Biology of colon cancer: an overview

Establishment of new predictive markers for distant recurrence of colorectal cancer using lectin microarray analysis

We evaluated the clinical benefits of novel predictive markers for distant recurrence with colorectal cancer using lectin microarray analysis of cell surface glycan modifications. Glycoproteins were extracted from formalin-fixed, paraffin-embedded tumor specimens and normal epithelium from 53 consecutive curatively resected stage I–III colorectal cancer cases and then subjected to lectin microarray to obtain lectin–glycan interaction (LGI) values. In addition, clinicopathological factors associated with distant recurrence were identified. LGI values that were associated with distant recurrence were validated with an additional 55 curatively resected stage II colorectal cancer cases. LGI values for Agaricus bisporus (ABA) lectin, prominent in cancer tissues, were statistically associated with distant recurrence. ABA lectin staining exhibited strikingly intense signals in the cytoplasm and apical surfaces of cancer cells, while weak staining was observed in the supranuclear regions of normal epithelium. This ABA tumor/normal LGI ratio may be a new predictive biomarker for distant recurrence of curatively resected colorectal cancer.

Changes in [3H]galactose uptake in human colonic mucosa with carcinoma: an ultrastructural study

As part of our investigation on glycoprotein synthesis in pre-malignant colonic epithelium, changes in the uptake of [3H]galactose were studied at the ultrastructural level. Normal control mucosa from rectal biopsies of patients with no known gastro-intestinal disease and mucosa adjacent to carcinoma ('transitional' mucosa) from specimens resected for colo-rectal cancel were compared. These tissues were incubated in TC 199 medium containing [3H]galactose for various intervals of time and for pulse labelling. Silver grain distribution was statistically analysed. The results showed a reduction in the incorporation of the galactose by 'transitional' mucosa. The uptake by this mucosa was less uniform than normal and showed considerable peaking in the endoplasmic reticulum of the goblet cells and in the Golgi of the absorptive cells, suggesting a blockage or alteration in glycoprotein synthesis. The differences were most marked in the middle crypt (the region of differentiation) and in the upper crypt (the region of maturation).