Histological Subtyping of Lung Carcinomas: From the Targeted Therapy Perspective

INTRODUCTION[|]As a result of recent advances in therapies, the subtyping of non-small cell lung carcinomas (NSCLC) has become more important. This study was an evaluation of the use of cytomorphological characteristics and immunohistochemical markers to predict the subtype of NSCLC in fine-needle aspiration (FNA) material.[¤]METHODS[|]Records of 73 cases of surgically resected NSCLC that had been preoperatively diagnosed with FNA biopsy were reviewed. Cytology specimens were reviewed for cytomorphological features of squamous cell carcinoma (SCC) and adenocarcinoma (AC), and the contribution of immunohistochemistry to histological subtyping was evaluated.[¤]RESULTS[|]The sensitivity, specificity, and positive predictive values for keratinized lamellar cytoplasm and dense chromatin in SCC, and for flat sheets and nucleocytoplasmic polarity in AC were more than 60%. Immunohistochemical analysis revealed 60% sensitivity and 93% specificity for thyroid transcription factor 1 in AC. P63 and cytokeratin 5/6 had 73% and 64% sensitivity and 78% and 96% specificity, respectively, in SCC. The immunohistochemistry results of the cell blocks and the resection material demonstrated 94% conformity.[¤]DISCUSSION AND CONCLUSION[|]Immunohistochemistry is helpful in subtyping NSCLC, including poorly differentiated tumors. The cell block method of representing the immune profile of the tumors was found to be reliable.[¤]