Chuang and colleagues prepared RPMI-1640 medium containing 10% heat-inactivated fetal bovine serum to cultivate renal pelvis urothelial carcinoma and, unexpectedly, a population of CD19 + /CD20 + tumor infiltrating B lymphocytes overgrew the adherent cells [4], Interestingly, specific DNA fragments of EBV differed between these cells and peripheral blood mononuclear cells. Here, CD19 is linked to neoplasm.