PIK3CA Mutations Detected in Patients with Central Nervous System Metastases of Non-small Cell Lung Cancer

Abstract

Background: In non-small cell lung cancer (NSCLC) the phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (PIK3CA) gene mutations have been reported in fewer than 5% of primary tumors.

Materials and methods: We assessed PIK3CA gene mutations in 145 tissue samples from central nervous system (CNS) metastases of NSCLC using three polymerase chain reaction (PCR) techniques: high resolution melting-PCR (HRM-PCR), allele-specific-quantitative PCR (ASP-qPCR) and TaqMan PCR.

Results: HRM analysis allowed us to select three PIK3CA-positive specimens (2.1% of the studied group) and ASP-qPCR techniques identified them as one E542K and two H1047R substitutions, which were confirmed by TaqMan probes. The PIK3CA mutations were indicated only in males (3% of all males). One of the patients was reported to be a non-smoker with adenocarcinoma (AC; 2.5% of the AC group), however, the other two patients were smokers with squamous cell carcinoma (SCC; 3.4% of SCC group).

Conclusion: This is the first report of the presence of PIK3CA gene mutation in CNS-metastatic lesions of NSCLC worldwide that could broaden therapeutic choices in such patients.

Keywords: ASP-qPCR; HRM-PCR; NSCLC; PIK3CA mutations; central nervous system metastases; real-time PCR.