EGFR gene mutation, ALK and PDL-1 expression in non-small cell lung cancer. Local and multicenter study

Abstract

During the last decades there have been changes in the epidemiology of non-small cell lung cancer (NSCLC), there was an increase in the histological
lineage adenocarcinoma. Substantial progress has been made in the characterization of molecular abnormalities in the EGFR gene, ALK gene fusion and
PDL-1 expression in NSCLC, which are being used as molecular targets and predictive biomarkers.
The purpose of this study was to determine the frequency of molecular alterations in the EGFR gene, ALK gene fusion and PD-L1 expression and to
evaluate the association with age, gender and tobacco habit in the local population.
We studied 171 biopsies and resection samples from patients (pts) with NSCLC during the period 2014 - 2019. Characteristics of histopathological type,
immunohistochemical (IHC) and molecular profile were analyzed, a subgroup of 39 pts was analyzed for PD-L1 expression. Molecular profiles were
correlated with different clinical variables (age, sex and tobacco use). Qualitative variables were compared with the chi-square or Fisher test and
quantitative variables were compared with the Test-T.
Tobacco use was associated with sex 29.82% and 59% of smokers were women and men, respectively (p = 0.012). Women were younger than men (p =
0.032). EGFR alterations ware associated with sex (p = 0.002), women were more likely to have positive gene alterations. Only 1.8% of subjects reported
ALK alterations and they were not related to sex (p = 0.55). In a patients subgroup where PD-L1 was tested, univariate analysis showed no association of
PD-L1 expression with sex (p = 0.3006), age (p = 0.7747), tobacco habit (p = 1) and EGFR gene mutation (p = 1).
The results showed a frequency of expression of mutations in EGFR and ALK fusion oncogene comparable to the data reported in the western
population. The alterations present in the EGFR are the most prevalent in women with adenocarcinoma.

Keywords: lungcancer; EGFR; ALK; adenocarcinoma