The use of the CAXII marker could improve the classification of breast tumors
Breast cancer is a heterogeneous disease, which cannot be effectively targeted by a common, single treatment. In two-thirds of cases, the estrogen receptor alpha (ERα), a receptor activated by sex hormones, is expressed and can be targeted therapeutically by hormone therapy. However, ERα levels can vary between and within tumors, complicating its detection and subsequent choice of therapy. The progesterone receptor (PR) is commonly used clinically as a co-marker for selection of tumors qualifying for hormone therapy. Indeed, this estrogen-regulated marker is thought to reflect ERa activity. In a new study published in the journal Cancers, Sylvie Mader, director of the Molecular Targeting in Breast Cancer Treatment Research Unit at IRIC, and her PhD student Lucas Porras show that PR detection imperfectly reflects ERα activity and identify a new, more reliable co-marker.