ANALYSIS OF THE DPC4 GENE IN GASTRIC-CARCINOMA

Allelic loss on chromosome 18q is involved in the progression of gastr ic carcinoma. Recently, DPC4 (deleted in pancreatic carcinoma, locus 4 ), a candidate tumor suppressor gene, has been localized at 18q21.1. T his gene is inactivated in nearly one half of pancreatic carcinomas. W e tested for DPC4 gene mutations and allelic status at 18q21 in 30 pri mary gastric carcinomas and 5 gastric carcinoma cell lines. Polymerase chain reaction single-strand conformation polymorphism and sequencing analyses revealed no DPC4 mutations in any of the primary tumors or c ell lines. Homozygous deletion of DPC4 was observed in only 1 (MKN-45) of the 5 (20%) cell lines. This suggests that the target gene for los s on 18q is not DPC4. The true tumor suppressor gene, encoded near DPC 4, has yet to be identified.