Factors Affecting Recurrence and Survival for Patients with High-Risk Stage II Melanoma.

BACKGROUND: In the current era of effective adjuvant therapies and de-escalation of surgery, distinguishing which patients with high-risk stage II melanoma are at increased risk of recurrence after excision of the primary lesion is essential to determining appropriate treatment and surveillance plans. METHODS: A single-center retrospective study analyzed patients with stage IIB or IIC melanoma. Demographic and tumor data were collected, and genomic analysis of formalin-fixed, paraffin-embedded tissue samples was performed via an internal next-generation sequencing (NGS) platform (SNaPshot). The end points examined were relapse-free survival (RFS), distant metastasis-free survival (DMFS), overall survival (OS), and melanoma-specific survival (MSS). Uni- and multivariable Cox regressions were performed to calculate the hazard ratios. RESULTS: The study included 92 patients with a median age of 69 years and a male/female ratio of 2:1. A Breslow depth greater than 4 mm, a higher mitotic rate, an advanced T stage, and a KIT mutation had a negative impact on RFS. A primary lesion in the head and neck, a mitotic rate exceeding 10 mitoses per mm2, a CDH1 mutation, or a KIT mutation was significantly associated with a shorter DMFS. Overall survival was significantly lower with older age at diagnosis and a higher mitotic rate. An older age at diagnosis also had a negative impact on MSS. CONCLUSION: Traditional histopathologic factors and specific tumor mutations displayed a significant correlation with disease recurrence and survival for patients with high-risk stage II melanoma. This study supported the use of genomic testing of high-risk stage II melanomas for prognostic prediction and risk stratification.

Factors associated with skeletal-related events in patients with bone metastatic melanoma: A retrospective study of 481 patients.

OBJECTIVES: Metastatic bone disease is estimated to develop in up to 17% of patients with melanoma, compromising skeleton integrity resulting in skeletal-related events (SREs), which impair quality of life and reduce survival. The objective of the study was to investigate (1) the proportion of melanoma patients developing SREs following diagnosis of bone metastasis and (2) the predictors for SREs in this patient cohort. METHODS: Four hundred and eighty-one patients with bone metastatic melanoma from two tertiary centers in the United States from 2008 to 2018 were included. The primary outcome was 90-day and 1-year occurrence of a SRE, including pathological fractures of bones, cord compression, hypercalcemia, radiotherapy, and surgery. Fine-Gray regression analysis was performed for overall SREs and pathological fracture, with death as a competing risk. RESULTS: By 1-year, 52% (258/481) of patients experienced SREs, and 28% (137/481) had a pathological fracture. At 90-day, lytic lesions, bone pain, elevated calcium and absolute lymphocyte, and decreased albumin and hemoglobin were associated with higher SRE risk. The same factors, except for decreased hemoglobin, were shown to predict development of SREs at 1-year. CONCLUSION: The high incidence of SREs and pathological fractures warrants vigilance using the identified factors in this study and preventative measures during clinical oncological care.

Increased risk of cutaneous immune-related adverse events in patients treated with talimogene laherparepvec and immune checkpoint inhibitors: A multi-hospital cohort study.

BACKGROUND: Previous studies have shown that combining immune checkpoint inhibitors (ICIs) with talimogene laherparepvec (TVEC) may improve antitumor responses. However, the risk of developing cutaneous immune-related adverse events (cirAEs) in patients treated with ICI and TVEC has not been studied. OBJECTIVE: To evaluate the differences in cirAE development between patients treated with ICI alone and both ICI and TVEC (ICI + TVEC). METHODS: Patients with cutaneous malignancy receiving ICI with or without TVEC therapy at the Massachusetts General Brigham healthcare system were included. CirAE development, time from ICI initiation to cirAE, cirAE grade, cirAE morphology, and survival were analyzed. Pearson's χ2 test or Fisher's exact test for categorical variables and t test or Kruskal-Wallis test for continuous variables were used. To account for immortal time bias, we performed adjusted time-varying Cox proportional hazards modeling. RESULTS: The rate of cirAE development was 32.3% and 38.7% for ICI only and ICI + TVEC, respectively. After adjusting for covariates, ICI + TVEC was associated with a 2-fold increased risk of cirAE development (hazard ratio: 2.03, P = .006) compared to patients receiving ICI therapy alone. LIMITATIONS: The retrospective nature and limited sample size from a tertiary-level academic center. CONCLUSION: These findings underscore potential opportunities for dermatologists and oncologists in counseling and monitoring patients.

Mixed Response to Immunotherapy in Patients with Metastatic Melanoma.

BACKGROUND: Immunotherapy has improved overall survival in metastatic melanoma. Response to therapy can be difficult to evaluate as the traditionally used RECIST 1.1 criteria do not capture heterogeneous responses. Here we describe the clinical characterization of melanoma patients with a clinically defined mixed response to immunotherapy. METHODS: This was a single institution, retrospective analysis of stage IV melanoma patients who received first-line anti-CTLA-4, anti-PD1, or combination anti-CTLA-4/anti-PD1. Therapy response was assessed via clinical definitions, which consisted of cross-sectional imaging combined with clinical exam. Course of disease, clinicopathological characteristics, and management in patients with a mixed clinical response were analyzed. RESULTS: In 292 patients (anti-CTLA4 = 63; anti-PD1 = 148, anti-CTLA4/anti-PD1 = 81), 103 were responders (35%), 64 mixed responders (22%), and 125 patients had progressive disease (43%). Of patients with a mixed response, 56% eventually had response to therapy (mixed response followed by response, MR-R), while 31% progressed on therapy (MR-NR). MR-NR patients had higher median LDH (p < 0.01), 3 or more organ sites with metastases (p < 0.01), and more frequently had M1d disease (p < 0.01). Mixed responders who underwent surgery (n = 20) had a significantly longer mean OS compared to patients who did not undergo surgery (6.9 years, 95% CI 6.2-7.6 vs. 6.0 years, 95% CI 4.6-7.3, p = 0.02). DISCUSSION: Mixed response to immunotherapy in metastatic melanoma was not uncommon in our cohort (22%). Clinical characteristics associated with progression of disease after initial mixed response included higher LDH, brain metastases, and ≥ 3 organ sites with metastases. Surgical treatment for highly selected patients with a mixed response was associated with improved outcomes.

Activity-dependent phosphorylation of MeCP2 threonine 308 regulates interaction with NCoR.

Rett syndrome (RTT) is an X-linked human neurodevelopmental disorder with features of autism and severe neurological dysfunction in females. RTT is caused by mutations in methyl-CpG-binding protein 2 (MeCP2), a nuclear protein that, in neurons, regulates transcription, is expressed at high levels similar to that of histones, and binds to methylated cytosines broadly across the genome. By phosphotryptic mapping, we identify three sites (S86, S274 and T308) of activity-dependent MeCP2 phosphorylation. Phosphorylation of these sites is differentially induced by neuronal activity, brain-derived neurotrophic factor, or agents that elevate the intracellular level of 3',5'-cyclic AMP (cAMP), indicating that MeCP2 may function as an epigenetic regulator of gene expression that integrates diverse signals from the environment. Here we show that the phosphorylation of T308 blocks the interaction of the repressor domain of MeCP2 with the nuclear receptor co-repressor (NCoR) complex and suppresses the ability of MeCP2 to repress transcription. In knock-in mice bearing the common human RTT missense mutation R306C, neuronal activity fails to induce MeCP2 T308 phosphorylation, suggesting that the loss of T308 phosphorylation might contribute to RTT. Consistent with this possibility, the mutation of MeCP2 T308A in mice leads to a decrease in the induction of a subset of activity-regulated genes and to RTT-like symptoms. These findings indicate that the activity-dependent phosphorylation of MeCP2 at T308 regulates the interaction of MeCP2 with the NCoR complex, and that RTT in humans may be due, in part, to the loss of activity-dependent MeCP2 T308 phosphorylation and a disruption of the phosphorylation-regulated interaction of MeCP2 with the NCoR complex.

A bird's-eye view of MeCP2 binding.

In this issue of Molecular Cell, work from Skene, Bird, and colleagues reexamines MeCP2 function in the brain by characterizing the abundance and distribution of MeCP2 protein in mouse neurons and its role in regulating chromatin structure (Skene et al., 2010).

The Role of Surgery for Melanoma in an Era of Effective Systemic Therapy.

PURPOSE OF REVIEW: The recent discovery of effective systemic treatments for melanoma has dramatically improved the prognosis for patients with advanced disease. As a result, the multidisciplinary management of melanoma has evolved significantly. In the past decades surgery was reserved for symptomatic palliation in patients with metastatic melanoma. Today surgical treatment of patients responding to systemic therapies has become an integral part of disease control. RECENT FINDINGS: Current efforts are focused on minimizing the morbidity of surgery (laparoscopic inguinal lymph node dissection, selective completion lymphadenectomy) as well as combining surgery with systemic therapy in novel ways (neoadjuvant targeted and/or immunotherapy, isolated limb infusion/perfusion with systemic immunotherapy). This review examines the use of surgery for advanced melanoma in the era predating modern systemic therapy as well as potential applications moving forward.

MeCP2 phosphorylation limits psychostimulant-induced behavioral and neuronal plasticity.

The methyl-DNA binding protein MeCP2 is emerging as an important regulator of drug reinforcement processes. Psychostimulants induce phosphorylation of MeCP2 at Ser421; however, the functional significance of this posttranslational modification for addictive-like behaviors was unknown. Here we show that MeCP2 Ser421Ala knock-in mice display both a reduced threshold for the induction of locomotor sensitization by investigator-administered amphetamine and enhanced behavioral sensitivity to the reinforcing properties of self-administered cocaine. These behavioral differences were accompanied in the knock-in mice by changes in medium spiny neuron intrinsic excitability and nucleus accumbens gene expression typically observed in association with repeated exposure to these drugs. These data show that phosphorylation of MeCP2 at Ser421 functions to limit the circuit plasticities in the nucleus accumbens that underlie addictive-like behaviors.

Defining clinically useful biomarkers of immune checkpoint inhibitors in solid tumours.

Although more than a decade has passed since the approval of immune checkpoint inhibitors (ICIs) for the treatment of melanoma and non-small-cell lung, breast and gastrointestinal cancers, many patients still show limited response. US Food and Drug Administration (FDA)-approved biomarkers include programmed cell death 1 ligand 1 (PDL1) expression, microsatellite status (that is, microsatellite instability-high (MSI-H)) and tumour mutational burden (TMB), but these have limited utility and/or lack standardized testing approaches for pan-cancer applications. Tissue-based analytes (such as tumour gene signatures, tumour antigen presentation or tumour microenvironment profiles) show a correlation with immune response, but equally, these demonstrate limited efficacy, as they represent a single time point and a single spatial assessment. Patient heterogeneity as well as inter- and intra-tumoural differences across different tissue sites and time points represent substantial challenges for static biomarkers. However, dynamic biomarkers such as longitudinal biopsies or novel, less-invasive markers such as blood-based biomarkers, radiomics and the gut microbiome show increasing potential for the dynamic identification of ICI response, and patient-tailored predictors identified through neoadjuvant trials or novel ex vivo tumour models can help to personalize treatment. In this Perspective, we critically assess the multiple new static, dynamic and patient-specific biomarkers, highlight the newest consortia and trial efforts, and provide recommendations for future clinical trials to make meaningful steps forwards in the field.

PDGFRß Signaling Cooperates with ß-Catenin to Modulate c-Abl and Biologic Behavior of Desmoid-Type Fibromatosis.

PURPOSE: This study sought to identify ß-catenin targets that regulate desmoid oncogenesis and determine whether external signaling pathways, particularly those inhibited by sorafenib (e.g., PDGFRß), affect these targets to alter natural history or treatment response in patients. EXPERIMENTAL DESIGN: In vitro experiments utilized primary desmoid cell lines to examine regulation of ß-catenin targets. Relevance of results was assessed in vivo using Alliance trial A091105 correlative biopsies. RESULTS: CTNNB1 knockdown inhibited hypoxia-regulated gene expression in vitro and reduced levels of HIF1α protein. ChIP-seq identified ABL1 as a ß-catenin transcriptional target that modulated HIF1α and desmoid cell proliferation. Abrogation of either CTNNB1 or HIF1A inhibited desmoid cell-induced VEGFR2 phosphorylation and tube formation in endothelial cell co-cultures. Sorafenib inhibited this activity directly but also reduced HIF1α protein expression and c-Abl activity while inhibiting PDGFRß signaling in desmoid cells. Conversely, c-Abl activity and desmoid cell proliferation were positively regulated by PDGF-BB. Reduction in PDGFRß and c-Abl phosphorylation was commonly observed in biopsy samples from patients after treatment with sorafenib; markers of PDGFRß/c-Abl pathway activation in baseline samples were associated with tumor progression in patients on the placebo arm and response to sorafenib in patients receiving treatment. CONCLUSIONS: The ß-catenin transcriptional target ABL1 is necessary for proliferation and maintenance of HIF1α in desmoid cells. Regulation of c-Abl activity by PDGF signaling and targeted therapies modulates desmoid cell proliferation, thereby suggesting a reason for variable biologic behavior between tumors, a mechanism for sorafenib activity in desmoids, and markers predictive of outcome in patients.

Cancer immunotherapy responses persist after lymph node resection.

Surgical removal of lymph nodes (LNs) to prevent metastatic recurrence, including sentinel lymph node biopsy (SLNB) and completion lymph node dissection (CLND), are performed in routine practice. However, it remains controversial whether removing LNs which are critical for adaptive immune responses impairs immune checkpoint blockade (ICB) efficacy. Here, our retrospective analysis demonstrated that stage III melanoma patients retain robust response to anti-PD1 inhibition after CLND. Using orthotopic murine mammary carcinoma and melanoma models, we show that responses to ICB persist in mice after TDLN resection. Mechanistically, after TDLN resection, antigen can be re-directed to distant LNs, which extends the responsiveness to ICB. Strikingly, by evaluating head and neck cancer patients treated by neoadjuvant durvalumab and irradiation, we show that distant LNs (metastases-free) remain reactive in ICB responders after tumor and disease-related LN resection, hence, persistent anti-cancer immune reactions in distant LNs. Additionally, after TDLN dissection in murine models, ICB delivered to distant LNs generated greater survival benefit, compared to systemic administration. In complete responders, anti-tumor immune memory induced by ICB was systemic rather than confined within lymphoid organs. Based on these findings, we constructed a computational model to predict free antigen trafficking in patients that will undergo LN dissection.

Phosphorylation of MeCP2 at Ser421 contributes to chronic antidepressant action.

Although tricyclic antidepressants rapidly activate monoaminergic neurotransmission, these drugs must be administered chronically to alleviate symptoms of depression. This observation suggests that molecular mechanisms downstream of monoamine receptor activation, which include the induction of gene transcription, underlie chronic antidepressant-induced changes in behavior. Here we show that methyl-CpG-binding protein 2 (MeCP2) regulates behavioral responses to chronic antidepressant treatment. Imipramine administration induces phosphorylation of MeCP2 at Ser421 (pMeCP2) selectively in the nucleus accumbens and the lateral habenula, two brain regions important for depressive-like behaviors. To test the role of pMeCP2 in depressive-like behaviors, we used male mice that bear a germ-line mutation knocked into the X-linked Mecp2 locus that changes Ser421 to a nonphosphorylatable Ala residue (S421A). MeCP2 S421A knock-in (KI) mice showed increased immobility in forced-swim and tail-suspension tests compared with their wild-type (WT) littermates. However, immobility of both MeCP2 WT and KI mice in forced swim was reduced by acute administration of imipramine, demonstrating that loss of pMeCP2 does not impair acute pharmacological sensitivity to this drug. After chronic social defeat stress, chronic administration of imipramine significantly improved social interaction in the MeCP2 WT mice. In contrast, the MeCP2 KI mice did not respond to chronic imipramine administration. These data suggest novel roles for pMeCP2 in the sensitivity to stressful stimuli and demonstrate that pMeCP2 is required for the effects of chronic imipramine on depressive-like behaviors induced by chronic social defeat stress.

Impact of supraphysiologic MDM2 expression on chromatin networks and therapeutic responses in sarcoma.

Amplification of MDM2 on supernumerary chromosomes is a common mechanism of P53 inactivation across tumors. Here, we investigated the impact of MDM2 overexpression on chromatin, gene expression, and cellular phenotypes in liposarcoma. Three independent regulatory circuits predominate in aggressive, dedifferentiated tumors. RUNX and AP-1 family transcription factors bind mesenchymal gene enhancers. P53 and MDM2 co-occupy enhancers and promoters associated with P53 signaling. When highly expressed, MDM2 also binds thousands of P53-independent growth and stress response genes, whose promoters engage in multi-way topological interactions. Overexpressed MDM2 concentrates within nuclear foci that co-localize with PML and YY1 and could also contribute to P53-independent phenotypes associated with supraphysiologic MDM2. Importantly, we observe striking cell-to-cell variability in MDM2 copy number and expression in tumors and models. Whereas liposarcoma cells are generally sensitive to MDM2 inhibitors and their combination with pro-apoptotic drugs, MDM2-high cells tolerate them and may underlie the poor clinical efficacy of these agents.

Ultrasensitive Detection of Circulating LINE-1 ORF1p as a Specific Multicancer Biomarker.

Improved biomarkers are needed for early cancer detection, risk stratification, treatment selection, and monitoring treatment response. Although proteins can be useful blood-based biomarkers, many have limited sensitivity or specificity for these applications. Long INterspersed Element-1 (LINE-1) open reading frame 1 protein (ORF1p) is a transposable element protein overexpressed in carcinomas and high-risk precursors during carcinogenesis with negligible expression in normal tissues, suggesting ORF1p could be a highly specific cancer biomarker. To explore ORF1p as a blood-based biomarker, we engineered ultrasensitive digital immunoassays that detect mid-attomolar (10-17 mol/L) ORF1p concentrations in plasma across multiple cancers with high specificity. Plasma ORF1p shows promise for early detection of ovarian cancer, improves diagnostic performance in a multianalyte panel, provides early therapeutic response monitoring in gastroesophageal cancers, and is prognostic for overall survival in gastroesophageal and colorectal cancers. Together, these observations nominate ORF1p as a multicancer biomarker with potential utility for disease detection and monitoring. SIGNIFICANCE: The LINE-1 ORF1p transposon protein is pervasively expressed in many cancers and is a highly specific biomarker of multiple common, lethal carcinomas and their high-risk precursors in tissue and blood. Ultrasensitive ORF1p assays from as little as 25 µL plasma are novel, rapid, cost-effective tools in cancer detection and monitoring. See related commentary by Doucet and Cristofari, p. 2502. This article is featured in Selected Articles from This Issue, p. 2489.

Brain-specific phosphorylation of MeCP2 regulates activity-dependent Bdnf transcription, dendritic growth, and spine maturation.

Mutations or duplications in MECP2 cause Rett and Rett-like syndromes, neurodevelopmental disorders characterized by mental retardation, motor dysfunction, and autistic behaviors. MeCP2 is expressed in many mammalian tissues and functions as a global repressor of transcription; however, the molecular mechanisms by which MeCP2 dysfunction leads to the neural-specific phenotypes of RTT remain poorly understood. Here, we show that neuronal activity and subsequent calcium influx trigger the de novo phosphorylation of MeCP2 at serine 421 (S421) by a CaMKII-dependent mechanism. MeCP2 S421 phosphorylation is induced selectively in the brain in response to physiological stimuli. Significantly, we find that S421 phosphorylation controls the ability of MeCP2 to regulate dendritic patterning, spine morphogenesis, and the activity-dependent induction of Bdnf transcription. These findings suggest that, by triggering MeCP2 phosphorylation, neuronal activity regulates a program of gene expression that mediates nervous system maturation and that disruption of this process in individuals with mutations in MeCP2 may underlie the neural-specific pathology of RTT.

Continued Improvement in Rectal Cancer Survival Outcomes Will Require True Multidisciplinary Treatment Approaches.

The management of rectal cancer has undergone a significant paradigm shift, with an increased interest in the utilization of all tools in our current armamentarium of fighting it: chemotherapy, radiotherapy and surgery. Research is also underway in deciding on the best sequence for these treatments. In this review, we provide an update on some of this important work.

Plasma-derived extracellular vesicle analysis and deconvolution enable prediction and tracking of melanoma checkpoint blockade outcome.

Immune checkpoint inhibitors (ICIs) show promise, but most patients do not respond. We identify and validate biomarkers from extracellular vesicles (EVs), allowing non-invasive monitoring of tumor- intrinsic and host immune status, as well as a prediction of ICI response. We undertook transcriptomic profiling of plasma-derived EVs and tumors from 50 patients with metastatic melanoma receiving ICI, and validated with an independent EV-only cohort of 30 patients. Plasma-derived EV and tumor transcriptomes correlate. EV profiles reveal drivers of ICI resistance and melanoma progression, exhibit differentially expressed genes/pathways, and correlate with clinical response to ICI. We created a Bayesian probabilistic deconvolution model to estimate contributions from tumor and non-tumor sources, enabling interpretation of differentially expressed genes/pathways. EV RNA-seq mutations also segregated ICI response. EVs serve as a non-invasive biomarker to jointly probe tumor-intrinsic and immune changes to ICI, function as predictive markers of ICI responsiveness, and monitor tumor persistence and immune activation.

Apoptosis, axonal growth defects, and degeneration of peripheral neurons in mice lacking CREB.

CRE-binding protein (CREB) belongs to a family of transcription factors that mediates stimulus-dependent gene expression in neuronal and non-neuronal cells. Here we show that CREB is phosphorylated on its transcriptional regulatory site, Ser-133, in vivo in a neurotrophin-dependent manner. In mice harboring a null mutation in the Creb gene, sensory neurons exhibit excess apoptosis and degeneration, and display impaired axonal growth and projections. Interestingly, excess apoptosis is not observed in the central nervous system. CREB is required within sensory and sympathetic neurons for survival and axon extension since both of these neurotrophin-dependent processes are compromised in cultured neurons from CREB null mice. Thus, during their period of neurotrophin dependency, peripheral neurons require CREB-mediated gene expression for both survival and growth in vivo.