NUMERICAL CHROMOSOMAL ABERRATION IN NODE-POSITIVE EARLY GASTRIC CARCINOMAS - ANALYSIS BY FLUORESCENCE IN-SITU HYBRIDIZATION AND IMMUNOHISTOCHEMICAL STAINING

Tissue from surgically resected early gastric carcinomas with nodal in volvement (NI) and without nodal involvement (NNI) were examined by fl uorescence in situ hybridization (FISH) by use of a set of alpha-satel lite probes. Numerical gain was ob served in seven cases (70%) by a pr obe of chromosome 17 and in three cases (30%) by a probe of chromosome 18 among the NI cases, whereas such a gain was not detected in any NN I cases examined. Cases with numerical aberration in chromosome 17 exh ibited immunohistochemical positivity of oncogene or tumor suppressor gene products related to chromosome 17 more frequently than the cases lacking those aberrations. Numerical chromosomal aberration as well as DNA aneuploidy determined by FISH may be related to genetic instabili ty and biological behavior in early gastric carcinomas.