Usefulness of epidermal growth factor receptor and p53 cocktail immunostaining for differential diagnosis with urine cytology.

To investigate immunochemical markers of assisting cytologic diagnosis to evade the inaccuracy to be caused by alteration of urinary samples. We used p53 and epidermal growth factor receptor (EGFR) in an immunostaining cocktail for the differential diagnosis of urine cytology. We reviewed urothelial tumor tissues resected from 36 cases, normal urothelium tissues collected from 20 autopsy cases and 108 separate urine samples. No positive case was obtained from the autopsy cases. In 20 of the cancer cases treated by transurethral resection, the average positive rates of EGFR and p53 cells were 69% and 12%, respectively. As for the urine smears, positive findings were observed in atypical cells in 20 of 21 cytologically positive cases (95%), which were also confirmed to be malignant in histologic examinations. In contrast, color development was observed in urothelial cells from only 9 of 87 cases (10%), which were unclear for atypia and judged benign, though 5 of those 9 specimens were from patients with a previous history of urothelial cancer. In 2 of those 5 cases, recurrences were confirmed later. For urine cytology, we found that our cocktail immunostaining method was useful for the differential diagnosis.