Molecular profile of non-small cell lung cancer in northeastern Brazil.

OBJECTIVE: To investigate the histological subtypes and mutational profiles of non-small cell lung cancer in Brazil, looking for correlations among histological subtypes, expression of anaplastic lymphoma kinase (ALK), EGFR mutation status, and programmed death-ligand 1 (PD-L1) expression. METHODS: We evaluated 173 specimens obtained from patients with lung adenocarcinoma in northeastern Brazil. Expression of PD-L1 and ALK was evaluated by immunohistochemistry; EGFR mutation status was evaluated by sequencing. We categorized the histological subtypes in accordance with the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification. RESULTS: The most common histological subtypes of lung adenocarcinoma were solid predominant (in 46.8%), acinar predominant (in 37.0%), and lepidic predominant (in 9.8%). ALK expression was detected in 10.4% of the samples, and 22.0% of the tumors harbored EGFR mutations. The most common EGFR mutation was an exon 21 L858R point mutation (in 45.5%), followed by an exon 19 deletion (in 36.3%). The tumor proportion score for PD-L1 expression was ≥ 50% in 18.2% of the samples, 1-49% in 32.7%, and 0% in 49.5%. The solid predominant subtype was significantly associated with wild-type EGFR status (p = 0.047). Positivity for PD-L1 expression was not found to be significantly associated with ALK expression or EGFR mutation status. CONCLUSIONS: Our results suggest that the molecular profile of non-small cell lung cancer in northeastern Brazil differs from those of populations in other regions of the country, with ALK positivity being higher than the other biomarkers. Further studies including clinical and genetic information are required to confirm these differences, as well as studies focusing on populations living in different areas of the country.

Molecular profile of non-small cell lung cancer in northeastern Brazil / Perfil molecular do carcinoma pulmonar de células não pequenas no Nordeste brasileiro

ABSTRACT Objective: To investigate the histological subtypes and mutational profiles of non-small cell lung cancer in Brazil, looking for correlations among histological subtypes, expression of anaplastic lymphoma kinase (ALK), EGFR mutation status, and programmed death-ligand 1 (PD-L1) expression. Methods: We evaluated 173 specimens obtained from patients with lung adenocarcinoma in northeastern Brazil. Expression of PD-L1 and ALK was evaluated by immunohistochemistry; EGFR mutation status was evaluated by sequencing. We categorized the histological subtypes in accordance with the International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society classification. Results: The most common histological subtypes of lung adenocarcinoma were solid predominant (in 46.8%), acinar predominant (in 37.0%), and lepidic predominant (in 9.8%). ALK expression was detected in 10.4% of the samples, and 22.0% of the tumors harbored EGFR mutations. The most common EGFR mutation was an exon 21 L858R point mutation (in 45.5%), followed by an exon 19 deletion (in 36.3%). The tumor proportion score for PD-L1 expression was ≥ 50% in 18.2% of the samples, 1-49% in 32.7%, and 0% in 49.5%. The solid predominant subtype was significantly associated with wild-type EGFR status (p = 0.047). Positivity for PD-L1 expression was not found to be significantly associated with ALK expression or EGFR mutation status. Conclusions: Our results suggest that the molecular profile of non-small cell lung cancer in northeastern Brazil differs from those of populations in other regions of the country, with ALK positivity being higher than the other biomarkers. Further studies including clinical and genetic information are required to confirm these differences, as well as studies focusing on populations living in different areas of the country.

RESUMO Objetivo: Investigar os subtipos histológicos e perfis de mutação do carcinoma pulmonar de células não pequenas no Brasil, bem como as correlações entre os subtipos histológicos, a expressão do gene anaplastic lymphoma kinase (ALK, quinase do linfoma anaplásico), o estado de mutação do gene EGFR e a expressão de programmed death-ligand 1 (PD-L1, ligante de morte celular programada 1). Métodos: Avaliamos 173 espécimes provenientes de pacientes com adenocarcinoma pulmonar no Nordeste brasileiro. A expressão de PD-L1 e ALK foi avaliada por meio de imuno-histoquímica, ao passo que o estado de mutação do EGFR foi avaliado por meio de sequenciamento. Os subtipos histológicos foram classificados de acordo com a International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society. Resultados: Os subtipos histológicos mais comuns de adenocarcinoma pulmonar foram o predominantemente sólido (em 46,8%), o predominantemente acinar (em 37,0%) e o predominantemente lepídico (em 9,8%). A expressão de ALK foi detectada em 10,4% das amostras, e 22,0% dos tumores apresentavam mutações do gene EGFR. As mutações mais comuns do EGFR foram a mutação pontual L858R no éxon 21 (em 45,5%) e a deleção do éxon 19 (em 36,3%). O tumor proportion score relativo à expressão de PD-L1 foi ≥ 50% em 18,2% das amostras, = 1-49% em 32,7% e = 0% em 49,5%. O subtipo predominantemente sólido relacionou-se significativamente com EGFR selvagem (p = 0,047). A expressão positiva de PD-L1 não se relacionou significativamente com a expressão de ALK ou o estado de mutação do EGFR. Conclusões: Nossos resultados sugerem que o perfil molecular do carcinoma pulmonar de células não pequenas no Nordeste brasileiro difere do de populações em outras regiões do país: a expressão positiva de ALK é maior que os demais biomarcadores. Mais estudos com informações clínicas e genéticas são necessários para confirmar essas diferenças, além de estudos que se concentrem em populações em diferentes áreas do país.