Fibroblastic reticular cells predict response to cancer immunotherapy

While the role of CD8+ T cells in mediating response to cancer immunotherapy is well established, the role of other cell types, including B cells, remains more controversial. By conducting the largest gene expression study of response to immune checkpoint blockade (ICB) to date, here we show that pre-treatment expression of B cell genes is associated with ICB response independently of CD8+ T cells. Strikingly, we discovered that such association is completely explained by a single gene expressed in fibroblastic reticular cells (FRCs). We further validated this finding in three independent cohorts of patients treated with ICB, in both melanoma and renal cell carcinoma.