SMO and pachyonychia congenita: It has also been shown that the inhibition of the hedgehog cascade, by using either an anti-SHH antibody or a specific inhibitor of smoothened (SMO) activity, such as cyclopamine, suppressed the growth and induced the apoptosis of PC cells in vitro and in vivo, whereas normal prostate epithelial cells were insensitive to the cytotoxic effects of these agents [14, 15, 19, 20].