In line with the data obtained from mouse models, human CRC cells, in which MSI status is related to increased CIP2A level and decreased PPP2R1A level and in which the loss of MMR genes and the induction of MSI status are caused by PP2A inhibition, may also respond to ICB therapy when it is combined with PP2A inactivation. Here, MRC1 is linked to colorectal carcinoma.