Update on the most promising biomarkers of response to immune checkpoint inhibitors in clear cell renal cell carcinoma.

In the last few years, the standard of care for metastatic clear cell renal cell carcinoma (mccRCC) has changed dramatically with the emergence of the immune checkpoint inhibitors (ICI): anti-PD(L)-1 used as a monotherapy or as in combination either with an anti CTLA-4 or with an anti-angiogenic molecule (VEGFR tyrosine kinase inhibitor (TKI)). These combinations are now recommended in first line setting for mccRCC, according to the last European recommendations. In the face of these new therapeutic options, the question of selecting the best treatment arises as well as the optimal sequence. Predictive biomarkers are required to guide the therapeutic choice and provide a personalized treatment for each patient. This narrative review will provide an overview of the main predictive biomarkers assessed in mccRCC treatment, with a particular focus on mRNA panel signatures.

Prolactin-induced prostate tumorigenesis links sustained Stat5 signaling with the amplification of basal/stem cells and emergence of putative luminal progenitors.

Current androgen ablation therapies for prostate cancer are initially successful, but the frequent development of castration resistance urges the generation of alternative therapies and represents an important health concern. Prolactin/signal transducer and activator of transcription 5 (STAT5) signaling is emerging as a putative target for alternative treatment for prostate cancer. However, mechanistic data for its role in development or progression of prostate tumors are scarce. In vivo mouse studies found that local prolactin induced the amplification of prostate epithelial basal/stem cells. Because these cells are proposed cells of origin for prostate cancer and disease recurrence, we looked further into this amplification. Our results indicated that sustained Stat5 activation was associated with the occurrence of abnormal basal/stem cell clusters in prostate epithelium of prostate-specific prolactin-transgenic mice. Analysis of epithelial areas containing these clusters found high proliferation, Stat5 activation, and expression of stem cell antigen 1. Furthermore, enhanced prolactin signaling also led to amplification of a luminal cell population that was positive for stem cell antigen 1. These cells may originate from amplified basal/stem cells and might represent important progenitors for tumor development in prostate epithelium. These data provide a deeper understanding of the initial stages of prostate tumorigenesis induced by prolactin to help determine whether this hormone or its downstream messengers could be useful targets for prostate cancer treatment in the future.

Longitudinal Study of Advanced Non-Small Cell Lung Cancer with Initial Durable Clinical Benefit to Immunotherapy: Strategies for Anti-PD-1/PD-L1 Continuation beyond Progression.

BACKGROUND AND AIM: A better understanding of resistance to checkpoint inhibitors is essential to define subsequent treatments in advanced non-small cell lung cancer. By characterizing clinical and radiological features of progression after anti-programmed death-1/programmed death ligand-1 (anti-PD-1/PD-L1), we aimed to define therapeutic strategies in patients with initial durable clinical benefit. PATIENTS AND METHODS: This monocentric, retrospective study included patients who presented progressive disease (PD) according to RECIST 1.1 criteria after anti-PD-1/PD-L1 monotherapy. Patients were classified into two groups, "primary resistance" and "Progressive Disease (PD) after Durable Clinical Benefit (DCB)", according to the Society of Immunotherapy of Cancer classification. We compared the post-progression survival (PPS) of both groups and analyzed the patterns of progression. An exploratory analysis was performed using the tumor growth rate (TGR) to assess the global growth kinetics of cancer and the persistent benefit of immunotherapy beyond PD after DCB. RESULTS: A total of 148 patients were included; 105 of them presented "primary resistance" and 43 "PD after DCB". The median PPS was 5.2 months (95% CI: 2.6-6.5) for primary resistance (p < 0.0001) vs. 21.3 months (95% CI: 18.5-36.3) for "PD after DCB", and the multivariable hazard ratio was 0.14 (95% CI: 0.07-0.30). The oligoprogression pattern was frequent in the "PD after DCB" group (76.7%) and occurred mostly in pre-existing lesions (72.1%). TGR deceleration suggested a persistent benefit of PD-1/PD-L1 blockade in 44.2% of cases. CONCLUSIONS: PD after DCB is an independent factor of longer post-progression survival with specific patterns that prompt to contemplate loco-regional treatments. TGR is a promising tool to assess the residual benefit of immunotherapy and justify the continuation of immunotherapy in addition to radiotherapy or surgery.

CXCR6 expressing T cells: Functions and role in the control of tumors.

CXCR6 is a receptor for the chemokine CXCL16, which exists as a membrane or soluble form. CXCR6 is a marker for resident memory T (TRM) cells that plays a role in immunosurveillance through their interaction with epithelial cells. The interaction of CXCR6 with CXCL16 expressed at the membrane of certain subpopulations of intratumor dendritic cells (DC) called DC3, ideally positions these CXCR6+ T cells to receive a proliferation signal from IL-15 also presented by DC3. Mice deficient in cxcr6 or blocking the interaction of CXCR6 with its ligand, experience a poorer control of tumor proliferation by CD8+ T cells, but also by NKT cells especially in the liver. Intranasal vaccination induces CXCL16 production in the lungs and is associated with infiltration by TRM expressing CXCR6, which are then required for the efficacy of anti-tumor vaccination. Therapeutically, the addition of CXCR6 to specific CAR-T cells enhances their intratumoral accumulation and prolongs survival in animal models of pancreatic, ovarian and lung cancer. Finally, CXCR6 is part of immunological signatures that predict response to immunotherapy based on anti-PD-(L)1 in various cancers. In contrast, a protumoral role of CXCR6+T cells has also been reported mainly in Non-alcoholic steatohepatitis (NASH) due to a non-antigen specific mechanism. The targeting and amplification of antigen-specific TRM expressing CXCR6 and its potential use as a biomarker of response to immunotherapy opens new perspectives in cancer treatment.

Biomarkers of resistance to immune checkpoint inhibitors in non-small-cell lung cancer: myth or reality?

Immune checkpoint inhibitors represent a major therapeutic advance in non-small-cell lung cancer with several approved anti-programmed death-1 and anti-programmed death-L1 immunotherapies. A majority of patients however, will not respond to immune checkpoint inhibitors and display primary resistance while a subset of initially responsive patients will present secondary resistance. Thus, there is a crucial need for biomarkers to enable better prediction and diagnosis, and to overcome such resistance. Along with improvement in the understanding of immune escape, new biomarkers are being developed, including large scale proteomic, genomic and transcriptomic approaches in tumor and blood samples. We review the novel biomarkers that have been investigated in non-small-cell lung cancer and discuss how they can rationalize therapeutic strategies.