Molecular epidemiology of EGFR mutations,ALK rearrangement and PD-L1 expression in lung Non-small cell carcinoma and its correlation with clinicohistological features

Abstract

Lung cancer is the leading cause of cancer death in the world due to its high prevalence and severe prognosis. Identification of common mutations such as EGFR and ALK rearrangement and introduction of TKI and other immunotherapy drugs caused this carcinomas treatment to enter a new phase. Objective: In this study, the prevalence of EGFR mutations, ALK rearrangement and PD-L1 expression and its relationship to Clinicopathological features were investigated. Material and Methods: All patients who were diagnosed with pulmonary adenocarcinoma within 18 months since the project began, were included in this study. The H&E slides were prepared and histologically examined from paraffin block of lung tumor samples that were sent to the laboratory. EGFR mutation were examined by PCR, exon type by sequencing, ALK-EML4 fusion using RT-PCR and PD-L1 expression by IHC staining. The obtained data were analyzed by descriptive statistical methods using SPSS 21 software. Results: In this study, the most common molecular disorder observed was EGFR mutation, with the most common exons involved exon 20 with Qln787Qln and exon 21 with L858R point mutation. EGFR mutation was more common in Patients over the age of 60 years, women, adenocarcinoma histology, non-smokers and alcoholics. ALK rearrangement was more common in patients under the age of 60 years, women and smokers. PD-L1 is more common in patients under the age of 60 years, women, adenocarcinoma histologists, and smokers. The overall survival rate is 79.7% with an average survival of 618.26 days with a standard deviation of 96.13. The overall survival rate of patients with EGFR mutation was 90% and the average survival is 403 days with a standard deviation of 44.9 (Log Rank:0.67). During the study, no deaths were reported in the ALK rearrangement (Log Rank: 0.85) and In the case of PD-L1, there was no difference in the survival rate of the two groups (Log Rank: 0.49).