The study of the expression of different biological markers in non-neoplastic, pre-neoplastic and neoplastic lesions of prostate could help to better understand their role in carcinogenesis and to find new diagnostic and prognostic tools. In the present work we evaluated, by immunohistochemistry, the presence and the expression of PCNA, p53, HSP60, HSP10 and MUC-2 in a series of nodular hyperplasia, low- and high-grade prostatic intraepithelial lesions and adenocarcinomas. Our data confirmed that: 1) PCNA expression could be related to the grade of progression of cancer; and that 2) p53 mutation could be a late event in prostate carcinogenesis. Moreover, we reported that: 1) HPS60 and HPS10 were overexpressed early in prostate carcinogenesis; and that 2) MUC-2 is absent in both tumoral and non-tumoral prostatic tissue. We suggest the further examination, by molecular and genetic studies, of the role of HSP60 and HSP10 during carcinogenesis of the prostate as well as of other organs.