Immunoreactivity to neurohormonal polypeptide in colorectal carcinomas and tumor-neighboring mucosa, and its significance.

Abstract

To clarify whether advanced colorectal carcinomas possess an amphocrine nature and produce both pancreatic and gut neurohormonal polypeptide and epithelial mucin in comparison with surrounding colorectal mucosa. Retrospective analysis of paraffin-embedded specimens from 100 cases of colorectal carcinoma (39 colonic and 61 rectal) and surrounding mucosa, with histochemical and immunohistochemical studies. The immunoreactivity of the carcinomas and surrounding mucosa by the labeled streptavidin-biotin complex method for polyclonal rabbit antibody against human vasoactive intestinal polypeptide, pancreatic polypeptide, and somatostatin was 61%, 59%, and 82% respectively; that of mucosa neighboring immunoreactive tumors was 87%, 85%, and 90%; and that of mucosa neighboring nonimmunoreactive tumors was 67%, 63% and 61%. Double staining for different types of neurohormonal polypeptide revealed that most carcinoma cells had a multiendocrine nature, and a number of neurohormonal polypeptide--positive and epithelial mucin-positive carcinoma cells (amphocrine cells) were found in almost every histological type of carcinoma by double staining for immunoreactivity and periodic acid-Schiff reaction or mucicarmin. Colorectal carcinomas exhibit not only multiendocrine characteristics, producing various types of neurohormonal polypeptide, but also amphocrine characteristics of different grades, and most tumor-neighboring crypt cells possess those characteristics, too. We concluded that these characteristics of colorectal carcinomas may be related to their origin as multipotential endodermal stem cells.