Probes for P16

HDAC inhibitors show therapeutic promise for skin malignancies; however, the roles of specific HDACs in adult epidermal homeostasis and disease are poorly understood. We find that homozygous epidermal co-deletion of Hdac1 and Hdac2 in adult mouse epidermis causes reduced basal cell proliferation, apoptosis, inappropriate differentiation, and eventual loss of Hdac1/2-null keratinocytes. Hdac1/2 deficient epidermis displays elevated acetylated p53 and increased expression of the senescence gene p16. Loss of p53 partially restores basal proliferation, whereas p16 deletion promotes long-term survival of Hdac1/2-null keratinocytes. In activated GLI2-driven pre-basal cell carcinoma, Hdac1/2 deletion dramatically reduces proliferation and increases apoptosis, and knockout of either p53 or p16 partially rescues both proliferation and basal cell viability. Topical application of the HDAC inhibitor Romidepsin to normal epidermis or GLI2ΔN-driven lesions produces similar defects to genetic Hdac1/2 deletion, and these are partially rescued by loss of p16. These data reveal essential roles for HDAC1/2 in maintaining proliferation and survival of adult epidermal and basal cell carcinoma progenitors and suggest efficacy of therapeutic HDAC1/2 inhibition will depend in part on the mutational status of p53 and p16.

Detecting human papillomavirus (HPV) infection in head and neck squamous cell carcinoma (HNSCC) is clinically relevant, but there is no agreement about the most appropriate methodology. We have studied 64 oropharyngeal carcinomas using p16 immunohistochemistry, HPV DNA in situ hybridisation (ISH) and HPV DNA polymerase chain reaction (PCR) followed by pyrosequencing. We have also evaluated a new assay, RNAscope, designed to detect HPV E6/E7 RNA transcripts. Using a threshold of 70 % labelled tumour cells, 21 cases (32.8 %) were p16 positive. Of these, 19 cases scored positive with at least one HPV detection assay. Sixteen cases were positive by HPV DNA-ISH, and 18 cases were positive using the E6/E7 RNAscope assay. By PCR and pyrosequencing, HPV16 was detected in 15 cases, while one case each harboured HPV33, 35 and 56. All p16-negative cases were negative using these assays. We conclude that p16 expression is a useful surrogate marker for HPV infection in HNSCC with a high negative predictive value and that p16-positive cases should be further evaluated for HPV infection, preferably by PCR followed by type determination. Using RNase digestion experiments, we show that the RNAscope assay is not suitable for the reliable discrimination between E6/E7 RNA transcripts and viral DNA.

Oropharyngeal squamous cell carcinoma (SCC) is strongly associated with human papillomavirus (HPV) infection, which is distinctively different from most other head and neck cancers. However, a robust quantitative reverse transcription PCR (RT-qPCR) method for comprehensive expression profiling of HPV genes in routinely fixed tissues has not been reported. To address this issue, we have established a new real-time RT-PCR method for the expression profiling of the E6 and E7 oncogenes from 13 high-risk HPV types. This method was validated in cervical cancer and by comparison with another HPV RNA detection method (in situ hybridization) in oropharyngeal tumors. In addition, the expression profiles of selected HPV-related human genes were also analyzed. HPV E6 and E7 expression profiles were then analyzed in 150 archived oropharyngeal SCC samples and compared with other variables and with patient outcomes. Our study showed that RT-qPCR and RNA in situ hybridization were 100% concordant in determining HPV status. HPV transcriptional activity was found in most oropharyngeal SCC (81.3%), a prevalence that is higher than in previous studies. Besides HPV16, three other HPV types were also detected, including 33, 35 and 18. Furthermore, HPV and p16 had essentially identical expression signatures, and both HPV and p16 were prognostic biomarkers for the prediction of disease outcome. Thus, p16 mRNA or protein expression signature is a sensitive and specific surrogate marker for HPV transcriptional activity (all genotypes combined).

Abstract BACKGROUND: The majority of human papillomavirus (HPV)-associated oropharyngeal carcinomas are squamous cell carcinomas; however, there are rare reports of HPV-associated neuroendocrine carcinomas (HPV-NECs) in the upper aerodigestive tract. The aim of this study was to characterize the diagnostic features of fine-needle aspiration (FNA) cases of head and neck HPV-NEC. METHODS: Cytology cases of HPV-NEC were identified over a 3-year period from 2 institutions. Clinical, cytomorphologic, and ancillary test results were evaluated. RESULTS: Five FNA cases of HPV-NEC were identified from 4 patients with cervical lymph node metastases with primaries in the oropharynx (n = 2), nasopharynx (n = 1), and larynx (n = 1). Three cases showed mixed small cell and large cell neuroendocrine morphologies; 1 case was a small cell carcinoma, and the last case appeared as a large cell neuroendocrine carcinoma. All tumors were strongly positive for synaptophysin and p16 and negative for p63/p40. Two cases tested for INSM1 showed diffuse nuclear staining. HPV was confirmed by in situ hybridization in 4 cases, and HPV-18 was detected by polymerase chain reaction in the fifth case. Retinoblastoma (Rb) staining was moderate to weak (5/5), and p53 was weakly positive (5/5). CONCLUSIONS: Head and neck HPV-NEC is a rare, aggressive entity that can show mixed small and large cell features and p16 upregulation; p53 and Rb are variable with limited diagnostic utility. Because p16 positivity can be nonspecific, confirmatory HPV testing is required and may be helpful in determining the primary site for neuroendocrine carcinoma of an unknown primary. The accurate diagnosis of HPV-NEC is also important because of its worse prognosis in comparison with HPV-associated squamous cell carcinoma.

Objective: To assess the clinical features and treatment outcomes in patients with primary ovarian squamous cell carcinoma (POSCC). Methods: Fifteen patients with primary ovarian squamous cell carcinoma diagnosed from January 2009 to December 2018 in Cancer Hospital of the University of Chinese Academy of Sciences were collected. The expression of p16, hMLH1, hMSH2, hMSH6 and PMS2 in POSCC was detected by immunohistochemistry, and the status of high-risk human papillomavirus (HPV) by RNAscope test. Results: Squamous cell carcinoma with different degrees of differentiation was found in 15 cases, including three cases with high differentiation and 12 cases with medium to low differentiation. There were four cases with in situ squamous cell carcinoma, four cases with teratoma, one case with endometrial carcinoma/atypical hyperplasia, and one case with endometriosis. p16 was expressed in five cases (5/15), indicating coexisting high-risk HPV infection. There was no high-risk HPV infection in the remaining 10 cases, and p16 staining was negative. There was no deficient mismatch repair protein in all cases. The overall survival time (P=0.038) and progression free survival (P=0.045) of patients with high-risk HPV infection were longer than those without HPV infection. Conclusions: POSCC is more commonly noted in postmenopausal women and often occurs unilaterally. Elevated serological indexes CA125 and SCC are the most common finding. Morphologically, the tumors show variable degrees of differentiation, but the current data suggest that the degree of differentiation cannot be used as an independent prognostic index. High-risk HPV infection may be associated with the occurrence of POSCC, and that the prognosis of POSCC patients with HPV infection is better than that of patients without infection.