Multiple markers of malignancy in sera of patients with colorectal carcinoma: preliminary clinical studies.

Eleven potential biochemical markers were measured in serum from 33 patients with malignant and 13 with benign colorectal disease: four isoenzymes (creatine kinase-BB, homoarginine-sensitive alkaline phosphatase, salivary-type amylase, and macro-creatine kinase type 2), five specific proteins (ferritin, alpha 1-acid glycoprotein, C-reactive protein, alpha 1-antitrypsin, and ceruloplasmin), one oncofetal antigen (carcinoembryonic antigen, CEA), and one hormone (beta human choriogonadotropin). The sensitivity of individual markers for the detection of early-stage malignancy (n = 11) ranged from 0% to 64% (CEA 18%); for late-stage colon malignancy (n = 12) from 8% to 83% (CEA 83%). Specificity in patients (n = 10) with benign intestinal disease ranged from 80% to 100% (CEA 100%). The five most-sensitive markers--C-reactive protein, alpha 1-glycoprotein, CEA, macrocreatine kinase type 2, and homoarginine-sensitive alkaline phosphatase--were selected for use as a "colon panel." In retrospective comparison, use of the colon panel instead of CEA alone increased sensitivity by 17% and 64% for late-and early-stage cancer, respectively; specificity, however, decreased by 30%, but should improve with serial testing.