A new approach to fecal occult blood testing based on the detection of haptoglobin.
BACKGROUND
Colorectal carcinoma is a common disease, occurring in 1 in 20 adults in Western society, and there is a compelling need for an effective early diagnostic test. Several serum tests, including carcinoembryonic antigen have been used, but none are sufficiently sensitive for the early diagnosis of the disease.


METHODS
In a novel approach using fecal extracts from patients with colorectal cancer as the antigen for immunization, several MoAbs were produced. One (FE14.1) was found to react with the feces from patients with colon cancer, but not with those from normal subjects. A sandwich enzyme-linked immunoadsorbent assay was developed, and its ability to diagnose colorectal carcinoma evaluated.


RESULTS
Of the patients with colorectal carcinoma, 91.5% (43/46) were positive compared with 1.9% of normal individuals (4/211). Analysis of the N-terminal amino acid sequence of a subunit of the molecule detected by FE14.1 shows it to be the beta chain of haptoglobin.


CONCLUSIONS
The assay developed in this study has several advantages compared with current fecal occult blood tests, including no requirement for dietary restriction and the ability to distinguish between upper and lower gastrointestinal bleeding, while retaining the sensitivity and specificity of the current tests. Furthermore, the sensitivity of the tests increases to 100% if the FE14.1 and HemeSelect are combined. In addition, the study shows the potential to produce anticancer agents by immunizing with fecal material.
Xing
P X
PX
Austin Research Institute, Heidelberg, Australia.
Young
G P
GP
Ho
D
D
Sinatra
M A
MA
Hoj
P B
PB
McKenzie
I F
IF
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor / Q000032:analysis*; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006242:Haptoglobins / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009780:Occult Blood; D012680:Sensitivity and Specificity
D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D006242:Haptoglobins