HLA in breast cancer: its relevance for immunotherapy

Clinical trials of immunotherapy are now underway in breast carcinoma. Presentation of antigens by the major histocompatibility complex plays a central role in the proposed mechanism of action of these agents. Many studies have shown no consistent association between human leucocyte antigen (HLA) class I type and breast cancer risk although some have suggested that certain HLA class I types may be over represented in specific disease subclasses (noteably poor risk disease). HLA class II has not been investigated in detail for breast carcinoma. The melanoma model suggests that generation of a cytotoxic T cell response to tumour antigens is HLA class I restricted and there is evidence that a similar restricted response to breast tumour cells can be generated in vitro. The poor expression of HLA class I by some breast tumours is a major problem for immunotherapy. Strategies to overcome this, including cytokine therapy, require consideration.