Due to the variation in PIK3CA mutation rates between 1/35 (2.9%) and 5/24 (20.8%) in US patient populations [95, 104] and the relatively small number of HNSCC tumor samples that have been sequenced worldwide, additional cohort studies are warranted to further consider potential associations between rates of genetic aberration and patient ethnicity or epidemiologic risk. The gene discussed is PIK3CA; the disease is head and neck squamous cell carcinoma.