C5AR2 and breast cancer: In analogous to this emerging paradigm of the functional heterogeneity of CAFs, in human breast cancer and NSCLC tissues, a distinct subpopulation of CAFs was found to express CD10 as well as the complement 5 a receptor G-protein coupled receptor 77 (GPR-77) and are proficient in promoting CSCs and their stemness properties and inducing chemoresistance of tumor cells through persistent NF-κB activation along with the resultant IL-6 and IL-8 secretion (72).