Cotransfer of memory phenotype control and Ptpn22–/– CD8+ cells cleared s.c. EL4-OVA tumors, while the ratio of Ly5.1+/Ly5.2+ donor cells in lymph nodes and at the tumor site (skin) was assessed weekly by ex vivo FACS analysis (Figure 2, B and C). The gene discussed is PTPN22; the disease is neoplasm.