Fig. 3.

Different tiers of tumors based on their origins with respect to development stages of stem cells regulated by NuRD/CRCs. Tumor I and II are derived from so-called ‘stem cells’ in sense of their differentiation potency. Type I occurs when the differentiated cells fail to lose proliferation potential, especially malfunctions of NuRD/CRCs; while type II occurs when abnormal cell types are generated unexpectedly. Tumor III and IV are derived from differentiated cells at each level. Type III occurs when the reverse process of differentiation fails to produce the expected progenitors; type IV occurs when the doomed terminal cells ‘create’ their own descendant cell types, regaining capability of proliferation. NuRD/CRCs could have abnormal functions during such processes. Such stem cell biology could be at part directly tested in models of anchor cell (AC) invasion, vulva development in C. elegans