Immunohistochemical detection of p53 protein in neoplastic, preneoplastic and normal bronchial mucosa specimens obtained during diagnostic bronchoscopy.

The expression of p53 protein was evaluated immunochemically in cancer tissue, preneoplastic lesions and normal bronchial mucosa obtained during diagnostic bronchoscopy from 53 patients with lung cancer and 12 patients with benign lung diseases. In lung cancer patients, positive p53 staining was detected in 26/53 (49%) of the tumour specimens. In preneoplastic lesions p53 positive staining was found in 8 of 24 (33.3%) squamous metaplasia, 1 of 4 hyperplasia and 1 of 3 dysplasia lesions. In the same group of patients, 12 cases were found with positive p53 cells in normal bronchial mucosa. In patients with benign diseases, positive p53 staining was found in 1 of 4 cases with squamous metaplasia and in one normal mucosa. Our results provide evidence that somatic genetic alterations may occur in early stages of lung tumorigenesis, raising the possibility that molecular analyses is useful in the early diagnosis of precancerous lesions of the bronchial mucosa, and results indicate that p53 expression can be studied in small tissue specimens obtained during bronchoscopy.