[Changes in the APUD system of the large intestine as a risk factor for colorectal cancer]

A common population of endocrine cells, apudocytes producing serotonin, melatonin, vaso-intestinal peptides and mast cells were examined on unaffected mucous membranes of 27 colorectal cancer patients. Light and electron microscopy, immunohistochemical and morphometric methods were used. A marked decrease in total number of apudocytes, hypoplasia of cells producing serotonin, melatonin, vaso-intestinal peptides were revealed at early stages of cancer irrespective of the tumor structure. Mast cells in premetastatic period outnumbered those after emergence of metastases. The results obtained may serve as additional criteria of early colorectal cancer diagnosis.