Authors: Izquierdo M, Tresserra F, Gallardo M, Baulies S, Ara C, García S, Rodríguez I, Fábregas R.
Background: The proliferative activity of the tumor-measured immunohistochemically by Ki-67 has a high variability. Clinical use can be improved if its measurement is considered with the histological grade.
Methods: Ki-67 was studied in 566 breast cancers from 2007 to 2013 in our institution using the monoclonal antibody MIBI. The histological grade and the status of the hormonal receptors were also evaluated.
Results: In 293 (51.7%) tumors the histological grade was I, in 219 (38.7%) tumors was histological grade II and III in 54 (16.8%) tumors. The estrogen receptor was positive in 166 (29.5%) tumors and the progesterone receptor was positive in 95 (16.8%) tumors. None of the tumors with a histological grade III had a Ki-67 value of less than 10%. Only in 1 case (7%) of tumors with histological grade I had a Ki-67 greater than 25%.
Conclusion: Ki-67 values higher than 25% should be repeated and confirmed in those cases a histological grade I, and Ki-67 values lower than 10 in cases with histological grade III.
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