Morphogenetic aspects of colorectal cancer

Patterning is a spatial and temporal process by which ordered arrangements of cells and tissue structure are attained. The term is mostly applied to the morphogenesis in developmental pathology, but it can also be useful for the neomorphogenesis in tumor biology. Despite increasing data on the proliferation and differentiation of tumor cells, processes of tumor patterning are rarely studied and poorly understood. A fundamental embryonic process of patterning is the embryonic gastrulation and a basic patterning is found in the colonic adenomacarcinoma sequence. Both processes exhibit distinct nuclear translocation and expression of beta-catenin, which is considered to be a decisive transcriptional regulator. Our recent studies demonstrated striking analogies of patterning and nuclear beta-catenin expression between the colonic adenoma-carcinoma sequence and the steps of gastrulation. The shared patterns are dissociation, reassembly, tubular reconstruction and branching of neoplastic cells in association with nuclear beta-catenin expression. These findings establish patterning as a relevant concept for tumor formation and link the neoplastic morphogenesis with embryogenesis.