PROX1 and breast cancer: In contrast, loss of PROX1 function has been detected in hematologic malignancies, sporadic breast cancer, and carcinomas of the biliary system.21–23 Mutations and DNA methylation appear to be the major causes behind loss of PROX1 function in some tumors.22–24 Recently, an antimetastatic role of PROX1 was observed in PROX1-silenced hepatocarcinoma cell lines via TWIST1 gene inhibition.25 In OSCC, Sasahira et al26 demonstrated that PROX1 and FOXC2 act as oncogenes by inducing lymphangiogenesis and angiogenesis.