Cytogenetic studies in patients with gastric cancer.

Banded cytogenetic studies of gastric carcinoma are still relatively scarce, comprised of only a small number of patients. This study was performed on peripheral blood lymphocytes and malignant cells of 16 patients with gastric carcinoma. The lymphocytes were analyzed by standard techniques. All patients had a normal constitutional karyotype; 90% of the patients presented an increased breakage rate and nonrandom chromosomal instability mainly in the heterochromatic regions of chromosomes 1, 9, and 16. Decreased response to phytohemagglutinin was observed in 6 (38%) patients. The tissue specimens were analyzed using direct techniques. Normal ploidy was observed in only one patient, 3 tumors were near-diploid, 4 hyperdiploid, 4 near-triploid, and 4 near-tetraploid. Those with the near-triploid or near-tetraploid constitution were in a more advanced pathological stage, most of them with a more complex cytogenetic profile. Particular involvement was found for chromosomes 1 to 4, 7 to 9, 17, and 20, but the more specific nonrandom changes seemed to involve chromosomes 7, 8, 9, and 17.