CYCS and cancer: Meanwhile, treatment of acquired chemoresistant cancer cells with Robo and cyc, specific small molecular inhibitors targeting SHh and Smo, respectively [28,29], caused significant reductions of the aberrant Hh pathway activity in acquired chemoresistant cancer cells K562/A02 and KB/VCR, whereas both Robo and cyc did not affect Hh pathway activity in respective chemosensitive cells (Figure 1B).