The numbers explain why the field has been so frustrated. According to Veglia, immunotherapy works in many different cancer types, but the same approach has yielded only a 10 percent success rate in glioblastoma. That failure is not simply a matter of the blood-brain barrier or the tumor’s aggressive growth, though both play a role. The deeper problem lies in the tumor microenvironment itself. Glioblastoma tumors are densely packed with myeloid cells, a family of immune cells that the tumor co-opts and reprograms into bodyguards. Rather than sounding the alarm against the cancer, these cells actively suppress the immune response, shutting down nearby T cells that would otherwise recognize and destroy tumor cells.

Even the few functional T cells that manage to reach the tumor face a second, independent obstacle. Once inside the hostile microenvironment, they become chronically activated, and that constant stimulation wears them down into a dysfunctional state known as T cell exhaustion. An exhausted T cell has essentially put down its weapons: it can no longer kill tumor cells effectively, no matter how well it initially recognized its target. Any strategy that hopes to make immunotherapy work in glioblastoma, the Wistar team reasoned, must therefore attack both problems simultaneously, disarming the myeloid suppressors while reinvigorating the T cells they have worn down.

To find the root cause of myeloid cell betrayal, Veglia’s laboratory, working with international collaborators, took a cell-by-cell inventory of the immune cells inside tumors in a preclinical model. This single-cell survey revealed something striking: the two most abundant and immunosuppressive myeloid cell populations in the tumor both displayed strong molecular signatures of hypoxia, or oxygen starvation. Tumors grow so quickly that they outstrip their blood supply, leaving interior regions chronically deprived of oxygen. The team then confirmed in laboratory experiments that this hypoxia was not merely a byproduct but a critical driver, showing that low oxygen alone was sufficient to convert myeloid cells into potent suppressors of T cell activity and to recruit them into the tumor’s service.

That mechanistic insight suggested a pharmacological opening. To relieve the oxygen starvation inside the tumor, the researchers turned to axitinib, a drug already approved for use in combination with immunotherapy to treat advanced kidney cancer. In the preclinical glioblastoma model, low-dose axitinib reduced hypoxia within the tumor and prevented myeloid cells from being reprogrammed into their immunosuppressive state. The effect on T cell traffic was immediate: more T cells began entering the tumor microenvironment. Yet the survival benefit remained modest. Axitinib alone extended median survival only from 17 to 19 days, a reminder that opening the gates to the tumor is not the same as winning the battle inside it.

The reason, Veglia explained, is that the newly arriving T cells quickly run into the second barrier. By reducing hypoxia, the team could impair the immunosuppressive activity of myeloid cells, and this resulted in the accumulation of more T cells in the tumor microenvironment. But this was not enough, because when T cells entered the tumor, they became exhausted. The influx of fresh troops was being neutralized by the very process of chronic activation that defines the glioblastoma microenvironment, leaving the treatment incomplete on its own.

Here the single-cell data provided the crucial clue. Many of the T cells that accumulated after axitinib treatment belonged to a category the researchers describe as effector-like exhausted T cells: cells that are on their way to exhaustion but have not yet reached a terminal, irreversibly dysfunctional state. In other words, these T cells were getting worn down but still retained the capacity to attack cancer. Notably, they carried a surface receptor called 4-1BB, also known as CD137, a marker indicating that they had already recognized their cancer target and were primed for action. The team reasoned that activating 4-1BB with an agonist, an immunotherapeutic approach designed to stimulate that receptor, could boost both the number and the quality of these partially exhausted fighters, pushing them back toward full anti-tumor function.

The combination proved far more powerful than either treatment alone. In murine models, pairing axitinib with the 4-1BB agonist extended median survival to 42 days, compared with 19 days for axitinib by itself and 17 days without treatment, and produced a 40 percent long-term survival rate. Perhaps most striking was what happened when the researchers re-exposed the surviving animals to tumor cells later on: no new tumors grew. That result indicates the immune system had developed durable memory against the cancer, the hallmark of a genuinely protective anti-tumor response rather than a temporary suppression of disease. For a cancer in which recurrence is nearly universal, the emergence of immunological memory is the single most encouraging signal in the study.

The path forward, Veglia says, runs toward the clinic. His next goal is to test the axitinib and 4-1BB agonist combination in a clinical trial with glioblastoma patients, translating the preclinical findings into a regimen that could be evaluated against a disease with no cure. His laboratory also plans to explore pairing axitinib with CAR T cell therapy, testing whether relieving tumor hypoxia can help engineered T cells perform better against solid tumors, an arena where CAR T approaches that have succeeded in blood cancers continue to struggle. Because hypoxic tumors are among the most resistant to immunotherapy, Veglia believes the strategy could eventually extend beyond the brain to other oxygen-starved malignancies, with pancreatic cancer, which is also highly hypoxic, a leading candidate.

The broader lesson of the study may prove as important as any single drug combination. Glioblastoma’s resistance to immunotherapy is not a single locked door but a series of interlocking defenses, and treatments that address only one of them, however elegantly targeted, have repeatedly fallen short. By identifying hypoxia-driven reprogramming of myeloid cells as a root cause of immune suppression, and by showing that the T cells liberated by relieving that suppression can be rescued from exhaustion through receptor agonism, the Wistar team has offered a template for rational combination design in tumors long considered immunologically inert. There are no cures for glioblastoma, Veglia noted, so this is an opportunity to make a real difference for patients, and he and his collaborators are eager to see whether the findings extend to other recalcitrant cancers and ultimately improve outcomes for those patients as well. If the clinical results mirror the preclinical ones, a two-pronged attack on hypoxia and T cell exhaustion could mark the moment glioblastoma finally becomes a plausible target for immunotherapy.

Subject of Research: A combination of hypoxia relief and 4-1BB agonism to overcome immunotherapy resistance in glioblastoma

Article Title: Wistar scientists uncover two-pronged strategy to overcome glioblastoma’s resistance to immunotherapy

Article References: Wistar scientists uncover two-pronged strategy to overcome glioblastoma’s resistance to immunotherapy. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: glioblastoma, immunotherapy, myeloid cells, hypoxia, T cell exhaustion, axitinib, 4-1BB, CD137, The Wistar Institute, Neuro-Oncology, brain cancer, preclinical study

Renal cell carcinoma ranks as the seventh most common malignant tumor in men and the tenth most common in women worldwide. Roughly one in four to one in three patients already harbor distant metastases when they are first diagnosed, with the disease seeding most frequently into regional lymph nodes, lungs, bones, and liver. Yet the bladder is an extraordinarily uncommon destination. Fewer than seventy cases of bladder metastasis from renal cell carcinoma have ever been reported in the medical literature, and virtually none have described this pattern emerging after a patient had already undergone radical nephrectomy, metastasectomy, and multiple lines of targeted therapy. That is precisely what makes this new case, published in Clinical Case Reports by clinicians at the First Affiliated Hospital of Zhejiang University School of Medicine, so noteworthy.

The technical details of the initial diagnosis illustrate how modern imaging dissects a renal mass. Contrast-enhanced computed tomography showed the tumor lighting up intensely during the arterial phase, a signature of the rich, disordered blood supply that characterizes clear cell carcinoma, while uneven enhancement pointed to localized ischemic necrosis deep within the lesion. These findings ruled out the principal differential diagnoses, including renal tuberculosis, kidney stones, renal cysts, and hamartomas, and staged the disease as T4N0M1, meaning a locally advanced primary tumor with distant metastatic involvement but no lymph node spread. Surgeons proceeded with a laparoscopic radical left nephrectomy, and pathology under the microscope confirmed clear cell renal cell carcinoma.

Because the disease was already metastatic at diagnosis, the oncology team initiated adjuvant systemic therapy with sunitinib, a tyrosine kinase inhibitor delivered at fifty milligrams daily. Sunitinib has historically been a cornerstone of first-line treatment, with landmark trials demonstrating significantly prolonged overall survival compared with interferon alpha. In this patient, however, the drug failed. Within three months, follow-up CT scans showed clear progression of the metastasis in the right adrenal gland. Surgeons removed the gland, pathology again confirming infiltration by clear cell carcinoma, and the team switched to a second tyrosine kinase inhibitor, axitinib at five milligrams twice daily, with imaging every three months. The message was already becoming unmistakable: this tumor was proving refractory to the standard pharmacological arsenal.

Ten months after the original surgery, the patient developed pain in her right thumb. Hand CT imaging revealed osteolytic bone destruction, a hole eaten into the base of the first metacarpal by metastatic cells, with associated soft tissue involvement. Surgeons resected the metastatic bone tumor, reconstructed the defect with a bone graft, and fixed it internally. Pathology confirmed clear cell renal cell carcinoma metastasis. One week later, a whole-body F-18 FDG PET/CT scan was performed, and the results expanded the map of the disease dramatically: the tracer lit up metastatic deposits in the skull, and, remarkably, in the bladder.

Cystoscopy, the direct visual inspection of the bladder interior, revealed two red neoplastic lesions on the bladder wall. Transurethral resection removed the tissue, and histopathological examination confirmed the stunning diagnosis: metastatic clear cell renal cell carcinoma growing inside the bladder, entirely asymptomatic. This last point carries real clinical weight. According to prior literature, roughly seventy percent of patients with bladder metastasis from renal cell carcinoma present with hematuria, visible blood in the urine. This patient had none. Her bladder metastasis was found purely incidentally on PET imaging, a discovery that would likely have been delayed, perhaps indefinitely, in a less thoroughly monitored patient.

Facing relentless progression, the clinicians escalated to combination therapy, pairing axitinib with toripalimab, an immune checkpoint inhibitor, at 240 milligrams. The rationale rested on recent phase III evidence from the RENOTORCH trial, which demonstrated that the combination of toripalimab and axitinib delivered superior clinical benefit compared with sunitinib monotherapy as first-line treatment for advanced renal cell carcinoma. The combination appeared to achieve local control where it mattered most in this case: after transurethral resection of the bladder tumor, follow-up cystoscopic examinations showed no evidence of bladder tumor recurrence, even after a full year of continuous combination therapy. Yet the systemic disease refused to stand still. Three months before the report was finalized, routine abdominal CT revealed new metastatic lesions in the right ninth rib and in the bilateral iliac bones of the pelvis, signaling that distant skeletal spread was continuing despite the intensified regimen.

The trajectory of this case underscores a sobering paradox in contemporary kidney cancer treatment. Targeted therapy and immunotherapy have genuinely transformed outcomes in advanced renal cell carcinoma, extending survival in large prospective clinical trials and converting what was once an almost uniformly fatal diagnosis into a chronic disease for many patients. Prolonged survival, however, creates a longer window in which the biology of the tumor can express itself in unusual ways, and clinicians are increasingly reporting metastases to rare sites such as the esophagus, the eyeball, and now the bladder. Previous case reports of bladder metastasis typically described patients with localized renal tumors who developed isolated bladder recurrence several years after partial or radical nephrectomy, without disease elsewhere, or involved non-classical histological subtypes. No previous report, as far as the authors know, had documented bladder metastasis in advanced renal cell carcinoma developing after first-line targeted therapy in a patient with widespread systemic disease.

Over the course of her care, this patient underwent five salvage tumor resections, including the nephrectomy, adrenalectomy, metacarpal resection, cranial metastasis resection, and transurethral bladder tumor resection, alongside continuously evolving systemic therapy. The authors emphasize that resecting bladder metastases may reduce local recurrence but cannot suppress distant spread, and that there is currently no standardized clinical guideline for managing bladder metastasis of renal cell carcinoma at all. For patients like this one, who remain refractory to first-line and second-line regimens and continue to accumulate metastases, the authors argue that genomic profiling to identify novel therapeutic targets may offer the next realistic avenue of clinical benefit. The patient remains under active follow-up, generally stable in condition even as her bone metastases progress, and her treatment regimen is expected to require further adjustment.

The broader lesson for clinicians and researchers alike is vigilance. Bladder metastasis of renal cell carcinoma is rare enough to escape suspicion, and its frequent association with hematuria means an asymptomatic presentation, as in this case, could easily evade detection without systematic PET/CT surveillance and cystoscopic confirmation. As targeted agents and immune checkpoint inhibitors continue to extend the lives of patients with metastatic kidney cancer, the population of long-term survivors will grow, and with it the likelihood that oncologists will encounter metastatic patterns that current guidelines never anticipated. This single patient’s two-year journey, from an incidental ultrasound finding to a bladder seeded with kidney cancer that never once bled, is a vivid reminder that in advanced clear cell renal cell carcinoma, the map of metastasis is still being drawn, and every unusual case redraws it a little further.

Subject of Research: A rare case of asymptomatic bladder metastasis from advanced clear cell renal cell carcinoma following radical nephrectomy, metastasectomy, and targeted and immunotherapy.

Article Title: Metastatic Clear Renal Cell Carcinoma in Bladder Following Radical Nephrectomy, Metastasectomy, and Targeted Therapy: A Rare Case Report

Article References: Zheng, X., Jiang, P., & Zhou, J. (2026). Metastatic Clear Renal Cell Carcinoma in Bladder Following Radical Nephrectomy, Metastasectomy, and Targeted Therapy: A Rare Case Report. Clinical Case Reports, 14(9), Article e73557. https://doi.org/10.1002/ccr3.73557

Image Credits: AI Generated

DOI: 10.1002/ccr3.73557

Keywords: clear cell renal cell carcinoma, bladder metastasis, radical nephrectomy, sunitinib, axitinib, toripalimab, tyrosine kinase inhibitor, immunotherapy, bone metastasis, FDG PET/CT, cystoscopy, case report