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. This evidence concerns the gene ITIH4 and breast cancer.