PCSK1N and breast cancer: For example, Kep has been shown to negatively correlate with histological vessel maturity in breast cancer osseous metastases (29), positively correlate with Ki67 and p53- and triple negative status in breast cancers (30), positively correlate with invasive ductal carcinoma tumor size (31), and positively correlate with microvessel density (32) and PTEN expression in prostate cancer (33).