However, there were few researches about Robo protein in HCC at present, such as silymarin prohibited apoptosis and metastasis of HepG2 cells by down-regulating Slit2/Robo1 signaling pathway21; Robo1 was over-expressed in cancer tissues of HCC patients, and maybe a potential therapeutic target for HCC22; Slit-Robo1 signaling pathway accelerated angiogenesis of malignant melanoma and neutralizing antibody of Robo1 significantly inhibited tumor growth23. Here, SLIT2 is linked to melanoma.