Prostate adenocarcinoma (PRAD), driven by both genetic and epigenetic factors, is a common malignancy that affects men worldwide. We aimed to identify and characterize differentially expressed epigenetic-related genes (ERGs) in PRAD and investigate their potential roles in disease progression and prognosis. We used PRAD samples from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) to identify prognosis-associated ERGs. Thirteen ERGs with two distinct expression profiles were identified through consensus clustering. Gene set variation analysis highlighted differences in pathway activities, particularly in the Hedgehog and Notch pathways. Higher epigenetic scores correlated with favorable prognosis and improved immunotherapeutic response. Experimental validation underscored the importance of CBX3 and KAT2A, suggesting their pivotal roles in PRAD. This study provides crucial insights into the epigenetic scoring approach and presents a promising prognostic tool, with CBX3 and KAT2A as key players. These findings pave the way for targeted and personalized interventions for the treatment of PRAD.