CIITA and classic Hodgkin lymphoma: In addition, decreased/absent protein expression of also MHC class II is observed in about 70% of the cases; in 15% of cHL cases this is a functional consequence of the rearrangement of the major histocompatibility complex (MHC) class II transactivator (CIITA), which is a master regulator of HLA class II transcription [111,112].