Zollinger-Ellison syndrome, acromegaly, and colorectal neoplasia.

Zollinger-Ellison syndrome (ZES) and acromegaly are two hypersecretory states in which colorectal neoplasia has been described, but the incidence in the former condition may not be increased. We describe four patients with colorectal neoplasia associated with the ZES and review other published cases. Tissue ELISA with Adnab-9 antibody, a putative colorectal cancer risk marker, from a patient with ZES and from seven patients with acromegaly was compared to 13 controls at average risk for colorectal neoplasia. The patient with ZES without detectable colonic neoplasia and seven patients with acromegaly had increased binding of Adnab-9 in the colonic mucosa by ELISA. The difference was significant for the acromegaly patients compared to the controls (p < 0.05). The accumulated 34 instances of colorectal neoplasia in ZES patients suggests that this association may not be rare. Adnab-9 expression, detectable in both ZES and acromegaly, may reflect predisposition to colorectal neoplasia in both hyper-secretory states. Therefore, while a basis for association of colorectal neoplasia and hypergastrinemia exists, the clinical data are not compelling enough to warrant surveillance of patients with ZES. To resolve this problem, more definitive case control studies should be conducted.

Cellular distribution of a colonic adenoma-associated antigen as defined by monoclonal antibody Adnab-9.

Adenomatous colonic polyps constitute a precursor for colorectal cancer. Antibodies to these precancerous lesions might identify specific early tumor antigens. Adnab-9 is a murine monoclonal antibody raised against membranes of colonic adenomas. Adnab-9 binding in colonic washings (effluent) correlates with the presence of colorectal cancer. Immunohistochemical staining with Adnab-9 shows cytoplasmic reactivity in scattered cells in 4 of 31 adenomatous tissue sections, 0 of 14 sections of colorectal cancer cells, and 1 of 8 normal-appearing colonic mucosa specimens examined. Adnab-9 recognized a dominant M(r) 87,000 protein species in tissue extracts in the membrane-bound fraction of effluent by Western blotting. Adnab-9 binding by enzyme-linked immunosorbent assay in adenomatous extracts is higher than cancer or normal tissue, is membrane-bound, and is absent from established colorectal cancer cell lines. This distribution and nature of immunostaining suggest that Adnab-9 recognizes a determinant associated with the membrane component of a subpopulation of adenoma cells which may have a role in early colorectal neoplasia.