Implication of the RAS and MYC oncoproteins in the pathogenesis of Mycosis Fungoides

In the present work, we studied the expression of the c-myc oncoprotein p-62 and the ras oncoprotein p-21 in the dermal cellular infiltrate of paraffin embedded skin specimens, obtained from patients suffering from Mycosis Fungoides and Sezary syndrome. Nineteen specimens from early stage Mycosis Fungoides, nineteen from advanced stage Mycosis Fungoides and four from Sezary syndrome were included in the study. The oncoprotein detection was achieved immunohistochemically, using the mouse monoclonal antibody myc 1-9E10 and the rat monoclonal antibody Y13-259 for p-62 and p-21 respectively. Increased detection of both p-62 and p-21 in atypic lymphoid cells was shown in advanced stages of Mycosis Fungoides (third stage plaques and tumors) as compared to early stages (premycotic erythema, second stage plaques). In advanced stages, however, the percentage of P-62+ atypic cells proved to be higher than that of p-21+ atypic lymphoid cells. The implication of increased p-62 and p-21 oncoprotein expression in the process of lymphomagenesis in cutaneous T-cell lymphomas is discussed.