European Journal of Cardiovascular Medicine

Introduction: Lung cancer is the leading cause of cancer related death worldwide and accounts for 28% of all cancer mortality and around 1.8 million new cases were diagnosed in 2012. The morphological distinction between pulmonary adenocarcinoma (ADC) and squamous cell carcinomas (SCC) is sometimes difficult, mainly in cases of poorly differentiated tumors or when degenerative changes, necrosis and crushing may obscure the cell characteristics. p63 is a homologue of the p53 tumour suppressor gene that is responsible for proliferation and differentiation of epithelial progenitor cells. p40 is consistently the predominant isoform expressed in squamous cell carcinoma; thus, it offers improved specificity for diagnosing squamous cell carcinoma.  Materials And Methods: This is a prospective and observational study conducted in the Department of Pathology, Tertiary care Teaching Hospital over a period of 1 year. Primary lung carcinoma cases included with unequivocal morphological diagnosis irrespective of age, gender and nature of biopsy material (endoscopic biopsy/ needle core biopsy / resected specimen). Cases diagnosed as Small cell carcinoma of lung, as metastatic lung cancers, poorly differentiated NSCLC-NOS and with inadequate material for IHC study were excluded from present study.  Results: In the present study, a total of 150 patients were included out of which 112 (74.6%) were males and 38 (25.4%) were females. In our study, most of the patients were >61 years i.e., 63 out of 150 (42%), followed by 51-60 years, i.e., 40 out of 150 (26.7%). All 8 cases of well differentiated Adenocarcinoma were positive for P40 and 5 cases showed P63 expression. Out of 13 cases of moderately differentiated Adenocarcinoma, 3 cases were positive for P40 and 10 cases were positive for p63 marker.  Out of 30 cases of well differentiated Squamous cell carcinoma 15 cases were P40 positive and 15 cases were P63 positive.  All 53 cases of moderately differentiated Squamous cell carcinoma showed positive P40 and P63 expression.  Conclusion: We conclude that strong and diffuse p40 expression is seen in majority of lung squamous cell carcinomas and absence of p40 expression in most of the lung adenocarcinomas. Expression of p63 is similar to that of p40 in lung squamous cell carcinoma, but there was variable p63 immunoreactivity in lung adenocarcinoma. In Moderately differentiated cases, a two-panel approach of p63 and p40 help to distinguish adenocarcinoma from squamous cell carcinoma. Thus, p40 is an excellent marker for distinguishing lung squamous cell carcinoma from adenocarcinoma and that its expression is equivalent to that of p63 in lung squamous cell carcinoma.