KLK3 and prostate carcinoma: The MetA and MetB subtypes can be differentiated by an immunohistochemical analysis combining assessments of prostate-specific antigen (PSA; marker for cell differentiation) and Ki-67 (marker for cell proliferation) [14], two markers that, together with AR immunoreactivity (IR), have previously been associated with prognosis in prostate cancer patients with MSCC [10], [13], [14].