Comparison of the efficacy of sunitinib and pazopanib in patients with advanced non-clear renal cell carcinoma.

Non-clear cell renal cell carcinoma (non-ccRCC) is a highly heterogeneous disease group, accounting for approximately 25% of all RCC cases. Due to its rarity and especially heterogeneity, phase III trial data is limited and treatment options generally follow those of clear cell RCC. In the literature, there exists a number of studies with sunitinib, cabozantinib, and everolimus, but data on the efficacy of pazopanib are limited. Our aim in this study was to compare the efficacy of pazopanib and sunitinib, in a multicenter retrospective cohort of non-ccRCC patients. Our study included patients diagnosed with non-ccRCC who received pazopanib or sunitinib treatment as first-line therapy from 22 tertiary hospitals. We compared the progression-free survival (PFS), overall survival (OS), and response rates of pazopanib and sunitinib treatments. Additionally, we investigated prognostic factors in non-ccRCC. PFS and response rates of sunitinib and pazopanib were found to be similar, while a numerical difference was observed in OS. Being 65 years and older, being in the intermediate or poor risk group according to the International Metastatic Renal Cell Carcinoma Database Consortium, having liver metastases, presence of a sarcomatoid component, and having de novo metastatic disease were found to be significantly associated with shorter PFS. Pazopanib treatment appears to have similar efficacy in the treatment of non-ccRCC compared to sunitinib. Though randomized controlled trials are lacking and will probably be never be available, we suggest that pazopanib could be a preferred agent like sunitinib and cabozantinib.

Pazopanib and sunitinib treatments show similar progression free survival, overall survival and objective response rate.IMDC risk group, liver metastasis, sarcomatoid component and de novo metastatic disease were determined as prognostic factors.

Focal therapy for oligometastatic and oligoprogressive renal cell carcinoma: a narrative review.

Metastatic renal cell carcinoma (RCC) can present with oligometastatic disease and/or develop oligoprogression following systemic therapy. Cytoreductive and focal metastasis-directed therapy options include resection, stereotactic ablative radiation and thermal ablation. Aggressive focal therapy may allow delay in initiation of or modification to systemic therapy and improve clinical outcomes. In this narrative review we synthesize current practice guidelines and prospective data on focal therapy management options and highlight future research. Patient selection and the choice of focal treatment techniques are controversial due to limited and heterogeneous data and patients may benefit from multidisciplinary evaluation. Prospective comparative trials with clearly defined inclusion criteria and relevant end points are needed to clarify the risks and benefits of different approaches.

[Box: see text].

CT-Guided Online Adaptive Radiotherapy Delivered via Personalized Ultrafractionated Stereotactic Adaptive Radiotherapy (PULSAR) for a Bulky Thoracic and Abdominal Mass in Oligometastatic Renal Cell Carcinoma.

In the context of oligometastatic renal cell carcinoma (RCC), local treatment with stereotactic body radiotherapy (SBRT) may improve oncologic outcomes. However, the location and size can often pose a technical challenge in standard SBRT delivery, and the dose is potentially limited by nearby organs at risk (OARs). Online adaptive radiotherapy (oART) improves radiation delivery by personalizing high-dose fractions to account for daily stochastic variations in patient anatomy or setup. The oART process aims to maximize tumor control and enhances precision by tailoring to a more accurate representation of a patient in near-real time. The proceeding re-optimization can mitigate the uncertainty inherent in the traditional radiation delivery workflow and precludes the need for larger margins that account for anatomical variations and setup errors. Here, we describe a case of oligometastatic RCC with a bulky (>300 cm3) pleural-based left lower lobe mass extending into the upper abdomen treated via personalized ultrafractionated stereotactic adaptive radiotherapy (PULSAR). Three fractions were delivered four weeks apart allowing for tumor shrinkage of these bulky lesions, and oART permitted on-table adaptation of the plan without traditional re-simulation and re-planning required during off-line adaptive radiotherapy. The plan was designed for the Ethos linear accelerator (Varian Medical Systems, Inc., Palo Alto, CA, USA). The prescription dose was 36 Gray (Gy) in three fractions, and the adapted plan was selected in each treatment over the scheduled plan due to better target coverage and reversal of OAR dose violations. The adapted plan met all OAR dose constraints, and it achieved higher target coverage in the first two PULSAR fractions compared to the scheduled plan. In the third fraction, the cumulative point dose was approaching the maximum heart tolerance, and target coverage was accordingly compromised based on clinical judgment. There was evidence of tumor regression throughout the course of treatment, and the patient did not develop any significant radiation-related toxicities. Follow-up imaging has demonstrated the overall stable size of her lesion without any evidence of disease progression. Our case reflects the benefit of adaptive SBRT delivery to a bulky mass near multiple OARs in the setting of oligometastatic RCC. The adapted plan allowed for prioritization of critical structures on a fraction-by-fraction basis while preserving the therapeutic intent of SBRT. Further integration of advanced imaging techniques, optimal disease-specific systemic immunotherapies or targeted therapies, and refinement of patient selection will be crucial in identifying which patients would most benefit from an adaptive approach.

A Rare Case of Collecting Duct Carcinoma: A Comprehensive Analysis Using Ultrasound, Computed Tomography, and Histopathological Examination.

Collecting duct renal cell carcinoma (cdRCC) is an exceptionally rare and aggressive subtype of renal cell carcinoma, accounting for approximately 1% of all renal tumors. This case is notable due to the comprehensive use of multi-modality imaging and detailed histopathological examination, offering valuable insights into the diagnostic challenges and management of this rare condition. A 64-year-old male presented with progressive right flank pain, hematuria, and decreased urine output. Imaging studies revealed a hypoechoic lesion in the right kidney, predominantly located in the hilar and perihilar regions, suggestive of a malignant renal tumor. Further diagnostic evaluation, including a right radical nephrectomy, was performed. The histopathological examination of the resected tissue confirmed the diagnosis of cdRCC, characterized by a tubulopapillary growth pattern, significant pleomorphism, and sarcomatoid changes. Immunohistochemical analysis showed strong positivity for epithelial membrane antigen and CK7, confirming the aggressive nature of the tumor. This case underscores the importance of early diagnosis and a comprehensive diagnostic approach to managing cdRCC. Despite advances in imaging techniques, a definitive diagnosis often relies on histopathological and immunohistochemical analysis. The aggressive nature of cdRCC and its generally poor prognosis highlight the need for prompt and accurate diagnosis to potentially improve patient outcomes. This report adds to the limited literature on cdRCC, emphasizing the challenges and considerations in diagnosing and managing this rare form of renal carcinoma.

Synchronous bilateral papillary renal cell carcinoma in the native kidneys after 10 Years of renal transplantation: Report of a case and review of the literature.

A case of synchronous bilateral native kidneys papillary RCC is presented in a 48 year old patient who underwent a living donor kidney transplant 10 years prior. He was on regular immunosuppressant therapy. Despite the long term follow-up, bilateral cystic and exophytic masses were incidentally found on CT scan. Subsequent bilateral open radical nephrectomy revealed papillary RCC in both kidneys.

Innovative lipid nanoparticles: A cutting-edge approach for potential renal cell carcinoma therapeutics.

The kidney plays a crucial role in regulating homeostasis within the human body. Renal cell carcinoma (RCC) is the most common form of kidney cancer, accounting for nearly 90 % of all renal malignancies. Despite the availability of various therapeutic strategies, RCC remains a challenging disease due to its resistance to conventional treatments. Nanotechnology has emerged as a promising field, offering new opportunities in cancer therapeutics. It presents several advantages over traditional methods, enabling diverse biomedical applications, including drug delivery, prevention, diagnosis, and treatment. Lipid nanoparticles (LNPs), approximately 100 nm in size, are derived from a range of lipids and other biochemical compounds. these particulates are designed to overcome biological barriers, allowing them to selectively accumulate at diseased target sites for effective therapeutic action. Many pharmaceutically important compounds face challenges such as poor solubility in aqueous solutions, chemical and physiological instability, or toxicity. LNP technology stands out as a promising drug delivery system for bioactive organic compounds. This article reviews the applications of LNPs in RCC treatment and explores their potential clinical translation, identifying the most viable LNPs for medical use. With ongoing advancement in LNP-based anticancer strategies, there is a growing potential to improve the management and treatment of renal cancer.

Impact of No-Clamping Partial Nephrectomy on Early Estimated Glomerular Filtration Rate Preservation.

Incidences of kidney cancers are steadily increasing. The surgical resection of renal tumors remains the treatment of choice, and different techniques provide similar oncological outcomes. Minimally invasive methods, especially partial nephrectomy (PN), have emerged as the preferred method of tumor resection, both in traditional and robot-assisted laparoscopy. PN may be performed as an open or laparoscopic operation. On-clamp PN is a variant of PN that includes the clamping of renal vessels; off-clamp PN is performed without any ischemia. Objectives: To assess the short-term loss of eGFR after on-clamp and off-clamp PN. Methods: Data from 2021 to 2024 were retrospectively collected from a hospital database. The patients included in the study had a diagnosed kidney tumor that was confirmed by MRI or CT imaging. The patients were divided into two groups depending on the type of treatment they received: on-clamp PN or off-clamp PN. Hematocrit (HCT), hemoglobin (Hb) and eGFR were measured and compared. Results: Both groups had comparable preoperative HTC, Hb, and eGFR. eGFR loss 24 h after the procedure was 35.4% lower in the off-clamp group compared to the on-clamp group (p = 0.027). Conclusions: Off-clamp PN is a safe and viable method for kidney tumor resection, both in traditional and robot-assisted laparoscopy. This technique results in a smaller perioperative loss of eGFR, which relates to better short-term functional outcomes than on-clamp PN.

RCC1 regulation of subcellular protein localization via Ran GTPase drives pancreatic ductal adenocarcinoma growth.

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy, with limited therapeutic options. Here, we evaluated the role of regulator of chromosome condensation 1 (RCC1) in PDAC. RCC1 functions as a guanine exchange factor for GTP-binding nuclear protein Ran (Ran) GTPase and is involved in nucleocytoplasmic transport. RCC1 RNA expression is elevated in PDAC tissues compared to normal pancreatic tissues and correlates with poor prognosis. RCC1 silencing by RNAi and CRISPR-Cas9 knockout (KO) results in reduced proliferation in 2-D and 3-D cell cultures. RCC1 knockdown (KD) reduced migration and clonogenicity, enhanced apoptosis, and altered cell cycle progression in human PDAC and murine cells from LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx1-Cre (KPC) tumors. Mechanistically, RCC1 KO shows widespread transcriptomic alterations including regulation of PTK7, a co-receptor of the Wnt signaling pathway. RCC1 KD disrupted subcellular Ran localization and the Ran gradient. Nuclear and cytosolic proteomics revealed altered subcellular proteome localization in Rcc1 KD KPC-tumor-derived cells and several altered metabolic biosynthesis pathways. In vivo, RCC1 KO cells show reduced tumor growth potential when injected as sub-cutaneous xenografts. Finally, RCC1 KD sensitized PDAC cells to gemcitabine chemotherapy treatment. This study reveals the role of RCC1 in pancreatic cancer as a novel molecular vulnerability that could be exploited to enhance therapeutic response.

Durable Local Control With Preserved Renal Function for Stereotactic Body Radiotherapy in Cryoablation-Refractory Clear Cell Renal Carcinoma.

Renal cell carcinoma (RCC) is the most common type of kidney cancer, accounting for most renal cancers. Oligoprogressive RCC (OP-RCC) describes metastatic RCC wherein one or a few metastatic sites continue to progress, while the majority of metastatic sites are stable on systemic therapy. Treatment options for the primary site for OP-RCC include cytoreductive nephrectomy, stereotactic body radiation therapy (SBRT), or ablative techniques, although there is no currently agreed-upon standard for treatment. This report describes a 76-year-old male with OP-RCC who was treated with salvage SBRT after failing cytoablation therapy. A review of the current literature on SBRT as a treatment option for OP-RCC is presented and discussed. This case demonstrates that SBRT may be a viable salvage treatment option for patients with OP-RCC that provides good local disease control while preserving long-term renal function.

Paraneoplastic Syndrome Prevalence and Survival in Racially-Diverse Cohort With Renal Cell Carcinoma.

INTRODUCTION: The prevalence of preoperative paraneoplastic syndromes (PNS) in renal cell carcinoma (RCC) is poorly understood. Many laboratory abnormalities representative of PNS have demonstrated prognostic value when incorporated into predictive survival models in RCC. We sought to characterize the relationship between baseline prevalence of PNS with overall survival (OS) and cancer-specific survival (CSS) in RCC patients following nephrectomy. METHODS: Our prospectively maintained nephrectomy database was retrospectively reviewed for any stage, major histology RCC patients that underwent surgery from 2000 to 2022. Baseline laboratory values within 90 days (closest used) were required. Presence of PNS was defined according to established laboratory cutoffs. Kaplan-Meier curves estimated survival rates, and multivariable Cox proportional hazards models examined the association between PNS with OS and CSS following nephrectomy. RESULTS: 2599 patients were included with listed staging: 1494 Stage I; 180 Stage II; 616 Stage III; 306 Stage IV. Proportion of patients presenting with >1 PNS significantly increased from stage I (31.3%) to stage IV (74.2%) RCC (P < .001). Elevated C-reactive protein was the most prevalent PNS (45.4%). On multivariable analysis, the presence of >1 PNS was associated with higher risk of all-cause (HR 2.09; P < .001) and cancer-specific mortality (HR 2.55; P < .001). The 10-year OS estimates as reported: 65.2% (no PNS), 52.3% (1 PNS), 36.6% (>1 PNS); and 10-year CSS estimates: 88.3% (no PNS), 79.3% (1 PNS), 61.6% (>1 PNS). DISCUSSION: Increased prevalence of PNS in major histology RCC was associated with a significant increase in the risk of all-cause and cancer-specific mortality even when accounting for patient and disease characteristics.

PSMD2 overexpression as a biomarker for resistance and prognosis in renal cell carcinoma treated with immune checkpoint and tyrosine kinase inhibitors.

BACKGROUND: Integrated immune checkpoint inhibitors (ICIs) plus tyrosine kinase inhibitors (TKIs) are now the recommended first-line therapy to manage renal cell carcinoma (mRCC). Proteasome 26S subunit non-ATPase 2 (PSMD2) overexpression in tumors has been correlated with tumor progression. Currently, mRCC lacks an established biomarker for the combination of ICI+TKI. METHODS: This study involved RNA sequencing of RCC patients from two cohorts treated with ICI+TKI (ZS-MRCC and JAVELIN-Renal-101). We utilized immunohistochemistry alongside flow cytometry, aiming at assessing immune cell infiltration and functionality in high-risk localized RCC samples. Response and progression-free survival (PFS) were evaluated relying upon RECIST criteria. RESULTS: PSMD2 was significantly overexpressed in advanced RCC and among non-responders to ICI+TKI therapy. Overexpressed PSMD2 was correlated with poor PFS in the ZS-MRCC and JAVELIN-101 cohorts. Multivariate Cox analysis validated PSMD2 as an independent PFS predictor. PSMD2 overexpression was related to a reduction in CD8+ T cells, especially GZMB+ CD8+ T cells, besides an increase in PD1+ CD4+ T cells. Additionally, tumors with high PSMD2 levels showed enhanced T cell exhaustion levels and a higher regulatory T cell presence. A Machine Learning (ML) model based on PSMD2 expression and other screened factors was subsequently developed to predict the effectiveness of ICI+TKI. CONCLUSIONS: Elevated PSMD2 expression is linked to resistance and decreased PFS in mRCC patients undergoing ICI+TKI therapy. High PSMD2 levels are also associated with impaired function and increased exhaustion of tumor-infiltrating lymphocytes. An ML model incorporating PSMD2 expression could potentially identify patients who may have a higher likelihood of benefiting from ICI+TKI.

Case report: response to immunotherapy and association with the fh gene in hereditary leiomyomatosis and renal cell cancer-associated renal cell cancer.

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is a rare autosomal dominant syndrome caused by a germline mutation in the fumarate hydratase (FH) gene that manifests with cutaneous leiomyomas, uterine fibroids, and renal cell cancer (RCC). Patients with HLRCC-associated RCC (HLRCC-RCC) have aggressive clinical courses, but there is no standardized therapy for advanced HLRCC-RCC. In this study, we described a case of aggressive HLRCC in a 33-year-old female who exhibited a novel heterozygous germline insertion mutation in exon 8 of the FH gene (c.1126 C > T; p.Q376*). The patient underwent laparoscopic resection of the right kidney, but metastases appeared within 3 months after surgery. Histological staining of the resected tumor revealed high expression levels of programmed cell death-ligand 1 (PD-L1). Therefore, the patient was treated with immunotherapy. The patient achieved a partial response to immunotherapy, and the treatment of metastatic lesions has continued to improve. A thorough literature review pinpointed 76 historical cases of HLRCC-RCC that had undergone immunotherapy. From this pool, 46 patients were selected for this study to scrutinize the association between mutations in the FH gene and the effectiveness of immunotherapy. Our results indicate that immunotherapy could significantly improve the overall survival (OS) of patients with HLRCC-RCC. However, no influence of different mutations in the FH germline gene on the therapeutic efficacy of immunotherapy was observed. Therefore, our study suggested that immunotherapy was an effective therapeutic option for patients with HLRCC regardless of the type of FH germline mutation.

Emerging Role of Hippo-YAP (Yes-Associated Protein)/TAZ (Transcriptional Coactivator with PDZ-Binding Motif) Pathway Dysregulation in Renal Cell Carcinoma Progression.

Although Hippo-YAP/TAZ pathway involvement has been extensively studied in the development of certain cancers, the involvement of this cascade in kidney cancer progression is not well-established and, therefore, will be the focus of this review. Renal cell carcinoma (RCC), the most prevalent kidney tumor subtype, has a poor prognosis and a high mortality rate. Core Hippo signaling inactivation (e.g., LATS kinases) leads to the nuclear translocation of YAP/TAZ where they bind to co-transcriptional factors such as TEAD promoting transcription of genes which initiates various fibrotic and neoplastic diseases. Loss of expression of LATS1/2 kinase and activation of YAP/TAZ correlates with poor survival in RCC patients. Renal-specific ablation of LATS1 in mice leads to the spontaneous development of several subtypes of RCC in a YAP/TAZ-dependent manner. Genetic and pharmacological inactivation of YAP/TAZ reverses the oncogenic potential in LATS1-deficient mice, highlighting the therapeutic benefit of network targeting in RCC. Here, we explore the unique upstream controls and downstream consequences of the Hippo-YAP/TAZ pathway deregulation in renal cancer. This review critically evaluates the current literature on the role of the Hippo pathway in RCC progression and highlights the recent scientific evidence designating YAP/TAZ as novel therapeutic targets against kidney cancer.

The Landscape of Stereotactic Ablative Radiotherapy (SABR) for Renal Cell Cancer (RCC).

Renal cell cancer (RCC) has traditionally been considered radioresistant. Because of this, conventional radiotherapy (RT) has been predominantly relegated to the palliation of symptomatic metastatic disease. The implementation of stereotactic ablative radiotherapy (SABR) has made it possible to deliver higher ablative doses safely, shifting the renal radioresistance paradigm. SABR has increasingly been adopted into the multidisciplinary framework for the treatment of locally recurrent, oligoprogressive, and oligometastatic disease. Furthermore, there is growing evidence of SABR as a non-invasive definitive therapy in patients with primary RCC who are medically inoperable or who decline surgery, unsuited to invasive ablation (surgery or percutaneous techniques), or at high-risk of requiring post-operative dialysis. Encouraging outcomes have even been reported in cases of solitary kidney or pre-existing chronic disease (poor eGFR), with a high likelihood of preserving renal function. A review of clinical evidence supporting the use of ablative radiotherapy (SABR) in primary, recurrent, and metastatic RCC has been conducted. Given the potential immunogenic effect of the high RT doses, we also explore emerging opportunities to combine SABR with systemic treatments. In addition, we explore future directions and ongoing clinical trials in the evolving landscape of this disease.

Mitochondrial NME6: A Paradigm Change within the NME/NDP Kinase Protein Family?

Eukaryotic NMEs/NDP kinases are a family of 10 multifunctional proteins that occur in different cellular compartments and interact with various cellular components (proteins, membranes, and DNA). In contrast to the well-studied Group I NMEs (NME1-4), little is known about the more divergent Group II NMEs (NME5-9). Three recent publications now shed new light on NME6. First, NME6 is a third mitochondrial NME, largely localized in the matrix space, associated with the mitochondrial inner membrane. Second, while its monomeric form is inactive, NME6 gains NDP kinase activity through interaction with mitochondrial RCC1L. This challenges the current notion that mammalian NMEs require the formation of hexamers to become active. The formation of complexes between NME6 and RCC1L, likely heterodimers, seemingly obviates the necessity for hexamer formation, stabilizing a NDP kinase-competent conformation. Third, NME6 is involved in mitochondrial gene maintenance and expression by providing (d)NTPs for replication and transcription (in particular the pyrimidine nucleotides) and by a less characterized mechanism that supports mitoribosome function. This review offers an overview of NME evolution and structure and highlights the new insight into NME6. The new findings position NME6 as the most comprehensively studied protein in NME Group II and may even suggest it as a new paradigm for related family members.

A future directions of renal cell carcinoma treatment: combination of immune checkpoint inhibition and carbon ion radiotherapy.

Renal cell carcinoma (RCC) is considered radio- and chemo-resistant. Immune checkpoint inhibitors (ICIs) have demonstrated significant clinical efficacy in advanced RCC. However, the overall response rate of RCC to monotherapy remains limited. Given its immunomodulatory effects, a combination of radiotherapy (RT) with immunotherapy is increasingly used for cancer treatment. Heavy ion radiotherapy, specifically the carbon ion radiotherapy (CIRT), represents an innovative approach to cancer treatment, offering superior physical and biological effectiveness compared to conventional photon radiotherapy and exhibiting obvious advantages in cancer treatment. The combination of CIRT and immunotherapy showed robust effectiveness in preclinical studies of various tumors, thus holds promise for overcoming radiation resistance of RCC and enhancing therapeutic outcomes. Here, we provide a comprehensive review on the biophysical effects of CIRT, the efficacy of combination treatment and the underlying mechanisms involved in, as well as its therapeutic potential specifically within RCC.

Mapping of Human Polyomavirus in Renal Cell Carcinoma Tissues.

Worldwide, the incidence of renal cell carcinoma (RCC) is rising, accounting for approximately 2% of all cancer diagnoses and deaths. The etiology of RCC is still obscure. Here, we assessed the presence of HPyVs in paraffin-embedded tissue (FFPE) resected tissue from patients with RCC by using different molecular techniques. Fifty-five FFPE tissues from 11 RCC patients were included in this study. Consensus and HPyV-specific primers were used to screen for HPyVs. Both PCR approaches revealed that HPyV is frequently detected in the tissues of RCC kidney resections. A total of 78% (43/55) of the tissues tested were positive for at least one HPyV (i.e., MCPyV, HPyV6, HPyV7, BKPyV, JCPyV, or WUyV). Additionally, 25 tissues (45%) were positive for only one HPyV, 14 (25%) for two HPyVs, 3 (5%) for three HPyVs, and 1 one (1%) tissue specimen was positive for four HPyVs. Eleven (20%) RCC specimens were completely devoid of HPyV sequences. MCPyV was found in 24/55 RCC tissues, HPyV7 in 19, and HPyV6 in 8. The presence of MCPyV and HPyV6 was confirmed by specific FISH or RNA-ISH. In addition, we aimed to confirm HPyV gene expression by IHC. Our results strongly indicate that these HPyVs infect RCC and nontumor tissues, possibly indicating that kidney tissues serve as a reservoir for HPyV latency. Whether HPyVs possibly contribute to the etiopathogenesis of RCC remains to be elucidated.

Use of Radiation Therapy for Ataxia-Telangiectasia Mutated (ATM)-Mutation Metastatic Renal Cell Carcinoma: A Case Report.

Papillary renal cell carcinoma (pRCC) is a rare kidney cancer with limited treatment options and poor outcomes when metastatic. We present a case of a 42-year-old male with metastatic pRCC harboring a somatic ataxia-telangiectasia mutated (ATM) mutation who was treated at our institution. After progression of disease (POD) on ipilimumab/nivolumab, followed by POD on cabozantinib, the patient was treated with radiation therapy to metastatic cervical lymphadenopathy to 60 Gy in 15 fractions as well as retroperitoneal lymphadenopathy to 36 Gy in 9 fractions, which was curtailed due to intolerance. This was followed by sequential systemic therapy with a poly (ADP-ribose) polymerase (PARP) inhibitor and pembrolizumab, which was also discontinued due to adverse effects. Despite not receiving any treatment for 10 months, his disease remains stable. We believe that the prolonged progression-free survival of this patient with ATM-mutation metastatic pRCC is likely due to the enhanced sensitivity of the tumor to radiation therapy due to ATM loss.

Anaplastic Lymphoma Kinase (ALK)-Rearranged Renal Cell Carcinoma: A Case Report Highlighting Diagnostic Challenges and Therapeutic Opportunities.

A 57-year-old male underwent an open right radical nephrectomy in 2015 for a 3-cm kidney tumor which was classified at the time as a combined tubulocystic and collecting duct carcinoma. One of six nodes was positive for metastatic carcinoma and the patient received adjuvant carboplatin/gemcitabine chemotherapy. In 2020, he developed enlarging retroperitoneal adenopathy and underwent a retroperitoneal lymph node dissection with 11 of 13 nodes in the resected specimen positive for the previously described renal carcinoma, followed by adjuvant radiotherapy. In November 2022, he again underwent surgery for further locoregional recurrence with resection of a right psoas mass lesion and right hemicolectomy. Pathology on this occasion was reclassified as anaplastic lymphoma kinase-rearranged renal cell carcinoma (ALK-RCC). Shortly afterward, a restaging CT revealed multiple liver metastases and evidence of further disease recurrence in the right renal bed. He commenced alectinib with a complete radiological response and has continued on it for 12 months at the time of writing this report. To our knowledge, there are only five prior reports of ALK-RCC treated with targeted ALK inhibitor therapy in the literature. We report this case to highlight the importance of recognizing and diagnosing this rare RCC subtype since it has significant therapeutic implications. Furthermore, to our knowledge, this patient has had the longest follow-up reported to date in the literature so far. A concerted effort by the histopathology and oncology community is needed to gather more data on the incidence and treatment outcomes of these tumors so that progress can be made in optimizing their management. It is important to consider novel and emerging entities from the most recent WHO 2022 classification, many of which are defined by molecular characteristics with associated therapeutic implications.