Detection of decay-accelerating factor in stool specimens of patients with colorectal cancer.

Colorectal cancers have an increased expression of decay-accelerating factor (DAF). The aim of this study was to determine whether stool specimens of patients with colorectal cancer contain increased amounts of DAF. DAF was measured using an immunoassay in the stool specimens of 40 persons with colorectal cancer, 18 with colorectal adenomatous polyps, 13 with upper gastrointestinal cancer, and 41 without gastrointestinal disease. Stool DAF concentrations in patients with colorectal cancer (0-9.8 ng/g stool; median, 1.6 ng/g) were significantly higher than those in patients with adenoma (0-6.4 ng/g; median, 0 ng/g) (P < 0.05), patients with upper gastrointestinal cancer (0-3.1 ng/g; median, 0 ng/g) (P < 0.05), and subjects without gastrointestinal disease (0-3.4 ng/g; median, 0 ng/g) (P < 0.01). Resection of colorectal cancers caused a marked decrease in stool DAF concentrations. The stool DAF test was positive in a substantial portion of patients with colorectal cancer whose tumors were small ( < 2 cm), at an early TNM stage, or unassociated with fecal occult blood positivity. The sensitivity of the test for colorectal cancer was 55%, and the specificity was 85%. The measurement of stood DAF deserves evaluation as a test for detection of colorectal cancer.