Differentially expressed Ptp4a2 (protein tyrosine phosphatase 4a2, also known as protein-tyrosine phosphatase of regenerating liver 2 or PRL-2) is a widely expressed gene (Dumaual et al. 2006) and is found overexpressed in some cancers (Hardy et al. 2010). The gene discussed is PTP4A2; the disease is cancer.