The differences in plasma samples that were observed between the gastrointestinal carcinoma patients and unaffected individuals suggest that the protein expression of heparanase-1 (50 kDa) and heparanase-2 and also the enzymatic action of heparanase-1 and cathepsin B can possibly be used to detect the presence of carcinoma. This evidence concerns the gene HPSE2 and digestive system carcinoma.