BRAF-mutated Patients Research Articles

Real-Life Outcomes of Adjuvant Targeted Therapy and Anti-PD1 Agents in Stage III/IV Resected Melanoma.

This study was carried out at the Dermatologic Clinic of the University of Turin, Italy, to assess the effectiveness and safety of adjuvant therapy in patients who received either targeted therapy (TT: dabrafenib + trametinib) or immunotherapy (IT: nivolumab or pembrolizumab) for up to 12 months. A total of 163 patients participated, including 147 with stage III and 19 with stage IV with no evidence of disease. The primary outcomes were relapse-free survival (RFS), distant metastasis-free survival (DMFS), and overall survival (OS). At 48 months, both TT and IT approaches yielded comparable outcomes in terms of RFS (55.6-55.4%, p = 0.532), DMFS (58.2-59.8%, p = 0.761), and OS (62.4-69.5%, p = 0.889). Whilst temporary therapy suspension was more common among TT-treated patients compared to IT-treated individuals, therapy discontinuation due to adverse events occurred at comparable rates in both groups. Predictors of relapse included mitoses, lymphovascular invasion, ulceration, and positive sentinel lymph nodes. Overall, the proportion of BRAF-mutated patients receiving IT stood at 7.4%, lower than what was observed in clinical trials.

Serum Uric Acid Level May Be a Predictive Factor for BRAF V600E Mutation in Older Patients with Metastatic Colorectal Cancer: An Exploratory Analysis

Introduction: This study aimed to show the relationship between the serum uric acid level measured at diagnosis and the BRAF mutation status in the primary tumor tissue in patients with metastatic colorectal cancer. Methods: In this retrospective cross-sectional study, 264 patients (64% male) whose serum uric acid level was measured at the time of diagnosis and whose BRAF mutation status in the primary tumor was determined were included. Results: The BRAF mutation rate was 14% (n = 37). The median serum uric acid levels of all patients were 6.9 mg/dL (25%, 75% percentile range 3.7, 8.2). The serum uric acid level cut-off value was 6.6 mg/dL. Sensitivity and specificity for BRAF mutated patients were 84% and 27%, respectively. These rates were calculated as 85% and 70% in BRAF-mutated patients aged 65 and over. There was a significant correlation between BRAF mutation and high serum uric acid level, female gender, tumor located in the ascending colon, and multiple metastatic sites. The independent factors affecting BRAF mutation were age 65 and over, tumor in the ascending colon, and high serum uric acid level. Conclusion: As a result, we concluded that high serum uric acid level measured during diagnosis in metastatic colorectal cancer is an accessible and economical biomarker that can predict BRAF mutation in patients aged 65 and over.

CDK4/6 inhibition to resensitize BRAF/EGFR inhibitor in patient-derived BRAF/PTEN-mutant colon cancer cells.

In v-raf murine sarcoma viral oncogene homolog B1 (BRAF)-mutant colorectal cancer (CRC), encorafenib-cetuximab has been established as standard second-line therapy, but not all patients respond and the duration of response is relatively short. Overcoming intrinsic or acquired resistance to BRAF/EGFR inhibitors is crucial for enhancing treatment outcomes in metastatic BRAF-mutated CRC. The aim of the study is to investigate the resistance mechanisms in BRAF-mutant CRC patient refractory to BRAF/EGFR targeted therapy. We established patient-derived cells (PDCs) from a patient with BRAF/PTEN-mutant metastatic colon cancer who progressed rapidly on encorafenib plus cetuximab. To explore potential treatment options for inherent resistance caused by simultaneous PTEN mutation in BRAF-mutated CRC, we conducted cell viability assays using PDCs treated with encorafenib-cetuximab in combination with a cyclin-dependent kinase-4 and 6 (CDK4/6) inhibitor. The patient's tumor had concurrent PTEN loss-of-function alteration at diagnosis and PDCs were generated from ascites after resistance to the BRAF/EGFR inhibitor. The PDCs were resistant to the encorafenib-cetuximab combination even at a high concentration of cetuximab (up to 500 µg/mL). Adding the CDK4/6 inhibitor, ribociclib, to encorafenib-cetuximab showed a synergistic effect in a proliferation assay. Ribociclib plus encorafenib-cetuximab represented a significantly lower expression of Ki-67 compared to the dual combination alone. An MTS assay showed that triplet therapy with ribociclib, encorafenib, and cetuximab suppressed cell viability more efficiently than the two-drug combinations. Investigating the combined effect of triplet therapy using the calculated combination index (CI) showed that ribociclib had a synergistic effect with encorafenib-cetuximab when applied to PDCs with a concurrent BRAF/PTEN mutation. Our results suggest that combining the CDK4/6 inhibitor with the BRAF/EGFR inhibitormight be a novel treatment strategy for concomitant BRAF and PTEN-mutant CRC.

Recent Trends and Potential of Radiotherapy in the Treatment of Anaplastic Thyroid Cancer.

Anaplastic thyroid cancer (ATC) is a rare but highly aggressive malignancy characterized by advanced disease at diagnosis and a poor prognosis. Despite multimodal therapeutic approaches that include surgery, radiotherapy, and chemotherapy, an optimal treatment strategy remains elusive. Current developments in targeted therapies and immunotherapy offer promising avenues for improved outcomes, particularly for BRAF-mutant patients. However, challenges remain regarding overcoming drug resistance and developing effective treatments for BRAF-wild-type tumors. This comprehensive review examines the clinical and biological features of ATC, outlines the current standards of care, and discusses recent developments with a focus on the evolving role of radiotherapy. Moreover, it emphasizes the necessity of a multidisciplinary approach and highlights the urgent need for further research to better understand ATC pathogenesis and identify new therapeutic targets. Collaborative efforts, including large-scale clinical trials, are essential for translating these findings into improved patient outcomes.

Patients with radioiodine-refractory differentiated thyroid cancer (RAI-R DTC) with BRAF V600E and/or K601E mutation status: A real-world view of effectiveness of lenvatinib monotherapy.

6098 Background: Lenvatinib was approved for the treatment of patients RAI-R DTC in the United States (US) in 2015, and the treatment landscape has evolved with agents targeting specific driver mutations. We assessed real-world clinical effectiveness of first line therapy with lenvatinib in patients with BRAF-mutated tumors, wild-type (WT) tumors, and patients who have not been tested for BRAF mutations (BRAF untested tumors). Methods: A retrospective chart review of RAI-R DTC patients in the US who initiated first-line lenvatinib monotherapy between February 13, 2015, and September 30, 2020. Data, including a boosted cohort of patients with BRAF-mutated tumors collected in late 2023, were abstracted from patients’ electronic health records and were de-identified. Descriptive analyses were conducted in patient cohorts with BRAF V600E and/or K601E mutated tumors, wild-type (WT) tumors, and BRAF untested tumors. Best response in first-line therapy was captured, real-world progression-free survival (rwPFS) and real-world overall survival (rwOS) were assessed using Kaplan-Meier methods. Results: Of the 361 patients reviewed, 185 had records showing BRAF mutational status testing. 89 had BRAF V600E and/or K601E mutated tumors, 96 had WT tumors. 176 patients did not have BRAF mutational assessment. Of all subjects, 73.7% were White/Caucasian, 15.2% were African American, and 16.8% were Hispanic/Latino; 27.1% had ECOG performance status ≥2. The median follow-up times for each cohort were 30.0, 18.7 and 18.0 months, showing the longer follow up period for the BRAF-mutated cohort boost. Kaplan-Meier estimation for lenvatinib treatment discontinuation for the three cohorts at 24-months were as shown in the table below. Provider-reported overall response rate (complete or partial response) was 76.4%, 75.0% and 69.3% respectively. The estimated 24-month rwPFS rates (95% CI) were 74.1% (62.2%-82.8%), 61.7% (49.6%-71.8%), and 69.8% (60.9%-77.0%) respectively. Median rwOS was not reached for patients with BRAF-mutated and WT tumors, median OS was 54.2 months for BRAF untested tumors. Estimated rwOS rates at 12- and 48-months were 93.2% (85.4%-96.9%) and 83.9% (73.3%-90.3%) in BRAF-mutated patients, 90.6% (82.8%-95.0%) and 68.5% (53.4%-79.6%) in WT patients, and 90.2% (84.7%-93.8%) and 72.5% (61.6%-80.7%) in BRAF untested patients respectively. Conclusions: In this US real-world experience, the effectiveness of lenvatinib is consistent across a diverse cohort of RAI-R DTC patients with BRAF-mutated, WT, and BRAF untested tumors. This has implications for the first-line use of lenvatinib in BRAF mutated patients. [Table: see text]

Efficacy-effectiveness analysis on survival in a population-based real-world study of BRAF-mutated metastatic colorectal cancer patients treated with encorafenib-cetuximab.

Encorafenib-cetuximab has been approved for pretreated BRAFV600E-mutated metastatic colorectal cancer (mCRC) patients based on efficacy demonstrated in the randomized phase III BEACON trial. The aim of this real-world effectiveness study is to improve knowledge on the generalizability of trial results. This population-based real-world study includes all mCRC patients in the Netherlands treated with encorafenib-cetuximab since approval. Individual patient data and pathology reports were collected. Overall survival (OS) was compared to BEACON and subgroup analyses were conducted for patients who would have been eligible and ineligible for BEACON. 166 patients were included with a median follow-up time of 14.5 months. Median OS was 6.7 months (95% CI:6.0-8.3) and differed from BEACON (9.3 months; 95% CI:8.0-11.3, p-value 0.002). Thirty-six percent of real-world patients would have been ineligible for the BEACON trial. Trial ineligible subgroups with symptomatic brain metastases and WHO performance status ≥2 had the poorest median OS of 5.0 months (95% CI:4.0-NR) and 3.9 months (95% CI:2.4-NR). This real-world cohort of mCRC patients treated with encorafenib-cetuximab showed a clinically relevant efficacy-effectiveness gap for OS. The chance of survival benefit from encorafenib-cetuximab in patients with brain metastases and/or WHO performance status ≥2 is negligible as neither efficacy nor effectiveness has been demonstrated.

A Phase 1/2 Study of Disulfiram and Copper With Concurrent Radiation Therapy and Temozolomide for Patients With Newly Diagnosed Glioblastoma

This phase 1/2 study aimed to evaluate the safety and preliminary efficacy of combining disulfiram and copper (DSF/Cu) with radiation therapy (RT) and temozolomide (TMZ) in patients with newly diagnosed glioblastoma (GBM). Patients received standard RT and TMZ with DSF (250-375 mg/d) and Cu, followed by adjuvant TMZ plus DSF (500 mg/d) and Cu. Pharmacokinetic analyses determined drug concentrations in plasma and tumors using high-performance liquid chromatography-mass spectrometry. Thirty-three patients, with a median follow-up of 26.0 months, were treated, including 12 IDH-mutant, 9 NF1-mutant, 3 BRAF-mutant, and 9 other IDH-wild-type cases. In the phase 1 arm, 18 patients were treated; dose-limiting toxicity probabilities were 10% (95% CI, 3%-29%) at 250 mg/d and 21% (95% CI, 7%-42%) at 375 mg/d. The phase 2 arm treated 15 additional patients at 250 mg/d. No significant difference in overall survival or progression-free survival was noted between IDH- and NF1-mutant cohorts compared with institutional counterparts treated without DSF/Cu. However, extended remission occurred in 3 BRAF-mutant patients. Diethyl-dithiocarbamate-copper, the proposed active metabolite of DSF/Cu, was detected in plasma but not in tumors. The maximum tolerated dose of DSF with RT and TMZ is 375 mg/d. DSF/Cu showed limited clinical efficacy for most patients. However, promising efficacy was observed in BRAF-mutant GBM, warranting further investigation.

Адъювантная таргетная терапия и анти-PD-1-иммунотерапия у пациентов с меланомой кожи III стадии с мутацией в гене BRAF. Данные реальной клинической практики

Targeted therapy and anti-PD1 immunotherapy are standard of adjuvant stage III (or equivalent stage III) melanoma treatment. Both treatments significantly improve relapse-free survival compared with placebo and ipilimumab. The impact of adjuvant immunotherapy on overall survival remains unclear. Targeted therapy improved 3-year overall survival, but data didn’t reach statistical significance. There is still a lack of direct comparison in randomized trials between targeted therapy and immunotherapy. Data limited to a few retrospective studies. We conducted a single-center observational retrospective study comparing two adjuvant treatment options in BRAF-mutated high-risk melanoma patients who were treated or consulted at the N.N. Blokhin National Medical Research Center of Oncology.

Targeting DUSP5 suppresses malignant phenotypes of BRAF-mutant thyroid cancer cells and improves their response to sorafenib.

The role of dual-specificity phosphatase-5 (DUSP5) in BRAF-mutant thyroid cancers remains unclear. The aims of this study are to investigate the role of DUSP5 in BRAF-mutant thyroid cancer cells, explore its value in the diagnosis and evaluate therapeutic potential of targeting DUSP5 combined with sorafenib for BRAF-mutant thyroid cancer patients. The role of DUSP5 in thyroid cancer cells was determined by a series of in vitro and in vivo experiments. Underlying mechanisms were explored by western blotting analysis. The diagnostic value of combination detection of DUSP5 expression and BRAFV600E mutation was evaluated using ROC curve. Knocking down DUSP5 in BRAF-mutant thyroid cancer cells significantly inhibited colony formation, cell migration and invasion, meanwhile, induced cell cycle arrest and cell apoptosis. Moreover, inhibition of DUSP5 improved the anti-tumor efficacy of sorafenib both in vitro and in vivo. Besides, combination detection of DUSP5 expression and BRAFV600E mutation showed much more accuracy in preoperative diagnosis of thyroid cancer. Our data demonstrate an oncogenic role of DUSP5 in BRAF-mutant thyroid cancer cells, and combined analysis of its expression and BRAFV600E mutation can accurately diagnose thyroid cancer. In addition, inhibition of DUSP5 improves the response of BRAF-mutant thyroid cancer cells to sorafenib.

Assessing melanoma prognosis: the interplay between patient profiles, survival, and BRAF, NRAS, KIT, and TWT mutations in a retrospective multi-study analysis.

The incidence and prevalence of melanoma are increasing globally, presenting a significant public health concern. The main genetic drivers of melanoma include BRAF, NRAS, KIT and triple wild-type (TWT) mutations. Little is known about the effects of these mutations on outcomes in terms of demographics and patient characteristics. We examined differences in melanoma mortality risk and mutation count across mutation type and patient disease profile. We extrapolated primary melanoma patient data from 14 studies via the cBioportal database. Patients were divided into demographic groups and classified according to BRAF, NRAS, KIT and TWT mutation status. Analyses included two-sample Student t -test and two-way analysis of variance tests analysis with Tukey's post hoc test. Survival outcomes were compared via Kaplan-Meier curve and Cox regression. NRAS-mutated patients exhibited decreased overall survival compared to BRAF-mutated patients. Male patients had higher mutation counts across all gene groups than females, with the fewest TWT mutations in comparison to BRAF, NRAS and KIT mutations. Males also exhibited increased mortality risk for NRAS, KIT and TWT mutations compared to BRAF mutations. An unknown primary melanoma was associated with increased mortality risk across all gene groups. NRAS-mutated acral melanoma patients had an increased mortality risk compared to NRAS-mutated cutaneous melanoma patients. Older patients had a higher mortality risk than younger patients. Patients with heavier versus lower weights had lower mortality risk, which was more pronounced for BRAF-mutated patients. These relationships highlight the importance of demographic and pathologic relationships to aid in risk assessment and personalize treatment plans.

The effects of Aurora Kinase inhibition on thyroid cancer growth and sensitivity to MAPK-directed therapies

ABSTRACT Thyroid cancer is one of the deadliest endocrine cancers, and its incidence has been increasing. While mutations in BRAF are common in thyroid cancer, advanced PTC patients currently lack therapeutic options targeting the MAPK pathway, and despite the approved combination of BRAF and MEK1/2 inhibition for BRAF-mutant ATC, resistance often occurs. Here, we assess growth and signaling responses to combined BRAF and MEK1/2 inhibition in a panel of BRAF-mutant thyroid cancer cell lines. We first showed that combined BRAF and MEK1/2 inhibition synergistically inhibits cell growth in four out of six of the ­BRAF-mutant thyroid cancer cell lines tested. Western blotting showed that the MAPK pathway was robustly inhibited in all cell lines. Therefore, to identify potential mechanisms of resistance, we performed RNA-sequencing in cells sensitive or resistant to MEK1/2 inhibition. In response to MEK1/2 inhibition, we identified a downregulation of Aurora Kinase B (AURKB) in sensitive but not resistant cells. We further demonstrated that combined MEK1/2 and AURKB inhibition slowed cell growth, which was phenocopied by inhibiting AURKB and ERK1/2. Finally, we show that combined AURKB and ERK1/2 inhibition induces apoptosis in BRAF-mutant thyroid cancer cell lines, together suggesting a potential combination therapy for BRAF-mutant thyroid cancer patients.

Abstract 1997: The small GTPase ARF6 augments BRAF and PI3K expression to promote melanoma survival

Abstract RAF and MEK inhibitors greatly benefit BRAF-mutant melanoma patients, but eventually, nearly 80% of patients relapse. Reactivation of MAPK signaling and activation of PI3K/AKT signaling play a major role in the development of targeted therapy resistance. Therefore, understanding how tumor cells regulate these signaling pathways may yield new insights into drug resistance. The small GTPase ARF6, a member of the RAS superfamily, influences oncogenic signaling by controlling cytoskeletal rearrangements and through endomembrane trafficking. We previously reported that ARF6 is aberrantly activated in metastatic melanoma and that activation of ARF6 is sufficient to promote invasion and accelerate spontaneous metastasis in vivo through WNT5A/beta-catenin and PI3K/AKT signaling. In contrast to ARF6 activation, herein we show that tumor-specific deletion of Arf6 significantly limits development and progression of BRAFV600E melanoma in vivo. Mechanistically, we discovered these ARF6-dependent phenotypes may be attributed to a previously unknown role for ARF6 in augmenting BRAFV600E and PI3K protein levels. Specifically, pharmacologic or genetic activation ARF6 (ARF6-GTP) is sufficient to increase BRAFV600E and PI3K protein levels in both murine and human melanoma. As a result, ARF6-GTP is also sufficient to enhance activation of MEK, ERK and AKT. Importantly, murine tumors expressing constitutively active ARF6 (ARF6Q67L) show increased expression of anti-apoptotic proteins compared to ARF6WT tumors. Together these data suggest that ARF6 promotes tumor survival through augmentation of the BRAF/MAPK and PI3K/AKT pathways. To test this, we pharmacologically activated ARF6 during serum withdrawal or vemurafenib treatment. In both conditions, ARF6 activation is sufficient to prevent apoptosis. Surprisingly, we found that vemurafenib treatment leads to ARF6 activation, suggesting that ARF6 may be an important component of the cellular machinery that reactivates MAPK signaling after RAF inhibition. Indeed, pharmacologic activation of ARF6 maintains MAPK signaling (pERK levels) in the presence of vemurafenib and enhances pERK and pAKT-mediated suppression of apoptotic signaling. In summary, our data suggest that in addition to well-established roles in tumor cell invasion, ARF6 is a crucial mediator of survival during tumor progression and in the context of BRAF targeted therapy. More work is needed to understand how ARF6 activation increases BRAF and PI3K expression and if ARF6 activation contributes to the development of persister cells in melanoma. Citation Format: Junhua Wang, Coulson Rich, Aaron Rogers, Sheri Holmen, Roger Wolff, Allie Grossmann. The small GTPase ARF6 augments BRAF and PI3K expression to promote melanoma survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1997.

Comparison of Immunotherapy versus Targeted Therapy Effectiveness in BRAF-Mutant Melanoma Patients and Use of cGAS Expression and Aneuploidy as Potential Prognostic Biomarkers.

BRAF-mutant melanoma patients can be treated with targeted therapy or immunotherapies, and it is not clear which should be provided first. Targeted treatments do not work in up to one-third of cases, while immunotherapies may only be effective in up to 60% and come with a high risk of immune-related side effects. Determining which treatment to provide first is thus of critical importance. Recent studies suggest that chromosomal instability and aneuploidy and cyclic GMP-AMP synthase (cGAS) can act as biomarkers for cancer severity and patient outcome. Neither potential biomarker has been extensively studied in melanoma. We examined 20 BRAF-mutant melanomas treated with immunotherapy or targeted therapy and measured chromosomal aneuploidy and cGAS expression levels. Treatment type, aneuploidy, and cGAS expression were correlated with progression-free survival (PFS) in these patients. Those treated with immunotherapy first had significantly better outcomes than those treated with targeted therapy, suggesting immunotherapy should be strongly considered as the first-line therapy for patients bearing BRAF-mutant melanoma. We found that there was no correlation of aneuploidy with outcome while there was some positive correlation of cGAS levels with PFS. Further studies are needed to confirm these findings and to test other potential biomarkers.

Preclinical efficacy of carfilzomib in BRAF-mutant colorectal cancer models.

Serine/threonine-protein kinase B-raf (BRAF) mutations are found in 8-15% of colorectal cancer patients and identify a subset of tumors with poor outcome in the metastatic setting. We have previously reported that BRAF-mutant human cells display a high rate of protein production, causing proteotoxic stress, and are selectively sensitive to the proteasome inhibitors bortezomib and carfilzomib. In this work, we tested whether carfilzomib could restrain the growth of BRAF-mutant colorectal tumors not only by targeting cancer cells directly, but also by promoting an immune-mediated antitumor response. In human and mouse colorectal cancer cells, carfilzomib triggered robust endoplasmic reticulum stress and autophagy, followed by the emission of immunogenic-damage-associated molecules. Intravenous administration of carfilzomib delayed the growth of BRAF-mutant murine tumors and mobilized the danger-signal proteins calreticulin and high mobility group box 1 (HMGB1). Analyses of drug-treated samples revealed increased intratumor recruitment of activated cytotoxic T cells and natural killers, concomitant with the downregulation of forkhead box protein P3 (Foxp3)+ T-cell surface glycoprotein CD4 (CD4)+ T cells, indicating that carfilzomib promotes reshaping of the immune microenvironment of BRAF-mutant murine colorectal tumors. These results will inform the design of clinical trials in BRAF-mutant colorectal cancer patients.

Clinical features and mutation analysis of class 1/2/3 BRAF mutation colorectal cancer.

BRAF (B-Raf proto-oncogene, serine/threonine kinase)-mutated colorectal cancer (CRC) still has poor prognostic. The efficacy of BRAF inhibitor is unpredictable just that intrinsic genetic complexity, immune microenvironment and partially unknown reason. Understanding the co-mutation mechanism can help improve treatment and follow-up strategies. We retrospectively analyzed 35 (BRAF-mutated/BRAF wild-type) Chinese CRC and 125 Western CRC who underwent next-generation sequencing (NGS). Co-occurrence mutation analysis, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was enabled in this study. Thirty-five (10.32%) patients were BRAF-mutated, with 17 patients were BRAF V600E in Beijing Hospital. Patients with BRAF mutation had significant association with high tumor mutational burden (TMB-H) (P=0.0004) and high microsatellite instability (MSI-H) (P=0.0003) than those with BRAF wild-type. In 125 BRAF-mutated Western CRC patients, the frequency of age at diagnosis, gender, sample type, Tumor-Node-Metastasis (TNM), MSI, TMB, and BRAF mutation type was consistent with Chinese data. However, the primary tumor location showed significant statistical differences (P<0.0001). Class 1 were more likely to occur in elder and female. Western cohort was consistent with above in Chinese cohort. Other clinicopathological features were not significantly associated with mutation type. However, Western cohort showed class 1 exhibited primary sample type predominance in both class 1 vs. others (P<0.05) and class 1 vs. class 3 (P<0.05). Meanwhile, the data showed TMB-H (57.69% vs. 11.76%, P<0.001) and MSI-H (28.21% vs. 0%, P<0.05) of the class 1 BRAF mutation proportion were significantly higher, compared with class 3 BRAF mutation. In concurrent oncogenic mutations, compared with non-class 1 BRAF mutation, class 1 are more likely to co-occur with passenger mutation. Data from Western populations showed similar results. We also found that the class 1 mutation was mutually exclusive with co-KRAS (Kirsten rat sarcoma viral oncogene homologue) mutation in CRC, and co-APC (APC regulator of WNT signaling pathway) mutation appeared more frequently in non-class 1 BRAF mutation. KEGG pathway showed that fewer proto-cancer signaling pathways were enriched in the class 1, which further confirmed that this type had stronger tumorigenicity. GO enrichment also proved that class 1 had stronger tumorigenicity. Finally, prognostic analysis showed median overall survival (mOS) of 19.43 months in class 1 vs. 47.57 months in non-class 1 (P=0.0002). Further study showed that the mOS of class 1, class 2, class 3 and class NA (unknown) was 19.43, 28.50, 47.57 months and not reached (P=0.0001), respectively. This study showed class 1/non-class 1 BRAF mutation in CRC had significantly differences in co-mutation features, genomic markers and prognostic. Understanding BRAF mutation types and co-mutation mechanism will contribute to accurately grasping treatment and follow-up strategies and promoting the development of precision therapy for CRC in the future.

Abstract A010: Longitudinal histology and spatial transcriptomics profiling in targeted treatment of melanoma patient-derived models interrogates persister and resistant cell populations

Abstract Over half of BRAF-mutant melanoma patients with initial response to targeted therapy will recur with resistant disease. It is thought that recurrence arises from the ability of resistant clonal populations to enter and exit a slow-cycling persister state, evading treatment in quiescence before returning to a proliferative state. However, clonal transcriptional profiles and their spatial relationships in the tumor environment are not well characterized. Through longitudinal profiling of tumors from pre-treatment through the growth of resistant tumors, we track clonal lineages and transcriptional state changes to identify recurrent evolutionary patterns. BRAF mutant patient-derived melanoma xenografts were treated with BRAF/MEK inhibitors through maximum tumor size reduction and re-growth. Spatial transcriptomics (ST) and H&amp;E histological staining were performed at five timepoints across 94 and 133 days of PDX models WM4237 and WM4007 treatment, tracking clonal populations with intact tissue structure. Deep learning feature extraction on high-resolution H&amp;E-stained images allowed the detection of histological features that co-localize with expression levels. A novel computational workflow performed integration of samples across time points, pathway enrichment analysis, and pseudotemporal ordering, allowing spatial recreation of copy number variation based clonal phylogenies and cell fate trajectory inference during the treatment course. We characterize the clonal populations by the burden of accumulated copy number variations and establish clonal phylogeny. With the added temporal resolution, ST profiling during melanoma treatment enables observation of a global shift where all lineages begin the transition into the persister transcriptional state. The drug-sensitive cells are eliminated due to treatment, and distinct transcriptional states arise due to metabolic plasticity regardless of the lineage of origin. The clones of the transient persister state constitute the minimal residual disease, where melanoma cells have an increase in invasive capacity and a slowing of the cell cycle. The ability to survive through the persister state and re-emerge into a proliferating clone where the cell cycle is upregulated varies by lineage. We observe that the transcriptional changes during emergence from dormancy show decreased invasiveness and continued reliance on oxidative respiration versus glycolysis. We compare the re-emerged resistant cell populations and pre-treatment samples to pinpoint the changes in the transcriptional state of the MAPK signaling pathway and find that sets of upregulated genes differ by the model, WM4237 and WM4007. We connect deep learning imaging features extracted from longitudinal histology profiling to ST profiles to associate histology data with the cell cycle activation, invasiveness, hypoxia state, and metabolic mode across the timepoints. We observe that the imaging features alone can be potentially used to track the evolution of the tumor cell population phenotypes during drug treatment. Citation Format: Sergii Domanskyi, Todd B. Sheridan, Brian J. Sanderson, SungHee Park, Jessica Kaster, Haiyin Li, Olga Anczukow, Meenhard Herlyn, Jeffrey H. Chuang, Jill C. Rubinstein. Longitudinal histology and spatial transcriptomics profiling in targeted treatment of melanoma patient-derived models interrogates persister and resistant cell populations [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Translating Cancer Evolution and Data Science: The Next Frontier; 2023 Dec 3-6; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_2):Abstract nr A010.

Oral Adverse Events Associated with BRAF and MEK Inhibitors in Melanoma Treatment: A Narrative Literature Review.

Melanoma cancer represents the most lethal type of skin cancer originating from the malignant transformation of melanocyte cells. Almost 50% of melanomas show the activation of BRAF mutations. The identification and characterization of BRAF mutations led to the development of specific drugs that radically changed the therapeutic approach to melanoma. We conducted a narrative review of the literature according to a written protocol before conducting the study. This article is based on previously conducted studies. We identified articles by searching electronic databases (Medline, Google Scholar and PubMed). We used a combination of "melanoma", "Braf-Mek inhibitors", " targeted therapy" and "oral side effects". Eighteen studies were reported in this article showing the relationship between the use of targeted therapy in melanoma cancer and the development of oral side effects, such as mucositis, hyperkeratosis and cellular proliferation. Targeted therapy plays an important role in the treatment of melanoma cancer, showing a notable increase in response rate, prolonged progression-free survival and overall survival in BRAF-mutated melanoma patients. Oral side effects represent a common finding over the course of treatment. However, these adverse effects can be easily managed in a multidisciplinary approach involving collaboration between medical oncologists and dental doctors.

Combined BET and MEK Inhibition synergistically suppresses melanoma by targeting YAP1.

Rationale: The response rate to the MEK inhibitor trametinib in BRAF-mutated melanoma patients is less than 30%, and drug resistance develops rapidly, but the mechanism is still unclear. Yes1-associated transcriptional regulator (YAP1) is highly expressed in melanoma and may be related to MEK inhibitor resistance. The purpose of this study was to investigate the mechanism of YAP1 in MEK inhibitor resistance in melanoma and to screen YAP1 inhibitors to further determine whether YAP1 inhibition reverses MEK inhibitor resistance. Methods: On the one hand, we analyzed paired melanoma and adjacent tissue samples using RNA-seq and found that the Hippo-YAP1 signaling pathway was the top upregulated pathway. On the other hand, we evaluated the transcriptomes of melanoma samples from patients before and after trametinib treatment and investigated the correlation between YAP1 expression and trametinib resistance. Then, we screened for inhibitors that repress YAP1 expression and investigated the mechanisms. Finally, we investigated the antitumor effect of YAP1 inhibition combined with MEK inhibition both in vitro and in vivo. Results: We found that YAP1 expression levels upon trametinib treatment in melanoma patients were correlated with resistance to trametinib. YAP1 was translocated into the nucleus after trametinib treatment in melanoma cells, which could render resistance to MEK inhibition. Thus, we screened for inhibitors that repress YAP1 expression and identified multiple bromodomain and extra-terminal (BET) inhibitors, including NHWD-870, as hits. BET inhibition repressed YAP1 expression by decreasing BRD4 binding to the YAP1 promoter. Consistently, YAP1 overexpression was sufficient to reverse the proliferation defect caused by BRD4 depletion. In addition, the BET inhibitor NHWD-870 acted synergistically with trametinib to suppress melanoma growth in vitro and in vivo. Conclusions: We identified a new vulnerability for MEK inhibitor-resistant melanomas, which activated Hippo pathway due to elevated YAP1 activity. Inhibition of BRD4 using BET inhibitors suppressed YAP1 expression and led to blunted melanoma growth when combined with treatment with the MEK inhibitor trametinib.

BRAF Inhibitors in BRAF-Mutated Colorectal Cancer: A Systematic Review.

Colorectal cancer (CRC) is the second-leading cause of cancer-related deaths globally. BRAF mutation is present in about 10% of CRC patients and is associated with a poor response to chemotherapy. These patients have a relatively poor prognosis. This review aims to assess the efficacy and safety of BRAF inhibitors in BRAF-mutated CRC patients. A literature search was performed on PubMed and Embase, and clinical trials relevant to BRAF inhibitors in CRC were included. Data were extracted for efficacy and safety variables. Two randomized clinical trials (n = 765) and eight non-randomized trials (n = 281) were included based on inclusion criteria. In RCTs, an overall response was reported in 23% of the patients treated with BRAF inhibitor-based regimens compared to 2.5% with control regimens. The hazard ratio of overall survival was also significantly better with triplet encorafenib therapy at 0.52 (95% CI = 0.39-0.70). In single-arm trials, ORR was 17% and 34% in two-drug and three-drug regimens, respectively. BRAF inhibitor-based regimens were safe and effective in the treatment of BRAF-mutated CRC. Large-scale randomized trials are needed to find a suitable population for each regimen. PROSPERO registration No. CRD42023471627.

Effect and Interactions of BRAF on Lymph Node Metastasis in Papillary Thyroid Carcinoma With Hashimoto Thyroiditis.

The role of B-Raf proto-oncogene (BRAF) in papillary thyroid carcinoma (PTC) with Hashimoto thyroiditis (HT) is unknown. We aimed to explore risk factors affecting lymph node (LN) metastasis and interaction effect of BRAF in PTC patients with HT. We retrospectively collected the data of 994 PTC patients with HT who underwent surgery at the West China Hospital. We analyzed the correlations between preoperative characteristics and LN metastasis in overall, and different BRAFV600E-mutation patients. Logistic regression was applied to analyze the risk factors for LN metastasis. Finally, we performed an interaction effect analysis to identify the interaction effect of BRAF. The overall LN metastasis rate was 52.71% (524/994); the overall BRAF mutation rate was 26.9% (268/994). BRAF mutation rates were significantly different in LN metastasis and nonmetastasis patients (31.7% vs 21.5%; P < .001). In all 994 patients, age, body mass index (BMI), hypertension, tumor maximum diameter, BRAF mutation, tumor location, aspect ratio, calcification, and extrathyroidal invasion were risk factors for LN metastasis (P < .05). In BRAF-mutant patients, smoking, hypertension, maximum diameter, calcification, and multifocality were risk factors for LN metastasis (P < .05). In BRAF wild-type patients, age, BMI, maximum diameter, tumor location, aspect ratio, tumor shape, calcification, and extrathyroidal invasion were risk factors (P < .05). Additionally, we found statistically significant interactions between BRAF and BMI, hypertension, maximum diameter, and calcification (P < .05), suggesting the potential interaction effect of BRAF. BRAF is a risk factor for LN metastasis in PTC with HT. Meanwhile, BRAF can interact with age, BMI, hypertension, and calcification, which together influence LN metastasis.