ITPR1 and breast cancer: In luminal A BC, there were no significant differences in the IH expression scores for the three IP3R subtypes (IH expression scores in luminal A BC: 0.97 ± 0.17 (N = 17) for IP3R1, vs. 1.61 ± 0.16 (N = 14) for IP3R2 and: 1.33 ± 0.17 (N = 17) for IP3R1; p = 0.2) (Figure 5A).