ERBB2 and breast cancer: In the groups of Luminal A and Luminal B HER2-negative BC patients, we found significantly higher concentrations of MMP-7 (1.35 ng/mL, p. = 0.002; 1.78 ng/mL, p < 0.001, respectively) and the comparative marker CA 15-3 (19.98 IU/mL, p = 0.0075; 20.2 IU/mL p = 0.0248, respectively) compared to the group of healthy women (Figure 2 and Figure 3).