The predictive value of hENT 1 molecule for gemcitabine treatment in bladder cancer.

Abstract

e15540 Background: Human equilibrative nucleoside transporter 1 (hENT1) is the nucleoside transporter protein which plays the main role for transportation of gemcitabine into the cells. We aim to assess the predictive value of the hENT 1 molecule in bladder cancer patients treated with gemcitabine based chemoterapy. Methods: Clinically and histologically documented stage III and stage IV invazive bladder cancer patients were included in the study. The patients were assessed retrospectively. All patients were received gemsitabine-platine based chemotherapy as the first line treatment. Spesific hENT1 antibody staining was performed on the chemo-naive bladder tumor specimens immunuhistochemically. Vascular endotel and lymphocytes served as an external positive control for hENT 1 immunuhistochemistry. Staining intensity was graded as 0,absent; 1+, less intens than control tissue, 2, equally positive as control tissue; 3, more intense than control tissue. Tumor spesimens with having 3+ intensity staining in >50% of the tumor cells were accepted as showing high expression of hENT 1. Results: Fifty one patients were included in the study. The median age was 67 (range 41-85). Ninety two percent(n=52) of patients were male. Twenty six (46.4%) and 25 (44.6%) patients were stage III and stage IV disease at the beginning of the therapy, respectively. Thirty four (60.7%) patients were in neoadjuvant treatment group and 17 (30.4%) patients were in metastatic group. Tumor grades could be assessed in 33 patients; 2 (11.4%) were low grade and 31 (88%) were high grade. The median folllow up period was 13 (range 1-58) months. In neoadjuvant group 5 (14%) patients have low hENT 1 level and 21 (60%) patients have high hENT 1 level. In metastatic group 1 (5%) patients have low hENT1 level and 13 (95%) patients have high hENT 1 level. We found no statistically significant difference between hENT 1 low and hENT 1 high groups in terms of response to therapy in metastatic and neoadjuvant groups (p=0.426 and p=0.684 respectively). Conclusions: More stuides are needed to demonstrate the real role of hENT 1 molecule in terms of response to gemsitabine treatment.