Feasibility of obtaining biomarker profiles from endoscopic biopsy specimens in upper tract urothelial carcinoma: preliminary results

Objective: To prospectively evaluate the feasibility of obtaining a reliable histochemical assessment of cell cycle biomarkers from endoscopic biopsy specimens of patients with upper tract urothelial cancer.

Methods: Overall, 17 patients were identified who had an available biopsy as well as those who underwent subsequent radical nephroureterectomy (RNU) or segmental ureterectomy (SU) for clinically localized high-grade upper tract urothelial cancer of the renal pelvis or ureter. Of those 17 patients, 15 (88%) had sufficient tissue to undergo immunohistochemical staining. Biopsies were obtained using various endoscopic techniques. Tumor characteristics were recorded and prospectively evaluated for immunohistochemical expression of 5 biomarkers: p21, p27, p53, cyclin E, and Ki67/pRb. Unfavorable prognostic score (PS) was defined as>2 altered markers.

Results: The median age of the patients was 68 years (range: 53-82y) with 87% being males. Of the 15 specimens, 9 (60%) tumors were organ confined (T≤2 and N0), and all were high grade. Of the 15 patients, 4 (27%), 7 (46.6%), 3 (20%), and 1 (6.7%) individuals had 1, 2, 3, and 5 markers altered on biopsy marker profiling, respectively, with Ki67 being the most frequent alteration (13/15; 87.7%). An overall concordance rate of 60% (9/15) was seen between biopsy and RNU/SU PS. Those patients with favorable biopsy biomarker PS were less likely to display adverse pathological features, with organ-confined disease in 7/11 (63.6%) patients and 9/11 (81.8%) being free of carcinoma in situ in the final specimen. Additionally, 10/11 (91%) had no evidence of necrosis and 7/11 (64%) had no evidence of lymphovascular invasion on final pathologic evaluation.

Conclusions: Preliminary results suggest that obtaining interpretable biomarker profile of ureteroscopic biopsy specimens is feasible. Tumor heterogeneity and limited biopsy material may account for the discordance between biopsy and RNU/SU specimens. Meaningful biopsy biomarker profiling could serve as a powerful tool for individualizing treatment regimens and augmenting current predictive variables. Further studies are needed to evaluate clinical applicability.