Why is bladder cancer cytology positive and hpv negative?

Not related: Hpv or human papilloma virus is associated with many cancers : cervical, throat, mouth, anal, & maybe lung. It is not known to be assocaited with bladder cancer. If bladder washings or bladder cytology (kind of like a pap smear for the bladder) then cystoscopy (visual inspection of the bladder lining) and biopsy are needed.

Different issues: Hpv infection has not been shown to cause bladder cancer, therefore bladder/urine cytology and hpv infection are unrelated.