Chromosomal imbalances in gastric cancer. Correlation with histologic subtypes and tumor progression

DNA copy number changes were analyzed by comparative genomic hybridization (CGH) in 38 gastric carcinomas and correlated with tumor histologic type and progression. Gains of copy numbers were observed in all tumors, affecting all chromosomes except chromosome 16. The average number of copy number gains was 7 (range, 1-13), most frequently located on chromosomes 11, 12, 15, 17, and 20 in 45% to 97% of tumors. High-level amplifications were found on chromosomes 12, 15, 17, and 20; the latter was affected most frequently (66%). Loss of DNA copy numbers was detected in 14 tumors affecting 7 chromosomes. No statistically significant differences in the frequency and pattern of chromosomal imbalances were observed in tumor histologic type (Lauren classification) and grade of differentiation, as well as the prognostic parameters depth of invasion (pT) and lymph node involvement (pN). Our results indicate that in gastric cancer there is no specific recurrent pattern of DNA aberrations to be correlated with tumor histologic type or stage. However, CGH analysis could reveal new, recurrent genetic changes in gastric cancer affecting chromosomes sites that harbor genes known to participate in tumorigenesis and progression of several human malignant neoplasms.