Cytogenetic aberrations in colorectal adenocarcinomas and their correlation with clinicopathologic features

Little is known about the karyotypes of colorectal carcinomas and, in particular, about how the cytogenetic findings correlate with clinicopathologic features.

Short-term cultures from 49 colorectal adenocarcinomas were analyzed cytogenetically. The karyotypes were correlated with grade, stage, lymphocytic infiltration, and site (using the chi-square test), with patient age and tumor size (using the Student t test), and with survival (using the log-rank or Mantel-Haenszel test).

Normal karyotypes were detected in 17, simple numeric changes in 22, and multiple structural and numeric abnormalities in 10. The most common numeric aberrations were +7, -Y, -18, and -22. The most common structural rearrangements were, in decreasing order of frequency, of chromosomes 1 (eight samples, leading to loss of 1p material in five), 3, 11, 17, 6, 8, 13, and 20. Marked or moderate lymphocytic infiltration was seen significantly less often (P < 0.05) in tumors with complex chromosomal abnormalities than in those with simple anomalies or normal karyotypes. The subset of patients who had tumors with multiple chromosomal abnormalities had a significantly shorter survival time (P < 0.025) than those who had lesions with simple changes or normal karyotypes.

Loss of 1p material is the most consistent chromosomal change in colorectal carcinomas but probably represents a progressional rather than a primary event. Structural changes of chromosomes 3 and 11 seem to be more common in tumors located in the distal part of the large intestine. The significantly shorter survival time of patients with complex aberrations indicates that the karyotype could be used as a prognostic parameter in patients with colorectal cancer.