PTP4A3 and melanoma: Indeed, transient down-regulation of PRL-3 expression with small interfering RNA (siRNA) in DLD-1 colorectal cancer cells abrogated motility in vitro and hepatic colonization in vivo[12], and down-regulation of PRL-3 in breast cancer cells [13], melanoma cells [14], and gastric cancer cells [15] also consistently reduced motility and metastasis.