Abstract

A fluorescence bronchoscope system has been developed for detecting early lung cancer including dysplasia and carcinoma in situ. To determine the histologic findings and genetic alterations of the lung tissues, which were biopsied by the fluorescence bronchoscope, we analyzed 104 specimens from 62 heavy smokers for their histopathology, cell proliferation index, and genetic mutations of p53 and K-ras. We used immunohistochemistry for MIB-1 and p53, and PCR-SSCP and direct DNA sequencing for p53 and K-ras. The histology was variable from reactive conditions to invasive cancers, and consisted of basal cell hyperplasia (26.9%), dysplasia (4.8%), carcinoma in situ (1.9%), squamous cell carcinoma (7.7%), adenocarcinoma (4.8%), and small cell carcinoma (10.6%). The cellular proliferation index of the lesions increased as their aggressiveness increased. p53 and K-ras mutations were detected in 33.7% and 14.4% of all tissues, respectively. In dysplasia, p53 and K-ras mutations were observed in 3 of 5 and in 2 of 5 tissues, respectively. However, these genetic alterations were not found in carcinoma in situ. Interestingly, 28.6% of basal cell hyperplasia showed p53 mutations. In conclusion, these data suggest that the biopsy specimens using fluorescence bronchoscopy show variable histologic findings, ranging from reactive conditions to invasive cancers. In addition, some of the dysplastic lesions are related to p53 and K-ras mutations, although these genetic alterations are also seen in basal cell hyperplasia.

• Keywords: Early lung cancer;Fluorescence bronchoscopy;p53;K-ras;