-independent GOF mutant p53-AMPK-FOXO3a-FOXM1 signaling cascade that plays an important role in mediating mutant p53s’ gain-of-function activities in HNSCCs.

Mouse double minute 4 variants modify susceptibility to risk of recurrence in patients with squamous cell carcinoma of the oropharynx

Given the crucial role of Mouse double minute 4 (MDM4) oncoprotein in p53 pathway, single nucleotide polymorphisms (SNPs) could serve as such biomarkers for prediction of SCCOP recurrence. Thus, we investigated associations between three tagging putatively functional variants of MDM4, two in the 3' untranslated region of 3' UTR [rs11801299 (NC_000001.10:g.204529084G>A) and rs10900598(NC_000001.10:g.204525568G>T)] and one in intron 1 [rs1380576(NC_000001.10:g.204488278G>C)], and recurrence risk of SCCOP in 1,008 incident patients. A log-rank test and multivariable Cox models were used to assess associations. Patients with MDM4-rs10900598 GT/TT had a worse disease-free survival (DFS) compared with corresponding GG genotype, while those with rs11801299 AG/AA genotypes had a lower recurrence risk than the cases with rs11801299 GG genotype (both log-rank, P < 0.001). Multivariable analysis showed that significantly different recurrence risk were found among patients with MDM4-rs10900598 GT/TT and rs11801299 AG/AA variant genotypes (HR, 2.0, 95% CI, 1.4-2.9 and HR, 0.4, 95% CI, 0.3-0.6, respectively) compared with their corresponding common homozygous genotypes. Furthermore, after combining the risk genotypes of the three SNPs, patients among low-risk group had a significantly lower risk of SCCOP recurrence than those in high-risk group (HR, 0.2, 95% CI, 0.1-0.3). The risk for both individual SNPs or combined risk genotypes was restricted to HPV-positive SCCOP patients. Our findings suggest that the MDM4 polymorphisms may, individually or in combination, confer an independent risk of SCCOP recurrence, particularly in HPV-positive SCCOP patients. However, larger studies are needed to validate our findings.

Disease-relevant signalling-pathways in head and neck cancer: Taspase1's proteolytic activity fine-tunes TFIIA function

Head and neck cancer (HNC) is the seventh most common malignancy in the world and its prevailing form, the head and neck squamous cell carcinoma (HNSCC), is characterized as aggressive and invasive cancer type. The transcription factor II A (TFIIA), initially described as general regulator of RNA polymerase II-dependent transcription, is part of complex transcriptional networks also controlling mammalian head morphogenesis. Posttranslational cleavage of the TFIIA precursor by the oncologically relevant protease Taspase1 is crucial in this process. In contrast, the relevance of Taspase1-mediated TFIIA cleavage during oncogenesis of HNSCC is not characterized yet. Here, we performed genome-wide expression profiling of HNSCC which revealed significant downregulation of the TFIIA downstream target CDKN2A. To identify potential regulatory mechanisms of TFIIA on cellular level, we characterized nuclear-cytoplasmic transport and Taspase1-mediated cleavage of TFIIA variants. Unexpectedly, we identified an evolutionary conserved nuclear export signal (NES) counteracting nuclear localization and thus, transcriptional activity of TFIIA. Notably, proteolytic processing of TFIIA by Taspase1 was found to mask the NES, thereby promoting nuclear localization and transcriptional activation of TFIIA target genes, such as CDKN2A. Collectively, we here describe a hitherto unknown mechanism how cellular localization and Taspase1 cleavage fine-tunes transcriptional activity of TFIIA in HNSCC.

SKLB188 inhibits the growth of head and neck squamous cell carcinoma by suppressing EGFR signalling

BACKGROUND

Overexpression of epidermal growth factor receptor (EGFR) occurs in approximately 90% of head and neck squamous cell carcinoma (HNSCC), and is correlated with poor prognosis. Thus, targeting EGFR is a promising strategy for treatment of HNSCC. Several small molecule EGFR inhibitors have been tested in clinical trials for treatment of HNSCC, but none of them are more effective than the current chemotherapeutic drugs. Thus, it is urgently needed to develop novel EGFR inhibitors for HNSCC treatment.

METHODS

By screening an in-house focused library containing approximately 650 000 known kinase inhibitors and kinase inhibitor-like compounds containing common kinase inhibitor core scaffolds, we identified SKLB188 as a lead compound for inhibition of EGFR. The anticancer effects of SKLB188 on HNSCC cells were investigated by in vitro cell growth, cell cycle and apoptosis assays, as well as in vivo FaDu xenograft mouse model. Molecular docking, in vitro kinase profiling and western blotting were performed to characterise EGFR as the molecular target.

RESULTS

SKLB188 inhibited HNSCC cell proliferation by inducing G1 cell cycle arrest, which was associated with downregulating the expression of Cdc25A, cyclins D1/A and cyclin-dependent kinases (CDK2/4), and upregulating the expression of cyclin-dependent kinase (CDK) inhibitors (p21Cip1 and p27Kip1), leading to decreased phosphorylation of Rb. SKLB188 also induced caspase-dependent apoptosis of HNSCC cells by downregulating the expression of Mcl-1 and survivin. Molecular docking revealed that SKLB188 could bind to the kinase domain of EGFR through hydrogen bonds and hydrophobic interactions. In vitro kinase assay showed that SKLB188 inhibited the activity of a recombinant human EGFR very potently (IC50=5 nM). Western blot analysis demonstrated that SKLB188 inhibited the phosphorylation of EGFR and its downstream targets, extracellular signal-regulated protein kinases 1 and 2 (Erk1/2) and Akt in the cells. In addition, SKLB188 dose-dependently inhibited FaDu xenograft growth in nude mice, and concurrently inhibited the phosphorylation of Erk1/2 and Akt in the tumours.

CONCLUSIONS

SKLB188 potently inhibits the growth of HNSCC cells in vitro and in vivo by targeting EGFR signalling. The results provide a basis for further clinical investigation of SKLB188 as a targeted therapy for HNSCC. Our findings may open a new avenue for development of novel EGFR inhibitors for treatment of HNSCC and other cancers.

MDM4 genetic variants predict HPV16-positive tumors of patients with squamous cell carcinoma of the oropharynx

The increasing incidence of squamous cell carcinoma of the oropharynx (SCCOP) is majorly attributed to the human papillomavirus (HPV) infection. Both HPV and MDM4 play a critical role in inhibition of p53 activity, thus affecting HPV tumor status of SCCOP. Three polymorphisms in MDM4 were genotyped from blood genomic DNA samples and HPV16 status in tumor specimens was examined. Odds ratio (OR) and 95% confidence intervals (CIs) in univariate and multivariable logistic regression models were calculated for the associations between these polymorphisms and HPV16 status. Three MDM4 variant genotypes were significantly associated with HPV16 tumor status among SCCOP patients compared with the common homozygous genotypes (OR, 0.6; 95% CI, 0.4–1.0 for rs10900598; OR, 1.6, 95% CI; 1.1–2.4 for rs1380576; and OR, 1.8, 95% CI, 1.1–2.9 for rs11801299; respectively). When we combined all risk genotypes of the 3 polymorphisms, the patients carrying 1-3 MDM4 risk genotypes were approximately 2.5 time as likely to have an HPV16-positive tumor than those with no risk genotypes (OR, 2.5, 95% CI, 1.6–3.9). Additionally, modifying effect of MDM4 risk genotypes was more pronounced among non-Hispanic white, never-smokers, and never-drinkers. Potential functional polymorphisms in MDM4 may serve as biomarkers for predicting tumor HPV16 status among SCCOP patients, particularly in non-Hispanic white, never-smokers and never-drinkers. However, validation of these results in larger studies is needed.

Prognostic Stratification of Patients With Advanced Oral Cavity Squamous Cell Carcinoma

PURPOSE OF REVIEW

Prognosis of advanced oral squamous cell carcinoma remains a challenge for clinicians despite progress in its diagnosis and treatment over the past decades. In this review, we assessed clinicopathological factors and potential biomarkers along with their prognostic relevance in an attempt to develop optimal treatment strategies for these patients.

RECENT FINDINGS

In addition to several pathologic factors that have been proposed to improve prognostic stratification and treatment planning in the eighth edition of the American Joint Committee staging manual on cancer, we reviewed some other imaging and clinicopathological parameters demonstrated to be closely associated with patient prognosis, along with the biomarkers related to novel target or immune therapy. Evaluation of current literature regarding the prognostic stratification used in contemporary clinicopathological studies and progress in the development of targeted or immune therapy may help these patients benefit from tailored and personalized treatment and obtain better oncological results.

Identification of a novel ATM inhibitor with cancer cell specific radiosensitization activity

Treatment of advanced head and neck squamous cell carcinoma (HNSCC) is plagued by low survival and high recurrence rates, despite multimodal therapies. Presently, cisplatin or cetuximab is used in combination with radiotherapy which has resulted in minor survival benefits but increased severe toxicities relative to RT alone. This underscores the urgent need for improved tumor-specific radiosensitizers for better control with lower toxicities. In a small molecule screen targeting kinases, performed on three HNSCC cell lines, we identified GSK635416A as a novel radiosensitizer. The extent of radiosensitization by GSK635416A outperformed the radiosensitization observed with cisplatin and cetuximab in our models, while exhibiting virtually no cytotoxicity in the absence of radiation and in normal fibroblast cells. Radiation induced phosphorylation of ATM was inhibited by GSK635416A. GSK63541A increased DNA double strand breaks after radiation and GSK63541A mediated radiosensitization was lacking in ATM-mutated cells thereby further supporting the ATM inhibiting properties of GSK63541A. As a novel ATM inhibitor with highly selective radiosensitizing activity, GSK635416A holds promise as a lead in the development of drugs active in potentiating radiotherapy for HNSCC and other cancer types.

Analysis of full coding sequence of the TP53 gene in invasive vulvar cancers: Implications for therapy

OBJECTIVE

This study evaluates the frequency and type of TP53 gene mutations and HPV status in 72 consecutively diagnosed primary invasive vulvar squamous cell carcinomas (SCC) during the past 5years.

METHODS

DNA of formalin-fixed and paraffin embedded tumour tissue was analysed for 32 HPV subtypes and the full coding sequence of the TP53 gene, and correlated with results of p53 immunohistochemistry.

RESULTS

13/72 (18%) cancers were HPV-induced squamous cell carcinomas, of which 1/13 (8%) carcinoma harboured a somatic TP53 mutation. Among the 59/72 (82%) HPV-negative cancers, 59/72 (82%) SCC were HPV-negative with wild-type gene in 14/59 (24%) SCC and somatic TP53 mutations in 45/59 (76%) SCC. 28/45 (62%) SCC carried one (n=20) or two (n=8) missense mutations. 11/45 (24%) carcinomas showed a single disruptive mutation (3× frame shift, 7× stop codon, 1× deletion), 3/45 SCC a splice site mutation. 3/45 (7%) carcinomas had 2 or 3 different mutations. 18 different "hot spot" mutations were observed in 22/45 cancers (49%; 5× R273, 3× R282; 2× each Y220, R278, R248). Immunohistochemical p53 over expression was identified in most SCC with missense mutations, but not in SCC with disruptive TP53 mutations or TP53 wild-type. 14/45 (31%) patients with TP53 mutated SCC died of disease within 12months (range 2-24months) versus 0/13 patients with HPV-induced carcinomas and 0/14 patients with HPV-negative, TP53 wild-type carcinomas.

CONCLUSION

80% of primary invasive vulvar SCC were HPV-negative carcinomas with a high frequency of disruptive mutations and "hot spot" TP53 gene mutations, which have been linked to chemo- and radioresistance. The death rate of patients with p53 mutated vulvar cancers was 31%. Immunohistochemical p53 over expression could not reliably identify SCC with TP53 gene mutation. Pharmacological therapies targeting mutant p53 will be promising strategies for personalized therapy in patients with TP53 mutated vulvar cancers.

High-Risk HPV, Biomarkers, and Outcome in Matched Cohorts of Head and Neck Cancer Patients Positive and Negative for HIV

In this study, high-risk HPV (hrHPV) incidence, prognostic biomarkers, and outcome were assessed in HIV-positive (case) and HIV-negative (control) patients with head and neck squamous cell cancer (HNSCC). HIV-positive cases were matched to controls by tumor site, sex, and age at cancer diagnosis. A tissue microarray (TMA) was constructed and DNA isolated from tumor tissue. MultiPlex-PCR MassArray, L1-PCR, and in situ hybridization were used to assess hrHPV. TMA sections were stained for p16ink4a, TP53, RB, CCND1, EGFR, and scored for intensity and proportion of positive tumor cells. The HNSCC cohort included 41 HIV-positive cases and 41 HIV-negative controls. Tumors from 11 of 40 (28%) cases, and 10 of 41 (24%) controls contained hrHPV. p16 expression, indicative of E7 oncogene activity, was present in 10 of 11 HPV-positive cases and 7 of 10 HPV-positive controls. Low p16 and high TP53 expression in some HPV-positive tumors suggested HPV-independent tumorigenesis. Survival did not differ in cases and controls. RB expression was significantly associated with poor survival (P = 0.01). High TP53 expression exhibited a trend for poorer survival (P = 0.12), but among cases, association with poor survival reached statistical significance (P = 0.04). The proportion of HPV-positive tumors was similar, but the heterogeneity of HPV types was higher in the HIV-positive cases than in HIV-negative controls. High RB expression predicted poor survival, and high TP53 expression was associated with poorer survival in the HIV-positive cases but not HIV-negative controls.

IMPLICATIONS

HIV infection did not increase risk of death from HNSCC, and HPV-positive tumors continued to be associated with a significantly improved survival, independent of HIV status. Mol Cancer Res; 15(2); 179-88. ©2016 AACR.