C4A and prostate cancer: Such findings are uncommon and may be overlooked, particularly when clinical suspicion for prostate cancer is low or when urinary cytology is performed for unrelated indications. Supporting this, Tang et al. found that only 19.5% of urine cytology specimens from patients with histology-proven prostate cancer showed atypia or higher (C3+), and just 3.4% were suspicious or higher (C4+) [4].