PTPRC and neoplasm: However, co-expression on CD45− hematopoietic tumor cells of either B cell markers (i.e., CD19) or T-cell-associated proteins (e.g., cyCD3, smCD3), usually in the absence of CD56 [47,48], were critical for correct hematopoietic vs. non-hematopoietic lineage assignment in these patients.