Epigenetic silencing and loss-of-function mutation of
negative regulators of the canonicalWNT pathway occur in a variety of human cancer.WNT,
fibroblast growth factor (FGF), Notch, Hedgehog, and transforming growth factor h/bone
morphogenetic protein signaling network are implicated in themaintenance of tissue homeostasis
by regulating self-renewal of normal stem cells as well as proliferation or differentiation of
progenitor (transit-amplifying) cells.