Combined PD-1, BRAF and MEK inhibition in BRAFV600E colorectal cancer: a phase 2 trial

First-line oxaliplatin-based chemotherapy and nivolumab for metastatic microsatellite-stable colorectal cancer-the randomised METIMMOX trial

BACKGROUND

We evaluated first-line treatment of metastatic microsatellite-stable colorectal cancer with short-course oxaliplatin-based chemotherapy alternating with immune checkpoint blockade.

METHODS

Patients were randomly assigned to chemotherapy (the FLOX regimen; control group) or alternating two cycles each of FLOX and nivolumab (experimental group). Radiographic response assessment was done every eight weeks with progression-free survival (PFS) as the primary endpoint. Cox proportional-hazards regression models estimated associations between PFS and relevant variables. A post hoc analysis explored C-reactive protein as signal of responsiveness to immune checkpoint blockade.

RESULTS

Eighty patients were randomised and 38 in each group received treatment. PFS was comparable-control group: median 9.2 months (95% confidence interval (CI), 6.3-12.7); experimental group: median 9.2 months (95% CI, 4.5-15.0). The adjusted Cox model revealed that experimental-group subjects aged ≥60 had significantly lowered progression risk (p = 0.021) with hazard ratio 0.17 (95% CI, 0.04-0.76). Experimental-group patients with C-reactive protein <5.0 mg/L when starting nivolumab (n = 17) reached median PFS 15.8 months (95% CI, 7.8-23.7). One-sixth of experimental-group cases (all KRAS/BRAF-mutant) achieved complete response.

CONCLUSIONS

The investigational regimen did not improve the primary outcome for the intention-to-treat population but might benefit small subgroups of patients with previously untreated, metastatic microsatellite-stable colorectal cancer.

TRIAL REGISTRATION

ClinicalTrials.gov number, NCT03388190 (02/01/2018).

Mechanisms of myeloid-derived suppressor cell-mediated immunosuppression in colorectal cancer and related therapies

Severe immunosuppression is a hallmark of colorectal cancer (CRC). Myeloid-derived suppressor cells (MDSCs), one of the most abundant components of the tumor stroma, play an important role in the invasion, metastasis, and immune escape of CRC. MDSCs create an immunosuppressive microenvironment by inhibiting the proliferation and activation of immunoreactive cells, including T and natural killer cells, as well as by inducing the proliferation of immunosuppressive cells, such as regulatory T cells and tumor-associated macrophages, which, in turn, promote the growth of cancer cells. Thus, MDSCs are key contributors to the emergence of an immunosuppressive microenvironment in CRC and play an important role in the breakdown of antitumor immunity. In this narrative review, we explore the mechanisms through which MDSCs contribute to the immunosuppressive microenvironment, the current therapeutic approaches and technologies targeting MDSCs, and the therapeutic potential of modulating MDSCs in CRC treatment. This study provides ideas and methods to enhance survival rates in patients with CRC.

Organoids derived from metastatic cancers: Present and future

Organoids are three-dimensional structures derived from primary tissue or tumors that closely mimic the architecture, histology, and function of the parental tissue. In recent years, patient-derived organoids (PDOs) have emerged as powerful tools for modeling tumor heterogeneity, drug screening, and personalized medicine. Although most cancer organoids are derived from primary tumors, the ability of organoids from metastatic cancer to serve as a model for studying tumor biology and predicting the therapeutic response is an area of active investigation. Recent studies have shown that organoids derived from metastatic sites can provide valuable insights into tumor biology and may be used to validate predictive models of the drug response. In this comprehensive review, we discuss the feasibility of culturing organoids from multiple metastatic cancers and evaluate their potential for advancing basic cancer research, drug development, and personalized therapy. We also explore the limitations and challenges associated with using metastasis organoids for cancer research. Overall, this review provides a comprehensive overview of the current state and future prospects of metastatic cancer-derived organoids.

Current knowledge about immunotherapy resistance for melanoma and potential predictive and prognostic biomarkers

Melanoma still reaches thousands of new diagnoses per year, and its aggressiveness makes recovery challenging, especially for those with stage III/IV unresectable melanoma. Immunotherapy, emerging as a beacon of hope, stands at the forefront of treatments for advanced melanoma. This review delves into the various immunotherapeutic strategies, prominently featuring cytokine immunotherapy, adoptive cell therapy, immune checkpoint inhibitors, and vaccinations. Among these, immune checkpoint inhibitors, notably anti-programmed cell death-1 (PD-1) and anti-cytotoxic T lymphocyte antigen-4 (CTLA-4) antibodies, emerge as the leading strategy. However, a significant subset of melanoma patients remains unresponsive to these inhibitors, underscoring the need for potent biomarkers. Efficient biomarkers have the potential to revolutionize the therapeutic landscape by facilitating the design of personalized treatments for patients with melanoma. This comprehensive review highlights the latest advancements in melanoma immunotherapy and potential biomarkers at the epicenter of recent research endeavors.

Multikinase inhibitors modulate non-constitutive proteasome expression in colorectal cancer cells

Introduction: Proteasomes are multi-subunit protein complexes responsible for protein degradation in cells. Immunoproteasomes and intermediate proteasomes (together non-constitutive proteasomes) are specific forms of proteasomes frequently associated with immune response, antigen presentation, inflammation and stress. Expression of non-constitutive proteasome subunits has a prognostic value in several types of cancer. Thus, factors that modulate non-constitutive proteasome expression in tumors are of particular interest. Multikinase inhibitors (MKIs) demonstrate promising results in treatment of cancer. At the same time, their immunomodulatory properties and effects on non-constitutive proteasome expression in colorectal cancer cells are poorly investigated. Methods: Proteasome subunit expression in colorectal cancer was evaluated by bioinformatic analysis of available datasets. Two colorectal cancer cell lines, expressing fluorescent non-constitutive proteasomes were treated with multikinase inhibitors: regorafenib and sorafenib. The proteasome subunit expression was assessed by real-time PCR, Western blotting and flow cytometry. The proteasome activity was studied using proteasome activity-based probe and fluorescent substrates. Intracellular proteasome localization was revealed by confocal microscopy. Reactive oxygen species levels following treatment were determined in cells. Combined effect of proteasome inhibition and treatment with MKIs on viability of cells was estimated. Results: Expression of non-constitutive proteasomes is increased in BRAF-mutant colorectal tumors. Regorafenib and sorafenib stimulated the activity and synthesis of non-constitutive proteasomes in examined cell lines. MKIs induced oxidative stress and redistribution of proteasomes within cells. Sorafenib stimulated formation of cytoplasmic aggregates, containing proteolyticaly active non-constitutive proteasomes, while regorafenib had no such effect. MKIs caused no synergistic action when were combined with the proteasome inhibitor. Discussion: Obtained results indicate that MKIs might affect the crosstalk between cancer cells and immune cells via modulation of intracellular proteasome pool. Observed phenomenon should be considered when MKI-based therapy is applied.

Clinical Use of Molecular Biomarkers in Canine and Feline Oncology: Current and Future

Molecular biomarkers are central to personalised medicine for human cancer patients. It is gaining traction as part of standard veterinary clinical practice for dogs and cats with cancer. Molecular biomarkers can be somatic or germline genomic alterations and can be ascertained from tissues or body fluids using various techniques. This review discusses how these genomic alterations can be determined and the findings used in clinical settings as diagnostic, prognostic, predictive, and screening biomarkers. We showcase the somatic and germline genomic alterations currently available to date for testing dogs and cats in a clinical setting, discussing their utility in each biomarker class. We also look at some emerging molecular biomarkers that are promising for clinical use. Finally, we discuss the hurdles that need to be overcome in going 'bench to bedside', i.e., the translation from discovery of genomic alterations to adoption by veterinary clinicians. As we understand more of the genomics underlying canine and feline tumours, molecular biomarkers will undoubtedly become a mainstay in delivering precision veterinary care to dogs and cats with cancer.

Early Immune Remodeling Steers Clinical Response to First-Line Chemoimmunotherapy in Advanced Gastric Cancer

Adding anti-programmed cell death protein 1 (anti-PD-1) to 5-fluorouracil (5-FU)/platinum improves survival in some advanced gastroesophageal adenocarcinomas (GEA). To understand the effects of chemotherapy and immunotherapy, we conducted a phase II first-line trial (n = 47) sequentially adding pembrolizumab to 5-FU/platinum in advanced GEA. Using serial biopsy of the primary tumor at baseline, after one cycle of 5-FU/platinum, and after the addition of pembrolizumab, we transcriptionally profiled 358,067 single cells to identify evolving multicellular tumor microenvironment (TME) networks. Chemotherapy induced early on-treatment multicellular hubs with tumor-reactive T-cell and M1-like macrophage interactions in slow progressors. Faster progression featured increased MUC5A and MSLN containing treatment resistance programs in tumor cells and M2-like macrophages with immunosuppressive stromal interactions. After pembrolizumab, we observed increased CD8 T-cell infiltration and development of an immunity hub involving tumor-reactive CXCL13 T-cell program and epithelial interferon-stimulated gene programs. Strategies to drive increases in antitumor immune hub formation could expand the portion of patients benefiting from anti-PD-1 approaches.

SIGNIFICANCE

The benefit of 5-FU/platinum with anti-PD-1 in first-line advanced gastric cancer is limited to patient subgroups. Using a trial with sequential anti-PD-1, we show coordinated induction of multicellular TME hubs informs the ability of anti-PD-1 to potentiate T cell-driven responses. Differential TME hub development highlights features that underlie clinical outcomes. This article is featured in Selected Articles from This Issue, p. 695.

Ex vivo tissue modelling informs drug selection for rare cancers

The identification and therapeutic targeting of actionable gene mutations across many cancer types has resulted in improved response rates in a minority of patients. The identification of actionable mutations is usually not sufficient to ensure complete nor durable responses, and in rare cancers, where no therapeutic standard of care exists, precision medicine indications are often based on pan-cancer data. The inclusion of functional data, however, can provide evidence of oncogene dependence and guide treatment selection based on tumour genetic data. We applied an ex vivo cancer explant modelling approach, that can be embedded in routine clinical care and allows for pathological review within 10 days of tissue collection. We now report that ex vivo tissue modelling provided accurate longitudinal response data in a patient with BRAFV600E -mutant papillary thyroid tumour with squamous differentiation. The ex vivo model guided treatment selection for this patient and confirmed treatment resistance when the patient's disease progressed after 8 months of treatment.

Tissue-Agnostic Cancer Therapy Approvals

Tumor-agnostic, or histology-agnostic, cancer therapy marks a groundbreaking evolution in the realm of precision oncology. In stark contrast to conventional cancer treatments that categorize malignancies based on their tissue of origin (eg, breast, lung, renal cell, etc), tumor-agnostic therapies transcend histologic boundaries, honing in on the genetic and molecular attributes of tumors, regardless of their location. This article offers a comprehensive review of the current landscape of tissue-agnostic cancer therapies and provides clinical insights to empower surgical oncologists with a deeper understanding of these innovative therapeutic approaches.

A novel fluorescence-electrochemiluminescence dual-mode sensing platform for high-precision BRAF gene detection

In this study, we innovatively synthesized bipyridine ruthenium cluster nanosheets (RuMOFNCs), a novel metal-organic framework material that exhibits both fluorescence and electrochemiluminescence. Gold nanoparticles (AuNPs) were anchored onto RuMOFNCs via bipyridine chelation, enhancing optical signals and creating sites for attaching biologically functional probes. We employed tetraferrocene-modified DNA probes, linked via gold-sulfur (Au-S) bonds, to construct a dual-mode fluorescence-electrochemiluminescence biosensor. This sensor, exploiting exonuclease III (Exo III)-mediated cyclic amplification, inhibits the electron transfer from RuMOFNC to tetraferrocene, resulting in amplified fluorescence and electrochemiluminescence signals. The sensor demonstrates exceptional sensitivity for detecting the BRAF gene, with fluorescence and electrochemiluminescence detection limits of 10.3 aM (range: 0.1 fM to 1 nM) and 3.1 aM (range: 1 aM to 10 pM), respectively. These capabilities are attributed to RuMOFNCs' luminescence properties, tetraferrocene's quenching effect, and the specificity of base pairing. This study's findings hold substantial promise for biomedical research and clinical diagnostics, particularly in precision medicine and early disease detection.

BRAF - a tumour-agnostic drug target with lineage-specific dependencies

In June 2022, the FDA granted Accelerated Approval to the BRAF inhibitor dabrafenib in combination with the MEK inhibitor trametinib for the treatment of adult and paediatric patients (≥6 years of age) with unresectable or metastatic BRAFV600E-mutant solid tumours, except for BRAFV600E-mutant colorectal cancers. The histology-agnostic approval of dabrafenib plus trametinib marks the culmination of two decades of research into the landscape of BRAF mutations in human cancers, the biochemical mechanisms underlying BRAF-mediated tumorigenesis, and the clinical development of selective RAF and MEK inhibitors. Although the majority of patients with BRAFV600E-mutant tumours derive clinical benefit from BRAF inhibitor-based combinations, resistance to treatment develops in most. In this Review, we describe the biochemical basis for oncogenic BRAF-induced activation of MAPK signalling and pan-cancer and lineage-specific mechanisms of intrinsic, adaptive and acquired resistance to BRAF inhibitors. We also discuss novel RAF inhibitors and drug combinations designed to delay the emergence of treatment resistance and/or expand the population of patients with BRAF-mutant cancers who benefit from molecularly targeted therapies.

Clinical implications of PD-L1 expression and pathway-related molecular subtypes in advanced Asian colorectal cancer patients

The expression level of PD-L1 does not accurately predict the prognosis of advanced colorectal cancer (CRC) patients, but it still reflects the tumor microenvironment to some extent. By stratifying PD-L1 status, gene subtypes in PD-L1 positivity-related pathological pathways were analyzed for their relationship to MSI or TMB to provide more individualized treatment options for CRCs. A total of 752 advanced CRCs were included, and their genomic variance was measured by a targeted next generation sequencing panel in this study. MSI and TMB were both measured by NGS, while PD-L1 expression level was measured using the PD-L1 colon 22C3 pharmDx kit. We found RTK/RAS pathway was positively related to high PD-L1 expression, with BRAF V600E and most KRAS mutations (G12 and G13) subtypes showing a significant correlation. Conversely, the Wnt and p53 pathways were negatively related to high PD-L1 expression, with APC C-terminal alterations and other non-inactivation mutations in TP53 making a primary contribution with significant statistical significance. Major subtypes showing a significantly higher proportion of TMB-H or MSI-H were irrespective of PD-L1 status. These findings demonstrate pathological pathways associated with high PD-L1 expression, suggesting that pathway-induced oncogenic constructive PD-L1 upregulation may be the reason for the corresponding patients' primary resistance to immune checkpoint inhibitors (ICIs), rather than a lack of pre-existing immune responses.

Neutralizing IL-16 enhances the efficacy of targeting Aurora-A therapy in colorectal cancer with high lymphocyte infiltration through restoring anti-tumor immunity

Cancer cells can evade immune elimination by activating immunosuppressive signaling pathways in the tumor microenvironment (TME). Targeting immunosuppressive signaling pathways to promote antitumor immunity has become an attractive strategy for cancer therapy. Aurora-A is a well-known oncoprotein that plays a critical role in tumor progression, and its inhibition is considered a promising strategy for treating cancers. However, targeting Aurora-A has not yet got a breakthrough in clinical trials. Recent reports have indicated that inhibition of oncoproteins may reduce antitumor immunity, but the role of tumor-intrinsic Aurora-A in regulating antitumor immunity remains unclear. In this study, we demonstrated that in tumors with high lymphocyte infiltration (hot tumors), higher tumor-intrinsic Aurora-A expression is associated with a better prognosis in CRC patients. Mechanically, tumor-intrinsic Aurora-A promotes the cytotoxic activity of CD8+ T cells in immune hot CRC via negatively regulating interleukin-16 (IL-16), and the upregulation of IL-16 may impair the therapeutic effect of Aurora-A inhibition. Consequently, combination treatment with IL-16 neutralization improves the therapeutic response to Aurora-A inhibitors in immune hot CRC tumors. Our study provides evidence that tumor-intrinsic Aurora-A contributes to anti-tumor immunity depending on the status of lymphocyte infiltration, highlighting the importance of considering this aspect in cancer therapy targeting Aurora-A. Importantly, our results suggest that combining Aurora-A inhibitors with IL-16-neutralizing antibodies may represent a novel and effective approach for cancer therapy, particularly in tumors with high levels of lymphocyte infiltration.

Cetuximab as a Key Partner in Personalized Targeted Therapy for Metastatic Colorectal Cancer

Cetuximab, a chimeric IgG1 monoclonal antibody targeting the epidermal growth factor receptor (EGFR), has revolutionized personalized treatment of metastatic colorectal cancer (mCRC) patients. This review highlights the mechanism of action, characteristics, and optimal indications for cetuximab in mCRC. Cetuximab has emerged as a pivotal partner for novel therapies in specific molecular subgroups, including BRAF V600E, KRAS G12C, and HER2-altered mCRC. Combining cetuximab with immunotherapy and other targeted agents further expands the therapeutic landscape, offering renewed hope for mCRC patients who face the development of resistance to conventional therapies. Ongoing clinical trials have continued to uncover innovative cetuximab-based treatment strategies, promising a brighter future for mCRC patients. This review provides a comprehensive overview of cetuximab's role and its evolving importance in personalized targeted therapy of mCRC patients, offering valuable insights into the evolving landscape of colorectal cancer treatment.

High-Fidelity Identification of Single Nucleotide Polymorphism by Type V CRISPR Systems

Accurate and sensitive detection of single nucleotide polymorphism (SNP) holds significant clinical implications, especially in the field of cancer diagnosis. Leveraging its high accuracy and programmability, the CRISPR system emerges as a promising platform for advancing the identification of SNPs. In this study, we compared two type V CRISPR/Cas systems (Cas12a and Cas14a) for the identification of cancer-related SNP. Their identification performances were evaluated by characterizing their mismatch tolerance to the BRAF gene. We found that the CRISPR/Cas14a system exhibited superior accuracy and robustness over the CRISPR/Cas12a system for SNP detection. Furthermore, blocker displacement amplification (BDA) was combined with the CRISPR/Cas14a system to eliminate the interference of the wild type (WT) and increase the detection accuracy. In this strategy, we were able to detect BRAF V600E as low as 103 copies with a sensitivity of 0.1% variant allele frequency. Moreover, the BDA-assisted CRISPR/Cas14a system has been applied to identify the BRAF mutation from human colorectal carcinoma cells, achieving a high sensitivity of 0.5% variant allele frequency, which is comparable to or even superior to those of most commercially available products. This work has broadened the scope of the CRISPR system and provided a promising method for precision medicine.

KRAS Wild-Type Pancreatic Cancer: Decoding Genomics, Unlocking Therapeutic Potential

In a landscape dominated by pivotal KRAS mutations, there has been limited exploration of KRAS wild-type pancreatic cancer. A recent study highlights other mitogen-activated kinase pathway alterations as alternative drivers in these tumors, which holds the key to unlocking a realm of targeted therapies for patients with this understudied cancer subtype. See related article by Singh et al., p. 4627.

Clinical research progress on BRAF V600E-mutant advanced colorectal cancer

Colorectal cancer is one of the malignant tumors that pose a serious threat to human health. A particularly bad prognosis might be expected for colorectal tumors with the unique molecular subtype BRAF V600E mutation. With the development of precision therapy, the advent of molecularly targeted therapies and immune checkpoint inhibitors has improved the outcome of intermediate to advanced colorectal cancer. However, the duration of drug benefit is usually short, and overall survival and progression-free survival remain suboptimal. Therefore, investigators are exploring more rational, safe, and effective drug combination regimens through clinical trials to provide longer survival for patients with such genetic mutations with metastatic colorectal cancer (mCRC). This article reviews the progress of clinical research on molecularly targeted drugs, immune checkpoint inhibitors, first-line chemotherapeutic agents, and different combination therapy regimens (including different targeted drug combinations, immune combination targeting, and chemotherapy combination targeting) for colorectal cancer patients with BRAF V600E mutation, which provides a reference for further in-depth clinical exploration of the treatment of colorectal cancer patients with BRAF V600E mutation.

BRAF Inhibitors in Metastatic Colorectal Cancer and Mechanisms of Resistance: A Review of the Literature

Metastatic colorectal cancer (mCRC) with mutated BRAF exhibits distinct biological and molecular features that set it apart from other subtypes of CRC. Current standard treatment for these tumors involves a combination of chemotherapy (CT) and VEGF inhibitors. Recently, targeted therapy against BRAF and immunotherapy (IT) for cases with microsatellite instability (MSI) have been integrated into clinical practice. While targeted therapy has shown promising results, resistance to treatment eventually develops in a significant portion of responsive patients. This article aims to review the available literature on mechanisms of resistance to BRAF inhibitors (BRAFis) and potential therapeutic strategies to overcome them.

Identification of an optimal mutant allele frequency to detect activating KRAS, NRAS, and BRAF mutations in a commercial cell-free DNA next-generation sequencing assay in colorectal and pancreatic adenocarcinomas

Background

Evaluation for activating mutations in KRAS, NRAS, and BRAF in colorectal cancer (CRC) and in KRAS in pancreatic ductal adenocarcinoma (PDAC) is essential for clinical care. Plasma cell-free DNA (cfDNA) next-generation sequencing (NGS) allows convenient assessment of a tumor's molecular profile, however low tumor DNA shedding limits sensitivity. We investigated mutant allele frequency (MAF) of other oncogenic dominant genes to identify a threshold for accurate detection of KRAS, NRAS, and BRAF (RAS/RAF) mutations in cfDNA.

Methods

Molecular and clinical data were obtained from the Duke Molecular Registry of Tumors and the SCRUM-Japan GOZILA study. Patients with CRC or PDAC and a KRAS, NRAS, or BRAF activating single nucleotide variant (SNV) present on tissue NGS and with available cfDNA assays were included. Recursive partitioning and Wilcoxon-rank statistics methods identified potential cut-points for discriminative MAF values.

Results

One hundred and thirty-five CRC and 30 PDAC cases with 198 total cfDNA assays met criteria. Greatest non-RAS/RAF dominant gene MAF of 0.34% provided maximum discrimination for predicting RAS/RAF SNV detection. Sensitivity for RAS/RAF SNVs increased with dominant gene MAF, with MAF ≥1% predicting sensitivity >98%, MAF between 0.34 and 1% predicting sensitivity of 84.0%, and MAF £0.34% predicting sensitivity of 50%. For 43 cfDNA assays that did not detect RAS/RAF SNVs, 18 assays detected 34 other oncogenic variants, of which 80.6% were not also detected on tissue.

Conclusions

Non-RAS/RAF dominant oncogenic mutation MAF ≥1% on cfDNA NGS predicts high sensitivity to detect RAS/RAF oncogenic SNVs in CRC and PDAC. MAF £0.34% indicates an assay may not reliably detect RAS/RAF SNVs, despite detection on tissue testing. Most variants from assays that did not detect RAS/RAF had MAF <1% and were not detected on tissue, suggesting potential confounding. These data suggest a practical approach to determining cfDNA assay adequacy, with implications for guiding clinical decisions in CRC and PDAC.

Immunocheckpoint Inhibitors in Microsatellite-Stable or Proficient Mismatch Repair Metastatic Colorectal Cancer: Are We Entering a New Era?

Colorectal cancer (CRC) is the third most frequent cancer and the second leading cause of cancer-related deaths in Europe. About 5% of metastatic CRC (mCRC) are characterized by high microsatellite instability (MSI) due to a deficient DNA mismatch repair (dMMR), and this condition has been related to a high sensitivity to immunotherapy, in particular to the Immune Checkpoint Inhibitors (ICIs). In fact, in MSI-H or dMMR mCRC, treatment with ICIs induced remarkable response rates and prolonged survival. However, the majority of mCRC cases are mismatch-repair-proficient (pMMR) and microsatellite-stable (MSS), and unfortunately these conditions involve resistance to ICIs. This review aims to provide an overview of the strategies implemented to overcome ICI resistance and/or define subgroups of patients with MSS or dMMR mCRC who may benefit from immunotherapy.

Kinesin superfamily member KIFC2 as an independent prognostic biomarker of colon adenocarcinoma associated with poor immune response

Clinical outcomes of colon adenocarcinoma (COAD) exhibit heterogeneity among different patients, highlighting the need for novel prognostic biomarkers. Kinesin superfamily members have been shown to play a crucial role in tumors and can predict cancer diagnosis and prognosis. However, the role of kinesin family member C2 (KIFC2) in tumors, particularly its prognostic value in COAD, remains poorly understood. Our bioinformatics analysis of the cancer genome atlas and GEO databases revealed significantly higher expression of KIFC2 in COAD, correlating with a worse prognosis in the cancer genome atlas-COAD and GSE17536 cohorts. Additionally, differentially expressed genes in COAD were enriched in immune-related pathways, and patients with higher KIFC2 expression showed fewer activated CD4 + T cells. These findings suggest KIFC2 as a potential prognostic biomarker for COAD, warranting further validation in clinical studies.

Optimizing the first-line treatment for metastatic colorectal cancer

Colorectal cancer represents an important oncological challenge both for its incidence, which makes it an important health problem, and for its biological complexity, which has made clinical results very difficult in terms of outcome for this category of patients. To date these diseases should not be treated as a single entity but it is necessary to distinguish colorectal cancers based on characteristics that nowadays are essential to have greater therapeutic benefits. These include the sideness of the disease, the state of microsatellites, the presence of prognostic and predictive mutations of response to treatments currently available in clinical practice, which are associated with new therapeutic targets. The greatest challenge in the future will be to circumvent the resistance mechanisms that make this disease very difficult to treat with good long-term results by studying effective combination treatments with a good toxicity profile. Once such combinations or targeted treatments are consolidated, it will be desirable to shift the best therapies to the first line treatment to make them immediately accessible to the patient. It will also be essential to refine the selection of patients who can benefit from these treatments.

Tumor Cell Resistance to the Inhibition of BRAF and MEK1/2

BRAF is one of the most frequently mutated oncogenes, with an overall frequency of about 50%. Targeting BRAF and its effector mitogen-activated protein kinase kinase 1/2 (MEK1/2) is now a key therapeutic strategy for BRAF-mutant tumors, and therapies based on dual BRAF/MEK inhibition showed significant efficacy in a broad spectrum of BRAF tumors. Nonetheless, BRAF/MEK inhibition therapy is not always effective for BRAF tumor suppression, and significant challenges remain to improve its clinical outcomes. First, certain BRAF tumors have an intrinsic ability to rapidly adapt to the presence of BRAF and MEK1/2 inhibitors by bypassing drug effects via rewired signaling, metabolic, and regulatory networks. Second, almost all tumors initially responsive to BRAF and MEK1/2 inhibitors eventually acquire therapy resistance via an additional genetic or epigenetic alteration(s). Overcoming these challenges requires identifying the molecular mechanism underlying tumor cell resistance to BRAF and MEK inhibitors and analyzing their specificity in different BRAF tumors. This review aims to update this information.

Single-cell dissection of tumor microenvironmental response and resistance to cancer therapy

Cancer treatment strategies have evolved significantly over the years, with chemotherapy, targeted therapy, and immunotherapy as major pillars. Each modality leads to unique treatment outcomes by interacting with the tumor microenvironment (TME), which imposes a fundamental selective pressure on cancer progression. The advent of single-cell profiling technologies has revolutionized our understanding of the intricate and heterogeneous nature of the TME at an unprecedented resolution. This review delves into the commonalities and differential manifestations of how cancer therapies reshape the microenvironment in diverse cancer types. We highlight how groundbreaking immune checkpoint blockade (ICB) strategies alone or in combination with tumor-targeting treatments are endowed with comprehensive mechanistic insights when decoded at the single-cell level, aiming to drive forward future research directions on personalized treatments.

Preliminary exploration of the effects of environmental factors on the microsatellite status of BRAF-mutated colorectal cancer

BACKGROUND

To investigate the expression of EBV products and frequency of gallstone disease (GD) among different microsatellite status in colorectal cancer (CRC) with BRAFV600E mutation.

METHODS

We collected 30 CRC patients with BRAFV600E mutation and 10 BRAF ( -) CRC patients as well as 54 healthy subjects. Tumor tissue samples were collected to detect the mutation of BRAF, KRAS, and TP53. Microsatellite status was determined by immunohistochemistry and PCR. EBER in situ hybridization was performed to detect EBV. In addition, we also collected clinical information about the patients.

RESULTS

We found that although EBV products were detected in CRC, there were no significant differences in the EBV distribution between the different BRAF groups. Our study demonstrated that BRAFV600E mutation and BRAFV600E with MSI were significantly more frequent in the right CRC. Furthermore, the KRAS mutation rate in the BRAF-wild-type group was proved to be significantly higher than that in the BRAF mutation group. In addition, we revealed that BRAF mutation and MSI were independent risk factors of TNM stage. The frequency of GD was higher in CRC patients than in general population, and although there was no significant difference between CRC with or without BRAFV600E mutation, the highest frequency of GD was found in MSS CRC with BRAFV600E mutation.

CONCLUSIONS

EBV plays a role in CRC, but is not a determinant of different microsatellite status in CRC with BRAFV600E mutation. The frequency of GD in MSS CRC with BRAFV600E mutation is significantly higher than that in the general population.

BRAFV600E Metastatic Colorectal Cancer: Perspective from a Patient, a Caregiver, and an Oncologist

This article has been co-authored by a patient with right-sided BRAFV600E metastatic colorectal cancer (mCRC), his caregiver, and an oncologist. Here the patient and caregiver discuss their personal experiences struggling with cancer, including their fears, expectations, and attitudes as the disease progresses. The oncologist describes how patients with BRAFV600E mCRC are treated and how the management strategy can be balanced to mitigate any side effects. Improved diagnostic techniques and the availability of numerous treatment options, including various chemotherapy schemes and molecular-targeted drugs, can aid rapid implementation of treatment algorithms. The pivotal roles of patients' associations in the general support of patients and those close to them, and in facilitating the link with healthcare professionals, are highlighted in this perspective piece.

Beyond EGFR inhibitors in advanced colorectal cancer: Targeting BRAF and HER2

The addition of antiepidermal growth factor receptor (EGFR) monoclonal antibodies, cetuximab or panitumumab, to conventional chemotherapy has improved clinical outcomes for rat sarcoma virus (RAS) wild-type advanced colorectal cancer patients, however, durable responses and 5-year overall survival rates remain limited. BRAF V600E somatic mutation and human epidermal growth factor receptor (HER2) amplification/overexpression have been separately implicated in primary resistance to anti-EGFR therapeutic strategies via aberrant activation of the mitogen-activated protein kinase (MAPK) signaling pathway, resulting in poorer outcomes. In addition to being a negative predictive biomarker for anti-EGFR therapy, BRAF V600E mutation and HER2 amplification/overexpression serve as positive predictors of response to therapies targeting these respective tumor promoters. This review will highlight key clinical studies that support the rational use of v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) and HER2-targeted therapies, often in combination with other targeted agents, cytotoxic chemotherapy, and immune checkpoint inhibitors. We discuss current challenges with BRAF and HER2-targeted therapies in metastatic colorectal cancer and potential opportunities for improvement.

Treatment of BRAF-V600E mutant metastatic colorectal cancer: new insights and biomarkers

INTRODUCTION

The presence of a BRAF-V600E mutation in metastatic colorectal cancer (mCRC) is observed in approximately 12% of cases and is associated with poor prognosis and aggressive disease. Unlike melanoma, the development of successful BRAF blockade in colorectal cancer has been complex. The phase III BEACON trial made significant progress in the development of BRAF inhibitors by establishing encorafenib-cetuximab as the new standard of care for patients with mCRC who have progressed to one or two previous lines of treatment. Nonetheless, not all patients respond to encorafenib-based combinations, and some responses are short-lived. Identifying new strategies to boost antitumor activity and improve survival is paramount.

AREAS COVERED

The development of targeted therapy for BRAF-V600E mCRC starting with BRAF inhibitors as monotherapy through novel combinations with anti-VEGF or anti-PD1 agents to enhance antitumor activity is reviewed, with a particular focus on the development of predictive and prognostic biomarkers.

EXPERT OPINION

There is a crucial need to better understand tumor biology and develop accurate and reliable biomarkers to enhance the antitumor activity of encorafenib-based combinations. The RNF43 mutation is an accurate and reliable predictive biomarker of response, and combinations that target crosstalk between the MAPK pathway, the immune system, and WNT pathways seem promising.

Expanding the Benefit: Dabrafenib/Trametinib as Tissue-Agnostic Therapy for BRAF V600E-Positive Adult and Pediatric Solid Tumors

The recent US Food and Drug Administration (FDA) approval of the dabrafenib/trametinib combination as a tissue-agnostic treatment for solid tumors with BRAF V600E mutation is the result of more than 20 years of extensive research into BRAF mutations in human cancer, the underlying biological mechanisms that drive BRAF-mediated tumor growth, and the clinical testing and refinement of selective RAF and MEK kinase inhibitors. Such approval marks a significant achievement in the field of oncology and represents a major step forward in our ability to treat cancer. Early evidence supported the use of dabrafenib/trametinib combination in melanoma, non-small-cell lung cancer, and anaplastic thyroid cancer. Furthermore, data from basket trials have demonstrated consistently good response rates in various tumors, including biliary tract cancer, low-grade glioma, high-grade glioma, hairy cell leukemia, and multiple other malignancies, which has been the basis for FDA approval of a tissue-agnostic indication in adult and pediatric patients with BRAF V600E-positive solid tumors. From a clinical standpoint, our review delves into the efficacy of the dabrafenib/trametinib combination for BRAF V600E-positive tumors: examining the underlying rationale for its use, evaluating the latest evidence on its potential benefits, and discussing the possible associated adverse effects and strategies to minimize their impact. Additionally, we explore potential resistance mechanisms and future landscape of BRAF-targeted therapies.

Spatial analysis of human lung cancer reveals organized immune hubs enriched for stem-like CD8 T cells and associated with immunotherapy response

The organization of immune cells in human tumors is not well understood. Immunogenic tumors harbor spatially-localized multicellular 'immunity hubs' defined by expression of the T cell-attracting chemokines CXCL10/CXCL11 and abundant T cells. Here, we examined immunity hubs in human pre-immunotherapy lung cancer specimens, and found that they were associated with beneficial responses to PD-1-blockade. Immunity hubs were enriched for many interferon-stimulated genes, T cells in multiple differentiation states, and CXCL9/10/11 + macrophages that preferentially interact with CD8 T cells. Critically, we discovered the stem-immunity hub, a subtype of immunity hub strongly associated with favorable PD-1-blockade outcomes, distinct from mature tertiary lymphoid structures, and enriched for stem-like TCF7+PD-1+ CD8 T cells and activated CCR7 + LAMP3 + dendritic cells, as well as chemokines that organize these cells. These results elucidate the spatial organization of the human intratumoral immune response and its relevance to patient immunotherapy outcomes.