MKI67 and breast cancer: In other cancer types such as breast cancer, patients with increased KI67 expression post‐treatment have been correlated to worse outcomes compared to those with decreased or low KI67 expression.[50] We additionally calculated apoptosis‐to‐proliferation ratios to compare chemosensitivity[22, 51] as a result of perivascular co‐culture and observed a significant increase in cPARP+/KI67+ cells in response to temozolomide treatment, but only in tumor‐only samples.