To validate the expression pattern of the two IO targets, CD274 and IL8, qRT-PCR, and western blotting were used to detect the expression of mRNA and protein from two basal-like (BT549 and MDA-MB-231) and two luminal-like (MCF7 and T47D) breast cancer cell lines (Neve et al., 2006). Here, CD274 is linked to breast cancer.