CPA4 is imprinted and may be a strong candidate gene for the aggressiveness of prostate cancer (36) as well as a promising diagnostic serum biomarker for both pancreatic cancer and non-small cell lung cancer (37, 38) and an adverse prognostic marker for gastric cancer, NSCLC, and colorectal cancer (37, 39, 40). Here, CPA4 is linked to prostate cancer.