Case Report

Emerging biomarkers in metastatic urothelial carcinoma: tumour mutational burden, PD-L1 expression and apolipoprotein B mRNA editing catalytic (APOBEC) polypeptide-like signature in a patient with complete response to anti-programmed cell death protein-1 inhibitor

22 Oct 2021
Marcello Moro Queiroz, Zenaide Silva de Souza, Aline Bobato Lara Gongora, Felipe de Galiza Barbosa, Carlos Alberto Buchpiguel, Marilia Germanos de Castro, Mariana Petaccia de Macedo, Rafael Ferreira Coelho, Ethan Samuel Sokol, Anamaria Aranha Camargo, Diogo Assed Bastos

Immunotherapy has recently been incorporated into the treatment guidelines for metastatic urothelial carcinoma. Nevertheless, the role of prognostic and predictive biomarkers in this setting is not completely defined. To date, PD-L1 expression and a high tumour mutational burden (TMB) seem to predict better responses to immune checkpoint inhibitors, but patients without these biomarkers may still respond to immunotherapy. There are some caveats regarding these biomarkers, such as lack of standardisation of techniques, tumour heterogeneity and other factors influencing the tumour microenvironment. Genomic signatures are other promising emerging strategies. We hereby discuss the management of a 70-year-old man with a metastatic recurrence of urothelial carcinoma within 1 year after neoadjuvant chemotherapy and radical cystectomy. Tumour next-generation sequencing showed a high TMB and a CD274 (PD-L1) amplification. The patient was treated with pembrolizumab and achieved a complete response.

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