MYCOSIS-FUNGOIDES - EXPRESSION OF C-MYC P62 P53, BCL-2 AND PCNA PROTEINS AND ABSENCE OF ASSOCIATION WITH EPSTEIN-BARR-VIRUS

The expression of C-myc p62, bcl-2, p53, PCNA and EB V-encoded LMP-I p roteins was studied by immunohistochemistry on paraffin-embedded skin specimens from 14 patients with early stage (premycotic erythema and s econd stage plaques) mycosis fungoides (MF), 21 patients with advanced stage MF (third stage plaques and tumors), 3 patients with Sezary's s yndrome (SS) and 3 patients with pleomorphic medium and large cell cut aneous T-cell lymphomas (PML-CTCL). All 41 cases were also screened fo r the presence of EBV by using RNA in situ hybridization with EBER 1/2 oligonucleotides. Increased expression of C-myc p62, p53 and PCNA pro teins was found in PML-CTCL and advanced stages of MF as compared to e arly stages of ME These results suggest a relationship between levels of c-myc p62, p53 and PCNA proteins and aggressiveness of the cutaneou s T-cell lymphomas. Furthermore, C-myc p62 and bcl-2 proteins were fou nd to be frequently coexpressed in the present series. In view of the background information from in vitro findings and animal models that c ooperation of C-myc and bcl-2 is important for lymphomagenesis, our re sults suggest that coexpression of these oncogenes may be implicated i n the pathogenesis and/or the progression of cutaneous T-cell lymphoma s. Neither LMP-1 expression nor EBV EBER1/2 transcripts were detected in our series suggesting that EBV is not involved in the pathogenesis of cutaneous T-cell lymphomas.