- In recent years the frequency of nonsmokers among lung cancer patients has increased to 10% to 15%. The measles virus has rarely been evoked as an etiological agent in malignant tumors and its role in carcinogenesis remains doubtful. It has been suggested that measles virus phosphoprotein may inhibit ubiquitination of Pirh2, which has been reported to be overexpressed in lung carcinoma and is responsible for degrading the cell cycle regulator p53. The authors conducted a clinicopathological study of newly diagnosed patients with non-small cell lung carcinoma of all stages seen in a 10-year period. Immunohistochemical studies for measles virus antigens, p53, and Pirh2 were performed using the avidin-biotin peroxidase complex. The authors found expression of measles virus antigens in 54 of 65 cases of non-small cell lung carcinoma. This finding is associated with the older age of the patients and with expression of Pirh2. The presence of Pirh2 itself was associated with improved survival.