Systemic chemotherapy is the main treatment option for patients with advanced intrahepatic cholangiocarcinoma (iCCA), however, its efficacy is limited. Herein, we report a young patient with NRAS-mutated chemoresistant metastatic iCCA, who received second-line therapy with a combination of trametinib (MEK1/2 inhibitor), hydroxychloroquine (autophagy inhibitor), and bevacizumab (angiogenesis inhibitor). A significant response was achieved during therapy, resulting in a 25% decrease in the size of tumor lesions after 2 months of treatment and an improvement in the patient\'s condition. The duration of this response was 4 months, but the patient died 10 months after the initiation of this triple therapy. This case report and the analysis of other available studies warrant further investigations on combined MEK and autophagy inhibition in RAS-mutated tumors.

BACKGROUND: Pediatric gastroenteropancreatic neuroendocrine tumors are exceedingly rare, resulting in most pediatric treatment recommendations being based on data derived from adults. Trametinib is a kinase inhibitor that targets MEK1/2 and has been employed in the treatment of cancers harboring mutations in the Ras pathway.
METHODS: We utilized an established human pediatric gastroenteropancreatic neuroendocrine-like tumor patient-derived xenograft (PDX) with a known NRAS mutation to study the effects of MEK inhibition. We evaluated the effects of trametinib on proliferation, motility, and tumor growth in vivo. We created an intraperitoneal metastatic model of this PDX, characterized both the phenotype and the genotype of the metastatic PDX and again, investigated the effects of MEK inhibition.
RESULTS: We found target engagement with decreased ERK1/2 phosphorylation with trametinib treatment. Trametinib led to decreased in vitro cell growth and motility, and decreased tumor growth and increased animal survival in a murine flank tumor model. Finally, we demonstrated that trametinib was able to significantly decrease gastroenteropancreatic neuroendocrine intraperitoneal tumor metastasis.
CONCLUSIONS: The results of these studies support the further investigation of MEK inhibition in pediatric NRAS mutated solid tumors.

Although V600E accounts for the majority of the BRAF mutations in metastatic colorectal cancer (mCRC), non-V600 BRAF variants have been shown in recent years to represent a distinct molecular subtype. This study provides a comprehensive profile of BRAF variants in mCRC using a large genomic database of circulating tumor DNA (ctDNA) and analyzing clinical outcomes in a cohort of patients with atypical (non-V600) BRAF variants (aBRAF; class II, class III, unclassified). Overall, 1733 out of 14,742 mCRC patients in the ctDNA cohort had at least one BRAF variant. Patients with atypical BRAF variants tended to be younger and male. In contrast to BRAFV600E, BRAF class II and III variants and their co-occurrence with KRAS/NRAS mutations were increased at baseline and especially with those patients predicted to have prior anti-EGFR exposure. Our clinical cohort included 38 patients with atypical BRAF mCRC treated at a large academic referral center. While there were no survival differences between atypical BRAF classes, concurrent RAS mutations or liver involvement was associated with poorer prognosis. Notably, patients younger than 50 years of age had extremely poor survival. In these patients, the high-frequency KRAS/NRAS co-mutation and its correlation with poorer prognosis underlines the urgent need for novel therapeutic strategies. This study represents one of the most comprehensive characterizations to date of atypical BRAF variants, utilizing both ctDNA and clinical cohorts.

About 25% of melanoma harbor activating NRAS mutations, which are associated with aggressive disease therefore requiring a rapid antitumor intervention. However, no efficient targeted therapy options are currently available for patients with NRAS-mutant melanoma. MEK inhibitors (MEKi) appear to display a moderate antitumor activity and also immunological effects in NRAS-mutant melanoma, providing an ideal backbone for combination treatments. In our study, the MEKi binimetinib, cobimetinib and trametinib combined with the BRAF inhibitors (BRAFi) encorafenib, vemurafenib and dabrafenib were investigated for their ability to inhibit proliferation, induce apoptosis and alter the expression of immune modulatory molecules in sensitive NRAS-mutant melanoma cells using two- and three-dimensional cell culture models as well as RNA sequencing analyses. Furthermore, NRAS-mutant melanoma cells resistant to the three BRAFi/MEKi combinations were established to characterize the mechanisms contributing to their resistance. All BRAFi induced a stress response in the sensitive NRAS-mutant melanoma cells thereby significantly enhancing the antiproliferative and proapoptotic activity of the MEKi analyzed. Furthermore, BRAFi/MEKi combinations upregulated immune relevant molecules, such as ICOS-L, components of antigen-presenting machinery and the \"don\'t eat me signal\" molecule CD47 in the melanoma cells. The BRAFi/MEKi-resistant, NRAS-mutant melanoma cells counteracted the molecular and immunological effects of BRAFi/MEKi by upregulating downstream mitogen-activated protein kinase pathway molecules, inhibiting apoptosis and promoting immune escape mechanisms. Together, our study reveals potent molecular and immunological effects of BRAFi/MEKi in sensitive NRAS-mutant melanoma cells that may be exploited in new combinational treatment strategies for patients with NRAS-mutant melanoma.

OBJECTIVE: To investigate the molecular characteristics and clinical prognosis of the neuroblastoma RAS viral oncogene (NRAS) in patients with primary cytogenetically normal acute myeloid leukemia (AML).
METHODS: A total of 171 adult patients with cytogenetically normal primary AML were collected, and 34 gene mutations in these patients were detected by targeted next-generation sequencing.
RESULTS: Among 171 patients with cytogenetically normal AML(CN-AML), 17 (9.9%) patients had found NRAS mutations. Among the 17 NRAS mutant patients, 16 cases were associated with the concomitant gene, and NRAS mutation (NRASmut) was significantly positively correlated with DNMT3A mutation (DNMT3Amut) (P=0.011) and KRAS mutation (P=0.008) compared with the NRAS wild-type (NRASwt) group. The frequency of NRASmutDNMT3Amut clone was significantly higher in CN-AML patients with NRAS mutation (8/17, 47%). The total NRASmut group showed no significant differences on clinical characteristics, CR rate after induction therapy, OS, and RFS as compared with NRASwt group. However, patients with NRASmutDNMT3Amut provided a shorter effect on OS (median:7 vs 15 months; P=0.036) and RFS (median: 3 vs 12 months; P=0.003) than those with NRASwt, though no statistic differences on demographics, lab parameters, treatment and CR rate of patients receiving induction therapy. Multivariate analysis showed that NRASmutDNMT3Amut subtype could independently affect the RFS of CN-AML patients (HR:3.210, 95%CI:1.078-9.557, P=0.036).
CONCLUSIONS: NRASmutDNMT3Amut clones have a high frequency of occurrence and show a poor survival prognosis. Our findings highlight potentially novel aspects of the underlying biology of NRASmutDNMT3Amut commutation in adult de novo CN-AML.

BACKGROUND: In the transplant setting, the definition of the risk of neoplastic transmission from donor to recipient often requires intraoperative pathological evaluation on frozen sections. Although most lesions can be easily classified into acceptable or unacceptable risk according to the Italian National Guidelines, there are cases in which unusual histologic features cannot be further investigated because of the lack of ancillary techniques on frozen sections.
METHODS: Here we present a case of a liver lesion in a 51-year-old male donor, subjected to histopathological on-call examination. The frozen sections showed a well-demarcated lesion consisting of epithelioid cells disposed in laminar structures and intermingled with a dense lymphocytic population: this led to organ discard with interruption of the donation process. The definitive histological analysis required an extensive immunohistochemical (IHC) investigation: the final diagnosis was \"bile duct adenoma with oncocytic features\", eventually confirmed by a strongly positive anti-mitochondrial IHC. Finally, an NGS panel analysis was performed, which revealed NRAS mutation.
CONCLUSIONS: To the best of our knowledge, this is the first case of oncocytic bile duct adenoma confirmed by anti-mitochondrial IHC and with NRAS mutation. The most challenging aspect of this case was represented by the transplant setting. In fact, the oncocytic features and the dense lymphocytic infiltrate represented concomitant unusual histological features that led to the halt of the organ donation procedures.

Mutations in the NRAS gene are common alterations in malignant melanoma. However, there are no specific treatment options approved for NRAS-mutated melanoma patients besides immune checkpoint inhibition. Since preclinical data suggests a synergistic effect of a MEK inhibitor (MEKi) and the oncolytic virus talimogene laherparepvec (T-VEC), we have treated three melanoma patients with this combination. All of the three patients had been suffering from recurring cutaneous and subcutaneous in-transit metastases. Upon treatment one patient (case 1) presented full regression of locoregional metastases and remained progression-free until date, for almost three years. The second patient (case 2) showed a partial regression of painful gluteal satellite metastases but died from brain metastases. The third patient (case 3) showed a durable response of locoregional metastases for seven months. The combination treatment was well tolerated with common adverse events known for each single agent. This report is the first case series presenting a clinical benefit of the combined T-VEC and MEKi treatment. We suggest the combination of T-VEC and MEKi as an off-label treatment option for patients with NRAS mutations, especially with recurrent in-transit or satellite metastases.

Hotspot mutations in the NRAS gene are causative genetic events associated with the development of melanoma. Currently, there are no FDA-approved drugs directly targeting NRAS mutations. Previously, we showed that p38 acts as a tumor suppressor in vitro and in vivo with respect to NRAS-mutant melanoma. We observed that because of p38 activation through treatment with the protein synthesis inhibitor, anisomycin leads to a transient upregulation of several targets of the cAMP pathway, representing a stressed cancer cell state that is often observed by therapeutic doses of MAPK inhibitors in melanoma patients. Meanwhile, genetically induced p38 or its stable transduction leads to a distinct cellular transcriptional state. Contrary to previous work showing an association of invasiveness with high p38 levels in BRAF-mutated melanoma, there was no correlation of p38 expression with NRAS-mutant melanoma invasion, highlighting the difference in BRAF and NRAS-driven melanomas. Although the role of p38 has been reported to be that of both tumor suppressor and oncogene, we show here that p38 specifically plays the role of a tumor suppressor in NRAS-mutant melanoma. Both the transient and stable activation of p38 elicits phosphorylation of mTOR, reported to be a master switch in regulating autophagy. Indeed, we observed a correlation between elevated levels of phosphorylated mTOR and a reduction in LC3 conversion (LCII/LCI), indicative of suppressed autophagy. Furthermore, a reduction in actin intensity in p38-high cells strongly suggests a role of mTOR in regulating actin and a remodeling in the NRAS-mutant melanoma cells. Therefore, p38 plays a tumor suppressive role in NRAS-mutant melanomas at least partially through the mechanism of mTOR upregulation, suppressed autophagy, and reduced actin polymerization. One or more combinations of MEK inhibitors with either anisomycin, rapamycin, chloroquine/bafilomycin, and cytochalasin modulate p38 activation, mTOR phosphorylation, autophagy, and actin polymerization, respectively, and they may provide an alternate route to targeting NRAS-mutant melanoma.

Despite recent advances in treatment and surveillance, metastatic melanoma still carries a poor prognosis. Large/giant congenital melanocytic nevi (CMNs) constitute a known risk factor for the condition, with the greatest risk for malignant transformation thought to be during childhood (median age at diagnosis of 3 years in a previous cohort). Herein, we present the case of a 30-year-old male who, after undergoing multiple excision/grafting procedures for a giant CMN as a child, was diagnosed with an NRAS-mutant, MDM2-amplified metastatic melanoma more than 20 years later. Response to ipilimumab/nivolumab immunotherapy, cisplatin/vinblastine/temozolomide chemotherapy, and nivolumab/relatlimab immunotherapy was poor. This case highlights the importance of lifetime monitoring with once-yearly dermatological examination (including lymph node palpation) in large/giant CMN patients, as well as the need for further clinical trials evaluating novel therapies for NRAS-mutant melanoma.

The host defense derived peptide was assessed in different model systems with increasing complexity employing the highly aggressive NRAS mutated melanoma metastases cell line MUG-Mel2. Amongst others, fluorescence microscopy and spectroscopy, as well as cell death studies were applied for liposomal, 2D and 3D in vitro models including tumor spheroids without or within skin models and in vivo mouse xenografts. Summarized, MUG-Mel2 cells were shown to significantly expose the negatively charged lipid phosphatidylserine on their plasma membranes, showing they are successfully targeted by RDP22. The peptide was able to induce cell death in MUG-Mel2 2D and 3D cultures, where it was able to kill tumor cells even inside the core of tumor spheroids or inside a melanoma organotypic model. In vitro studies indicated cell death by apoptosis upon peptide treatment with an LC50 of 8.5 µM and seven-fold specificity for the melanoma cell line MUG-Mel2 over normal dermal fibroblasts. In vivo studies in mice xenografts revealed effective tumor regression upon intratumoral peptide injection, indicated by the strong clearance of pigmented tumor cells and tremendous reduction in tumor size and proliferation, which was determined histologically. The peptide RDP22 has clearly shown high potential against the melanoma cell line MUG-Mel2 in vitro and in vivo.