ALK Gene Rearrangement Screened by Immunohistochemistry and FISH in Non-Small Cell Bronchopulmonary Cancer (NSCLC) in Senegalese Subjects

Abstract

Introduction: Bronchopulmonary cancer is a worldwide scourge. In Senegal, the prevalence is 3.8%. The main objective of this work is to study ALK gene rearrangement, by immunohistochemistry and FISH, to propose a more targeted therapy to our patients. Patients and Methods: A multicenter, cross-sectional, descriptive, prospective study between 2018 and 2020 of bronchopulmonary cancer cases. Histology, immunohistochemistry, and FISH were performed. Results/Discussion: The mean age of patients was 60.29 ± 6.7 years. Non-small-cell lung cancer (NSCLC) predominated (92% of patients). In NSCLC, adenocarcinoma was the most frequent histological entity (34.2%). The ALK-antibody was searched in all NSCLC. Immunohistochemistry, confirmed by FISH, yielded positive results for ALK expression in 4.5% of cases. The majority of ALK-positive patients were male (66.6%) and non-smokers (66%). Significant associations between ALK gene rearrangement and histological type, notably adenocarcinoma (p=0.001) and squamous cell carcinoma (p=0.002), were found. Age (p=0.5), gender (p=0.4), and smoking (p=0.4) were not significantly associated with ALK rearrangement. Despite the relatively low incidence, ALK rearrangement should be routinely investigated in NSCLC, particularly in patients with adenocarcinoma. The discovery of the molecular anomaly should lead to the prescription of targeted therapies with tyrosine kinase inhibitors, which will considerably improve our patients' survival. Conclusion: IHC analysis confirmed by FISH yielded positive results for ALK expression in 4.5% of patients. Progress in understanding oncogenesis has led to the development of targeted therapies. Therefore, the prescription of these drugs is conditioned by the presence of the target molecular anomaly, which must be routinely sought in our patients.