Mutational status of PIK3ca oncogene in oral cancer—In the new age of PI3K inhibitors

Abstract

In the new age of PI3K inhibitors, the mutational status of PI3Kca oncogene in the Cavity Squamous Cell Carcinoma (OC-SCC) needs further analysis. It is the sixth most common cancer in the world. The aim of this study was to evaluate PI3Kca oncogene mutations and to correlate them with the clinical-histological characteristics of individuals presenting these tumors. We recruited 74 individuals with OC-SCC diagnosis (period 2000–2014). Histological sections were used. DNA was purified; PIK3ca gene exons 9 and 20 were amplified and sequenced. In 49/74 cases (66 %), the complete sequence of both codons was analyzed by Sanger method. We found that 7/49 (14 %) individuals mutated. In exon 9 we found 1/49 (2 %), and in exon 20 M1043I 8/49 (16 %). We have found the coexistence of more than one mutation in a same individual (E542 K and M1043I). A positive association was observed between the mutational status of the codon 9 (E542 K) and the tongue location. In conclusion, the frequency of PI3Kca gene mutation in OC-SCC was 16 %, which is similar to that reported for other populations. We found a mutation not previously described (M1043I) in this pathology. Should its biological effect be confirmed, it must be added to the list of PIK3ca mutations. Total mutations in the PIK3ca were 32 %, with tongue being the site at the greatest risk (E542K-E545K-M1043I). These findings would facilitate the identification of patients with therapeutic targets in the near future.