The Hedgehog Signaling pathway is critical in proper tissue patterning and orientation during normal development of most animals. Hedgehog proteins induce cell proliferation in certain cells and differentiations in others. Aberrant activation of the Hedgehog pathway has been implicated in several types of cancers, Basal Cell Carcinoma in particular. This uncontrolled activation of the Hedgehog proteins can be caused by mutations to the signal pathway, which would be ligand independent, or a mutation that causes overexpression of the Hedgehog protein, which would be ligand dependent. In addition, therapy-induced Hedgehog pathway activation has been shown to be necessary for progression of Prostate Cancer tumors after androgen deprivation therapy. This connection between the Hedgehog signaling pathway and human cancers may provide for the possible of therapeutic intervention as treatment for such cancers. The Hedgehog signaling pathway is also involved in normal regulation of stem-cell populations, and required for normal growth and regeneration of damaged organs. This may provide another possible route for tumorigenesis via the Hedgehog pathway.