However,
along with this seemingly linear storyline in which retinoids block progesterone's promotion of CK5 + cells, previous work in the lab of CU Cancer Center investigator Peter Kabos, MD, and others shows that breast cancers treated with anti-estrogen drugs like tamoxifen or
aromatase inhibitors show an increased population of CK5 + cells — it is as if these therapies remove the roadblock of estrogen - dependent cells, leaving CK5 + cells to proliferate.
Dr. Oesterreich and her colleagues propose that future studies look at offering a combined therapy that,
along with
aromatase inhibitors, also introduces drugs that modify the epigenome to prevent or delay the cancer from repressing cancer - killing genes.