Expression of a marker for colonic crypt base cells is correlated with poor prognosis in human colorectal cancer

Abstract

Background: There is a need for markers in colorectal cancer which will allow subclassification of stage groups into subgroups with high versus low risk of recurrent disease.

Aims: To develop monoclonal antibodies that recognise antigens or immature crypt base cells, on the assumption that in a neoplasm undifferentiated but not the terminally differentiated cells will be responsible for tumour progression.

Methods: Colon crypt cells which were isolated from human colonic mucosa by EDTA/EGTA incubation were studied. By stepwise harvesting, crypt base cell enriched fractions were obtained, and after incubation with antibodies against dominant antigens, used as immunogens.

Results: Of one crypt base cell specific antibody (5E9), the reactive epitope appeared to be a non-terminal carbohydrate in the mucin O-glycans of the colon. The epitope did not seem to be colon specific, but was expressed in a variety of other tissues. In colorectal carcinomas, 5E9 immunoreactivity identified a subgroup of patients with a tendency for worse prognosis.

Conclusion: A mucin associated maturation epitope was identified in colonic crypt base cells, the expression of which in Dukes' stage B3 colorectal carcinoma may be associated with poor prognosis.

Figure 1

Immunoreactivity pattern of the monoclonal antibody 5E9 on various normal human tissues: (A) normal colonic mucosa; (B) pancreas; (C) gall bladder; (D) transitional colonic mucosa; (E) intestinal metaplasia in the stomach; (F) cervix uteri: squamocolumnar junction.

Figure 2

5E9 immunoreactivity pattern in colorectal adenocarcinoma: (A) overview; (B) detail.

Figure 3

5E9 immunoelectron microscopy. 5E9 immunogold reactivity is located intracellularly in goblet cells on the outer rim of mucin vacuoles: (A) overview; (B) detail.

Figure 4

Kaplan-Meier survival curves for colorectal adenocarcinoma with 5E9 immunoreactivity: (A) Dukes' stage A, B1, and B2 (p=0.75, n=63); (B) Dukes' stage B3 (p=0.037, n=117); (C) Dukes' stage C1 and C2 (p=0.95; n=91). Dotted lines, 5E9 expression; solid lines, no 5E9 expression.