High charge of cerebroid nests in nodular melanomas predicts tumor aggressiveness and high mutational tumoral burden: a pilot study.

Purpose: Even today, melanoma is a highly aggressive neoplasm with a high mortality rate. The nodular type is very aggressive and has cerebroid nests of melanocytes (CNMs) at the growth edge, morphologically similar to the poorly differentiated neoplastic epithelial cell clusters described in colorectal, breast, and endometrioid endometrial cancers. Patients and methods: We selected 25 nodular melanomas (NMs) with known molecular profiles, of which the entire paraffin-embedded lesion was available. We counted CNMs under a microscopic at a magnification of 20x (i.e., a microscopic field with a major axis of 1 mm). Based on the number of CNMs in the area, melanomas were classified into three groups: G1 (CNMs ranging from 0 to 4), G2 (CNMs ranging from 5 to 9), and G3 (CNMs ≥ 10). The presence of CNMs and their counts were compared with molecular and histopathological data. Results: Seventeen (NMs) were grouped as G1 (68%), 5 as G2 (20%), and 3 as G3 (12%) based on CNMs count. The presence of CNMs correlated with epithelioid cell morphology (p < 0.05), Clark IV and V levels (p < 0.05), vascular invasion (p < 0.05), and biological mutants (p < 0.05). Melanomas with ≥ 10 CNMs more frequently show ulceration (p < 0.02) and the BRAF V600E mutation (p < 0.02). Conclusion: CNMs count has a predictive role regardless of tumor size; their association with the BRAF V600E mutation suggests their predictive significance in response to biologics. However, further investigations are needed to strengthen this hypothesis.

Combination Atezolizumab, Cobimetinib, and Vemurafenib as a Treatment Option in BRAF V600 Mutation-Positive Melanoma: Patient Selection and Perspectives.

The treatment landscape for advanced and metastatic melanoma has drastically changed in recent years, with the advent of novel therapeutic options such as immune checkpoint inhibitors and targeted therapies offering remarkable efficacy and significantly improved patient outcomes compared to traditional approaches. Approximately 50% of melanomas harbor activating BRAF mutations, with over 90% resulting in BRAF V600E. Tumors treated with BRAF inhibitor monotherapy have a high rate of developing resistance within six months. Combination therapy with MEK inhibitors helped to mitigate this treatment resistance and led to improved outcomes. Due to the up-regulation of PD-1/PD-L1 receptors in tumors treated with BRAF/MEK inhibitor therapy, further studies included a third combination agent, anti-PD-1/PD-L1 inhibitors. This triple combination therapy may have superior efficacy and a manageable safety profile when compared with single or double agent therapy regimens.

Effective treatment of advanced and metastatic melanoma can be challenging. Newer treatment methods for patients with BRAF-mutated tumors include a combination of drugs with different complementary mechanisms. These drugs include BRAF-inhibitors, MEK-inhibitors, and PD-1/PD-L1 inhibitors. When these three medications are used in combination, patients may have better response rates and survival outcomes, when compared to using just one or two of these medications together. Toxicity rates are higher with a triple-medication regimen, so careful patient selection is important to consider.

Efficacy of BRAF/MEK-inhibitor therapy for epithelioid glioblastoma with a novel BRAFV600 mutation.

Epithelioid glioblastoma (eGB), a very aggressive and rare brain tumour, is associated with a dismal median overall survival. Effective therapies for patients with eGB, particularly with leptomeningeal dissemination, are still lacking. Here, we describe a case of a 25-year-old male diagnosed with an intramedullary cervical tumour with subsequent leptomeningeal disease. Histopathology identified a highly necrotising, epithelioid-type tumour with high cell density, most compatible with the diagnosis of an eGB. DNA analysis revealed an unprecedented B-Raf protooncogene, serine/threonine kinase (BRAF) gene variant in exon 15 (ENST00000288602.6, c.1799_1810delinsATG, p.(V600_W604delinsDG)), triggering activation of the mitogen-activated protein kinase (MAPK) pathway. Consequently, we initiated MAPK inhibitor (MAPKi) therapy, utilizing a combination of BRAF and mitogen-activated protein kinase kinase (MEK) inhibitors. Liquid chromatography-tandem mass spectrometry analysis confirmed the drugs' presence in the patient's cerebrospinal fluid, indicating their capacity to cross the blood-brain barrier. Remarkably, the patient responded very well to therapy and transitioned from a near-comatose state to significantly improved health, sustained for over three months. This study highlights that MAPKi, particularly targeted towards novel BRAFV600 mutations, might offer promising advancements in eGB treatment strategies.

A two-stage maintenance trial of cetuximab-based treatment in RAS and BRAF wild-type unresectable metastatic colorectal cancer: a retrospective real-world study.

Background: To investigate the effectiveness and safety of maintenance regimens based on cetuximab, we conducted a real-world, single-arm, retrospective study at a single center. Methods: In Fujian Medical University Union Hospital, patients with unresectable metastatic colorectal cancer (mCRC) who received cetuximab-based maintenance therapy between December 2020 and December 2021 were included. All patients had RAS and BRAF wild-type. The maintenance regimen consisted of 6-12 cycles of cetuximab plus irinotecan (Phase 1) and cetuximab (Phase 2). Patients could receive reintroduction therapy in case of disease progression during Phase 2. Progression-free survival (PFS), overall survival (OS), and safety data were collected. Results: According to the inclusion and exclusion criteria of the study, a total of 108 subjects who received maintenance therapy were included- 51 experienced disease progression during Phase 1, with PFS (1) of 7.3 months. Among the 52 patients who entered Phase 2, 17 were still in this phase at the end of follow-up, with PFS (2) of 10.1 months. In Phase 2, 35 patients experienced disease progression, of whom 24 received reintroduction therapy, with PFS (3) of 6.7 months. The overall PFS (total) during the maintenance period was 11.9 months, and the OS was 39.2 months. Grade III or higher adverse events were 4.6% during Phase 1 and 0% during Phase 2. Conclusion: Innovative cetuximab-based maintenance therapy showed a trend toward improving the prognosis of mCRC patients with RAS and BRAF wild-type, while the toxic side effects of maintenance therapy were manageable. Clinical trial registration: https://www.chictr.org.cn, identifier ChiCTR2000040940.

Intraglandular dissemination: a special pathological feature.

Intraglandular dissemination is an important pathological feature of thyroid cancer, yet the biological characteristics of this phenomenon remain relatively underexplored. This paper aims to provide a comprehensive overview of its biological behaviors, protein expressions, and identification methods. Several retrospective studies have found that thyroid cancers with intraglandular dissemination have higher rates of lymph node metastasis, capsule invasion, and vascular invasion, exhibiting more aggressive biological behavior. Immunohistochemistry results show abnormal expression of proteins such as FKBP5, CENPF, CX26, KIF11, PTK7, which are associated with poor prognosis in thyroid cancers with intraglandular dissemination, offering potential guidance for specific targeted therapy in the future. Moreover, adjunctive techniques including ultrasound, fine-needle aspiration, and genetic testing offer valuable support in accurately identifying these cases, facilitating moreproactive treatment and closer follow-up.

An Automated Real-Time PCR Assay versus Next-Generation Sequencing in the Detection of BRAF V600 Mutations in Melanoma Tissue Samples.

BACKGROUND: Next-generation sequencing (NGS) is the most commonly used method for determining BRAF mutational status in patients with advanced melanoma. Automated PCR-based methods, such as the IdyllaTM system, are increasingly used for mutation diagnostics, but it is unclear what impact the choice of diagnostic method has on the management of melanoma. OBJECTIVES: To compare the concordance rate of BRAF V600 mutational analysis using IdyllaTM and NGS and to analyze the technical and clinical turnaround time. The clinical relevance is compared by analyzing the impact on the treatment decision. METHODS: In this monocentric prospective cohort study, the BRAF mutation status of 51 patients was determined using both methods in parallel. RESULTS: BRAF V600 mutation was detected in 23/51 cases (45%). IdyllaTM showed a 100% concordant result with a faster turnaround time (0.2 days) compared to NGS (12.2 days). In general, less tumor material was required for IdyllaTM than for NGS. Most patients received immunotherapy as a first-line therapy regardless of the BRAF V600 status. CONCLUSIONS: IdyllaTM testing proved to be a reliable and rapid alternative to NGS in the determination of BRAF V600 mutation. Although BRAF. status was available earlier, this had no influence on the treatment decision in most cases.

Intriguing Insights From 100 Consecutive Colorectal Cancer Cases in Mid-Kerala: Sparse BRAF Gene Mutations and Mismatch Repair Deficiency (MMR-D).

Colorectal cancer (CRC) is among the most prevalent types of cancer globally. It is well established that the development of CRC primarily results from the sequential activation of oncogenes and the simultaneous inactivation of tumor suppressor genes. It has also been noted that after the initial oncogenic mutation, many subpopulations with different mutational profiles are created, causing heterogeneity among the tumors. This retrospective study analyzed 100 patients diagnosed with CRC through colectomy over an eighteen-month period at a tertiary referral center in mid-Kerala, India. Pathology records and histological slides were reviewed by two pathologists, and clinicopathological data were collected from pathology reports. Immunohistochemical analysis for BRAF mutation and possible microsatellite instability (MSI) (by mismatch repair (MMR) protein study) was conducted on tumor tissue blocks sent to an external center due to the lack of an automated platform at the hospital. The study utilized Roche's Benchmark XT platform for BRAF analysis and assessed MMR protein expression using antibodies for MLH1, MSH2, MSH6, and PMS2. The mean age of patients was 58.36 years, with a male predominance (58.0%). Most tumors were classified as T3 (71.0%, n-71) and T2/T4a (14.0% each, n-14), while nodal involvement included N0 (35.0%, n-35), N1 (26.0%, n-26), N2 (19.0%, n-19), and NX (20.0%, n-20). Histological examination revealed predominantly well-differentiated tumors (78.0%, n-78), with lymphatic invasion noted in 41.0% (n-41) and vascular invasion in 5.0% (n-5) of cases. Left-sided tumors predominated (33.0%, n-33), followed by rectal carcinoma (37.0%, n-37), and right-sided colon cancers (30.0%, n-30). Genetic profiling showed sparse BRAF mutations (1.0%, n-1) and MSI (1.0%, n-1), with some cases exhibiting loss of MMR proteins (MLH1, PMS2, MSH2, and MSH6) by immunohistochemistry (IHC). The study highlights the rarity of BRAF mutations in this cohort and emphasizes the diverse pathological and molecular characteristics observed. The discussion focuses on the implications of these findings, suggesting that CRC in this population exhibits unique clinicopathological features potentially influenced by factors beyond genetic mutations. Further multicentric studies are warranted to comprehensively explore these factors and refine risk stratification and treatment strategies for CRC patients in similar demographics.

USP25 Promotes the Antimycobacterial Response of Macrophages Through Stabilizing B-Raf and C-Raf.

Ubiquitin-specific peptidase 25 (USP25) is one of the best-characterized deubiquitinating enzymes and plays a vital regulatory role in various biological processes, especially in cancer development and immune regulation. However, the exact role of USP25 and its underlying mechanisms in macrophage activation and immunogenicity during Mycobacterium tuberculosis infection remain unclear. In this study, we found that M tuberculosis infection induced USP25 expression in human and mouse macrophages. In particular, USP25 expression is elevated in multiple cell types, especially monocytes, in patients with tuberculosis. Additionally, USP25 deficiency in macrophages and mice resulted in compromised immunity against M tuberculosis infection, accompanied by reduced expressions of various proinflammatory cytokines and chemokines. Mechanistically, USP25 in macrophages promoted the activation of the ERK signaling pathway through deubiquitination and stabilization of B-Raf and C-Raf. These findings collectively suggest the critical roles of USP25 in M tuberculosis infection and its potential as a therapeutic target.

Clinical outcomes for immune checkpoint inhibitors plus chemotherapy in non-small-cell lung cancer patients with uncommon driver gene alterations.

BACKGROUND: Limited data exists on the efficacy of immune checkpoint inhibitor (ICI) combinations in non-small-cell lung cancer (NSCLC) with uncommon driver alterations in genes such as ERBB2, BRAF, RET, and MET. This study retrospectively assessed ICI-combination therapy outcomes in this molecular subset of NSCLC. METHODS: We retrospectively analyzed patients with advanced NSCLC confirmed with driver alterations in genes including ERBB2, BRAF, RET or MET, and received ICI combined with chemotherapy (ICI + chemo) and/or targeted therapy (ICI + chemo/TT) as first-line (1L) or second- or third-line (≥ 2L) treatment at Hunan Cancer Hospital between January 2018 and May 2024. RESULTS: Of the 181 patients included in the study, 131 patients received 1L-ICI + chemo (ERBB2, n = 64; BRAF, n = 34; RET, n = 23; and MET, n = 10), and 50 patients received ≥ 2L-ICI + chemo/TT (ERBB2, n = 16; BRAF, n = 7; RET, n = 14; MET, n = 13). The full cohort had an overall response rate (ORR) of 45.9% and disease control rate of 84.0%. Among patients who received 1L-ICI + chemo, ORR ranged between 51.6% and 60.0%, with the median progression-free survival (mPFS) and overall survival (mOS) of 8.2 and 21.0 months for those with ERBB2-altered tumors, 10.0 and 15.0 months for BRAF-altered tumors, 12.1 months and OS not reached for RET-altered tumors, and 6.2 and 28.0 months for MET-altered tumors, respectively. Additionally, ORR ranged between 14.3% and 30.8% for ≥ 2L-ICI + chemo/TT; mPFS and mOS were 5.4 and 16.2 months for patients with ERBB2-altered tumors, 2.7 and 5.0 months for BRAF-altered tumors, 6.2 and 14.3 months for RET-altered tumors, and 5.7 and 11.5 months for MET-altered tumors, respectively. CONCLUSION: ICI-based combination therapies, regardless of treatment line, were effective in treating patients with advanced NSCLC harboring driver alterations in ERBB2, BRAF, RET, or MET. This suggests their potential as alternative treatment options in this patient population.

POU5F1B is responsible for the acquired resistance to dabrafenib in papillary thyroid cancer cells with the BRAF V600E mutation.

BACKGROUND: Dabrafenib, an inhibitor of the B-Raf proto-oncogene (BRAF) V600E mutant, has become the major drug for targeted therapy of papillary thyroid cancer (PTC) with the BRAF V600E mutant; however, acquired resistance is inevitable. OBJECTIVE: To identify key transcription factors (TFs) involved in dabrafenib resistance and identify targets to reverse dabrafenib resistance. METHODS: Dabrafenib-resistant PTC cell lines BCPAP/DabR and K1/DabR were established, and phenotypic assays were performed to validate the malignant phenotype. RNA sequencing and bioinformatics analyses were used to identify differentially expressed genes (DEGs) and screen TFs involved in resistant phenotype-related pathways. The role of the key TF POU5F1B in dabrafenib resistance was further validated using gene gain-and-loss assays. RESULTS: BCPAP/DabR and K1/DabR were resistant to dabrafenib, with a resistance index of 5-8. Resistant cells exhibited slower proliferation, strong migration, and spheroid-forming abilities. RNA sequencing screened 6233 DEGs in the resistant group, including 2687 protein-coding RNA (mRNA). Venn analysis indicated that three genes, E2F2, WNT4, and POU5F1B, were involved in resistant phenotype-related pathways and were included in the TF regulatory network. Four TFs of the three genes, POU5F1B, TBX4, FOXO4, and FOXP3, were validated, and POU5F1B showed the highest validated fold-change. Overexpression of POU5F1B in sensitive cells resulted in resistance to dabrafenib and induced a malignant phenotype, whereas silencing it sensitized the resistant cells and reversed the resistant phenotype. CONCLUSION: This study successfully established two dabrafenib-resistant PTC cell lines, and POU5F1B could be a potential target for reversing dabrafenib resistance.

Osimertinib-induced BRAF mutation in a single metastatic lesion among multiple pulmonary lesions in a case of lung cancer with EGFR exon 19 deletion.

One of the resistant mechanisms of EGFR-TKIs is BRAF V600E mutation. Herein, we present the case of a 54-year-old Japanese female who underwent a right middle lobectomy for pathological stage IIB lung adenocarcinoma. One year and nine months after the surgery, she developed multiple intrapulmonary metastases. Osimertinib was administered due to EGFR exon 19 deletion. Although all intrapulmonary metastases had shrunk, the nodule at the superior segment of left lung enlarged after postoperative 4 years. The tumour was resected and BRAF V600E mutation and exon 19 deletion were detected. Three months after treatment with dabrafenib and trametinib instead of osimertinib, the remaining intrapulmonary metastases increased again. The continued growth of the metastatic foci even after EGFR-TKI may indicate an acquired resistance. Thus, a repeat biopsy will aid in confirming the new gene expression. It should have been necessary to administer an additional dose of dabrafenib and trametinib without discontinuing osimertinib.

Three-Year Analysis of Adjuvant Therapy in Postoperative Melanoma including Acral and Mucosal Subtypes.

BACKGROUND: Adjuvant therapy has improved the clinical prognosis for postoperative melanoma patients. However, the long-term efficacy of this therapy on the melanoma acral and mucosal subtypes has not been fully evaluated in previous trials. This study assessed the 3-year recurrence-free survival and overall survival of patients with melanoma, including the acral and mucosal subtypes, treated with anti-PD-1 antibody (Ab) or with the combination of the BRAF and MEK inhibitors dabrafenib and trametinib. METHODS: We retrospectively analyzed both the 3-year time to relapse (TTR) and overall survival (OS) of 120 patients treated with anti-PD-1 antibody (Ab), or with the combination of dabrafenib and trametinib. RESULTS: The overall median TTR was 18.4 months, with a range of 0.69 to 36 months. The 3-year TTR of the acral and mucosal types was 28.1% and 38.5%, respectively. Baseline tumor thickness (TT) and acral type were associated with the TTR in subgroup analysis. Moreover, we classified 104 acral and non-acral cutaneous patients into the anti-PD-1 Abs or dabrafenib plus trametinib combined therapies cohort in multiple analyses. The acral subtype and TT were detected as important prognostic factors. In the 3-year OS, only tumor ulceration was associated with the OS in both univariate and multiple analyses. There was no significant difference in baseline or treatment-related factors of the mucosal type (p > 0.05). CONCLUSION: This study suggests that adjuvant therapy is more effective with non-acral cutaneous melanoma than either the acral or mucosal types at the 3-year TTR endpoint.

In vivo vulnerabilities to GPX4 and HDAC inhibitors in drug-persistent versus drug-resistant BRAFV600E lung adenocarcinoma.

The current targeted therapy for BRAFV600E-mutant lung cancer consists of a dual blockade of RAF/MEK kinases often combining dabrafenib/trametinib (D/T). This regimen extends survival when compared to single-agent treatments, but disease progression is unavoidable. By using whole-genome CRISPR screening and RNA sequencing, we characterize the vulnerabilities of both persister and D/T-resistant cellular models. Oxidative stress together with concomitant induction of antioxidant responses is boosted by D/T treatment. However, the nature of the oxidative damage, the choice of redox detoxification systems, and the resulting therapeutic vulnerabilities display stage-specific differences. Persister cells suffer from lipid peroxidation and are sensitive to ferroptosis upon GPX4 inhibition in vivo. Biomarkers of lipid peroxidation are detected in clinical samples following D/T treatment. Acquired alterations leading to mitogen-activated protein kinase (MAPK) reactivation enhance cystine transport to boost GPX4-independent antioxidant responses. Similarly to BRAFV600E-mutant melanoma, histone deacetylase (HDAC) inhibitors decrease D/T-resistant cell viability and extend therapeutic response in vivo.

Validation, Reliability, and Clinical Significance of the Arabic Version of Bristol Rheumatoid Arthritis Fatigue Multi-Dimensional Questionnaire.

BACKGROUND: Clinically relevant fatigue in rheumatoid arthritis (RA) patients significantly affects their quality of life. Almost all studies have assessed fatigue in this population using non-specific scales. The present multi-centric study aimed to assess the validity, reliability, and clinical significance of the Arabic version of the Bristol Rheumatoid Arthritis Fatigue Multi-Dimensional Questionnaire (BRAF-MDQ). METHODS: The present cross-sectional multicentric study was conducted at Aswan, Mansoura, Port Said, and Al-Azhar University Hospitals over a 6-month duration. The study included 311 patients with RA diagnosed according to the 2010 criteria of the American College of Rheumatology. The Arabic version of BRAF-MDQ was developed to assess fatigue in these patients. All patients were subjected to careful history taking, thorough clinical assessment, and standard laboratory work-up. The obtained Arabic BRAF-MDQ was tested for construct validity, internal consistency, testretest reproducibility, and criterion validity. Construct validity was evaluated using factor analysis with the Kaiser Meyer Olkin tool of sampling adequacy and Bartlett's sphericity test. Internal consistency of subscales was assessed using Cronbach's alpha. Test-retest reproducibility was assessed after a 1-week interval using the intraclass correlation coefficient. Pearson's correlation coefficient was used to correlate numerical variables. Predictors of fatigue were identified using binary logistic regression analysis. RESULTS: The present study included 311 RA patients. Construct validity assessment showed a high loading of questionnaire items within the proposed construct subscales with a KMO measure of sphericity of 0.927 and Bartlett's test of sphericity p-value < 0.001. Internal consistency assessment showed adequate Cronbach's alpha of Arabic BRAF-MDQ subscales. Total Arabic BRAFMDQ had excellent criterion validity, as indicated by the high correlations with MAFS (r=0.95, p < 0.001) and SF-36 vitality subscale (r=-0.91, p < 0.001). Clinically significant fatigue was identified in 214 patients (68.8%). Multivariate logistic regression analysis revealed age (OR (95% CI): 1.07 (1.02-1.12), p < 0.001), disease duration (OR (95% CI): 1.82 (1.43-2.33), p < 0.001), DAS28CRP (OR (95% CI): 8.62 (4.63-16.02), p < 0.001), and mHAQ (OR (95% CI): 3.85 (1.07-13.9), p = 0 .039) as significant predictors of fatigue development in the studied patients. CONCLUSION: The Arabic version of the Bristol Rheumatoid Arthritis Fatigue Multi-Dimensional Questionnaire is a valid, consistent, and reliable tool for the assessment of fatigue in Egyptian rheumatoid arthritis patients. Clinically significant fatigue was identified in 214 patients (68.8%). Further, risk factors for fatigue included older age, longer disease duration, and higher disease activity.

Review on radiomic analysis in 18F-fluorodeoxyglucose positron emission tomography for prediction of melanoma outcomes.

Over the past decade, several strategies have revolutionized the clinical management of patients with cutaneous melanoma (CM), including immunotherapy and targeted tyrosine kinase inhibitor (TKI)-based therapies. Indeed, immune checkpoint inhibitors (ICIs), alone or in combination, represent the standard of care for patients with advanced disease without an actionable mutation. Notably BRAF combined with MEK inhibitors represent the therapeutic standard for disease disclosing BRAF mutation. At the same time, FDG PET/CT has become part of the routine staging and evaluation of patients with cutaneous melanoma. There is growing interest in using FDG PET/CT measurements to predict response to ICI therapy and/or target therapy. While semiquantitative values such as standardized uptake value (SUV) are limited for predicting outcome, new measures including tumor metabolic volume, total lesion glycolysis and radiomics seem promising as potential imaging biomarkers for nuclear medicine. The aim of this review, prepared by an interdisciplinary group of experts, is to take stock of the current literature on radiomics approaches that could improve outcomes in CM.

Therapeutic implications of the metabolic changes associated with BRAF inhibition in melanoma.

Melanoma metabolism can be reprogrammed by activating BRAF mutations. These mutations are present in up to 50% of cutaneous melanomas, with the most common being V600E. BRAF mutations augment glycolysis to promote macromolecular synthesis and proliferation. Prior to the development of targeted anti-BRAF therapies, these mutations were associated with accelerated clinical disease in the metastatic setting. Combination BRAF and MEK inhibition is a first line treatment option for locally advanced or metastatic melanoma harboring targetable BRAF mutations. This therapy shows excellent response rates but these responses are not durable, with almost all patients developing resistance. When BRAF mutated melanoma cells are inhibited with targeted therapies the metabolism of those cells also changes. These cells rely less on glycolysis for energy production, and instead shift to a mitochondrial phenotype with upregulated TCA cycle activity and oxidative phosphorylation. An increased dependence on glutamine utilization is exhibited to support TCA cycle substrates in this metabolic rewiring of BRAF mutated melanoma. Herein we describe the relevant core metabolic pathways modulated by BRAF inhibition. These adaptive pathways represent vulnerabilities that could be targeted to overcome resistance to BRAF inhibitors. This review evaluates current and future therapeutic strategies that target metabolic reprogramming in melanoma cells, particularly in response to BRAF inhibition.

Applications of machine learning to MR imaging of pediatric low-grade gliomas.

INTRODUCTION: Machine learning (ML) shows promise for the automation of routine tasks related to the treatment of pediatric low-grade gliomas (pLGG) such as tumor grading, typing, and segmentation. Moreover, it has been shown that ML can identify crucial information from medical images that is otherwise currently unattainable. For example, ML appears to be capable of preoperatively identifying the underlying genetic status of pLGG. METHODS: In this chapter, we reviewed, to the best of our knowledge, all published works that have used ML techniques for the imaging-based evaluation of pLGGs. Additionally, we aimed to provide some context on what it will take to go from the exploratory studies we reviewed to clinically deployed models. RESULTS: Multiple studies have demonstrated that ML can accurately grade, type, and segment and detect the genetic status of pLGGs. We compared the approaches used between the different studies and observed a high degree of variability throughout the methodologies. Standardization and cooperation between the numerous groups working on these approaches will be key to accelerating the clinical deployment of these models. CONCLUSION: The studies reviewed in this chapter detail the potential for ML techniques to transform the treatment of pLGG. However, there are still challenges that need to be overcome prior to clinical deployment.

PRRX1 silencing is required for metastatic outgrowth in melanoma and is an independent prognostic of reduced survival in patients.

Paired related homeobox 1 (PRRX1) is an inducer of epithelial-to-mesenchymal transition (EMT) in different types of cancer cells. We detected low PRRX1 expression in nevus but increased levels in primary human melanoma and cell lines carrying the BRAFV600E mutation. High expression of PRRX1 correlates with invasiveness and enrichment of genes belonging to the EMT programme. Conversely, we found that loss of PRRX1 in metastatic samples is an independent prognostic predictor of poor survival for melanoma patients. Here, we show that stable depletion of PRRX1 improves the growth of melanoma xenografts and increases the number of distant spontaneous metastases, compared to controls. We provide evidence that loss of PRRX1 counteracts the EMT phenotype, impairing the expression of other EMT-related transcription factors, causing dysregulation of the ERK and signal transducer and activator of transcription 3 (STAT3) signaling pathways, and abrogating the invasive and migratory properties of melanoma cells while triggering the up-regulation of proliferative/melanocytic genes and the expression of the neural-crest-like markers nerve growth factor receptor (NGFR; also known as neurotrophin receptor p75NTR) and neural cell adhesion molecule L1 (L1CAM). Overall, our results indicate that loss of PRRX1 triggers a switch in the invasive programme, and cells de-differentiate towards a neural crest stem cell (NCSC)-like phenotype that accounts for the metastatic aggressiveness.

Polyamine and EIF5A hypusination downstream of c-Myc confers targeted therapy resistance in BRAF mutant melanoma.

BACKGROUND: BRAF inhibitors are widely employed in the treatment of melanoma with the BRAF V600E mutation. However, the development of resistance compromises their therapeutic efficacy. Diverse genomic and transcriptomic alterations are found in BRAF inhibitor resistant melanoma, posing a pressing need for convergent, druggable target that reverse therapy resistant tumor with different resistance mechanisms. METHODS: CRISPR-Cas9 screens were performed to identify novel target gene whose inhibition selectively targets A375VR, a BRAF V600E mutant cell line with acquired resistance to vemurafenib. Various in vitro and in vivo assays, including cell competition assay, water soluble tetrazolium (WST) assay, live-dead assay and xenograft assay were performed to confirm synergistic cell death. Liquid Chromatography-Mass Spectrometry analyses quantified polyamine biosynthesis and changes in proteome in vemurafenib resistant melanoma. EIF5A hypusination dependent protein translation and subsequent changes in mitochondrial biogenesis and activity were assayed by O-propargyl-puromycin labeling assay, mitotracker, mitoSOX labeling and seahorse assay. Bioinformatics analyses were used to identify the association of polyamine biosynthesis with BRAF inhibitor resistance and poor prognosis in melanoma patient cohorts. RESULTS: We elucidate the role of polyamine biosynthesis and its regulatory mechanisms in promoting BRAF inhibitor resistance. Leveraging CRISPR-Cas9 screens, we identify AMD1 (S-adenosylmethionine decarboxylase 1), a critical enzyme for polyamine biosynthesis, as a druggable target whose inhibition reduces vemurafenib resistance. Metabolomic and proteomic analyses reveal that polyamine biosynthesis is upregulated in vemurafenib-resistant cancer, resulting in enhanced EIF5A hypusination, translation of mitochondrial proteins and oxidative phosphorylation. We also identify that sustained c-Myc levels in vemurafenib-resistant cancer are responsible for elevated polyamine biosynthesis. Inhibition of polyamine biosynthesis or c-Myc reversed vemurafenib resistance both in vitro cell line models and in vivo in a xenograft model. Polyamine biosynthesis signature is associated with poor prognosis and shorter progression free survival after BRAF/MAPK inhibitor treatment in melanoma cohorts, highlighting the clinical relevance of our findings. CONCLUSIONS: Our findings delineate the molecular mechanisms involving polyamine-EIF5A hypusination-mitochondrial respiration pathway conferring BRAF inhibitor resistance in melanoma. These targets will serve as effective therapeutic targets that can maximize the therapeutic efficacy of existing BRAF inhibitors.

Heterogeneous pathogenesis of melanoma: BRAF mutations and beyond.

Melanoma pathogenesis, conventionally perceived as a linear accumulation of molecular changes, discloses substantial heterogeneity driven by non-linear biological processes, including the direct transformation of melanocyte stem cells. This heterogeneity manifests in diverse biological phenotypes and developmental states, influencing variable responses to treatments. Unveiling the aberrant mechanisms steering melanoma initiation, progression, and metastasis is imperative. Beyond mutations in oncogenic and tumor suppressor genes, the involvement of distinct molecular pathways assumes a pivotal role in melanoma pathogenesis. Ultraviolet (UV) radiations, a principal factor in melanoma etiology, categorizes melanomas based on cumulative sun damage (CSD). The genomic landscape of lesions correlates with UV exposure, impacting mutational load and spectrum of mutations. The World Health Organization's 2018 classification underscores the interplay between sun exposure and genomic characteristics, distinguishing melanomas associated with CSD from those unrelated to CSD. The classification elucidates molecular features such as tumor mutational burden and copy number alterations associated with different melanoma subtypes. The significance of the mutated BRAF gene and its pathway, notably BRAFV600 variants, in melanoma is paramount. BRAF mutations, prevalent across diverse cancer types, present therapeutic avenues, with clinical trials validating the efficacy of targeted therapies and immunotherapy. Additional driver mutations in oncogenes further characterize specific melanoma pathways, impacting tumor behavior. While histopathological examination remains pivotal, challenges persist in molecularly classifying melanocytic tumors. In this review, we went through all molecular characterization that aid in discriminating common and ambiguous lesions. Integration of highly sensitive molecular diagnostic tests into the diagnostic workflow becomes indispensable, particularly in instances where histology alone fails to achieve a conclusive diagnosis. A diagnostic algorithm based on different molecular features inferred by the various studies is here proposed.