Background: The authors investigated the frequency of aneuploidy and heterogeneity in DNA ploidy within one tumor by multiple sampling.
Methods: Using flow cytometry, the authors measured the nuclear DNA content of cells in fresh surgical specimens from 24 patients with carcinoma of the extrahepatic bile duct, 8 patients with carcinoma of the gallbladder, 5 patients with carcinoma of ampulla of Vater, and 14 patients with carcinoma of the pancreas.
Results: The frequency of aneuploidy was 91.7%, 87.5%, 80.0%, and 85.7% in carcinoma of the extrahepatic bile duct, gallbladder, ampulla of Vater, and pancreas, respectively. The incidence of heterogeneity in DNA ploidy within a tumor was 79.2%, 87.5%, 80.0%, and 85.7% in carcinoma of the extrahepatic bile duct, gallbladder, ampulla of Vater, and pancreas, respectively. The DNA index ranged mostly from 1.0-2.0. Hypodiploid samples constituted 23.5% of the total, and only five (9.8%) had a DNA content above tetraploid. Many of the patients in which the DNA index was about 1.0 (including diploid cases) tended to be in the relatively early stages of the disease.
Conclusions: It is necessary to take several fresh samples from the same tumor to accurately measure the variations in nuclear DNA content. The authors suggest that three or four samples should be studied to determine aneuploidy and that DNA ploidy heterogeneity should be analyzed in five or six samples.