Selected Articles from This Issue

Abstract

PD-1T tumor-infiltrating lymphocytes (TIL) are a dysfunctional T-cell population characterized by high PD-1 expression and tumor reactivity. To evaluate their potential as a biomarker for durable clinical benefit to PD-1 blockade, Hummelink and colleagues digitally quantified PD-1T TIL in 120 pretreatment samples from patients with advanced non-small cell lung cancer. PD-1T TIL showed a high sensitivity in predicting clinical benefit and survival to anti-PD-1 and were superior to PD-L1 or TLS as a biomarker. Importantly, the absence of PD-1T TIL reliably identified a patient group without benefit from PD-1 blockade, thereby providing a promising tool to reduce overtreatment.Immune checkpoint inhibitors (ICI) targeting programmed cell death protein 1 and its ligand (PD-1/PD-L1) have revolutionized therapeutic options for renal cell carcinoma (RCC). However, response rates to ICI vary widely (20–70%) in patients with RCC. Predicting responses using conventional tissue-based techniques evaluating PD-L1 expression is of limited value, owing to the dynamic and heterogenous nature of PD-L1 expression. Mulgaonkar and colleagues systematically examined the performance of immunoPET for PD-L1 imaging relative to immunohistochemistry in an RCC tumorgraft platform. This study demonstrates the promising potential of immunoPET for clinical real-time assessment of PD-L1 expression across tumor sites and heterogeneous intratumoral distribution.CSF1R inhibitor treatments have shown to be effective targeted therapies for TGCT. Trials are currently underway to study the effect of discontinuation and retreatment with CSF1R inhibitors. In this study, van IJzendoorn and colleagues investigate the tumor landscape in TGCT using single-cell sequencing and other molecular techniques. They show that the neoplastic cells are not targeted by CSF1R inhibitors, in contrast to what was previously postulated. The authors identify markers for the neoplastic cells and show the lack of an autocrine loop involving CSF1-CSF1R in the neoplastic cells. As a result, CSF1R inhibitor treatments are unlikely to affect the neoplastic cell population in TGCT as is currently assumed. Additionally, this work identifies two new pathways that could be targeted in future trials involving TGCT.The resistance of immunotherapy in renal cancer patients remains unclear despite the high infiltrations of CD8+T cells. Here, Benhamouda and colleagues show that baseline plasma soluble CD27 (sCD27) is associated with resistance to immunotherapy in renal cell carcinoma independently of clinical factors. sCD27 reflects the interaction between CD27 expressed by T lymphocytes and CD70 expressed by tumor cells, which associates with the apoptosis and dysfunction of T lymphocytes. Peripheral blood sCD27 could thus be considered as a marker of T-cell dysfunction due to the CD27-CD70 interaction in the tumor and predict the response to immunotherapy.