MHC II transcriptional activation is a consequence of the CIITA transactivator activity, that occurs in normal and tumour cells of hematopoietic origin, as well as in several tumours of nonhematopoietic origin and in a consistent number of cell lines (e.g., glioblastoma, pancreas adenocarcinoma, melanoma and bladder carcinoma, ATLAS data base), in some cases after IFNγ stimulation. The gene discussed is CIITA; the disease is melanoma.