Correlation between GP-170 expression, prognosis, and chemoresistance of superficial bladder carcinoma.

Purpose: To study GP-170 in superficial bladder cancer at initial diagnosis and at recurrence and to evaluate if intravesical chemoprophylaxis modifies the expression of GP-170 in tumor recurrences.
Materials and Methods: GP-170 was retrospectively assessed in 160 patients affected by primary superficial transitional cell carcinoma of the bladder and followed for up to 10 years. Eighty-four patients (52.5%) recurred after transurethral resection (TUR). Adjuvant intravesical chemotherapy after TUR was adopted in 52 patients. The correlations between GP-170 and G-grade, T-category, risk of recurrence and of progression, and adoption of adjuvant intravesical chemotherapy were investigated. The correlations between variations in grade and stage at recurrence and modifications in GP-170 expression were also studied.
Results: No significant correlation between GP-170 expression and G-grade and T-category was found. A significant correlation was detected between GP-170 expression and recurrence ( P=0.0383). It showed a biphasic pattern, i.e., tumors that did not express GP-170 had a higher recurrence rate, but high GP-170 levels were also associated with an increasing risk of recurrence. Intravesical chemotherapy did not induce significative variations in GP-170 expression. No correlation was found between progression and GP-170.
Conclusion: GP-170 seems to be an independent prognostic factor for recurrence in superficial bladder tumors. A negative GP-170 pattern and high levels of GP-170 are associated with an increasing risk of recurrence but have no impact upon progression. In our experience, GP-170 is neither induced nor modified by intravesical chemotherapy, although it might represent a factor of chemoresistance when strongly expressed.