Abstract 3349: Discovery and validation of methylated DNA markers of upper tract urothelial tract cancers
Authors: Bhagra Ojas , Taylor William R. , Gochanour Benjamin R. , Foote Patrick H. , Berger Calise K. , Cao Xiaoming , Mahoney Douglas W. , Then Sara S. , Gonser Anna M. , Doering Karen A. , Burger Kelli N. , Cheville John C. , Gettman Matthew T. , Kisiel John B. 
Published: June 2023

Objective: Upper tract urothelial cancers (UTUC) can be difficult to characterize, and non-invasive surveillance tools are lacking. UTUC are often treated with nephroureterectomy (NU). To address these gaps, we sought to discover and validate methylated DNA markers (MDMs) for detection of UTUC.

Methods: Archival formalin fixed paraffin embedded (FFPE) tissue samples from NU were pathologically reviewed and punched prior to DNA extraction. Reduced representation bisulfite sequencing (RRBS) was used to identify candidate MDMs that discriminated between UTUC and age-balanced control urothelial tissues (uninvolved ureter/renal pelvic of renal cell carcinoma at radical nephrectomy). Highest ranked (fold-change and p-value) candidate MDMs were biologically validated by quantitative methylation specific PCR in a 2nd independent set of UTUC and age-balanced controls. DNA from healthy donor urine and buffy coat samples was used to assess MDM background signal. Discrimination between UTUC and controls was assessed as the area under the receiver operator characteristic curve (AUC) with corresponding 95% confidence intervals.

Results: RRBS assessed 33 UTUC and 26 ureter/renal pelvis controls. 3.01 x 106 CpGs mapped to the reference genome with at least 10X read depth. From 358 candidates, 20 MDMs were selected for biological validation in independent patient samples which included 20 renal pelvis & 16 ureter UTUC and 17 renal pelvis & 15 ureter control specimens. Of UTUC and control patients, 36% and 65% of were men, respectively. Median AUC for comparison of UTUC vs control tissue was 0.87 (IQR 0.81-0.88); AUCs with corresponding 95% CIs are shown for the 10 most accurate MDMs (Table) across all control types.

Conclusion: We report discovery and validation of highly sensitive and specific MDMs with potential for accurate non-invasive screening supported by low background in urine and blood.

AUCs (95% CI) for selected methylated DNA markers for UTUC vs control tissue, urine, and blood UTUC vs Marker Control Tissue Control Urine Control Buffy C2orf55 0.92 (0.84-1) 0.93 (0.87-1) 0.96 (0.91-1) ANKRD35 0.91 (0.84-0.99) 0.93 (0.86-1) 0.98 (0.94-1) DLX6 0.91 (0.84-0.98) 0.78 (0.66-0.9) 0.97 (0.93-1) Chr8.9998 0.90 (0.82-0.97) 0.91 (0.84-0.97) 0.98 (0.96-1) SP9 0.88 (0.8-0.97) 0.95 (0.9-1) 0.99 (0.98-1) Chr13.1127 0.88 (0.8-0.97) 0.94 (0.89-1) 0.92 (0.85-1) Septin9.r2 0.88 (0.79-0.97) 0.95 (0.88-1) 0.98 (0.94-1) LBX2 0.88 (0.79-0.97) 0.94 (0.88-1) 0.96 (0.91-1) SIM2.r1 0.88 (0.79-0.97) 0.91 (0.82-1) 0.94 (0.86-1) Chr14.1037 0.88 (0.78-0.97) 0.93 (0.85-1) 0.96 (0.9-1)

Citation Format: Ojas Bhagra, William R. Taylor, Benjamin R. Gochanour, Patrick H. Foote, Calise K. Berger, Xiaoming Cao, Douglas W. Mahoney, Sara S. Then, Anna M. Gonser, Karen A. Doering, Kelli N. Burger, John C. Cheville, Matthew T. Gettman, John B. Kisiel. Discovery and validation of methylated DNA markers of upper tract urothelial tract cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3349.