The nuclear matrix is the RNA-protein network which forms the skeleton of the nucleus, and participates in DNA organization as well as in multiple cellular functions. Nuclear matrix proteins have been demonstrated to be tissue and cell type specific, as well as to reflect the state of cell differentiation and/or transformation. Previously, common nuclear matrix proteins were demonstrated between the rat prostate and the Dunning rat prostate adenocarcinoma cell lines. This study demonstrates that nuclear matrices derived from Dunning rat and human prostate cancer cell lines, as well as human tumors, share several common proteins. These common proteins suggest that alterations which occur in the nuclear matrix with prostate cell transformation may share a common basis.