Prevalence of class I-III BRAF mutations among 114,662 cancer patients in a large genomic database

BRAF Non-V600 Mutations in Metastatic Colorectal Cancer

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in the United States. Despite advancements in detection and therapeutic options, patients with metastatic CRC continue to face poor survival rates. The heterogeneity of oncogenic alterations, including BRAF mutations, poses a substantial challenge in identifying optimal treatment approaches. Notably, BRAF non-V600 mutations, encompassing class II and class III mutations, exhibit the distinct patterns of the signaling pathways and responses to targeted therapies compared to BRAF V600 mutations (class I). Nevertheless, the current classification system may underestimate the complexity and heterogeneity of BRAF-mutant CRC. Ongoing clinical trials are actively investigating targeted therapies for BRAF non-V600 mutations, but they are being confronted with patient recruitment obstacles due to the genetic diversity of these alterations. Continued research is needed to refine mutation subtyping, identify effective treatment strategies, and improve outcomes for patients with BRAF non-V600-mutant CRC. Enhancing our understanding and management of this specific subgroup of CRC is crucial for developing personalized treatment approaches and advancing patient care. This manuscript provides a comprehensive overview of the recent advances in and perspectives on BRAF non-V600 alterations in colorectal cancer, including relevant ongoing clinical trials.

BRAF Mutations in Melanoma: Biological Aspects, Therapeutic Implications, and Circulating Biomarkers

Melanoma is an aggressive form of skin cancer resulting from the malignant transformation of melanocytes. Recent therapeutic approaches, including targeted therapy and immunotherapy, have improved the prognosis and outcome of melanoma patients. BRAF is one of the most frequently mutated oncogenes recognised in melanoma. The most frequent oncogenic BRAF mutations consist of a single point mutation at codon 600 (mostly V600E) that leads to constitutive activation of the BRAF/MEK/ERK (MAPK) signalling pathway. Therefore, mutated BRAF has become a useful target for molecular therapy and the use of BRAF kinase inhibitors has shown promising results. However, several resistance mechanisms invariably develop leading to therapeutic failure. The aim of this manuscript is to review the role of BRAF mutational status in the pathogenesis of melanoma and its impact on differentiation and inflammation. Moreover, this review focuses on the mechanisms responsible for resistance to targeted therapies in BRAF-mutated melanoma and provides an overview of circulating biomarkers including circulating tumour cells, circulating tumour DNA, and non-coding RNAs.

Multidrug resistance in the standardized treatment of colon cancer harboring a rare fibrosarcoma B-type (BRAF) p.N581I mutation: a case report

BRAF non-V600 mutations are a distinct molecular subset of colorectal cancer (CRC) that has little to no clinical similarity to the BRAF V600 mutations. It is generally considered that the BRAF non-V600 mutations correlate with better survival of CRC patients. In this report, we present an unusual case of that a midlife female patient who was initially diagnosed with stage IIIC colon cancer, and multiple metastases were found 25 months after radical surgery. Next-generation sequencing (NGS) revealed the BRAF p.N581I (c.1742A>T) mutation. She received chemotherapy, targeted therapy, and immunotherapy. However, the disease progressed rapidly with rare metastasis of the bone and cerebellum. This case highlights that the BRAF non-V600 mutations, such as BRAF p.N581I mutant, may lead to resistance to epidermal growth factor receptor (EGFR) inhibitors and result in a rapid course in colorectal cancer. The role of BRAF p.N581I mutation in colorectal cancer demands more attention.

The significance of tissue-agnostic biomarkers in solid tumors: the more the merrier?

INTRODUCTION

To date, several emerging biomarkers have gained considerable interest in the field of predictive molecular oncology. The advent of precision medicine has led to the development of innovative drugs targeting rare molecular pathways independently from histology, defined as tissue-agnostic drugs.

AREAS COVERED

Although there is a lot of promise for this new tissue-agnostic model in the oncological scenario, crucial issues from both the diagnostic and therapeutic standpoint are emerging. This review aims to critically examine the role of tissue-agnostic biomarkers in different solid tumors, focusing on the prevalence and methods of detection of agnostic biomarkers together with drug approvals to guide clinicians in this evolving landscape.

EXPERT OPINION

To strengthen the framework for tissue-agnostic approvals, the dialogue between regulatory, industrial, and academic parties should be intensified. Critical questions include the development of an efficient network system that can overcome the heterogeneity of patients' inclusion criteria along with the increasingly difficult interpretation of next-generation sequencing (NGS) profiling technologies. Cost-effectiveness and risk-benefit studies are needed in the national context considering the modalities of access to diagnostic tests and reimbursement of treatments.

BRAF V600E Mutation of Non-Small Cell Lung Cancer in Korean Patients

Background and Objectives: BRAF mutational status in resected non-small cell lung cancer (NSCLC) in the Korean population is poorly understood. We explored BRAF (particularly BRAF V600E) mutational status among Korean patients with NSCLC. Materials and Methods: This study included 378 patients with resected primary NSCLC who were enrolled from January 2015 to December 2017. The authors obtained formalin-fixed paraffin-embedded (FFPE) tissue blocks and performed peptide nucleic acid (PNA)-clamping polymerase chain reaction (PCR) for detecting BRAF V600, real-time PCR for detecting BRAF V600E, and immunohistochemical analyses using the mutation-specific Ventana VE1 monoclonal antibody. For positive cases in any methods mentioned above, direct Sanger sequencing was additionally performed. Results: The PNA-clamping method revealed the BRAF V600 mutation in 5 (1.3%) of the 378 patients. Among these five patients, real-time PCR, direct Sanger sequencing detected BRAF V600E mutations in three (0.8%) patients. Thus, two cases showed differences in their PNA-clamping and the others. Direct Sanger sequencing of PNA-clamping PCR product was performed for two cases showing negative results on direct Sanger sequencing; both contained BRAF mutations other than V600E. All patients harboring BRAF mutations had adenocarcinomas, and all patients with V600E mutation exhibited minor micropapillary components. Conclusions: Despite the low incidence of the BRAF mutation among Korean patients with NSCLC, lung adenocarcinoma patients with micropapillary components should be prioritized in terms of BRAF mutation testing. Immunohistochemical staining using Ventana VE1 antibody may serve as a screening examination for BRAF V600E.

Immunotherapy and Targeted Therapy for Advanced Biliary Tract Cancer: Adding New Flavors to the Pizza

Biliary tract cancers (BTCs) are a rare pathology and can be divided into four major subgroups: intrahepatic cholangiocarcinoma, extrahepatic cholangiocarcinoma, hilar cholangiocarcinoma, and gallbladder cancer. In the era of precision oncology, the development of next-generation sequencing (NGS) allowed a better understanding of molecular differences between these subgroups. Thus, the development of drugs that can target these alterations and inhibit the abnormal pathway activation has changed the prognosis of BTC patients. Additionally, the development of immune checkpoint inhibitors and a better understanding of tumor immunogenicity led to the development of clinical trials with immunotherapy for this scenario. The development of biomarkers that can predict how the immune system acts against the tumor cells, and which patients benefit from this activation, are urgently needed. Here, we review the most recent data regarding targeted treatment and immunotherapy in the scenario of BTC treatment, while also discussing the future perspectives for this challenging disease.

KRAS, NRAS, BRAF, HER2 and MSI Status in a Large Consecutive Series of Colorectal Carcinomas

This study aimed to analyze clinical and regional factors influencing the distribution of actionable genetic alterations in a large consecutive series of colorectal carcinomas (CRCs). KRAS, NRAS and BRAF mutations, HER2 amplification and overexpression, and microsatellite instability (MSI) were tested in 8355 CRC samples. KRAS mutations were detected in 4137/8355 (49.5%) CRCs, with 3913 belonging to 10 common substitutions affecting codons 12/13/61/146, 174 being represented by 21 rare hot-spot variants, and 35 located outside the "hot" codons. KRAS Q61K substitution, which leads to the aberrant splicing of the gene, was accompanied by the second function-rescuing mutation in all 19 tumors analyzed. NRAS mutations were detected in 389/8355 (4.7%) CRCs (379 hot-spot and 10 non-hot-spot substitutions). BRAF mutations were identified in 556/8355 (6.7%) CRCs (codon 600: 510; codons 594-596: 38; codons 597-602: 8). The frequency of HER2 activation and MSI was 99/8008 (1.2%) and 432/8355 (5.2%), respectively. Some of the above events demonstrated differences in distribution according to patients' age and gender. In contrast to other genetic alterations, BRAF mutation frequencies were subject to geographic variation, with a relatively low incidence in areas with an apparently warmer climate (83/1726 (4.8%) in Southern Russia and North Caucasus vs. 473/6629 (7.1%) in other regions of Russia, p = 0.0007). The simultaneous presence of two drug targets, BRAF mutation and MSI, was observed in 117/8355 cases (1.4%). Combined alterations of two driver genes were detected in 28/8355 (0.3%) tumors (KRAS/NRAS: 8; KRAS/BRAF: 4; KRAS/HER2: 12; NRAS/HER2: 4). This study demonstrates that a substantial portion of RAS alterations is represented by atypical mutations, KRAS Q61K substitution is always accompanied by the second gene-rescuing mutation, BRAF mutation frequency is a subject to geographical variations, and a small fraction of CRCs has simultaneous alterations in more than one driver gene.

Non-small-cell lung cancer: how to manage BRAF-mutated disease

BRAF mutations are reported in about 3-5% of non-small-cell lung cancer (NSCLC), almost exclusively in adenocarcinoma histology, and are classified into three different classes. The segmentation of BRAF mutations into V600 (class 1) and non-V600 (classes 2 and 3) relies on their biological characteristics and is of interest for predicting the therapeutic benefit of targeted therapies and immunotherapy. Given the relative rarity of this molecular subset of disease, evidence supporting treatment choices is limited. This review aims to offer a comprehensive update about available therapeutic options for patients with NSCLC harbouring BRAF mutations to guide the physician in the choice of treatment strategies. We collected the most relevant available data, from single-arm phase II studies and retrospective analyses conducted in advanced NSCLC, regarding the efficacy of BRAF and MEK inhibitors in both V600 and non-V600 BRAF mutations. We included case reports and smaller experiences that could provide information on specific alterations. With respect to immunotherapy, we reviewed retrospective evidence on immune-checkpoint inhibitors in this molecular subset, whereas data about chemo-immunotherapy in this molecular subgroup are lacking. Moreover, we included the available, though limited, retrospective evidence of immunotherapy as consolidation after chemo-radiation for unresectable stage III BRAF-mutant NSCLC, and an overview of ongoing clinical trials in the peri-operative setting that could open new perspectives in the future.

Non-V600E/K BRAF Mutations in Metastatic Melanoma: Molecular Description, Frequency, and Effectiveness of Targeted Therapy in a Large National Cohort

PURPOSE

Mitogen-activating protein kinase inhibitors (MAPKis) are largely used in V600E/K BRAF–mutated metastatic melanomas, but data regarding effectiveness of targeted therapy in patients with rare BRAF mutations and molecular description of these infrequent mutations are scarce.

PATIENTS AND METHODS

A multicenter study was conducted on patients with metastatic melanoma harboring a well-identified mutation of BRAF and enrolled from March 2013 to June 2021 in the French nationwide prospective cohort MelBase. The molecular BRAF mutation pattern, response to MAPKis when applicable, and survival data were analyzed.

RESULTS

Of 856 selected patients, 51 (6%) harbored a non-V600E/K BRAF mutation involving codons V600 (24 of 51, 47%; V600G 27.4%, V600R 15.6%), K601 (6 of 51, 11.7%), and L597 (4 of 51, 7.8%). An objective response to MAPKis either BRAF inhibitor (BRAFi) alone or combined with MEK inhibitor was achieved in 56% (353 of 631) of V600E/K, 58% (11 of 19) of non-E/K V600, and 22% (2 of 9) of non-V600 BRAF-mutated patients, with a median progression-free survival of 7.7, 7.8, and 2.8 months, respectively. Overall, objective response rate was higher with BRAFi + MEK inhibitor combination than with BRAFi in monotherapy for each subset.

CONCLUSION

Rare BRAF mutations are not anecdotal in the metastatic melanoma population. Although data interpretation must remain careful owing to the limited size of some subsets of patients, non-E/K V600 BRAF mutations seem to confer a high sensitivity to targeted therapy, whereas MAPKis seem less effective in patients with non-V600 BRAF mutations. However, this strategy may be used as an alternative option in the case of immunotherapy failure in the latter population.

Clinical associations and genetic interactions of oncogenic BRAF alleles

BRAF is a serine/threonine-specific protein kinase that regulates the MAPK/ERK signaling pathway, and mutations in the BRAF gene are considered oncogenic drivers in diverse types of cancer. Based on the signaling mechanism, oncogenic BRAF mutations can be assigned to three different classes: class 1 mutations constitutively activate the kinase domain and lead to RAS-independent signaling, class 2 mutations induce artificial dimerization of BRAF and RAS-independent signaling and class 3 mutations display reduced or abolished kinase function and require upstream signals. Despite the importance of BRAF mutations in cancer, the clinical associations, genetic interactions and therapeutic implications of non-V600 BRAF mutations have not been explored comprehensively yet. In this study, the author analyzed publically available data from the AACR Project GENIE to further understand clinical associations and genetic interactions of oncogenic BRAF mutations. The analyses identified 93 recurrent BRAF mutations, out of which 50 could be assigned to a functional class based on literature review. The author could show that the frequency of BRAF mutations varies across cancer types and subtypes, and that the BRAF mutation classes are unequally distributed across cancer types and subtypes. Using permutation testing-based co-occurrence analyses, the author defined the genetic interactions of BRAF mutations in multiple cancer types and revealed unexplored genetic interactions that might define clinically relevant subgroups. With non-small cell lung cancer as example, the author further showed that the genetic interactions are BRAF mutation class-specific. The presented analyses explore the properties of oncogenic BRAF mutations and will help to further delineate the complex role of BRAF in cancer.

Genomic Landscape, Clinical Features and Outcomes of Non-Small Cell Lung Cancer Patients Harboring BRAF Alterations of Distinct Functional Classes

BACKGROUND

In non-small cell lung cancer (NSCLC), BRAF class 1 alterations are effectively targeted by BRAF inhibitors. Conversely, targeted therapies have very low or absent activity in patients carrying class 2 and 3 alterations. The spectrum of BRAF alterations in NSCLC patients, and their accompanying clinical features, genomic landscape and treatment outcomes have been poorly reported.

PATIENTS AND METHODS

We identified BRAF alterations of defined functional class across different tumors through a systematic review. Then, we selected NSCLC patients carrying BRAF alterations, according to the systematic review, in the cBioPortal (cBioPortal cohort) to collect and analyze clinical, biomolecular and survival data. Finally, we identified NSCLC patients carrying BRAF non-V600 mutations enrolled in POPLAR and OAK trials (POPLAR/OAK cohort), extracting clinical and survival data for survival analyses.

RESULTS

100 different BRAF non-V600 alterations were identified through the systematic review. In the cBioPortal cohort (n = 139), patients harboring class 2 and 3 alterations were more frequently smokers and had higher tumor mutational burden compared to those carrying class 1 alterations. The spectrum of most frequently co-altered genes was significantly different between BRAF alterations classes, including SETD2, STK11, POM121L12, MUC16, KEAP1, TERT, TP53 and other genes. In the POPLAR/OAK cohort, patients carrying non-V600 BRAF alterations were characterized by poor prognosis compared to BRAF wild-type patients.

CONCLUSIONS

Different classes of BRAF alterations confer distinctive clinical features, biomolecular signature and disease behavior to NSCLC patients. Non-V600 alterations are characterized by poor prognosis, but key gene co-alterations involved in cancer cell survival and immune pathways may suggest their potential sensitivity to tailored treatments.

Molecular Characterization of KRAS Wild-type Tumors in Patients with Pancreatic Adenocarcinoma

PURPOSE

KRAS mutation (MT) is a major oncogenic driver in pancreatic ductal adenocarcinoma (PDAC). A small subset of PDACs harbor KRAS wild-type (WT). We aim to characterize the molecular profiles of KRAS WT PDAC to uncover new pathogenic drivers and offer targeted treatments.

EXPERIMENTAL DESIGN

Tumor tissue obtained from surgical or biopsy material was subjected to next-generation DNA/RNA sequencing, microsatellite instability (MSI) and mismatch repair status determination.

RESULTS

Of the 2,483 patients (male 53.7%, median age 66 years) studied, 266 tumors (10.7%) were KRAS WT. The most frequently mutated gene in KRAS WT PDAC was TP53 (44.5%), followed by BRAF (13.0%). Multiple mutations within the DNA-damage repair (BRCA2, ATM, BAP1, RAD50, FANCE, PALB2), chromatin remodeling (ARID1A, PBRM1, ARID2, KMT2D, KMT2C, SMARCA4, SETD2), and cell-cycle control pathways (CDKN2A, CCND1, CCNE1) were detected frequently. There was no statistically significant difference in PD-L1 expression between KRAS WT (15.8%) and MT (17%) tumors. However, KRAS WT PDAC were more likely to be MSI-high (4.7% vs. 0.7%; P < 0.05), tumor mutational burden-high (4.5% vs. 1%; P < 0.05), and exhibit increased infiltration of CD8+ T cells, natural killer cells, and myeloid dendritic cells. KRAS WT PDACs exhibited gene fusions of BRAF (6.6%), FGFR2 (5.2%), ALK (2.6%), RET (1.3%), and NRG1 (1.3%), as well as amplification of FGF3 (3%), ERBB2 (2.2%), FGFR3 (1.8%), NTRK (1.8%), and MET (1.3%). Real-world evidence reveals a survival advantage of KRAS WT patients in overall cohorts as well as in patients treated with gemcitabine/nab-paclitaxel or 5-FU/oxaliplatin.

CONCLUSIONS

KRAS WT PDAC represents 10.7% of PDAC and is enriched with targetable alterations, including immuno-oncologic markers. Identification of KRAS WT patients in clinical practice may expand therapeutic options in a clinically meaningful manner.

The Prognostic Value of miR-125b, miR-200c and miR-205 in Primary Cutaneous Malignant Melanoma Is Independent of BRAF Mutational Status

Simple Summary

Melanoma accounts for the majority of skin cancer-related deaths. On the one hand, most melanomas contain mutations in the BRAF gene (predominantly V600E), and on the other hand, miRNAs modulate different steps in melanoma development and progression, but there are no reports that study the relation between BRAF mutational status and the expression of miRNAs, which is important for an accurate patient prognosis. The aim of our retrospective study was to know whether BRAF mutations influence the prognostic value of miR-125b, miR-200c and miR-205 intratumoral expression in primary cutaneous melanomas. Globally, our results showed that miR-125b, miR-200c and miR-205 expression predicted the clinical outcome of primary melanomas independently of BRAF status. Thus, our findings support that BRAF mutations alone do not predict the risk of metastasis development or melanoma survival and that miR-125b, miR-200c and miR-205 may be considered as accurate prognostic biomarkers in melanoma regardless of BRAF mutational status.

Abstract

BRAF mutations are present in around 50% of cutaneous malignant melanomas and are related to a poor outcome in advanced-stage melanoma patients. miRNAs are epigenetic regulators that modulate different cellular processes in cancer, including melanoma development and progression. However, there are no studies on the potential associations of the genetic alterations of the BRAF gene with miRNA expression in primary cutaneous melanomas. Here, in order to analyze the influence of BRAF mutations in the ability of selected miRNAs to predict clinical outcome and patient survival at the time of diagnosis, we studied the prognostic value of miR-125b, miR-200c and miR-205 expression depending on the BRAF mutational status in fresh, frozen primary tumor specimens. For this purpose, RNA was extracted for studying both BRAF mutations by Sanger sequencing and miRNA expression. Our results indicate that, although there seems to be a slight preference for their predictive ability in the BRAF mutated group, the expression of these three miRNAs serves effectively to predict the clinical outcome of melanoma patients independently of BRAF mutational status at the time of primary tumor diagnosis.

Case report: Spindle cell neoplasm presenting as a spontaneous intestinal perforation in a term infant

Spontaneous intestinal perforations in the neonatal population are mostly associated with low birth weight, prematurity, and necrotizing enterocolitis. Spontaneous intestinal perforation in the absence of these risk factors is extremely rare and should raise clinical concern for an underlying bowel pathology. Here we present a unique case of a normal-weight, full-term girl with spontaneous intestinal perforation due to a spindle cell neoplasm with a novel BRAF mutation and infantile fibrosarcoma-like morphology. Though rare, malignancy should be considered in the differential diagnosis for bowel perforation in an otherwise healthy, term infant as complete surgical excision can be curative.

Precision Medicine in Oncology: A Review of Multi-Tumor Actionable Molecular Targets with an Emphasis on Non-Small Cell Lung Cancer

Precision medicine is essential for the modern care of a patient with cancer. Comprehensive molecular profiling of the tumor itself is necessary to determine the presence or absence of certain targetable abnormalities or biomarkers. In particular, lung cancer is a disease for which targetable genomic alterations will soon guide therapy in the majority of cases. In this comprehensive review of solid tumor-based biomarkers, we describe the genomic alterations for which targeted agents have been approved by the United States Food and Drug Administration (FDA). While focusing on alterations leading to approvals in a tumor-agnostic fashion (MSI-h, TMB-h, NTRK) and on those alterations with approvals in multiple malignancies (BRAF, ERBB2, RET, BRCA, PD-L1), we also describe several biomarkers or indications that are likely to lead to an approved drug in the near future (e.g., KRAS G12C, PD-L1 amplification, HER2 overexpression in colon cancer, HER2 mutations in lung cancer). Finally, we detail the current landscape of additional actionable alterations (EGFR, ALK, ROS1, MET) in lung cancer, a biomarker-rich malignancy that has greatly benefitted from the precision oncology revolution.