Chromosome bands 3p14.2, 9p21, and 13q14 are frequently deleted in roentgenographically occult bronchogenic squamous cell carcinoma of the lung

Roentgenographically occult bronchogenic squamous cell carcinomas are early lung cancers that localize mainly within the bronchial wall and are thought to be a good model for elucidating chromosomal alterations during lung cancer progression. In this study, we analyzed allelic losses on chromosome regions 1p36, 3p14.2, 9p21, 10q25.3-q26.1, 13q14.12-q14.2, and 16q24.1-q24.2, in which there are putative tumor suppressor genes that may play roles in lung carcinogenesis. Forty-five cases with roentgenographically occult bronchogenic squamous cell carcinoma (ROC) and 47 cases of bronchogenic carcinoma with abnormal shadows (roentgenographically nonoccult bronchogenic squamous cell carcinoma [RNOC]) were examined. Highly frequent LOHs in both ROCs and RNOCs were observed in chromosome regions 3p14.2, 9p21, and 13q14.1-q14.2. LOHs were more frequently observed in RNOCs than in ROCs at two loci: 10q25.3-q26.1 and 16q24.1-q24.2. These results suggested that (I) putative tumor suppressor genes exist on 3p14.2, 9p21,10q25.3-q26.1,13q 14.12-q 14.2, and 16q24.1q24.2, which may play important roles in lung carcinogenesis; (2) mutations in genes at 3p14.2, 9p21, and 13q14.12-q14.2 represent rather early events in lung carcinogenesis; and (3) mutations in genes on 10q25.3-q26.1 and 16q24.1-q24.2 represent rather late events.