[Presidential address. Biological atypism of gastrointestinal epithelia]

Detection of atypical epithelia located between normal and cancer tissues, is one of the major interests in cancer pathology as well as of cancer surgeons. Atypical epithelia of GI tract have been diagnosed mainly by morphological features so far, remaining questions of their biological profiles concerning to malignancy in some cases. Recently we have developed a new biological criterion for detection of atypical epithelia of GI tract, demonstrating antigenic reversion on it. Differentiation antigens we used in this study were CEA, IMA and M-1 and the latter two were distinctive mucus antigens detectable in the intestinal and gastric mucus, respectively in adult tissues, where CEA was negative. However, in the atypical epithelia of GI tract, CEA and both mucus antigens were generally demonstrated coincidentally , as observed at fetal GI epithelia in 10-30 gestation weeks. Clinical evaluation of this novel criterion of atypical epithelia, for example, different potentials for malignancy between gastric and colonic adenomas was also described.