PRL-2 (Protein-tyrosine phosphatase of regenerating liver 2), also known as PTP4A2 (Protein tyrosine phosphatase type IVA, member 2), is a member of PTP family and has an important function in controlling cell growth. PRL-2 phosphatases may be multifunctional enzymes with diverse roles in a variety of tissue and cell types. The phosphatase of regenerating liver (PRL) family, comprising PRL-1, PRL-2 and PRL-3, is a group of prenylated phosphatases that are candidate cancer biomarkers and therapeutic targets. PRL-1, PRL-2, and PRL-3 represent a novel class of protein-tyrosine phosphatase with a C-terminal prenylation motif. They are three closely related intracellular enzymes that possess the PTP active site signature sequence CX 5R. The PRL-2 mRNA is elevated in primary breast tumors relative to matched normal tissue, and also dramatically elevated in metastatic lymph nodes compared with primary tumors. PRL-2 plays a role in breast cancer progression. PRL-2 is a pathogenic molecule in hematopoietic malignancies and suggest its potential as a novel therapeutic target.