[Direct chromosome analysis and FISH study of primary gastric cancer].

OBJECTIVE

To investigate chromosome aberrations and their role in the genesis and progression of primary gastric cancer.

METHODS

An improved, direct method of chromosome preparation from solid tumors was adopted for G-banding analysis followed by FISH on decolored G-banding chromosomes so that chromosome aberrations could be confirmed at DNA level.

RESULTS

A total of 28 primary gastric cancer specimens were studied. Case 1 and case 2 had simple chromosome numerical changes: 49, XY, +2, +8, +9 and 47, XX, +8, +20, respectively. All but case 1 and 2 had complicated chromosome abnormalities. Structural changes of frequent occurrence involved del(7q) (21/26), del(3p)(14/26), del(1p)(11/26) and del(17p)(10/26). The chromosome abnormalities could be simple or complicated. In the former, numerical changes involving 1 to 3 chromosomes could be observed. Trisomies 8 and 9 appeared to be a cytogenetic subgroup of primary gastric cancer. In the latter, del(7q) was the most consistent structural aberration. The 7q32-qter was the commonly lost segment.

CONCLUSION

Numerical and structural alterations of chromosomes are present in primary gastric cancer. Del(7q) is one of the structural changes characteristic of primary gastric cancer. In the 7q32-qter segment, a tumor suppressor gene probably exists and it may have close relation to the genesis and progression of gastric cancer.