 The antiproliferative B-cell translocation gene 2 (BTG2(TIS21/PC3)) is emerging as an important regulator of cell cycle dynamics.     ///    "Our results therefore indicate an imperfect correlation between the terminally differentiated phenotype and BTG2(TIS21/PC3) expression, but no correlation between basal cellular proliferative or apoptotic indices and BTG2(TIS21/PC3) expression levels.. "    ///    "Highest levels of BTG2(TIS21/PC3) expression were seen in kidney proximal tubules, lung alveolar bronchial epithelium and in the basal cell layer of prostate acini. "    ///    "BTG2(TIS21/PC3) expression increases in response to the induction of DNA damage, cell differentiation, cell quiescence, cell contact, and as part of a positive feedback mechanism in response to growth stimulation. "    ///    The objective of the present study was to provide further insight into the biological function of BTG2(TIS21/PC3) by determining the expression levels and cellular localization of BTG2(TIS21/PC3) in a spectrum of normal human tissues and to determine the proliferative indices (based on Ki-67 staining) and apoptotic indices (based on TUNEL assay) in those cell populations where BTG2(TIS21/PC3) was differentially expressed.     ///    BTG2(TIS21/PC3) was expressed at significantly different levels within the different epithelial populations of the kidney (proximal vs distal tubules) and prostate (acinar basal cells vs lumenal cells). 