Biomarkers play an essential role in the diagnosis and treatment of urothelial cancer (UC), with PD-L1, FGFR, and MMR proteins being the most clinically established. These biomarkers, derived from histological specimens, guide therapeutic decisions for bladder cancer (BCa) and upper tract urothelial cancer (UTUC). Recommendations from international guidelines, including the 2024 European Association of Urology (EAU), National Comprehensive Cancer Network (NCCN), and 2022 European Society for Medical Oncology (ESMO), emphasise the integration of these biomarkers into clinical practice. PD-L1 testing identifies patients eligible for immunotherapy, a cornerstone in managing advanced UC. For example, monoclonal antibodies targeting PD-L1 (atezolizumab) or PD-1 (pembrolizumab, nivolumab) have shown efficacy in trials like Checkmate 274, where nivolumab improved disease-free survival in high-risk patients post-surgery. However, while the US FDA approves nivolumab for all patients, the European Medicines Agency restricts its use to PD-L1-positive cases, highlighting the necessity of PD-L1 testing. Similarly, pembrolizumab has proven effective for cisplatin-ineligible UC patients, with higher response rates observed in individuals with a combined positive score (CPS) ≥10, as shown in the Keynote-052 trial. Both pembrolizumab and atezolizumab are recommended for platinum-ineligible patients with high PD-L1 expression. These guidelines are supported by the EAU, NCCN, and ESMO, which stress the importance of PD-L1 testing in formalin-fixed tumour samples. FGFR2/3 alterations also play a critical role in advanced UC, particularly for patients previously treated with systemic chemotherapy or those ineligible for cisplatin. The BLC2001 trial demonstrated an 80% disease control rate in patients with FGFR2/3 alterations, leading to the FDA\u2019s approval of erdafitinib for patients harbouring these mutations. FGFR testing, particularly with the Therascreen FGFR RT-PCR kit, is recommended to identify eligible patients, though erdafitinib is restricted to cases with susceptible FGFR3 alterations. MMR protein analysis is another valuable tool, particularly for identifying Lynch syndrome, a hereditary condition linked to UTUC. Loss of expression in MMR proteins (MLH1, MSH2, MSH6, PMS2) detected through immunohistochemistry or PCR prompts genetic testing. The EAU recommends germline DNA sequencing for suspected hereditary UTUC cases, aiding in risk assessment and family management. However, limited evidence supporting universal screening leaves clinicians with discretion in selecting candidates for testing. Identifying Lynch syndrome remains critical for guiding management and surveillance strategies for affected individuals and their families. Emerging biomarkers such as HER2 are reshaping UC treatment. The DESTINY-PanTumor02 trial highlighted the efficacy of trastuzumab deruxtecan in HER2-positive bladder cancer, resulting in FDA approval for HER2-positive solid tumours. Similarly, disitamab vedotin demonstrated promising survival outcomes in advanced BCa. Additionally, oral and intravesical FGFR inhibitors are being explored for non-muscle-invasive BCa, offering potential alternatives to traditional therapies. New agents, including enfortumab vedotin and sacituzumab govitecan, which target NECTIN4 and TROP2 respectively, broaden therapeutic options without requiring biomarker testing. Together, PD-L1 and FGFR testing form the foundation of advanced UC management, while MMR protein analysis and emerging biomarkers like HER2 advance the field of personalised medicine. Incorporating these biomarkers into clinical practice ensures more tailored and effective treatments for UC patients, aligning with current guidelines and innovations in cancer therapy.
Tissue-based biomarkers steering clinical decisions in patients with urothelial cancer
Reviewed by Asif H Ansari
Tissue-based biomarkers steering clinical decisions in patients with urothelial cancer.
