Relationship between Chromosomal Instability and Intratumoral Regional DNA Ploidy Heterogeneity in Primary Gastric Cancers

The purpose of this study was to elucidate the relationship between intratumoral regional heterogeneity in DNA ploidy and chromosomal instability (CIN) in primary gastric adenocarcinomas. In 45 sporadic gastric adenocarcinomas, we measured DNA ploidy and numerical aberrations for chromosomes 7, 11, 17, and 18 by laser scanning cytometry and fluorescence in situ hybridization, respectively, in small tissue specimens taken from 2 to 6 (on the average 4) different portions of the same tumor. A total of 231 specimens including 45 normal control specimens were examined. All 98 tumor specimens with DNA aneuploidy (DNA index ≥ 1.2) showed large intercellular variations in chromosome copy number, indicating CIN. In contrast, 85 tumor specimens with (near) diploidy (1.0 ≤ DNA index