Initial gene expression profiling experiments on urothelial carcinoma identified four prognostically distinctive classes. Which list correctly names these classes?

• A. UroB, UroA, GU, & SCCL
• B. UroB, UroA, GU, & SCCL-Variant
• C. UroC, UroA, GU, & SCCL
• D. UroB, UroD, GU, & SCCL

Answer: (A)

Gene expression profiling in urothelial carcinoma can reveal distinct molecular subtypes that correlate with prognosis. In the early profiling, four classes emerged: UroB and UroA representing urothelial-like programs, GU representing a genitourinary-like program, and SCCL representing a squamous cell–like program. Each class showed unique gene expression patterns and different clinical outcomes, providing a practical way to categorize tumors beyond what histology shows. The naming reflects the specific transcriptional programs, not variants, so labels like UroC, UroD, or SCCL-Variant do not match the original four. Therefore, UroB, UroA, GU, and SCCL best capture the initial findings.