ABSTRACT

Lung cancer is the carcinoma with the highest mortality and incidence. Genetic factors that cause lung cancer are the oncogenes and tumor suppressor genes underlying carcinogenesis. ALK gene is a transmembrane protein with tyrosine kinase activity. Because of inversion of ALK gene with EML4 gene, the EML4-ALK complex occurs. The EML4-ALK complex is continuously active, resulting in continuous cell proliferation. FISH is known as the ‘’gold standard’’ method to detect the EML4-ALK fusion gene, which is mostly seen in adenocarcinoma. In our study, we aimed to underlie the outcomes of detection of EML4-ALK gene rearrangement in clinics.

We selected and analyzed 50 cases (48 men, 2 women) with the FISH method, which are diagnosed as NSCLC after pathologic evaluation in years 2014-2016. The denaturation and hybridization of the test were performed with the Euro-Lone Hychrome instrument, and the results were analyzed with the Olympus BX-51 microscope.

The average age of 50 cases was 61.3 years, and 80% of these cases were diagnosed in the advanced stage. A total of 96% of cases were cigarette smokers, while 28% had familial cancer histories. The EML4-ALK rearrangement positive cases were detected in eight cases (16%). The positivity among the cases was seen in 50% of the smokers for 40 years, in 12.5% of the smokers for 20–30 years, and in 25% of the cases in non-smokers. A total of 75% of positive cases have metastasis, while 50% have positive familial history. The ALK inhibitor treatment began after the approval of positive results.

The ALK fusion gene, detected by the gold standard FISH method, plays an important role in the treatment of lung adenocarcinomas. Although some investigations suggest higher ALK positivity in young men, other studies show no relation between sex, age, and ALK positivity. Our study found no relationship between age, sex, cigarette smoking, stage, and ALK positivity.

Keywords: Non-small cell lung cancer, adenocarcinoma, ALK, EML4-ALK, FISH