“…Since its introduction by Farber, Diamond & Mercer (1948) methotrexate has been established in the chemotherapy of several malignant diseases (Capizzi, de Conti, Marsh & Bertino, 1970;Mitchell, Wawro, de Corti, Kaplan, Papac & Butino, 1968;Gottlieg & Serpick, 1970;Jaffe, 1972;Chabner, Myers, Coleman & Johns, 1975; Vincent, Pickren, Fergus & Takita, 1975). Gubner (1951) first described the effect of methotrexate on epithelial tissue and the drug has subsequently been used to treat some cases of psoriasis (McDonald & Bartino, 1969;Spiro & Dermis, 1969;Van Scott, Auerbach & Weinstein, 1964;Weistein, 1971;Baker, 1970).…”