Frequency and clinical characterization of NSCLC patients harboring PIK3CA mutations identified within a regional screening network.

10526 Background: PIK3CA mutations are a rare oncogenic event of potential therapeutic relevance in NSCLC. Here we report frequency and characteristics of patients with PIK3CA mutated lung tumors. Methods: Patients with NSCLC and PIK3CA mutations were identified within our regional Network for Molecular Screening in Lung Cancer. We further analyzed the presence of BRAF, KRAS, EGFR mutations as well as ALK translocation, ERBB2 and FGFR1 amplifications in PIK3CA mutated samples. Clinical data on age, sex, TNM classification and tumor stage, histological type, grading, overall survival, smoking status, comorbidity, BMI and secondary malignancies were retrieved from clinical charts in accordance with the local ethics committee. Results: PIK3CA mutations were detected with a frequency of 3.7% (24% exon 20,76% exon 9) in 1000 patients. Histologically 32% were defined as squamous cell carcinoma, 48% as adenocarcinoma and 18% other histological subtypes or NSCLC-NOS. Exon 9 mutations were present in the acinar an...