MKI67 and breast neoplasm: Finally, taking into account that an increased expression of LDHB has been associated with a high cellular viability and proliferation in previous reports [28, 29], and considering that this behavior was also observed in the MCF7Ecadvar cellular model (Fig. 5h), LDHB mRNA levels were compared in the 21 breast tumor tissues grouped according to the Ki-67 labeling index (samples with Ki-67 < 20% and samples with Ki-67 ≥ 20%).