We divided patients into three subgroups : ( 1 ) low pretreatment EBV DNA ( < 1,500 copies/mL ) and undetectable posttreatment EBV DNA ( pre-L/post-U ) , ( 2 ) high pretreatment EBV DNA ( > or = 1,500 copies/mL ) and undetectable posttreatment EBV DNA ( pre-H/post-U ) , and ( 3 ) low or high pretreatment EBV DNA and detectable posttreatment EBV DNA ( pre-L or H/post-D ) for prognostic analyses .
