To investigate proteins potentially involved in the survival of prostate epithelial cells, we initially collected prostate tissues from 32 BPH patients. Subsequently, we conducted immunohistochemistry (IHC) staining using an anti-alpha-smooth muscle actin (α-SMA) antibody, recognized as a marker for smooth muscle cells and myofibroblasts. We delineated the areas of the stroma, glandular epithelium, and glandular lumen based on this staining. We digitized and conducted subsequent analysis of the relative percentage of different tissue components, including the stroma/epithelium ratio (S/E). Specimens were ranked based on the S/E ratio, leading to the categorization of the 9 specimens with the lowest S/E into group 1 (Epithelium-hi), where the epithelial components may have more significant roles in BPH development. Conversely, the 9 specimens with the highest S/E were placed in group 2 (Epithelium-lo). Within each group, we further subdivided them into 3 subgroups labeled as A through E. Subsequently, we employed isobaric tags for relative and absolute quantitation (iTRAQ)-based liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify the differentially expressed proteins (DEPs) between the two main groups.