Characterization of genomic alterations and the significance of PI3K/mTOR pathway mutations and tumor mutational burden in non‑small cell lung cancer.

Lung cancer is the most prevalent cancer worldwide and non‑small cell lung cancer (NSCLC) is the most common subtype and accounts for 75% of all lung cancer cases. Although programmed death‑1/programmed death‑ligand‑1 (PD‑1/PD‑L1) blockade has shown good results in the clinic, numerous NSCLC patients still fail to respond to this therapy. In the current study, formalin‑fixed, paraffin‑embedded tumor and matched blood samples from 1,984 Chinese NSCLS patients were collected for detection of genomic alterations including single nucleotide variations, short and long insertions/deletions, copy number variations and gene rearrangements. The most common mutated genes were tumor protein p53 (55.70%; 1,105/1,984), epidermal growth factor receptor (52.47%; 1,041/1,184), KRAS proto‑oncogene GTPase (13.36%, 265/1084), cyclin dependent kinase inhibitor 2A (12.30%; 244/1,984), LDL receptor related protein 1B (11.09%; 220/1,984) and telomerase reverse transcriptase (10.58%; 210/1,984). Tumor mutational burden was calculated and results revealed that it was associated with PI3K/mTOR pathway gene mutations, and patient's gender, age, smoking status, and tumor stage. In addition, mutations of phosphatidylinositol‑4,5‑bisphosphate 3‑kinase catalytic subunit α or F‑box and WD repeat domain containing 7 were detected in 3 patients with NSCLC who were resistant to PD‑1 inhibitors nivolumab and pembrolizumab. Disease stabilization and tumor shrinkage were observed in these patients after mTOR inhibitor everolimus treatment. The current data showed that NSCLC with PI3K/mTOR mutations are sensitive to mTOR inhibitors.