Inversion (16)(p13q22) in tumor cells of sigmoid colon.

We report on the cytogenetic findings in direct preparations of two tumors of the sigmoid colon. Respectively, they had a near-triploid and a near-tetraploid constitution and relative numerical and other inconstant chromosomal imbalances. The only constant chromosomal structural anomaly apparently was inversion of chromosome #16, inv(16)(p13q22), which was found in all the cells examined. This rearrangement has been found to be associated with a type of acute myelomonocytic leukemia type M4. We suggest that an etiologic clastogenic (and oncogenic) agent responsible for this rearrangement may eventually be the cause of various kinds of malignancy.