TTF-1 and P40 immunohistochemical markers as a useful panel in diagnosis of Non Small Cell Lung Carcinoma (NSCLC) with histopathological correlation- A cross sectional study

Lungs are air-filled spongy organ located on either side of the chest. The inhaled air conducts through the large air passages that lead from the trachea to the lungs through called bronchi. The right and left bronchi after entering in to the lungs, they are further divided in to segmental bronchi. The segmental bronchi then further divided in to bronchioles, finally becoming microscopic. The bronchioles then further divided in to terminal bronchioles then in to respiratory bronchioles eventually end in clusters of microscopic air sacs called alveoli where exchange of gases takes place. In lungs, there are several types of lesions broadly classified as Inflammatory and Non-inflammatory, Polyp and Tumors. Tumors are classified as Benign includes Hamartomas, Bronchial adenomas, Chondromas, Fibromas, Lipomas and Malignant is histologically classified in to two main groups i.e. Small cell lung carcinoma (SCLC) constitutes 15% of all lung cancer and Non- Small cell lung carcinoma (NSCLC) constitutes 85% of all lung cancer while NSCLC is subclassified in to Adenocarcinoma, Squamous cell carcinoma, Large cell carcinoma in which adenocarcinoma is most predominant type.1Lung cancer is the second most common and major cause of death worldwide.2 Its generally a disease of elderly individuals, occurring most often between ages 55 and 84 years.1 In India, lung cancer constitutes 6.9% of all new cancer cases and 9.3% of all cancer related deaths in both sexes.3 Incidence of lung cancer in male is 1 in 68 and in female is 1 in 201.4The most common cause of lung cancer is Tobacco Smoking which accounts for 80% and other causes includes air pollution, industrial hazards like asbestos, arsenic, chromium, nickel, vinyl chloride which accounts for 20%.2  Early detection and treatment may result in decreasing incidence of the mortality and morbidity.