Patho-genomic feature of PI3K / AKT / mTOR pathway mutations in Chinese patients with non-small cell lung cancer.

Abstract

e21049 Background: Inhibition of PI3K/AKT/mTOR pathway has emerged as a promising anticancer strategy. Measuring genetic alterations in PI3K/AKT/mTOR pathway are critical for clinical decision making for patients with lung cancer. This study aims to analyze PI3K/AKT/mTOR pathway-related gene mutations in non-small cell lung cancer (NSCLC) in a consecutive cohort. Methods: 536 surgically resected tumor tissues were collected. Target region capture sequencing for 508 cancer-related genes was conducted on MGI-seq 2000 platform. Results: PI3K/AKT/mTOR pathway genes were mutated in 120 samples (22.4%). Female or older patients displayed higher mutation incidence of PI3K/AKT/mTOR pathway (P = 0.06 for female, P = 0.05 for patients ≥60 y). In NSCLC samples, mutations mainly occurred in NF1/2(18/499), PTEN (7/499), MTOR (4/499), TSC1/2(18/499), PIK3CA (26/499), PDK1 (2/499), AKT1/2/3 (5/499) and KRAS (49/499) genes. Genetic alterations of AKT2 (p = 0.003), mTOR (P = 0.03), PTEN (P = 0.005) and PIK3CA (P < 0.001) are preferred to occur in squamous NSCLC. PIK3CA variants (p.E542K, p.E545K, p.Q546K) were more enriched in non-squamous NSCLC, while amplification of PIK3CA was more prevalent in squamous NSCLC (P = 0.038). Histologically, TSC1/2 mutations were more correlate with micro-invasion subtype in non-squamous NSCLC (P = 0.002). Meanwhile, PIK3CA alterations, especially, amplification occurred more often in keratinizing squamous NSCLC (P < 0.001). In addition, four patients with biallelic NF1 loss of function mutations were exclusively found in non-squamous NSCLC without co-occurrence of mutation in known driver genes like EGFR or TP53, which indicated biallelic loss of function of NF1 might be sufficient to drive oncogenesis of non-squamous NSCLC. Conclusions: PI3K/AKT/mTOR pathway alterations present a heterogenous distribution across various types of lung malignancies especially in NSCLC. As more small molecule inhibitors developed to target PI3K/AKT/mTOR pathway, this study might shed light on further clinical investigation of these lately developed therapeutic approaches. [Table: see text]