STC2 and Familial prostate cancer: Under physiological conditions, STC2 is highly expressed in skeletal muscle, heart, testis and pancreas [8, 10]; while under pathological conditions, STC2 is upregulated in a plethora of human tumours, including hepatocellular carcinoma (HCC), cervical cancer, nasopharyngeal carcinoma, colorectal cancer, gastric cancer, oesophageal squamous cell carcinoma, prostate cancer, renal cell carcinoma, etc. [7, 8, 11, 12].