Identification of Tumor Suppressor Loci on the Short Arm of Chromosome 16 in Primary Small Cell Lung Cancers / 결핵

BACKGROUND: Loss of the short arm of chromosome 16 is a frequent event in various cancers, which suggests the presence of tumor suppressor gene(s) there. To map precise tumor suppressor loci on the chromosome arm for further positional cloning efforts, we tested 23 primary small cell lung cancers. METHODS: The DNAs extracted from paraffin embedded tissue blocks with primary tumor and corresponding control tissue were investigated. Twenty polymorphic microsatellite markers located in the short arm of chromosome 16 were used in the microsatellite analysis. RESULTS: We found that six (26.1%) of 23 tumors exhibited LOH in at least one of tested microsatellite markers. Two (8.7%) of 6 tumors exhibiting LOH lost a larger area in chromosome 16p. LOH was observed in five common deleted regions at 16p. Among those areas, LOH between D16S668 and D16S749 was most frequent (21.1%). LOH was also observed at four other regions, between D16S3024 and D16S748, D16S405, D16S420, and D16S753. Six of 23 tumors exhibited shifted bands in at least one of the tested microsatellite markers. Shifted bands occurred in 3.3% (15 of 460) of the loci tested. CONCLUSION: Our data demonstrated that at least five tumor suppressor loci might exist in the short arm of chromosome 16 and that they may play an important role in small cell lung cancer tumorigenesis.

Identification of Tumor Suppressor Loci on the Long Arm of Chromosome 15 in Primary Small Cell Lung Cancer

Small cell lung cancer (SCLC) frequently shows a loss of heterozygosity (LOH) on chromosome 15q. In order to define the commonly affected region on chromosome 15q, we tested 23 primary SCLCs by microsatellite analysis. By analyzing 43 polymorphic microsatellite markers located on chromosome 15q, we found that 14 (60.8%) of 23 tumors exhibited a LOH in at least one of the tested microsatellite markers. Two (14.3%) of the 14 tumors were found to have more than a 50% LOH on chromosome 15q. LOH was observed in five commonly deleted regions on 15q. Of those regions, LOH from D15S1012 to D15S1016 was the most frequent (47.8%). LOH was also observed in more than 20-30% of tumors at four other regions, from D15S1031 to D15S1007, from D15S643 to D15S980, from D15S979 to D15S202, and from D15S652 to D15S642. Four of the 23 tumors exhibited shifted bands in at least one of the tested microsatellite markers. Shifted bands occurred in 3.2% (29 of 914) of the loci tested. Our data suggests the presence of at least five tumor suppressor loci on chromosome 15q in SCLC, and further that these may play an important role in SCLC tumorigenesis.