High incidence of chromosomal abnormalities at 1p36 and 9p21 in early-stage central type squamous cell carcinoma and squamous dysplasia of bronchus detected by autofluorescence bronchoscopy

Abstract

Heavy smokers with central type squamous cell carcinoma (SCC) frequently have multiple cancerous lesions in the bronchus. Autofluorescence bronchoscopy (AFB) is useful in the detection of early bronchogenic cancer and dysplastic lesions. We investigated the loss of heterozygosity (LOH) and microsatellite instability (MSI) and expression of four proteins in 13 early stage SCC (early SCC) and 9 squamous dysplasia detected by AFB and 19 cases of surgically resected invasive SCC (invasive SCC). In early SCC and squamous dysplasia, LOH/MSI of chromosome 1p36 was found in 62 and 33%, respectively, and of 9p21 in 54 and 63%, respectively. TAp73 expression of early SCC and squamous dysplasia was lower than that of normal bronchial epithelium, and p16 expression was not detectable in these lesions. These results suggested that the genetic abnormalities had already developed in the early stage of carcinogenesis of SCC, including squamous dysplasia. The AFB system was able to reveal abnormal autofluorescence in these precancerous lesions, including squamous dysplasia.