Although we only determined MMP-2 expression in the current study, another study focusing on liver cancer found no change in TIMP-1 and TIMP-2 protein expression after the administration of Shh-N, anti-Shh, or cyclopamine, which suggests that TIMP-1 and TIMP-2 are not directly involved in Shh-mediated induction of MMP-2 expression [16]. Here, MMP2 is linked to liver cancer.