Identification of Uncommon PIK3CA Mutations in Lung Cancer by Using Pyrosequencing

Introduction: Phospatidylinositol-3-kinases (PI3K) play an important role in various cell processes. Oncogenic mutations in the PIK3CA gene, which codes for the catalytic subunit, have been identified in various malignancies and activate the PI3K/AKT/mTOR pathway, which is a critical driver of tumorigenesis. Methods: We tested 41 tumor samples with known KRAS, BRAF, and EGFR mutation status for the occurrence of mutations in the PIK3CA gene, using a pyrosequencing assay. Results: Pyrosequencing revealed 2 mutations (4.9%) in the PIK3CA gene, one in exon 9 and the other in exon 20. Both mutations have not been identified yet in lung tumor tissue. Discussion: The screening of our small patient cohort by pyrosequencing identified 2 mutations (4.9%) in PIK3CA, one in exon 9 (Q546H) and the other in exon 20 (M1043T). Both mutations have not been described in lung tumors yet and seem to be rather uncommon mutations. Future screening of large patient cohorts with pyrosequencing may contribute to the detection of more mutations in lung cancer because of the low limit of detections of this method and may contribute to a better understanding of the interaction of mutations and tumorigenesis.