Meta-analysis of the impact of human papillomavirus (HPV) on cancer risk and overall survival in head and neck squamous cell carcinomas (HNSCC)

An update on molecular diagnostics of squamous and salivary gland tumors of the head and neck

CONTEXT

Molecular testing in anatomic pathology is becoming standardized and can contribute valuable diagnostic, therapeutic, and prognostic information for the clinical management of patients. In head and neck pathology, recent advances in molecular testing have provided important targets in several different diagnostic areas, with particular emerging clinical applications in squamous and salivary gland pathology. In squamous mucosal-derived lesions, human papilloma virus has emerged as an important pathogenic etiology in a subset of oropharyngeal squamous cell carcinomas. Within the category of salivary gland tumors, 3 tumors have recently been recognized that contain oncogenic translocations.

OBJECTIVE

To describe the current state of information about the molecular alterations in squamous lesions and in salivary gland tumors of the head and neck.

DATA SOURCES

Published literature on squamous and salivary gland tumors of the head and neck.

CONCLUSIONS

The different approaches to identification of viral-associated tumors include assays using polymerase chain reaction, in situ hybridization, and immunohistochemistry. Most mucoepidermoid carcinomas harbor MECT1-MAML2 gene rearrangement. The MYB-NFIB translocations have recently been identified in adenoid cystic carcinomas. Finally, a newly described tumor of salivary gland, mammary analogue secretory carcinoma, harbors the ETV6-NTRK3 translocation. Although these translocations are just emerging as diagnostic targets, future roles may evolve as potential therapeutic targets.

Human papillomavirus and gene mutations in head and neck squamous carcinomas

BACKGROUND

Human papillomavirus (HPV) infection is implicated as an aetiological factor in head and neck squamous carcinomas (HNSCC), especially in the tonsils of the oropharyngeal region. This study investigates the frequency of HPV infection, p16 and p53 tumour profile and mutations in epidermal growth factor receptor (EGFR), Kirsten RNA Associated Rat Sarcoma 2 Virus (KRAS) and B-Raf proto-oncogene serine/threonine protein kinase (BRAF) genes in tonsillar and non-tonsillar HNSCCs and correlates with clinical outcome and histopathological parameters in previously unstudied cohort of patients.

METHODS

A retrospective clinical study was performed utilising the demographic data and pathological specimens from 60 out of 726 head and neck cancer patients. Smoking and alcohol history, tumour staging, treatment and outcomes were recorded. Histopathology and immunochemistry for p16 and p53 was performed and HPV DNA was detected with polymerase chain reaction. Genomic DNA from all cancers were analysed for somatic mutations of EGFR, BRAF and KRAS genes.

RESULTS

20 (33%) of 60 cases were tonsillar squamous carcinomas and 38 (66%) were non-tonsillar. 19 (95%) of the 20 tonsillar cancers and three (8%) of 38 non-tonsillar patients were patients who were HPV 16-positive. Nine (47%) of the 19 HPV 16-positive tonsillar cases were p16 positive. Gene mutations were rare. There was a statistically significant (P < 0.05) improved survival of patients with HPV positive tonsillar tumours, younger age and non-smokers.

CONCLUSION

Although limited in numbers, this study reinforces the role of HPV infection in HNSCC and its association with a more favourable clinical course in younger non-smokers worldwide. Gene mutation frequencies were low in all cancers tested and routine testing not recommended.

Specific TP53 mutations predict aggressive phenotype in head and neck squamous cell carcinoma: a retrospective archival study

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy in the world in developed countries. Despite the intense research in the area of squamous cell carcinomas of head and neck (HNSCC), long-term survival rate has not changed significantly in this malignancy during recent decades.

METHODS

In this study, we focused on TP53 mutations in specific regions, including DNA-binding surface, to determine whether mutations at specific locations of TP53 could be used to help in setting up prognosis and response to therapy of head and neck squamous cell carcinoma patients. We analysed TP53 mutations in 46 HNSCC by PCR-SSCP and sequencing and characterized how different TP53 mutations affect the patient outcome.

RESULTS

Tumours containing TP53 mutations in DNA-binding regions (L2, L3 and LSH motif) had a significantly poorer prognosis and response to radiotherapy than tumours outside those regions. Disease-specific 5-year survival of patients with TP53 mutations affecting DNA contacts was 43.5% while it was 77.8% (p < 0.05) in patients with TP53 mutations in other residues not involved in DNA contact. Moreover, nodal metastasis were more prevalent (although not statistically significantly) with TP53 mutations in DNA-binding surface regions. We noticed that the patients with TP53 mutations in L3/LSH motifs had a significantly poorer response (11.4% responding) to radiation than the patients with a wild type p53 (48.6%) or TP53 mutations outside the DNA-binding regions (40%) (p < 0.05).

CONCLUSIONS

These data indicate that a TP53 mutation in L2, L3 or LSH is worth pursuing as a marker for predicting prognosis and response to radiation among HNSCC patients.

p16(INK4a)/CDKN2 expression and its relationship with oral squamous cell carcinoma is our current knowledge enough?

Oral squamous cell carcinomas (OSCC) are the most common malignancy of the oral cavity and their multistep development requires the accumulation of multiple genetic and epigenetic alterations. Inactivation of p16(INK4a), encoded by the CDKN2 gene has been widely associated with this type of tumors. The purpose of this review is to elucidate the relationship between p16(INK4a) expression and the different clinical and pathological aspects of OSCC, analyze the variation in results between studies, detailing the described genetic/epigenetic alterations that result in gene silencing and the relationship between p16(INK4a) and HPV infection.