MKI67 and hereditary clear cell renal cell carcinoma: Importantly, within a subcutaneous renal cell carcinoma xenograft model, administration of C. acnes via an intraperitoneal injection also increased the number of Ki-67-positive renal cell carcinoma cells, as well as the number of CD31-positive endothelial cells, indicating that C. acnes can potentially regulate angiogenesis [126].