2 The technologies
2.1 Four tests available to the NHS were evaluated. Two are based on gene expression profiling: MammaPrint (Agendia) and Oncotype DX (Genomic Health). Two are based on immunohistochemistry (also known as protein expression profiling): IHC4 (academic sponsor – Royal Marsden Hospital and Queen Mary University, London) and Mammostrat (Clarient). These tests measure multiple markers within the tumour that may indicate how the tumour is likely to develop. Additional details are provided in section 4.