CD22 and leukemia: The list of antigens discussed above is by no means exhaustive and many ACT strategies are in the pipeline to target other leukemia antigens including PR1[29], human telomerase reverse transcriptase (hTERT)[26], receptor tyrosine kinase-like orphan receptor 1 (ROR1)[45], CD23[223], CD123[224], preferentially expressed antigen in melanoma (PRAME)[27], hyaluronan-mediated motility receptor (HMMR/Rhamm)[28], CD22[44], cathepsin G[30] and aurora kinase a (AURKA)[225] among others.