SHH and neoplasm: In many tumor types, the SHH signaling pathway has been reported to crosstalk with other critical molecular signaling pathways involved in cancer, such as RAS/RAF/MEK/ERK, PI3K/AKT/mTOR, EGFR, and Notch (Liu et al., 2006; Riobo et al., 2006; Morrow et al., 2009; Wall et al., 2009; Lauth, 2011; Mangelberger et al., 2012; Das et al., 2013).