Abstract
The aim of this study was to initiate a survey of human autoantibody responses to a panel of select colorectal tumor‐associated antigens identified by previous serological analysis of a cDNA expression library and to subsequently identify multiple serological biomarkers for the detection of colorectal cancer. For screening of autoantibodies against colorectal tumor‐associated antigens, sera from 94 colorectal cancer patients and 54 normal controls were analyzed by enzyme‐linked immunosorbent assay using recombinant rCCCAP, rHDAC5, rP53, rNMDAR and rNY‐CO‐16 proteins as coating antigens. Seropositivity among colorectal cancer patients to the 5 individual coating antigens varied from 18.1% to 35.1%. Seropositivity to any of the 5 coating antigens was 58.5% and combining this analysis with evaluation of serum carcinoembryonic antigen (≥5 ng/ml) significantly increased the seropositivity to 77.6%. Seropositivity of early‐stage (Dukes' Stages A and B) colorectal cancer patients to CEA was 21.9%, and seropositivity to any of the 5 colorectal cancer‐associated antigens was 53.7%, and the combination of these 2 measurements resulted in a higher diagnostic capacity (65.9%) than either marker alone. In conclusion, these results collectively indicated that combined detection of serum autoantibody profiles against our panel of colorectal tumor‐associated antigens and the analysis of carcinoembryonic antigen provides a promising diagnostic biomarker for colorectal cancer, particularly among early‐stage patients.