Abstract
Cytogenetic banding studies were performed on direct preparations from 31 large bowel tumors. Twenty‐eight of these were from primary sites and three from metastases. Some distinctive patterns were observed. The 31 tumors were separable into four groups: (1) Tumors with normal karyotypes (three cases); (2) tumors with simple gains of chromosomes (three cases); (3) tumors with gains, losses and structural aberrations (ten cases). Groups 1, 2 and 3 were all in the diploid range; and (4) tumors with hypotriploid‐hypotetraploid karyotypes (15 cases). Non‐random gains of several chromosomes, especially No. 8 and non‐random losses of No. 17 were seen in this series. Thirteen cases had sex chromosome abnormalities. The most prominent structural abnormalities involved chomosomes No. 1 and No. 5. Marker chromosomes were sometimes absent, but when present ranged from simple translocations to the most complex rearrangements. Doubling of chromosome and/or marker chromosomes were prominent in Group 4. Double minutes were seen in all three metastatic tumors and three primary cancers. Premature chromosome condensation was observed in three cases in the hypotriploid‐hypotetraploid group.