Utilização das técnicas de imuno-histoquímica e reação em cadeia da polimerase (PCR) no diagnóstico, na avaliação de fatores prognósticos e no direcionamento do tratamento do câncer de pulmão.

Abstract

Lung cancer is a high-mortality neoplasm, being the first in the world in both incidence and mortality. It is the second most common in men and the third in women. It is usually diagnosed at a locally advanced stage and it is leading cause of cancer death worldwide. Immunohistochemistry exam is widely used in the identification of the tumor subtype, in the evaluation of prognostic factors and in the direction of treatment. The identification of PD-L1 immunoexpression has enabled a new treatment premise involving the use of monoclonal antibodies. The use of the PCR technique to search for EGFR changes allows indicating treatment with tyrosine kinase inhibitor. This study aims to evaluate the immunohistochemical profile and alterations of the EGFR gene in a series of 29 patients diagnosed with lung cancer who underwent surgery, to show the importance of these techniques in the assessment of prognostic factors and treatment of lung cancer. The data show a higher prevalence of cases in women (66%), aged around 61 years. Primary lung tumors accounted for the majority of cases (86%). The predominant histological type was adenocarcinoma (38%), followed by squamous cell carcinoma (17%), carcinoid tumors (17%), lung metastasis (14%), and cases of other less frequent tumors (14%). Most of the cases were of a moderately differentiated histological grade (75%). Among adenocarcinomas, the acinar histological subtype was the most frequent (45%) and in the cases of secondary tumors (14%), half were metastases from primary liver tumors. PDL-1 expression and EGFR alteration were evaluated in 16 cases, with PD-L1 expression observed in 12% and EGFR alteration in 25%. Of the total carcinoid tumors analyzed, 80% were typical carcinoids and 20% were atypical carcinoids. Immunohistochemical profile of the cases of adenocarcinoma showed that all of them presented immunoexpression of TTF1 and the absence of staining for p63, whereas in the immunohistochemical profile of the cases of squamous cell carcinoma it showed the opposite. In cases of carcinoid tumors, a predominance of marking was observed in all cases of Chromogranin A and Synaptophysin, with ki67 being low in cases of typical carcinoid, and elevated in cases of atypical carcinoid.