MKI67 and neoplasm: Since the original description in 2008, which stated that a cut-off of 14% for the Ki-67 level differentiates between Luminal A and Luminal B tumours, the cut-off value has periodically undergone adjustments, such as shifting from 20% to 30% or being described as simply low and high, depending on the midrange Ki-67 levels measured at a specific pathology institution, and these modifications are still underway even currently1,2,4,6,8,11,13,19,23,27.