To investigate how tumor cells utilize CD45 molecules to escape from T cell killing, we transfected DLD1 cells with different isoforms of CD45-GFP fusion constructs, including the longest isoform (CD45RABC, CD45 in short), the resting isoform expressing on naive T cells (CD45RA) and the activated isoform specific to effector and memory T cells (CD45RO) (Fig. 4g–k). This evidence concerns the gene PTPRC and neoplasm.