New Insights in Histogenetic Pathways of Gastric Cancer.

The aim of this paper was to describe 3 possible histogenetic pathways for poorly cohesive (diffuse) carcinomas and 2 for intestinal-type gastric carcinomas (GCs), which might influence the behavior of GC. In the present observational study, 102 patients with early (n = 50) and advanced GCs (n = 52) were evaluated, and the histogenetic background was analyzed. All of the cases were sporadic GCs. For particular aspects, Maspin, E-cadherin, and SLUG immunostains were performed. For our final conclusions, the results were correlated with literature data. In early stages, poorly cohesive carcinomas can display 3 histogenetic pathways, with particular molecular behaviors: "carcinoma with intraepithelial pagetoid onset" (with or without a switch from E-cadherin to SLUG positivity), "carcinoma with early lymphatic invasion" (carcinoma limited to mucosa but with carcinomatosis of the lymph vessels from subjacent layers), and "microglandular-type poorly cohesive carcinoma" (the onset is similar with adenocarcinoma but abrupt dedifferentiation can be seen in the submucosa, with persistence of a dual component in the deep layers). The intestinal type carcinoma can be developed on the background of superficially located dysplasia ("classic adenocarcinoma") or in the submucosal heterotopic mucosa ("adenocarcinoma arising from the mucosal infolding in the submucosa"). Based on personal observations correlated with literature data, 5 histopathogenetic pathways are proposed with specific denominations. Each of them can partially explain the aberrant behavior of early gastric cancer.