Mast cells in colorectal neoplasias and premalignant disorders.

Mast cells have recently been found to be well correlated with the prognosis of patients with rectal cancer. This work aimed to characterize the role of mast cells in colonic premalignant conditions. Mast cells were quantified in various colonic disorders, particularly those with premalignant potential. Possible avenues of mast cell action were investigated using these tissue samples, by measuring basement membrane and collagen layer thickening. The mean number of mast cells in carcinoma sections was 0.967/0.9 mm2, in various colorectal neoplasias and related conditions it ranged from 1.36-3/0.9 mm2, and in normal histologic specimens it was 11.90/0.9 mm2. These data established statistically significant differences in mast cell numbers in the colonic disorders studied. The number of mast cells is greatest in the lamina propria level of the colon, a site often not examined because of the limited depth of samples obtained from endoscopic biopsies. Mast cell numbers were found to be correlated to the development from premalignancy to colonic malignancy. Mast cells may be useful as markers of colorectal neoplasia.