In luminal B and TN samples, the IH expression score was significantly lower for IP3R1 than for IP3R2 and IP3R3 (IH expression scores in luminal B BC: 0.62 ± 0.21 (N = 14) for IP3R1, vs. 1.54 ± 0.18 (N = 9; p = 0.002) for IP3R2 and 1.54 ± 0.18 (N = 15; p = 0.0002) for IP3R3 and IP3R1 IH expression scores in TN BC: 0.51 ± 0.36 (N = 8) for IP3R1 vs. 1.97 ± 0.26 (N = 6; p = 0.01) for IP3R2 and 1.48 ± 0.32 (N = 8; p = 0.02) for IP3R3) (Figure 5B,C). This evidence concerns the gene ITPR1 and breast cancer.