MKI67 and breast carcinoma: With regards to histopathology and immunohistochemistry (IHC), (Figure 3) we did not find significant numbers of CD56+ or CD16+ NK subsets in our patient’s primary breast cancer (lobular breast carcinoma stage pT2 pN2a Mo, luminal-A, with low Ki67 positivity), but found very significant IHC staining of CD56++ and CD16++ cells in placenta and decidua tissue from unrelated abortions (not used as “controls”, but to look for NK cells in “early” placental tissues) at 6–10 weeks of gestation secondary to embryonic natural death.