Molecular Diagnostics in Head and Neck Squamous Cell Carcinoma

Molecular diagnostics in Head and Neck Squamous cell carcinoma (HNSCC) is implemented in clinical practice to define the HPV-associated lesions specifically in the Oropharyngeal Squamous cell carcinoma (OPSCC), which has been separated from the conventional tobacco-related Non-HPV subtype and is known to have a better prognosis, different morphology as well as expression of p16 as a surrogate marker for HPV infection. HPV related lesions occur at other sites in the head and neck and relatively infrequent and not characterized as a distinguished entity. Tobacco-related cancers show p53 and cyclin D1 mutations and also show field carcinogenesis in a multistep progression of malignancy which may be useful in staging the lesion as well as in detecting molecular margins or molecular metastasis. Specific variants of HNSCC require mutation testing, for example, NUT carcinoma to get to a diagnosis. The chapter also addresses issues of HPV testing, epigenetic changes and chromosomal alterations in HNSCC as well the role of liquid biopsy in patients with HNSCC.