GENETIC ALTERATION IN GASTROINTESTINAL CANCER - A MOLECULAR AND CYTOGENETIC STUDY

We examined 16 cases of gastrointestinal cancer, of which 11 were from the colon, 1 from the rectum, and 4 of gastric origin, cytogeneticall y for expression and for loss of heterozygosity (LOH) on chromosome 18 using Deleted Colon Cancer (DCC) gene. LOH on chromosome 18 with DCC probe was detected in 7 out of 11 cases of colon, in 4 out of 4 cases of gastric and in 1 case of rectum cancer. In all gastrointestinal tum ors the expression of DCC gene was absent, while it was present in nor mal tissue. We also found rearrangements of chromosomes 18 (10 cases) and 17 (9 cases), leading respectively to deletions of long and short arms. Other additional abnormalities were observed involving chromosom es 5, 6, 15 and 19. The data recorded in our series differ from other authors' data in three respects: a high incidence of pseudodiploid chr omosome number, rearrangements of chromosome 19 and 15, and involvemen t of DCC gene in the development of gastric cancer, as well as in colo rectal cancer as previously reported.