GSTP1 and cancer: Moreover, results from several previous studies suggest that detection of hypermethylated GSTP1 and APC in cancer-negative prostate biopsies – either only these two genes26 or in combination with RARB2 (Retinoic Acid Receptor, beta transcript 2)25 or RASSF128, 29 - may also hold potential to increase diagnostic sensitivity by predicting a positive repeat biopsy.