Estrogen prevents sustained COLO-205 human colon cancer cell growth by inducing apoptosis, decreasing c-myb protein, and decreasing transcription of the anti-apoptotic protein bcl-2.

The proto-oncogene c-myb is overexpressed in human colon cancer cells. c-myb is known to be affected by estrogen in some breast cancers and leukemias. However, the mechanism of c-myb regulation via estrogen in colon cancer requires further investigation.