Specifically, miR-27a represses MHC class I surface exposure directly targeting calreticulin, a protein involved in the quality control of the assembly of this multi-subunit complex contributing to its stability and retrieval of suboptimally assembled MHC class I molecules.7, 8, 9, 10, 11 Mechanistically, calreticulin is a major downstream effector of miR-27a in repressing MHC class I surface exposure, a pivotal event in eliciting an efficient immune response and tumour eradication. This evidence concerns the gene CALR and neoplasm.