Immunohistochemical markers in the morphological diagnosis of lung carcinoma.

Conventional histopathological criteria based on light microscopy are used in pulmonary oncologic pathology in order to establish the diagnosis of tumor, but most frequently they are insufficient, accurate diagnosis requiring ultrastructural and immunohistochemical investigations. The method of immunostaining allowed some molecular marker to be evaluated. Some of them seem to be important in carcinogenesis as a general process, while others have high specificity for lung tumors. Estimation of EGFR and c-erbB-2 protein immunoreactivity showed a significantly stronger staining with NSCLC and was correlated to the poor differentiation of the tumors, undergoing an aggressive biological behavior and an unfavorable prognosis. The expression of p53 protein was found in 19 cases by immunostaining with DO-7 antibody. Immunotracing of more than 50% of the tumoral cells was a predictive factor for the progression of the disease. The growing rate of tumoral proliferative activity was evaluated by immunotracing technique (MIB-1), allowing the Ki-67 index of labeling to be calculated.