(A) Levels of MCJ mRNA according to breast tumor subtypes. Levels of expression are given in arbitrary units relative to the reference standard (n ≥ 3). (B) MCJ expression according to pathological response (residual cancer burden, RCB). The graph depicts MCJ expression at the time of diagnosis for each RCB patient group. Differences between the groups were not statistically significant (n ≥ 3, P = 0.14). (C) Association between MCJ mRNA levels and clinical response based on WHO criteria: cCR (clinical complete response), cPR (clinical partial response), and cSD (clinical stable disease). Differences between the groups were significant (mean ± SEM, n ≥ 3, P = 0.04, 1-way ANOVA). Post hoc Tukey’s test was significant only for cSD vs. cPR (*P < 0.05). (D) Association between MCJ expression and clinical response based on a simplified, 2-group criteria: NR, nonresponders; R, responders. Differences between NR and R groups were statistically significant (mean ± SEM, unpaired t test, n ≥ 5, *P = 0.01). (E). Comparison between cumulative relapse-free survival rates among patients with low (≤ 3.1) or high (> 3.1) MCJ expression units (log-rank [Mantel-Cox] test, n ≥ 6, *P = 0.0336).