Association of cyclin D1 expression in lung cancer and the smoking habits of patients

This study examined whether or not cyclin D1 expression is associated with the smoking habits of patients with non-small cell lung carcinomas (NSCLC). Immunohistochemistry was used to analyze 181 NSCLC samples for the expression of cyclin D1. Expression of cyclin D1 protein was found in 130 out of 181 cases (72%). A significant relationship between cyclin D1 expression and stage or histological classification was not observed. The carcinomas of smokers expressed cyclin D1 in 77% of the cases while carcinomas of non-smokers expressed this protein only 57% of the time (P<0.01, Fisherʹs exact test). The correlation between smoking and cyclin D1 expression was maintained when the analysis was limited to squamous cell lung carcinomas. However, no correlation was found between cyclin D1 expression and the smoking habits of patients with adenocarcinomas. This can be explained by the fact that the development of adenocarcinomas – in contrast to squamous cell lung carcinomas – is not closely related to tobacco smoke.