Chromosomal alterations detected by comparative genomic hybridization in nonfunctioning endocrine pancreatic tumors.

We have used comparative genomic hybridization to investigate changes in DNA copy number in 20 nonfunctioning endocrine pancreatic tumors. The total number of regional DNA imbalances per tumor showed variation from case to case and high genetic heterogeneity was observed. From 1 to 22 chromosomal anomalies were detected in 13 of the 20 cases evaluated. Overall gains predominated over losses with a ratio of about 3.9:1 (58 gains/15 losses). The mean total number of regions displaying imbalances increased from 1.25 per tumor for benign tumors to 5.25 for malignant tumors, although statistical significance was not reached (P=0.074).