Seven out of twenty proteins were observed differentially abundant between PCa and BPH (KNG1, IGHA1, IGHA2, HBB, ITIH4, AMBP, and MASP2), nineteen differed in abundance between PCa and BC (TF, KNG1, IGHA1, IGHA2, ATE1, FGG, AZGP1, HP, FGA, ITIH4, AMBP, PTGDS, IGKC, APCS, VMO1, CD59, RBP4, MASP2, and HSPG2) and only two proteins (IGHA1 and IGHA2) showed differential abundance between PCa and RC groups. The gene discussed is MASP2; the disease is benign prostatic hyperplasia.