Clinical and pathological significance of numerical aberrations of chromosomes 11 and 17 in colorectal neoplasms.

Numerical chromosome aberrations by interphase cytogenetic analysis have been reported in a few samples of colorectal neoplasms. No studies have defined a distinct relationship between these aberrations and clinicopathological features. To investigate the chromosome aberrations as a marker of invasiveness or prognosis, we conducted an interphase cytogenetic study using fluorescence in situ hybridization and examined 142 colorectal neoplasms consisting of 15 adenomas and 127 cancers. The target chromosomes were chromosomes 11 and 17. We also evaluated the nuclear DNA content as detected by flow cytometry, analyzed the relationship between the frequency of aneusomy and clinicopathological features, and examined the survival rate in these patients. The loss of chromosome 11 was observed in 31% of adenomas, whereas in cancers DNA aneuploidy was observed in 63% of cases, a gain of chromosome 17 was observed in 63% of cases, and a gain of chromosome 11 was observed in 42% of cases. Numerical chromosome aberrations in diploid DNA were also observed. Increased depth of invasion (>/=T3) and advanced Dukes' stage (>/=B) of malignant tumors were associated with a higher frequency of a gain of chromosome 11 (P < 0.01 and P < 0.05, respectively). Increased depth of invasion (>/=T2) in cancers was associated with a higher frequency of a gain of chromosome 17 (P < 0.05). Multivariate analysis of postoperative survival showed that a loss or gain of chromosome 11 was independently associated with a poor prognosis (P < 0.05). Numerical chromosome aberrations appear prior to the alteration of nuclear DNA content as detected by flow cytometry and influence the progression of colorectal cancers. Aneusomy of chromosome 11 is associated with poor postoperative prognosis of primary colorectal cancers.