PAX2 (Paired box gene 2)

PAX2 is the second member of the nine-member PAX gene family. PAX2's role begins as a developmental gene in late primitive streak stage embryos (Dressler et al., 1990). If PAX2 becomes expressed out of its normal context, its powerful functions as a transcription factor and epigenetic regulator (reviewed in Robson et al., 2006) can be recruited to the advantage of cancer cells (Robson et al., 2006; Li and Eccles, 2012). Normally PAX2 has key roles during embryogenesis, particularly in epithelial cell differentiation from mesenchyme (Rothenpieler and Dressler, 1993), such as in kidney development, and in mammary gland ductal morphogenesis (Silberstein et al., 2002). There is a requirement for the attenuation of PAX2 expression during development, particularly for the terminal differentiation of nephrogenic precursors (Dressler et al., 1993). Following the completion of development, PAX2 is capable of being re-expressed, such as in instances of nephrotoxicity or in other kidney damage (Cohen et al., 2007). In adult tissues, PAX2 is normally expressed in the pancreas (Zaiko et al., 2004), and also in subpopulations of nodal lymphocytes (Gilmore and Dewar, 2011). When expressed out of its normal context, expression of PAX2 is frequently observed in several cancer types (Robson et al., 2006). Expression of PAX2 has been linked with cell survival (Torban et al., 2000; Muratovska et al., 2003), cell migration and invasion (Buttiglieri et al., 2004), and mesenchyme-epithelial transition (MET) and epithelial-mesenchyme transition (EMT) (Doberstein et al., 2011)