TP53 and colorectal cancer: While little is known about the role of GSTA4 in cancer, particularly in colorectal cancer, previous studies have demonstrated that transfection of primary cell lines with human GSTA4-expressing plasmids causes cellular transformation and immortalization via upregulation of transforming growth factor, cyclin-dependent kinase 2, and protein kinase C beta II and downregulation of p53 (35).