AUA 2018: Carcinomas Of The Renal Medulla: A Comprehensive Genomic Profiling (Cgp) Study

San Francisco, CA USA ( Stephanie Gleicher, MD, urology resident at the State University of New York Upstate Medical University, presented on the genomic profiling (Cgp) of renal medullar carcinoma (RMC) and collecting duct carcinoma (CDC). The author opened by describing RMC and CDC as being extremely rare but aggressive subtypes of renal cancer, making up less than 1% of renal cancer cases, but also being associate with high probability of metastasis. Current treatment guidelines of both RMC and CDC are primarily chemotherapy, while preforming a debunking nephrectomy in conjunction to chemotherapy has shown to increase survival rates. Current drugs to treat CDC and RMC that were discussed were tyrosine kinase inhibitors, mTOR inhibitors, and immunotherapy. The overall goal of the study was to determine the genetic make-up of carcinomas from the renal medulla to better optimize treatment.

Cgp was done using next generation sequencing assays. The author mentions this new method of gene sequencing provides for multiple mutations to be seen simultaneously, which is advantageous when targeting for gene therapy. DNA was taken from specimens with CDC and RMC, in which 70% were from primary tumors while 30% were from metastatic tumors. All samples came from carcinomas that were both advanced stage and high grade. Both tumor mutational burden and microsatellite instability status were also calculated, and demographic data was also obtained.

This study group totaled to 70 cases, 24 being specimens from patients with RMC and 46 being from patients with CDC. Initial demographic data showed that median age between CDC and RMC were significantly different, CDC being 55 and RMC being much lower at 29. Amongst patients with CDC, 70% were male while only 46% of patients with RMC were male. As stated in Dr. Gleicher’s introduction, there was a statistically significant association between patients with these renal medullar cancers and sickle trait status (p<.0.0001). In terms of the genomic sequencing, one significant gene mutation found was SMARCB1, a gene involved in chromatin remodeling. Dr. Gleicher also addressed that the genes targeted by tyrosine kinase inhibitors, such as VHL, and mTOR inhibitors, such as TSC1/2 and NF2, showed no significant gene mutation for both CDC and RMC. The author suggested that this knowledge can allow proper and more specific treatment methods associated with CDC and RMC to be discovered.

Dr. Gleicher concluded that genetic profile can provide better and more specific treatment option for both CDC and RMC. The moderator posed the question if there is possible direct relation between CDC and RMC, in which the presenter answered was unknown but their similarities to urothelial carcinomas, in SMARCB1 mutations, medullar origin may be a factor.
Presented by: Diana K. Bowen, MD

Written by: Luke Limfueco, Department of Urology, University of California-Irvine at the 2018 AUA Annual Meeting - May 18 - 21, 2018 – San Francisco, CA USA