Absence of hotspot mutations in exons 9 and 20 of the PIK3CA gene in human oral squamous cell carcinoma in the Greek population

Objective. Phosphatidylinositol-3 kinases (PI3K) are a group of heterodimeric lipid kinases that regulate many cellular processes. Recent studies have reported high frequencies of somatic hotspot mutations in the phosphatidylinositol-3 kinase catalytic alpha (PIK3CA) gene, which encodes for one of these kinases, in several human solid tumors, including oral squamous cell carcinoma (OSCC). The aim of this study was to determine the frequency of hotspot mutations in exons 9 and 20 of the PIK3CA gene in OSCC in the Greek population. Study design. Eighty-six formalin-fixed and paraffin-embedded primary tumor specimens were analyzed by direct genomic DNA sequencing. Chi-square was used for statistical analysis. Results. No hotspot mutations were detected in any of the samples. Two intronic polymorphisms IVS8 and IVS9 were detected, mainly in patients with cancer of the buccal mucosa and lower gingival and alveolus respectively. Conclusions. PIK3CA hotspot mutations are unlikely to play a major role in the pathogenesis of OSCC in the Greek population. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 109: e53-e58)