The finding in colon carcinoma that cancerogenesis is a sequence of activation of different oncogenes and inactivation of tumor suppressor genes has increased the efforts to identify the genes that areresponsible for the progression of different kinds of cancer. Many activated oncogenes and inactivated tumor suppressor genes have been detected in cancer cells during the last decades, but for most cancers no network or sequence of oncogenes could be identified that could explain the progression of the disease and allow a molecular staging of the disease. Several strategies have been tried to find the genes that make cancer cells different from their normal counterparts, however, mostly only with little success. In this review article it will be reported how the strategy of transcription factor profiling helped to identify the genes that are responsible for the progression of two kinds of cutaneous lymphomas: Mycosis fungoides and the Sézary syndrome. By this way we were able to identify several agents that may be the prototypes of new drugs to fight these diseases
