Another study showed that exosomes from heat-stressed CEA-positive tumour cells (CEA+/HS-Exos) contained CEA and increased levels of HSP70 and MHC-I molecules after HLA-A2.1/Kb transgenic mice were immunized with CEA+/HS-Exos, and a more efficient CEA-specific CTL response was observed [52]. This evidence concerns the gene CEACAM5 and neoplasm.