Probes for P16

Oropharyngeal squamous cell carcinoma is frequently associated with high-risk HPV infection, which confers a good prognosis. Immunohistochemistry for p16 is used as a surrogate for HPV status, but discrepant results are occasionally seen. Here, we report a case with a unique pattern of partial loss of p16.A 63 year old male presented with a base of tongue nonkeratinizing squamous cell carcinoma and a large metastatic neck mass. The primary lesion and multiple regions of the metastatic mass were assessed with p16 immunohistochemistry, RNA in situ hybridization for high-risk HPV, and HPV16 genome sequencing.The primary lesion was p16 negative, and the metastatic neck mass had large, confluent regions that were either strongly p16 positive or entirely p16 negative. All of these regions were positive for high-risk HPV with identical HPV16 genomes.This unusual case illustrates a potential diagnostic pitfall, and it raises important questions regarding molecular mechanisms and prognostic implications of p16 staining in oropharyngeal squamous cell carcinoma.

Human papillomavirus (HPV) is responsible for a growing proportion of oropharyngeal squamous cell carcinomas (OPSCCs) among men and White individuals. Whether similar trends apply to women, non-Whites, and non-oropharyngeal squamous cell carcinomas (non-OPSCCs) is unknown.This is a cross-sectional analysis combining 2 multi-institutional case series of incident head and neck squamous cell carcinoma (HNSCC) cases. Incident HNSCCs from 1995 to 2012 were enrolled retrospectively using banked tumor samples and medical record abstraction. Incident HNSCCs from 2013 to 2019 were enrolled prospectively. The prevalence of tumor HPV biomarkers was tested over 3 time periods (1995-2003, 2004-2012, and 2013-2019). Centralized testing was done for p16 immunohistochemistry (p16) and oncogenic HPV in situ hybridization (ISH).A total of 1209 incident cases of HNSCC were included. Prevalence of p16- and ISH-positive tumors increased significantly for oropharynx cancers over time. The majority were positive after 2013 for White patients (p16, 92%; P < .001; ISH 94%; P < .001), Black patients (p16, 72%; P = .021; ISH 67%; P = .011), and Hispanic patients (p16, 100%; P = .04; ISH 100%; P = .013). For women with OPSCC, the prevalence of p16- and ISH-positive tumors increased significantly to 82% (P < .001) and 78% (P = .004), respectively. For non-OPSCCs, there was increased p16 and ISH positivity overall with 24% p16 and 16% ISH positivity in the most recent time period (P < .001 for both).The majority of OPSCCs in US tertiary care centers are now p16 and ISH positive for all sex and race groups. In some populations in the United States, 91% of OPSCCs are now caused by HPV. Few non-OPSCCs are p16 and ISH positive.

The pathogenesis of squamous cell neoplasms arising in the lacrimal drainage system is poorly understood, and the underlying genomic drivers for disease development remain unexplored. We aimed to investigate the genomic aberrations in carcinomas arising in the LDS and correlate the findings to human papillomavirus (HPV) status. The HPV analysis was performed using HPV DNA PCR, HPV E6/E7 mRNA in-situ hybridization, and p16 immunohistochemistry. The genomic characterization was performed by targeted DNA sequencing of 523 cancer-relevant genes. Patients with LDS papilloma (n = 17) and LDS carcinoma (n = 15) were included. There was a male predominance (68%) and a median age at diagnosis of 46.0 years (range 27.5-65.5 years) in patients with papilloma and 63.8 years (range 34.0-87.2 years) in patients with carcinoma. Transcriptional activity of the HPV E6/E7 oncogenes was detected in the whole tumor thickness in 12/15 (80%) papillomas (HPV6, 11, 16) and 10/15 (67%) squamous cell carcinomas (SCC) (HPV11: 3/15 (20%) and HPV16: 7/15 (47%)). Pathogenic variants in PIK3CA, FGFR3, AKT1, and PIK3R1, wildtype TP53, p16 overexpression, and deregulated high-risk E6/E7 transcription characterized the HPV16-positive SCC. The deregulated pattern of HPV E6/E7 expression, correlating with HPV DNA presence and p16 positivity, supports a causal role of HPV in a subset of LDS papillomas and carcinomas. The viral and molecular profile of LDS SCC resembles that of other HPV-driven SCC.

The transcriptional activity of high-risk human papillomaviruses (HR-HPV) within oropharyngeal squamous cell carcinomas (OPSCC) has been linked to improved survival of patients. HR-HPV mRNA silver in situ hybridization (SISH) was evaluated on a cohort of OPSCC and compared with viral HPV DNA tests and p16 expression. Clinical outcomes of HPV-driven OPSCC and non-HPV related OPSCC were also studied.We evaluated 67 OPSCC and 3 papillomas, obtained from 62 patients, for detection of HR-HPV DNA by PCR tests. The positive samples were additionally studied by the SISH method using three probes of HPV16, HPV18, and HP33, and for p16 expression detected by immunohistochemistry. SISH assays were evaluated for the presence/number and intensity of signals in cancer cells. Prognostic significance of HPV status in our cohort was evaluated with univariate and multivariate statistics.According to the HR-HPV PCR tests, 46 (69%) OPSCC cases were HPV positive, while three papillomas were negative. Of total 46 HPV-positive OPSCCs, 43 cases were also SISH-positive, while p16 overexpression was found in 45 of 46 HPV positive OPSCC cases. In OPSCC specimens, the sensitivity and specificity of the combined SISH probes (HPV16 and 33) were both 100.00%, when compared to HPV PCR. HPV positivity of the tumors appeared significant for predicting progression-free survival, cause specific survival and overall survival in a multivariate setting.The recently developed mRNA SISH methodology can detect HPV-driven OPSCCs without any additional test in 79% of cases. Positive SISH signals enable the visualization of viral transcripts required to recognize clinically relevant HPV infection. However, rare and tiny signals require an experienced pathologist to establish a consensus interpretation of results. The currently applied HR-HPV mRNA SISH analysis may serve as a groundwork for additional studies.

Rising prevalence rates of high-risk human papillomaviruses (hrHPV) infection in oropharyngeal carcinoma (up to 80 %) have been reported in North America and Scandinavia. We have analysed 424 German and 163 Brazilian head and neck squamous cell carcinomas (HNSCC) from the oral cavity (OSCC), oropharynx (OPSCC) and hypopharynx (HPSCC) using p16 immunohistochemistry, HPV DNA PCR and sequencing, hrHPV DNA in situ hybridisation (ISH) and hrHPV E6/E7 RNA ISH. In the German series, 52/424 cases (12.3 %) were p16-positive/hrHPV-positive (OSCC 3.8 % [10/265], OPSCC 34.4 % [42/122], HPSCC 0 % [0/37]). In addition, there were 9 cases that were p16-positive/hrHPV-negative (5 OPSCC and 4 OSCC). In the Brazilian series, the overall hrHPV DNA prevalence by PCR was 11.0 % ([18/163]; OSCC 6 % [5/83], OPSCC 15.5 % [11/71], HPSCC 22.2 % [2/9]). Ten of these cases were hrHPV-positive/p16-positive. The remaining 8 hrHPV-positive/p16-negative cases were also negative in both ISH assays. Furthermore, 5 p16-positive/hrHPV-negative cases (2 OPSCC and 3 OSCC) were identified. In both series, HPV16 was by far the most common HPV type detected. We confirm that regardless of geographical origin, the highest hrHPV prevalence in HNSCC is observed in oropharyngeal carcinomas. The proportion of HPV-associated OPSCC was substantially higher in the German cohort than in the Brazilian series (34.4 vs. 15.5 %), and in both groups, the prevalence of hrHPV in OPSCC was much lower than in recent reports from North America and Scandinavia. We suggest, therefore, that it may be possible to define areas with high (e.g. USA, Canada, Scandinavia), intermediate (e.g. Germany) and low (e.g. Brazil) prevalences of HPV infection in OPSCC.