BRAF V600E Mutation Lacks Association with Poorer Clinical Prognosis in Papillary Thyroid Carcinoma.

BACKGROUND: Previous literatures showed wide range of prevalence of BRAF V600E in papillary thyroid carcinoma (PTC). The correlation of BRAF V600E mutation with aggressive tumor characteristics and poor prognosis is controversial. The present study was designed to evaluate the association between BRAF V600E mutation with clinicopathological factors and tumor recurrence. PATIENTS AND METHODS: We performed a retrospective chart review of 672 patients who underwent thyroid surgery for PTC during 2013 and 2018. The prevalence of the BRAF V600E mutation was studied. Its correlation with clinicopathologic characteristics and aggressive features, including macroscopic extrathyroidal extension, lymph node metastasis, and distant metastasis, were analyzed with Fisher's exact test. RESULTS: A total of 672 patients who underwent surgical treatment for PTC were included in this study with a mean age of 49.7 (± 13.2) years; 76.8% of the patients were detected with BRAF V600E mutation. Mean tumor size was 1.30 (± 1.07) cm. A significant association was demonstrated between negative BRAF V600E and larger primary tumor size, distant metastasis, and advanced staging (p < 0.05), whereas there was no significant association with age, sex, lymph node metastasis, extrathyroidal extension, and multicentricity. Kaplan-Meier curve showed similar disease-free survival rate between the two groups. CONCLUSIONS: Negative BRAF V600E tumors show more aggressive behavior with a higher risk of developing distant metastasis in patients with PTC. The usefulness of BRAF in predicting the prognosis of PTC remains questionable. Further molecular analysis should be conducted for contribution to aggressive tumor phenotype.

Advances in the management of anaplastic thyroid carcinoma: transforming a life-threatening condition into a potentially treatable disease.

Anaplastic thyroid cancer (ATC) is an infrequent thyroid tumor that usually occurs in elderly patients. There is often a history of previous differentiated thyroid cancer suggesting a biological progression. It is clinically characterized by a locally invasive cervical mass of rapid onset. Metastases are found at diagnosis in 50% of patients. Due to its adverse prognosis, a prompt diagnosis is crucial. In patients with unresectable or metastatic disease, multimodal therapy (chemotherapy and external beam radiotherapy) has yielded poor outcomes with 12-month overall survival of less than 20%. Recently, significant progress has been made in understanding the oncogenic pathways of ATC, leading to the identification of BRAF V600E mutations as the driver oncogene in nearly 40% of cases. The combination of the BRAF inhibitor dabrafenib (D) and MEK inhibitor trametinib (T) showed outstanding response rates in BRAF-mutated ATC and is now considered the standard of care in this setting. Recently, it was shown that neoadjuvant use of DT followed by surgery achieved 24-month overall survival rates of 80%. Although these approaches have changed the management of ATC, effective therapies are still needed for patients with BRAF wild-type ATC, and high-quality evidence is lacking for most aspects of this neoplasia. Additionally, in real-world settings, timely access to multidisciplinary care, molecular testing, and targeted therapies continues to be a challenge. Health policies are warranted to ensure specialized treatment for ATC.The expanding knowledge of ATC´s molecular biology, in addition to the ongoing clinical trials provides hope for the development of further therapeutic options.

Clinicopathological characteristics and diagnostic accuracy of BRAF mutations in ameloblastoma: A Bayesian network analysis.

OBJECTIVE: This Bayesian network meta-analysis was performed to analyze the associations between clinicopathological characteristics and BRAF mutations in ameloblastoma (AM) patients and to evaluate the diagnostic accuracy. MATERIALS AND METHODS: Four electronic databases were searched from 2010 to 2024. The search terms used were specific to BRAF and AM. Observational studies or randomized controlled trials were considered eligible. The incidence of BRAF mutation and corresponding clinicopathological features in AM patients were subjected to Bayesian network analyses and diagnostic accuracy evaluation. RESULTS: A total of 937 AM patients from 20 studies were included. The pooled prevalence of BRAF mutations in AM patients was 72%. According to the Bayesian network analysis, BRAF mutations are more likely to occur in younger (odds ratio [OR], 2.3; credible interval [CrI]: 1.2-4.5), mandible site (OR, 3.6; 95% CrI: 2.7-5.2), and unicystic (OR, 1.6; 95% CrI: 1.1-2.4) AM patients. Similarly, higher diagnostic accuracy was found in the younger, mandible, and unicystic AM groups. CONCLUSIONS: The incidence, risk, and diagnostic accuracy of BRAF mutation in AM were greater in younger patients, those with mandible involvement, and those with unicystic AM than in patients with other clinicopathological features. In addition, there was a strong concordance in the diagnostic accuracy between molecular tests and immunohistochemical analysis.

Treatment of congenital Langerhans cell histiocytosis with cobimetinib.

We report a case of congenital multisystem Langerhans cell histiocytosis with cutaneous and hematopoietic involvement. After the failure of first-line (vinblastine and prednisolone) and second-line (vincristine and cytarabine) therapies, treatment with cobimetinib, a mitogen-activated protein kinase (MEK) inhibitor, led to the remission of disease and a sustained response after 11 months of ongoing treatment. Protein kinase inhibitors targeting BRAF or MEK could represent a promising future therapeutic option, also in children with LCH.

Assessment of RAS-RAF-MAPK Pathway Mutation Status in Healthy Skin, Benign Nevi, and Cutaneous Melanomas: Pilot Study Using Droplet Digital PCR.

In the present study, we employed the ddPCR and IHC techniques to assess the prevalence and roles of RAS and RAF mutations in a small batch of melanoma (n = 22), benign moles (n = 15), and normal skin samples (n = 15). Mutational screening revealed the coexistence of BRAF and NRAS mutations in melanomas and nevi and the occurrence of NRAS G12/G13 variants in healthy skin. All investigated nevi had driver mutations in the BRAF or NRAS genes and elevated p16 protein expression, indicating cell cycle arrest despite an increased mutational burden. BRAF V600 mutations were identified in 54% of melanomas, and NRAS G12/G13 mutations in 50%. The BRAF mutations were associated with the Breslow index (BI) (p = 0.029) and TIL infiltration (p = 0.027), whereas the NRAS mutations correlated with the BI (p = 0.01) and the mitotic index (p = 0.04). Here, we demonstrate that the "young" ddPCR technology is as effective as a CE-IVD marked real-time PCR method for detecting BRAF V600 hotspot mutations in tumor biopsies and recommend it for extended use in clinical settings. Moreover, ddPCR was able to detect low-frequency hotspot mutations, such as NRAS G12/G13, in our tissue specimens, which makes it a promising tool for investigating the mutational landscape of sun-damaged skin, benign nevi, and melanomas in more extensive clinical studies.

BRAF V600E Mutation in Malignant Melanoma-A Romanian Research Experience.

Background and Objectives: The most common mutation in malignant melanoma (MM) is the single-point mutation of v-raf murine sarcoma viral oncogene homolog B1 (BRAF) oncogene. Our study aims to evaluate BRAF V600E mutation, highlighting its frequency differences in primary versus metastatic MM. Materials and Methods: The study group comprised 133 patients diagnosed with MM in several county hospitals of the north-eastern region of Romania who have been assigned for investigation into BRAF V600E mutation in the private medical system. The material consisted of archived formalin-fixed paraffin-embedded (FFPE) blocks. BRAF V600E mutation was identified using the fully automated IdyllaTM BRAF mutation test system. Results: Out of the total of 133 cases, 78 cases were primary tumors, while 55 cases were metastatic MMs. Genetic analysis revealed the presence of BRAF V600E mutation in 66 cases (49.62%) and the wild-type genotype in 67 cases (50.37%). We found a statistically significant difference of the mutation frequency according to age (p = 0.0072). The mutated genotype was found in 45 cases out of 78 primary MMs (57.69%) and in 21 cases out of 55 secondary MMs (38.18%), with a statistically significant difference in favor of primary tumors (p = 0.0413). The correlations between the histopathological types, Clark's level, Breslow index, ulceration, and lymphovascular invasion, respectively, and the mutated genotype were not statistically significant. BRAF V600E mutation was identified in 15 out of 40 secondary tumors with lymph node location (37.5%) and in 6 out of 15 secondary tumors with another location (40%) without statistically significant differences between the mutation frequency and the location of the secondary tumors. Conclusions: Our results support MM high genetic heterogeneity, pointing out the relationship between BRAF V600E mutation and several clinicopathological characteristics, in primary and metastatic MMs, stressing the importance of BRAF testing implementation in Romania.

Plasmatic BRAF-V600E allele fraction as a prognostic factor in metastatic colorectal cancer treated with BRAF combinatorial treatments.

BACKGROUND: Combination of a BRAF inhibitor (BRAFi) and an anti-epidermal growth factor receptor (EGFR), with or without a MEK inhibitor (MEKi), improves survival in BRAF-V600E-mutant metastatic colorectal cancer (mCRC) over standard chemotherapy. However, responses are heterogeneous and there are no available biomarkers to assess patient prognosis or guide doublet- or triplet-based regimens. In order to better characterize the clinical heterogeneity observed, we assessed the prognostic and predictive role of the plasmatic BRAF allele fraction (AF) for these combinations. PATIENTS AND METHODS: A prospective discovery cohort including 47 BRAF-V600E-mutant patients treated with BRAFi-anti-EGFR ± MEKi in clinical trials and real-world practice was evaluated. Results were validated in an independent multicenter cohort (n= 29). Plasmatic BRAF-V600E AF cut-off at baseline was defined in the discovery cohort with droplet digital PCR (ddPCR). All patients had tissue-confirmed BRAF-V600E mutations. RESULTS: Patients with high AF have major frequency of liver metastases and more metastatic sites. In the discovery cohort, median progression-free survival (PFS) and overall survival (OS) were 4.4 and 10.1 months, respectively. Patients with high BRAF AF (≥2%, n = 23) showed worse PFS [hazard ratio (HR) 2.97, 95% confidence interval (CI) 1.55-5.69; P = 0.001] and worse OS (HR 3.28, 95% CI 1.58-6.81; P = 0.001) than low-BRAF AF patients (<2%, n = 24). In the multivariable analysis, BRAF AF levels maintained independent significance. In the validation cohort, high BRAF AF was associated with worse PFS (HR 3.83, 95% CI 1.60-9.17; P = 0.002) and a trend toward worse OS was observed (HR 1.86, 95% CI 0.80-4.34; P = 0.15). An exploratory analysis of predictive value showed that high-BRAF AF patients (n = 35) benefited more from triplet therapy than low-BRAF AF patients (n = 41; PFS and OS interaction tests, P < 0.01). CONCLUSIONS: Plasmatic BRAF AF determined by ddPCR is a reliable surrogate of tumor burden and aggressiveness in BRAF-V600E-mutant mCRC treated with a BRAFi plus an anti-EGFR with or without a MEKi and identifies patients who may benefit from treatment intensification. Our results warrant further validation of plasmatic BRAF AF to refine clinical stratification and guide treatment strategies.

Different prognostic values of KRAS exon 2 submutations and BRAF V600E mutation in microsatellite stable (MSS) and unstable (MSI) stage III colon cancer: an ACCENT/IDEA pooled analysis of seven trials.

BACKGROUND: The prognostic value of KRAS and BRAFV600E mutations in stage III colon cancer (CC) remains controversial and has never been clearly analyzed in patients with microsatellite instability-high (MSI-H) tumors due to sample size limitations. Data are also lacking for KRAS submutations and prognosis. PATIENTS AND METHODS: We examined clinicopathological variables and prognosis in patients with surgically resected stage III CC who participated in seven clinical trials from the ACCENT/IDEA databases. Associations between KRAS exon 2 and BRAFV600E mutations and time to recurrence (TTR), overall survival (OS), and survival after recurrence (SAR) were assessed using a Cox model. We also analyzed the prognostic value of KRAS exon 2 submutations. RESULTS: Among 8460 patients, 11.4% had MSI-H status. In the MSI-H group, BRAFV600E, KRAS exon 2 mutants, and double-wild-type statuses were detected in 40.6%, 18.1%, and 41.3%, respectively, whereas and in the microsatellite stable (MSS) group, these were detected in 7.7%, 38.6%, and 53.8%, respectively. In the MSS group, 5-year TTR rates of 61.8%, 66.3%, and 72.9% were observed among patients with BRAFV600E, KRAS exon 2 mutants, and those who were DWT, respectively [adjusted hazard ratio (HR) = 1.58 and 1.31, both P < 0.001]. In the MSI-H group, 5-year TTR rates did not differ significantly among the mutated subgroups. Similar results were found for OS. However, survival after relapse was significantly shorter in the KRAS exon 2- and BRAFV600E-mutated patients in both MSS (adjusted HR = 2.06 and 1.15; both P < 0.05) and MSI-H (adjusted HR = 1.99 and 1.81; both P < 0.05) groups. In the MSS group, KRAS exon 2 mutations were associated with TTR, but only p.G12C, p.G12D, and p.G13D were associated with poor outcomes after disease recurrence. CONCLUSIONS: Testing for both KRAS and BRAFV600E mutations in stage III patients should be considered as they can better define individual patient prognosis, and may also enable patient selection for (neo)adjuvant trials dedicated to specific molecular subtypes with poor prognosis.

Craniopharyngioma-An update on metabolic and cognitive complications and new therapy.

Craniopharyngiomas (CPs) are rare primary brain epithelial tumors arising in the suprasellar region from remnants of Rathke's pouch. About 50% originate at the level of the third ventricle floor, including the hypothalamus (HT). CPs are characterized by a low proliferation rate and symptoms due to mass effect and local infiltration and are managed primarily with surgery and radiotherapy. Gross total removal of a CP will reduce the recurrence rate but increases the risk of HT damage. Today, subtotal resection is the goal and will reduce the risk of HT damage. There are two histological subtypes of CP-adamantinomatous (ACP) and papillary CP (PCP)-that differ in their genesis and age distribution. ACPs are driven by somatic mutations in CTNNB1 gene (encoding ß-catenin), and PCPs frequently harbor somatic BRAF V600E mutations. There are also two phenotypes of outcome, the one with a rather good outcome without HT damage and the other with HT damage where recurrent operation with additional cranial radiotherapy results in HT obesity (HO), affecting psychosocial life and cognitive dysfunction. The group with HO suffers from metabolic syndrome, lower basal metabolic rate, and leptin and insulin resistances. There is currently no successful treatment for HO. The group with HT damage suffers from cognitive dysfunction with attention deficits, impaired episodic memory, and processing speed. Diffusion tensor imaging has shown significant microstructural white matter alteration in several areas important for cognition. Recently, complete or partial tumor response was shown to targeted therapy, with BRAF and Mekinist inhibitors for PCPs with BRAF V600E mutation.

A new subtype of diffuse midline glioma, H3 K27 and BRAF/FGFR1 co-altered: a clinico-radiological and histomolecular characterisation.

Diffuse midline gliomas (DMG) H3 K27-altered are incurable grade 4 gliomas and represent a major challenge in neuro-oncology. This tumour type is now classified in four subtypes by the 2021 edition of the WHO Classification of the Central Nervous System (CNS) tumours. However, the H3.3-K27M subgroup still appears clinically and molecularly heterogeneous. Recent publications reported that rare patients presenting a co-occurrence of H3.3K27M with BRAF or FGFR1 alterations tended to have a better prognosis. To better study the role of these co-driver alterations, we assembled a large paediatric and adult cohort of 29 tumours H3K27-altered with co-occurring activating mutation in BRAF or FGFR1 as well as 31 previous cases from the literature. We performed a comprehensive histological, radiological, genomic, transcriptomic and DNA methylation analysis. Interestingly, unsupervised t-distributed Stochastic Neighbour Embedding (tSNE) analysis of DNA methylation profiles regrouped BRAFV600E and all but one FGFR1MUT DMG in a unique methylation cluster, distinct from the other DMG subgroups and also from ganglioglioma (GG) or high-grade astrocytoma with piloid features (HGAP). This new DMG subtype harbours atypical radiological and histopathological profiles with calcification and/or a solid tumour component both for BRAFV600E and FGFR1MUT cases. The analyses of a H3.3-K27M BRAFV600E tumour at diagnosis and corresponding in vitro cellular model showed that mutation in H3-3A was the first event in the oncogenesis. Contrary to other DMG, these tumours occur more frequently in the thalamus (70% for BRAFV600E and 58% for FGFR1MUT) and patients have a longer overall survival with a median above three years. In conclusion, DMG, H3 K27 and BRAF/FGFR1 co-altered represent a new subtype of DMG with distinct genotype/phenotype characteristics, which deserve further attention with respect to trial interpretation and patient management.

Survival comparison of first-line treatment regimens in patients with braf-mutated advanced colorectal cancer: a multicenter retrospective study.

BACKGROUND: Patients with V-Raf murine sarcoma viral oncogene homolog B1 (BRAF) V600E-mutated advanced colorectal cancer (CRC) have a poor prognosis, and treatment options that can improve outcome are still under investigation. The purpose of this study was to discuss the differences of overall survival (OS) and progression-free survival (PFS) between patients with BRAF V600E-mutated advanced CRC who were treated with chemotherapy alone and chemotherapy combined with targeted therapy in advanced first-line therapy. METHODS: Grouping of 61 patients according to first-line treatment regimen (chemotherapy alone/chemotherapy combined with bevacizumab). Kaplan-Meier method and log-rank test were used to compare OS and PFS. Cox proportional hazards regression model was used to measure the risk of first-line medication therapies while correcting for confounding factors that may affect PFS and OS. RESULTS: There was no significant difference in OS between patients treated with chemotherapy alone and those treated with chemotherapy combined with bevacizumab (P = 0.93; HR, 1.027; 95% CI, 0.555-1.901). Likewise, there was no significant difference in PFS between the two groups (P = 0.29; HR, 0.734; 95% CI, 0.413-1.304). Subgroup analysis showed that OS and PFS of different treatment regimens were not significantly different among subgroups. Multivariate analysis suggested that surgical treatment of primary tumor (P = 0.001; HR, 0.326; 95% CI, 0.169-0.631) and presence of liver metastasis (P = 0.009; HR, 2.399; 95% CI, 1.242-4.635) may serve as independent prognostic indicators in patients with BRAF-mutated advanced CRC. Surgical treatment of the primary tumor (P = 0.041; HR, 0.523; 95% CI, 0.280-0.974) was significantly associated with PFS too. CONCLUSION: For patients with BRAF V600E-mutated advanced CRC, chemotherapy alone did not differ significantly in OS and PFS compared with chemotherapy + bevacizumab for advanced first-line therapy. Chemotherapy combined with targeted therapy did not render a survival benefit to these patients, demonstrating that the importance of developing new treatment options for this population.

The clinical spectrum and prognostic factors of Erdheim-Chester disease and mixed Langerhans cell histiocytosis and Erdheim-Chester disease.

Erdheim-Chester disease (ECD) is a rare and probably fatal multisystemic non-Langerhans cell histiocytosis (LCH). To comprehensively investigate the clinical features, genomic analysis, treatments, and prognostic factors of ECD, we retrospectively analyzed the clinical data of 75 ECD patients and 10 mixed LCH and ECD patients in our center. The median age at diagnosis was 46 years (range, 5-70). ECD patients were older at diagnosis (p = 0.006) and had more cardiac involvement (p = 0.011) as well as vascular (p = 0.031) involvement compared to mixed LCH and ECD patients. 64.8% of ECD patients and 87.5% of mixed LCH and ECD patients carried BRAFV600E mutation. The BRAFV600E mutation correlated with a greater number of affected organs (p = 0.030) and was associated with lung involvement (p = 0.033) as well as pleural involvement (p = 0.002). The median follow-up time was 38 months (range, 1-174). The estimated 5-year progression-free survival (PFS) and overall survival (OS) were 48.9% and 84.7%, respectively. In a multivariate analysis, right atrial pseudotumor (p = 0.013) and pancreatic involvement (p = 0.005) predicted worse OS, while pleural (p = 0.042) and central nervous system (CNS) involvement (p = 0.043) predicted worse PFS. Our study described the clinical spectrum of ECD and mixed LCH and ECD, while also revealed the prognostic value of right atrial pseudotumor and pancreatic, pleural, and CNS involvement for worse survival.

Monitoring tumour resistance to the BRAF inhibitor combination regimen in colorectal cancer patients via circulating tumour DNA.

AIMS: This study aimed to identify mechanisms of drug resistance to the combination of vemurafenib, irinotecan, and cetuximab (VIC) in BRAFV600E metastatic colorectal cancer (mCRC). METHODS: Forty-one patients with BRAFV600E mCRC from July 2018 and June 2020 were evaluated, with tissue and/or plasma samples collected. We profiled tissue and plasma samples using whole-exome sequencing and targeted sequencing of 425 cancer-relevant genes. Clinical cohort analysis from published studies was performed to consolidate our findings. RESULTS: BRAF mutant in baseline plasma and its dynamics are significantly associated with VIC-related response, and concurrent RNF43 mutation significantly sensitises tumour to VIC treatment. VIC resistance frequently involves genes in PI3K, MAPK pathway, and several novel resistance mechanisms such as TGFBR2 and SMAD4 mutations, and copy-number gains in PTK2, MYC, and GATA6 have been identified. We also firstly describe acquired altered genes in DNA damaging repair pathway, occurring in 33 % of patients after VIC treatment, and particularly, patients with this pre-treatment resistance subclones developed inferior responses, along with higher tumour mutation burden both at baseline and progression plasma. CONCLUSION: Analysis of ctDNA can provide novel insights into molecular resistance mechanisms to VIC in BRAFV600E mCRC patients, allowing accurate guidance for clinicians in personalised treatment strategies.

Real-World Experience in Treatment of Patients with Non-Small-Cell Lung Cancer with BRAF or cMET Exon 14 Skipping Mutations.

BRAF and cMET exon 14 skipping are rare mutations of NSCLC. The treatment sequence in these cases for the first and second line is not clear. An international registry was created for patients with advanced NSCLC harboring BRAF or cMET exon 14 skipping mutations, diagnosed from January 2017 to June 2022. Clinicopathological and molecular data and treatment patterns were recorded. Data on 58 patients, from eight centers across five countries, were included in the final analysis. We found that 40 patients had the cMET exon 14 skipping mutation and 18 had the BRAF V600E mutation. In total, 53 and 28 patients received first- and second-line treatments, respectively, among which 52.8% received targeted therapy (TT) in the first line and 53.5% in the second line. The overall response rate (ORR) and disease control rate (DCR) for first-line treatment with TT vs. other treatment such as immune checkpoint inhibitors ± chemotherapy (IO ± CT) were 55.6% vs. 21.7% (p = 0.0084) and 66.7% vs. 39.1% (p = 0.04), respectively. The type of treatment in first-line TT vs. other affected time to treatment discontinuation (TTD) was 11.6 m vs. 4.6 m (p= 0.006). The overall survival for the whole group was 15.4 m and was not statistically affected by the type of treatment (19.2 m vs. 13.5 m; p = 0.83).

The positive feedback loop of NHE1-ERK phosphorylation mediated by BRAFV600E mutation contributes to tumorigenesis and development of glioblastoma.

The v-raf murine sarcoma viral oncogene homolog B1 (BRAF) activating mutation V600E (BRAFV600E) is involved in glioblastoma multiforme (GBM). Na/H exchanger 1 (NHE1), a main pH regulator affecting cell microenvironment, is hyper-expressed in GBM. However, the relationship between BRAFV600E signal pathway and NHE1 in GMB cells remains unclear. This study found that NHE1 was a downstream target of BRAFV600E and an upstream factor of extracellular signal-regulated kinase (ERK). In addition, there was a positive feedback loop between NHE1-ERK phosphorylation under regulation of BRAFV600E mutation contributing to the proliferation and invasion of GBM cells. Moreover, the proliferation and invasion abilities of BRAFV600E-mutant and BRAF wild type GBM cells were all suppressed by the NHE1 inhibitor, BRAFV600E inhibitor and combination of them. The inhibitory effect of combination of the two inhibitors was better than each single drug both in vitro and in vivo. Combination of BRAFV600E and NHE1 inhibitors could be considered as a new therapeutic regimen for GBM, especially for GBM with BRAFV600E.

A phase II study of daily encorafenib in combination with biweekly cetuximab in patients with BRAF V600E mutated metastatic colorectal cancer: the NEW BEACON study.

BACKGROUND: Patients with BRAF V600E mutated metastatic colorectal cancer (mCRC) have a poor prognosis. The introduction of BRAF targeted therapy with encorafenib and weekly administered cetuximab have shown improved survival with a median progression free survival (PFS) of 4.3 months. However, a regimen with cetuximab given every second week may have comparable efficacy and is more convenient for patients. While BRAF targeted therapy is a new standard therapy in pre-treated patients with BRAF V600E mutated mCRC, resistance invariably occurs and is an emerging challenge. The aim of this study is to investigate the efficacy and tolerability of cetuximab given every second week in combination with daily encorafenib and to explore the correlation between markers of resistance and outcome. METHODS: The study is an open label, single arm, phase II study, investigating the efficacy and tolerability of cetuximab given every second week in combination with encorafenib in patients with BRAF V600E mutated mCRC. Furthermore, we will be investigating mechanisms of response and resistance against BRAF targeted therapy though comprehensive genomic profiling on tumor tissue and blood for circulating tumor DNA analysis. A total of 53 patients (19 + 34 in two steps) will be included according to Simon's optimal two stage design. The primary end point of the study is 2 months PFS rate. DISCUSSION: By combining BRAF inhibitor with cetuximab given every second week we can halve the number of visits in the hospital compared to the currently approved regimen with weekly cetuximab. This seems particularly relevant in a group of patients with a median overall survival of 9.3 months. Resistance after initial response to targeted therapy can be either adaptive (e.g., epigenetic, or transcriptomic alterations) or acquired (selective genetic alterations - e.g., activating de novo mutations) resistance. It is of great importance to untangle these complex mechanisms of resistance in patients with BRAF V600E mutated mCRC to improve treatment strategies in the future potentially even further. TRIAL REGISTRATION: EU Clinical Trial Register, Eudract no. 2020-003283-10 . Registered on 11 November 2020.

Droplet digital polymerase chain reaction for the assessment of disease burden in hairy cell leukemia.

BRAFV600E mutation is the pathogenic driver of hairy cell leukemia (HCL) found in the vast majority of cases both at onset and during recurrences. The identification of the mutated allele in blood and marrow correlates with the presence of neoplastic cells and can be considered a marker of active disease. Likewise, the absence of the mutation after treatment may indicate a state of deep response. The BRAFV600E burden was measured by droplet digital polymerase chain reaction (ddPCR) and expressed as fractional abundance in 35 HCL patients at different stages of disease (onset, relapse, complete response [CR] after treatment, long-term remission) in peripheral blood and/or bone marrow (when available). Mean values of fractional abundance for patients at diagnosis, relapse and response, respectively, were 12.26%, 16.52% and 0.02% in peripheral blood and 23.51%, 13.96% and 0.26% in bone marrow. Four patients out of 6 evaluated at response were molecularly negative for BRAFV600E in peripheral blood. Mean fractional abundance in peripheral blood tested in 14 patients with long lasting CR was 0.05%, and 10 patients were BRAFV600E negative. These preliminary results suggest that ddPCR permits to assess the active tumor burden in HCL at different disease phases and support the hypothesis that some patients in CR qualify for a molecular CR.

BRAF/MEK Dual Inhibitors Therapy in Progressive and Anaplastic Pleomorphic Xanthoastrocytoma: Case Series and Literature Review.

Recurrent and anaplastic pleomorphic xanthoastrocytoma (r&aPXA) is a rare primary brain tumor that is challenging to treat. Two-thirds of PXA tumors harbor a BRAF gene mutation. BRAF inhibitors have been shown to improve tumor control. However, resistance to BRAF inhibition develops in most cases. Concurrent therapy with MEK inhibitors may improve tumor control and patient survival. In this study, we identified 5 patients diagnosed with BRAF-mutated PXA who received BRAF and MEK inhibitors over a 10-year interval at our institution. Patient records were evaluated, including treatments, adverse effects (AEs), outcomes, pathology, next-generation sequencing, and MRI. The median age was 22 years (range, 14-66 years), 60% male, and 60% anaplastic PXA. Median overall survival was 72 months (range, 19-112 months); 1 patient died of tumor-related hemorrhage while off therapy, and the other 4 experienced long-term disease control (21, 72, 98, and 112 months, respectively). Dual BRAF/MEK inhibitors were well tolerated, with only grade 1-2 AEs, including rash, neutropenia, fatigue, abdominal discomfort, and diarrhea. No grade 3-5 AEs were detected. A literature review was also performed of patients diagnosed with BRAF-mutated PXA and treated with BRAF and/or MEK inhibitors through August 2021, with a total of 32 cases identified. The median age was 29 years (range, 8-57 years) and the median PFS and OS were 8.5 months (range, 2-35 months) and 35 months (range, 10-80 months), respectively. The most common AEs were grade 1-2 fatigue and skin rash. Results of this case series and literature review indicate that dual-drug therapy with BRAF and MEK inhibitors for r&aPXA with BRAF V600E mutation may delay tumor progression without unexpected AEs.

Surgical Resection for Local and Lateral Lymph Node Recurrence of MSI-high Cecal Cancer with the BRAF V600E Mutation.

An 84-year-old female underwent open right hemicolectomy with D3 lymph node dissection for cecal cancer, pathologically identified as pT4aN2M0 Stage IIIc and BRAF mutation-positive. Due to early recurrence of abdominal wall and right lateral lymph nodes, the patient was treated with FOLFOXIRI+Bevacizumab. Imaging after 5 courses of chemotherapy found tumor shrinkage and no new metastases. The patient did not tolerate chemotherapy well, and tumor resection was performed. Microsatellite instability (MSI) testing using multiplex polymerase chain reaction (PCR) fragment analysis revealed MSI-high status. The patient is currently recurrence-free without chemotherapy at 1 year postoperatively. BRAF-mutated colorectal cancer has a poor prognosis, and may require resection of the metastatic or recurrent tumor after comprehensive evaluation.

[BRAF mutation evolution in melanoma: Myth or reality?] / Évolution du statut braf dans le melanome : mythe ou Réalité ?

Knowledge of the BRAF mutational status has become essential for melanoma therapeutic management. B-Raf inhibitors are associated with significant overall survival in patients with BRAFV600-mutated metastatic melanoma. Although the BRAF mutation appears to be an early and driver mutation, some authors hypothesized that its expression was not stable during melanoma progression, suggesting a molecular heterogeneity. This argument is often used to explain discrepancy in molecular status among patients with melanoma, discrepancies that we occasionally met during our practice. We retrospectively compared BRAF mutational status on matched melanoma samples (primary & metastatic lesions), thus 150 samples from 56 patients were analysed through immunohistochemistry anti-BRAF, PCR-HRM and Sanger sequencing, Next Generation Sequencing (NGS) and digital PCR. Seven cases presented an apparent tumor heterogeneity. The analysis of these discrepancies by a technique of increasing sensitivity made it possible to identify 1 false-negative result for the immunohistochemistry, 1 false-negative result for the NGS sequencing and 5 (3%) false-negative results by PCR-HRM SANGER. Our results are consistent with the most recent data, demonstrating the stability of the BRAF mutation during the course of melanoma. Immunohistochemistry shows excellent sensitivity for detecting the main BRAF mutation. In our study, the mutational heterogeneity was actually misleading, a result of imperfect sensitivity of some older molecular approaches.