Intratumoral regional heterogeneity of DNA ploidy patterns in colorectal carcinomas

There is no agreement on the evaluation of intratumoral DNA ploidy heterogeneity, and its clinical significance remains controversial. We categorized intratumoral ploidy heterogeneity in an effort to avoid confusion and misunderstanding among investigators. We classified the heterogeneity into 3 major types (Types A, B and C) and a combined type (Type D), based on the intratumoral distribution profiles of DNA aneuploid lines identified by flow cytometry in 52 cases of colorectal cancer with intratumoral DNA ploidy heterogeneity selected from a consecutive series. Every carcinoma examined in this study fell into one of the 4 categories: Twenty-six tumors (50%) were classified as Type A, 6 (11%) as Type B, 2 (3%) as Type C, and 18 (36%) as Type D. We discussed the mechanisms of DNA ploidy heterogeneity evolution within a tumor, and also proposed a pathway to these types of DNA ploidy heterogeneity as an aid to understanding the relationship between tumor progression and DNA ploidy changes.