Molecular diagnostics of head and neck tumors. (section Head and Neck Pathology)

Abstract

Research has elucidated the detailed molecular mechanisms of carcinogenesis, tumour progression, and metastasis in different head and neck tumours in the recent decade. These advances have great impacts on pathology practices in areas including oral and head/neck squamous cell carcinoma, papillary thyroid carcinoma, head and neck paraganglioma and salivary gland tumours. (1) In oral and head/neck squamous cell carcinoma, human papilloma virus is an important independent prognostic variable and predictive factor for responsiveness to treatment. The presence of the virus is best reflected by immunohistochemical staining of p16. (2) In papillary thyroid carcinoma, presence of BRAF mutation is predictive of aggressive biological behaviour and could be useful for the diagnosis of papillary thyroid carcinoma. (3) For head/neck paragangliomas, the clinical impact in pathology is the role of pathologist in the detection of SDHB by immunohistochemistry in paraganglioma as SDHB mutations are correlated with presence of metastasis and poor prognosis. (4) In salivary gland tumours, chromosomal translocations as detected by FISH, are useful for diagnosis of tumours like hyalinising clear cell carcinoma and mammary analog secretory carcinoma. In conclusion, awareness of new advances in molecular pathology is essential for proper management of patients with head and neck tumours.