Immune checkpoint inhibitors in non-conventional histologies of renal-cell carcinoma

Banana-shaped survival curves of metastatic renal cell carcinoma treated with first-line immune-combinations, not just a matter of "palateau"

The first-line therapy of metastatic renal cell carcinoma (mRCC) has revolutionized with the approval of immune checkpoint inhibitors (ICIs) in combination with or without tyrosine kinase inhibitors (TKIs). The choice among the many different immuno-combinations (ICI-ICI or ICI-TKI) is challenging due to the lack of predictive factors. The different shapes of the Kaplan-Meier survival curves (e.g. "banana-shaped curves") have raised many questions on the long-term survival benefit. Here, we analyzed the factors that could have impacted the different long-term survival, including the prognostic factors distribution (IMDC score), histological factors (sarcomatoid features, PD-L1 expression), and treatment characteristics (mechanism of action, duration, discontinuation rate). This overview highlights the factors that should be considered in the first-line setting for the patients' therapeutic choice and prognostic assessment. They are also fundamental parameters to examined for head-to-head studies and real-life, large-scale studies.

Comparison of Primary and Metastatic Fumarate Hydratase-Deficient Renal Cell Carcinomas Documents Morphologic Divergence and Potential Diagnostic Pitfall With Peritoneal Mesothelioma

Fumarate hydratase (FH)-deficient renal cell carcinomas are rare neoplasms characterized by wide morphologic heterogeneity and pathogenetic mutations in the FH gene. They often show aggressive behavior with rapid diffusion to distant organs, so novel therapeutic scenarios have been explored, including EGFR inhibitors and PD-L1 expression for targeted immunotherapy. Herein, we investigated a series of 11 primary FH-deficient renal cell carcinomas and 7 distant metastases to evaluate tumor heterogeneity even in metastatic sites and estimate the specific spread rates to various organs. Furthermore, the tumors were tested for immunohistochemical PD-L1 expression and EGFR mutations. Most metastatic cases involved the abdominal lymph nodes (4/7; 57%), followed by the peritoneum (3/7; 42%), the liver (2/7; 29%), and the lungs (1/7; 14%). Six metastatic localizations were histologically documented, revealing a morphologic heterogeneous architecture often differing from that of the corresponding primary renal tumor. Peritoneal involvement morphologically resembled a benign reactive mesothelial process or primary peritoneal mesothelioma, thus advocating to perform an accurate immunohistochemical panel, including PAX8 and FH, to reach a proper diagnosis. A pure low-grade succinate dehydrogenase-looking primary FH-deficient renal cell carcinoma was also recorded. As for therapy, significant PD-L1 labeling was found in 60% of primary renal tumors, whereas none of them carried pathogenetic EGFR mutations. Our data show that FH-deficient renal cell carcinoma may be morphologically heterogeneous in metastases as well, which involve the lymph nodes, the liver, and the peritoneum more frequently than other renal tumors. Due to the high frequency of this latter (42%), pathologists should always be concerned about ruling out mesothelial-derived mimickers, and the occurrence of rarer, primary, low-grade-looking types. Finally, contrary to EGFR mutations, PD-L1 expression could be a possible predictive biomarker for the therapy of these tumors.

Clinical outcome predictors for metastatic renal cell carcinoma: a retrospective multicenter real-life case series

Over the last decades, the therapeutic armamentarium of metastatic renal cell carcinoma (mRCC) has been revolutionized by the advent of tyrosin-kinase inhibitors (TKI), immune-checkpoint inhibitors (ICI), and immune-combinations. RCC is heterogeneous, and even the most used validated prognostic systems, fail to describe its evolution in real-life scenarios. Our aim is to identify potential easily-accessible clinical factors and design a disease course prediction system. Medical records of 453 patients with mRCC receiving sequential systemic therapy in two high-volume oncological centres were reviewed. The Kaplan-Meier method and Cox proportional hazard model were used to estimate and compare survival between groups. As first-line treatment 366 patients received TKI monotherapy and 64 patients received ICI, alone or in combination. The mean number of therapy lines was 2.5. A high Systemic Inflammation Index, a BMI under 25 Kg/m2, the presence of bone metastases before systemic therapy start, age over 65 years at the first diagnosis, non-clear-cell histology and sarcomatoid component were correlated with a worse OS. No significant OS difference was observed between patients receiving combination therapies and those receiving exclusively monotherapies in the treatment sequence. Our relapse prediction system based on pathological stage and histological grade was effective in predicting the time between nephrectomy and systemic treatment. Our multicentric retrospective analysis reveals additional potential prognostic factors for mRCC, not included in current validated prognostic systems, suggests a model for disease course prediction and describes the outcomes of the most common therapeutic strategies currently available.

First-Line Treatments and Management of Metastatic Renal Cell Carcinoma Patients: An Italian Interdisciplinary Uro-Oncologic Group Algorithm

The treatment landscape for metastatic renal cell carcinoma (mRCC) has undergone significant transformations in recent years. The introduction of novel combination therapies involving tyrosine kinase inhibitors (TKI) and immune checkpoint inhibitors has resulted in improved oncological outcomes compared to traditional TKI monotherapy. In this evolving paradigm, the pivotal role of the multidisciplinary tumor board is underscored, particularly in shaping the therapeutic trajectory for patients eligible for locoregional interventions like cytoreductive nephrectomy and metastasectomy. In cases where systemic treatment is deemed appropriate, the absence of direct comparisons among the various combination therapies complicates the selection of a first-line approach. The clinician is faced with the challenge of making decisions based on patient-specific factors such as performance status, risk classification according to the International Metastatic Renal Cell Carcinoma Database Consortium, comorbidities, and disease characteristics, including the number and location of metastases and tumor histology. Considering these concerns, we propose, as a member of a Tuscany Interdisciplinary Uro-Oncologic Group, an algorithm to streamline the decision-making process for mRCC patients, offering guidance to clinicians in their day-to-day clinical practice.

Emerging roles of MITF as a crucial regulator of immunity

Microphthalmia-associated transcription factor (MITF), a basic helix-loop-helix leucine zipper transcription factor (bHLH-Zip), has been identified as a melanocyte-specific transcription factor and plays a critical role in melanocyte survival, differentiation, function, proliferation and pigmentation. Although numerous studies have explained the roles of MITF in melanocytes and in melanoma development, the function of MITF in the hematopoietic or immune system-beyond its function in melanin-producing cells-is not yet fully understood. However, there is convincing and increasing evidence suggesting that MITF may play multiple important roles in immune-related cells. Therefore, this review is focused on recent advances in elucidating novel functions of MITF in cancer progression and immune responses to cancer. In particular, we highlight the role of MITF as a central modulator in the regulation of immune responses, as elucidated in recent studies.