Ilya Dyugay, Daniil Lukyanov and Dmitriy Chudakov from Skoltech have co-authored a paper “Accounting for B-cell Behavior and Sampling Bias Predicts Anti–PD-L1 Response in Bladder Cancer” that has been published in Cancer Immunology Research journal. The researchers investigated the role of infiltrating B cells in bladder cancer via patient dataset analysis of intratumoral immunoglobulin repertoires. They showed that the IgG1/IgA ratio is a prognostic indicator for several subtypes of bladder cancer and for the whole IMVigor210 anti–PD-L1 immunotherapy study cohort. A high IgG1/IgA ratio associated with the prominence of a cytotoxic gene signature, T-cell receptor signaling, and IL21-mediated signaling. Immunoglobulin repertoire analysis indicated that effector B-cell function, rather than clonally produced antibodies, was involved in antitumor responses. On the basis of their findings, the scientists developed a predictor called PRedIctive MolecUlar Signature (PRIMUS), which outperformed PD-L1 expression scores and known gene signatures. PRIMUS allows for reliable identification of responders among patients with muscle-invasive urothelial carcinoma, including the subcohort with the low-infiltrated “desert” tumor phenotype. Full text of the paper is available here.