The mean density of CD8+Ki67+ cells ranged from 29 ± 68 cells/mm2 in pancreatic cancer to 128 ± 300 cells/mm2 in gastric cancer, while the mean CD8+Ki67+ proliferation rate ranged from 9.6 ± 13.2% in breast cancer to 25.8 ± 21.6% in ovarian cancer. This evidence concerns the gene MKI67 and breast carcinoma.