Analysis of Predictive Biomarkers in Patients With Lung Adenocarcinoma From Southern Brazil Reveals a Distinct Profile From Other Regions of the Country.

PURPOSE

Adenocarcinoma is the most common histologic subtype of non-small-cell lung cancer, representing 40% of all diagnoses. Several biomarkers are currently used to determine patient eligibility for targeted treatments, including analysis of molecular alterations in and , as well as programmed death-ligand 1 (PD-L1) protein expression. Epidemiologic data reporting the frequency of these biomarkers in Brazilian patients with lung adenocarcinoma (LUAD) are limited, and existing studies predominantly included patients from the southeast region of the country.

MATERIALS AND METHODS

The goal of this study was to investigate the frequency of somatic mutations in the and genes, ALK, and PD-L1 expression in a series of Brazilian patients diagnosed with LUAD predominantly recruited from centers in southern Brazil. Molecular analysis of the , and genes was performed by next-generation sequencing using DNA extracted from tumor tissue. Immunohistochemistry was used to detect ALK and PD-L1 expression.

RESULTS

Analysis of 619 tumors identified mutations in 189 (30.2%), mutations in 120 (19.16%), and mutations in 19 (3%). Immunohistochemistry demonstrated ALK and PD-L1 expression in 4% and 35.1% of patients, respectively.

CONCLUSION

To our knowledge, this is the first study investigating the molecular epidemiology of patients with LUAD from southern Brazil and the largest assessing the frequency of multiple predictive biomarkers for this tumor in the country. The study also reveals a distinct mutation profile compared with data originating from other regions of Brazil.