DNA extraction from biopsy print and GSTP1 hypermethylation analysis. (A) DNA was obtained from the biopsy print and from the corresponding biopsy and 1/5 of total DNA volume was subjected to electrophoresis run in 1.8% w/v agarose gel. (B) PCR-amplified products from bisulfite converted DNA were subjected to electrophoretic separation in agarose gel. DNA was extracted from three different biopsy prints (P) and the related biopsies (B) of the same patient (#1 as in 3C). (C) GSTP1 methylation status in PCa patients evaluated in three different biopsy prints and related biopsies (+ = GSTP1 hypermethylation).