GSTP1 and proliferative inflammatory atrophy: GSTP1 protein is, however, expressed at high levels at times in human prostatic luminal epithelial cells, apparently in response to cellular stress and/or inflammatory oxidants in atrophic lesions referred to as proliferative inflammatory atrophy (PIA) [49], and we have previously shown that these atrophic luminally located cells are not basal cells as they lack p63 expression [50].