Background: Although serum p53 autoantibodies (s-p53-Abs) are induced even in the early stages of colorectal cancer, their positive rate is only approximately 20%. Therefore, we assessed the possibility of using other serum autoantibodies to increase the positive rates for detecting colorectal cancer.
Methods: Autoantibodies against 17 tumor antigens (p53, RalA, HSP70, Galectin1, KM-HN-1, NY-ESO-1, p90, Sui1, HSP40, CyclinB1, HCC-22-5, c-myc, PrxVI, VEGF, HCA25a, p62, and Annexin II) were evaluated in 279 patients with colorectal cancer and 74 healthy controls. Cutoff values were fixed at mean + 3 standard deviations of serum titers in healthy controls.
Results: Autoantibodies with the highest positive rates were p53 (20%), RalA (14%), HSP70 (12%), and Galectin1 (11%). Combination assays using multiple autoantibodies increased the positive rates based on the number of autoantibodies used. Positive rates of 56, 62, 66, 71, and 73% were obtained with 6, 9, 11, 14, and 17 antibodies, respectively, for the overall disease. Moreover, these autoantibodies showed relatively high positive rates even during stage 0/I disease (55 and 70% with 6 and 17 antibodies, respectively).
Conclusion: The measurement of set of 17 autoantibodies allowed autoantibody profiling in patients with colorectal cancer. The combination assay of six tumor antigens (p53, RalA, HSP70, Galectin1, KM-HN-1, and NY-ESO-1) achieved a positive rate of 56%. Such high positive rates will be helpful for detecting colorectal cancer regardless of tumor stages.
Keywords: Autoantibody; Colorectal cancer; HSP70; RalA; p53.