The investigation from Karmali PP and colleagues demonstrated that metastatic numbers and foci in Bit1-depletion B16F1 cells were significantly increased compared with control B16F1 cells, whereas Bit1 overexpression by exogenous introduction reduced the formation of lung metastatic colonies [32], implying Bit1 functions as the suppressor of metastasis in melanoma. Here, PTRH2 is linked to melanoma.