[Study of genetic variants in 169 non-small cell lung cancer patients]

Lung cancer is the leading cause of cancer death in our country. Non-small cell lung cancer (NSCLC) represents the paradigm of personalized medicine. The main objective of this study is analysing the distribution of the most frequently described clinically significant variants in NSCLC, in our environment.

We studied the immunohistochemical expression of TTF1, p40 and PD-L1 and the genetic variants frequency using Next-Generation Sequencing (NGS) with a panel of 52 genes, in 174 NSCLC paraffin-embedded samples in 169 patients (111 men and 52 women) from the province of Cádiz.

The immunohistochemical expression of TTF1, p40 and PD-L1 was positive in 87%, 0% and 46% in adenocarcinoma, and 0%, 100% and 41% in squamous cell carcinoma. In NGS, the most common single nucleotide variants (SNVs) were KRAS (36%), EGFR (14%), BRAF (10%), PIK3CA (8%), and MET (3%). The most frequent copy number variants (CNVs) were amplifications in NF1 (30%), EGFR (18%), CCND1 (9%), MYC (9%) and KRAS (7%). In women, SNV in EGFR are more frequent than in men (P<.0001). Adenocarcinoma is the most frequent histological type with SNV in KRAS (P=.007361) or in EGFR (P<.0001). Gene fusions were detected in 16 patients (9.47%), in 9 cases in the MET gene.

We detected associations, not described so far, between immunohistochemical expression and specific gene variants, which could have an impact on the treatment of NSCLC patients.