CD19 and neoplasm: Antigen epitope alteration (11, 12, 21–26)CD19 gene mutationAlternative splicingDefects in CD19 Processing (27, 28)Loss of CD81Epitope Concealment (27, 29)CAR gene unintentionally introduced into tumor cellsImmune Pressure (12, 30, 31)CD19-negative tumor proliferatingPedigree Transformation (12, 27, 32–37)Tumor dedifferentiationCytokine induced myeloid differentiationThe Increase of Macrophages Leads to the Loss of Reversible Antigen (12, 38–40)