Testing of multiple samples increases the sensitivity of stool decay-accelerating factor test for the detection of colorectal cancer.
OBJECTIVE
We previously reported that the measurements of stool decay-accelerating factor (DAF), a membrane-bound, complement regulatory protein, may be valuable for the detection of colorectal cancer. Recently we have refined the immunoassay for stool DAF. In the present study, using the refined assay, we measured stool DAF concentrations in multiple samples from patients with colorectal cancer and in healthy controls to determine whether testing of multiple samples would increase the sensitivity of the stool DAF test.


METHODS
DAF was measured in three spontaneously passed stool samples from each of 100 patients with colorectal cancer and 100 control subjects without apparent colorectal disease.


RESULTS
The stool DAF concentrations in the patients with colorectal cancer (median 11.1 ng/g stool; interquartile range 2.9-32.7 ng/g) were significantly higher than concentrations in the subjects without colorectal diseases (median 1.6 ng/g stool; interquartile range 0.4-3.4 ng/g) (p<0.0001). Testing of two samples from each patient significantly increased the sensitivity (72%) of the stool DAF test without significantly decreasing its specificity (92%). The stool DAF test was positive in more than one half of patients with colorectal cancer at a relatively early TNM stage or with negative fecal occult blood test.


CONCLUSIONS
These findings suggest that stool DAF is a marker of colorectal cancer independent of fecal occult blood and testing of two samples increases the sensitivity of the stool DAF test. Measurement of stool DAF now seems worthy of further consideration as a noninvasive method for the detection of colorectal cancer.
Mizuno
Masakatsu
M
Department of Medicine and Medical Science (Medicine 1), Okayama University Graduate School of Medicine and Dentistry, Okayama, Japan.
Mizuno
Motowo
M
Iwagaki
Naofumi
N
Nasu
Junichirou
J
Okazaki
Hiroaki
H
Yamamoto
Kazuhide
K
Okada
Hiroyuki
H
Tsuji
Takao
T
Fujita
Teizo
T
Shiratori
Yasushi
Y
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D018958:CD55 Antigens / Q000032:analysis*; D016022:Case-Control Studies; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D016001:Confidence Intervals; D005243:Feces / Q000737:chemistry*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011336:Probability; D011379:Prognosis; D012016:Reference Values; D012680:Sensitivity and Specificity
D014408:Biomarkers, Tumor; D018958:CD55 Antigens