Human papillomavirus genotype distribution in head and neck cancer: Informing developing strategies for cancer prevention, diagnosis, treatment and surveillance.

Current clinical practice algorithms for HPV testing make no effort to discern the impact of genotypes for patients with head and neck squamous cell carcinoma (HNSC). Data was collected for all patients with HNSCs that had undergone HPV testing at an academic hospital as part of clinical care (2012-2019). Screening was performed using real-time PCR targeting L1 of low and high-risk HPV types, followed by genotyping of positive cases. Genotype status was correlated with age, site and histologic parameters. Of the 964 patients tested, 68% had HPV-positive cancers. Most arose from the oropharynx (OP) (89%) and sinonasal tract (5%). The most frequent genotype was 16 (84.4%) followed by 35 (5.6%), 33 (4.1%), 18 (2.7%), 45 (1.1%), 69 (0.8%) and others (1.3%). There was an association between genotype (16 vs non-16) and tumor origin (OP vs non-OP) (p < 0.0001). HPV18 was associated with transformation to an aggressive small cell phenotype, but HPV16 was not (22% vs 0%, p < 0.0001). Patients with HPV-non-16 OP carcinomas were older than patients with HPV16 OP carcinomas, but the difference was not significant. HPV genotypes are variable and unevenly distributed across anatomic sites of the head and neck. The association of HPV18 with small cell transformation suggests that variants can track with certain phenotypes in ways that may account for differences in clinical behavior. This study challenges the prevailing assumption of HPV equivalency across all high-risk genotypes in ways that may inform preventive, diagnostic, therapeutic and surveillance strategies.

Real-time PCR HPV genotyping in fine needle aspirations of metastatic head and neck squamous cell carcinoma: Exposing the limitations of conventional p16 immunostaining.

BACKGROUND: Given the propensity for HPV-positive head and neck squamous cell carcinoma (HPV-HNSCC) to metastasize to cervical lymph nodes, fine needle aspiration (FNA) plays an important diagnostic role in their initial detection. Indeed, there is now an unwavering commitment to HPV testing of FNAs even in the absence of clear methodologic guidelines and threshold criteria. A particular difficulty pertains to the interpretation of p16 staining. DESIGN: Data was collected for 210 patients with suspected regionally metastatic HNSCC that had undergone FNA as part of standard clinical care. Initial HPV screening was performed on cell blocks with real-time PCR using primers targeting L1 of high-risk HPV types. Additional genotyping was performed on HPV-positive cases. The results were compared to p16 staining and subsequent excisions when available. RESULTS: Of the 207 samples with sufficient DNA, 175 (85%) were HPV positive. HPV-16 was the most commonly detected genotype (90%). Of the HPV-positive cases, the primary site was the oropharynx (n = 154, 88.0%), supraglottic larynx (n = 2, 1.1%), nasal cavity (n = 1, 0.6%), hypopharynx (n = 1, 0.6%) or unknown (n = 17, 9.7%). On comparison with 31 paired surgical excisions, HPV status was concordant in all cases (100% correlation). Of 142 HPV-positive cases with matching p16 stains, p16 staining was reported as positive (n = 85, 60%), focal (n = 27, 19%), negative (n = 24, 17%) or non-contributory (n = 6, 4%); and only 33% reached the standard threshold limit (i.e. 70%) for HPV positivity. CONCLUSION: For patients with metastatic HNSCC, real-time PCR of FNAs reliably reflects HPV status, and is superior to conventional p16 immunostaining.