Rare Case of Bladder Metastasis of Kidney Cancer: Potential Role of Genomic Analysis
Posted: Monday, August 30, 2021
Metachronous metastasis in the bladder of patients with renal cell carcinoma is rare. However, a case study presented by Sumanta K. Pal, MD, of City of Hope Comprehensive Cancer Center, Duarte, California, and colleagues in JCO Precision Oncology “underscores the importance of performing sequential genomic testing so that we may better elucidate the true clonal architecture of atypical sites of metastasis.”
An 83-year-old man was treated for renal cell carcinoma and suspicious lung nodules with nephrectomy and the immune checkpoint inhibitors nivolumab and ipilimumab. A next-generation sequencing assay exhibited a frameshift deletion in von Hippel-Lindau (VHL) tumor suppressor (Y112fs) and a stop gain alteration in polybromo 1 (PBRM1). After 14 months of treatment, a complaint of hematuria led to a CT scan, which revealed a bladder tumor pathologically confirmed as metastatic kidney cancer. The genomic analysis confirmed a new missense mutation in mTOR and a new frameshift mutation in ASXL1. The patient declined further treatment and entered hospice.
Mutations in VHL/PBRM1 are understood to be part of oncogenesis by upregulating tumor metabolism and facilitating tumor migration via disruption of cell adhesion, Dr. Pal and colleagues explained. Furthermore, mTOR and ASXL1 mutations are activating events in renal cell carcinoma that harbor VHL and PBRM1 mutations. Although researchers caution that intratumoral heterogeneity may be present from the outset of illness, the genetic analysis helped to establish a model of plausible disease progression and spread of renal cell carcinoma to atypical sites of metastasis. Perhaps the most important finding in this research centers on ASXL1’s functional interaction with BAP1—a mutation more commonly seen in renal cell carcinoma—making ASXL1 “an intriguing actionable target” in patients with renal cell carcinoma.
Disclosure: For full disclosures of the study authors, visit ascopubs.org.