A lactate-SREBP2 signaling axis drives tolerogenic dendritic cell maturation and promotes cancer progression.

Conventional dendritic cells (DCs) are essential mediators of antitumor immunity. As a result, cancers have developed poorly understood mechanisms to render DCs dysfunctional within the tumor microenvironment (TME). After identification of CD63 as a specific surface marker, we demonstrate that mature regulatory DCs (mregDCs) migrate to tumor-draining lymph node tissues and suppress DC antigen cross-presentation in trans while promoting T helper 2 and regulatory T cell differentiation. Transcriptional and metabolic studies showed that mregDC functionality is dependent on the mevalonate biosynthetic pathway and its master transcription factor, SREBP2. We found that melanoma-derived lactate activates SREBP2 in tumor DCs and drives conventional DC transformation into mregDCs via homeostatic or tolerogenic maturation. DC-specific genetic silencing and pharmacologic inhibition of SREBP2 promoted antitumor CD8+ T cell activation and suppressed melanoma progression. CD63+ mregDCs were found to reside within the lymph nodes of several preclinical tumor models and in the sentinel lymph nodes of patients with melanoma. Collectively, this work suggests that a tumor lactate-stimulated SREBP2-dependent program promotes CD63+ mregDC development and function while serving as a promising therapeutic target for overcoming immune tolerance in the TME.

Efficacy and Safety of the Melphalan/Hepatic Delivery System in Patients with Unresectable Metastatic Uveal Melanoma: Results from an Open-Label, Single-Arm, Multicenter Phase 3 Study.

BACKGROUND: Uveal melanoma (UM) has a poor prognosis once liver metastases occur. The melphalan/Hepatic Delivery System (melphalan/HDS) is a drug/device combination used for liver-directed treatment of metastatic UM (mUM) patients. The purpose of the FOCUS study was to assess the efficacy and safety of melphalan/HDS in patients with unresectable mUM. METHODS: Eligible patients with mUM received treatment with melphalan (3.0 mg/kg ideal body weight) once every 6 to 8 weeks for a maximum of six cycles. The primary end point was the objective response rate (ORR). The secondary end points included duration of response (DOR), overall survival (OS), and progression-free survival (PFS). RESULTS: The study enrolled 102 patients with mUM. Treatment was attempted in 95 patients, and 91 patients received treatment. In the treated population (n = 91), the ORR was 36.3 % (95 % confidence interval [CI], 26.44-47.01), including 7.7 % of patients with a complete response. Thus, the study met its primary end point because the lower bound of the 95 % CI for ORR exceeded the upper bound (8.3 %) from the benchmark meta-analysis. The median DOR was 14 months, and the median OS was 20.5 months, with an OS of 80 % at 1 year. The median PFS was 9 months, with a PFS of 65 % at 6 months. The most common serious treatment-emergent adverse events were thrombocytopenia (15.8 %) and neutropenia (10.5 %), treated mostly on an outpatient basis with observation. No treatment-related deaths were observed. CONCLUSION: Treatment with melphalan/HDS provides a clinically meaningful response rate and demonstrates a favorable benefit-risk profile in patients with unresectable mUM (study funded by Delcath; ClinicalTrials.gov identifier: NCT02678572; EudraCT no. 2015-000417-44).

Articles from 2022 to 2023 to Inform Your Cancer Practice: Melanoma.

Modern effective systemic therapy for melanoma includes two important classes of treatment: immune checkpoint inhibitors (ICIs), comprising inhibitors of cytotoxic T-lymphocyte antigen 4, programmed cell death receptor 1, and lymphocyte-activation gene 3; and small molecule BRAF/MEK inhibitor therapy. These treatments have revolutionized the management of patients with advanced melanoma and have dramatically improved clinical outcomes. The melanoma treatment landscape continues to evolve as outcome data from completed trials continue to mature and as newer studies begin to report data. In 2022 and 2023, longer-term follow-up data for established single-agent ICI therapy has been published improving our understanding of both efficacy and durability of treatment responses. A trial of a novel combination ICI therapy has demonstrated enhanced efficacy, and a study examining the order/sequence of ICI therapy versus BRAF/MEK inhibitor therapy for first-line treatment of metastatic melanoma showed that survival is improved when patients start with ICI therapy. As the indications for these therapies have expanded to the adjuvant and neoadjuvant space, we also saw the publication of 5-year results of adjuvant therapy in resected stage III patients, new data on the role of adjuvant therapy in resected stage IIB and IIC patients, and, finally, a practice-changing trial demonstrating improved outcomes using a neoadjuvant approach for patients with macroscopic disease amenable to surgical resection. In this article, we review these articles and highlight key elements for surgical oncologists.

At the Intersection of Intersectionality: Race and Gender Diversity Among Surgical Faculty and Trainees.

OBJECTIVE: To compare the representation of intersectional (ie, racial/ethnic and gender) identities among surgical faculty versus medical students. BACKGROUND: Health disparities are pervasive in medicine, but diverse physicians may help the medical profession achieve health equity. METHODS: Data from the Association of American Medical Colleges for 140 programs (2011/2012-2019/2020) were analyzed for students and full-time surgical faculty. Underrepresented in medicine (URiM) was defined as Black/African American, American Indian/Alaskan Native, Hispanic/Latino/Spanish Origin, or Native Hawaiian/Other Pacific Islander. Non-White included URiM plus Asian, multiracial, and non-citizen permanent residents. Linear regression was used to estimate the association of year and proportions of URiM and non-White female and male faculty with proportions of URiM and non-White students. RESULTS: Medical students were comprised of more White (25.2% vs 14.4%), non-White (18.8% vs 6.6%), and URiM (9.6% vs 2.8%) women and concomitantly fewer men across all groups versus faculty (all P < 0.01). Although the proportion of White and non-White female faculty increased over time (both P ≤ 0.001), there was no significant change among non-White URiM female faculty, nor among non-White male faculty, regardless of whether they were URiM or not. Having more URiM male faculty was associated with having more non-White female students (estimate = +14.5% students/100% increase in faculty, 95% CI: 1.0% to 8.1%, P = 0.04), and this association was especially pronounced for URiM female students (estimate = +46.6% students/100% increase in faculty, 95% CI: 36.9% to 56.3%, P < 0.001). CONCLUSIONS: URiM faculty representation has not improved despite a positive association between having more URiM male faculty and having more diverse students.

Racial, Ethnic, and Gender Diversity Among Academic Surgical Leaders in the US.

Importance: Surgical department chairs remain conspicuously nondiverse despite the recognized importance of diverse physician workforces. However, the extent of diversity among non-chair leadership remains underexplored. Objective: To evaluate racial, ethnic, and gender diversity of surgical department chairs, vice chairs (VCs), and division chiefs (DCs) in the US. Design, Setting, and Participants: For this cross-sectional study, publicly accessible medical school and affiliated hospital websites in the US and Puerto Rico were searched from January 15 to July 15, 2022, to collect demographic and leadership data about surgical faculty. Two independent reviewers abstracted demographic data, with up to 2 additional reviewers assisting with coding resolution as necessary. In all, 2165 faculty were included in the analyses. Main Outcomes and Measures: Proportions of racial, ethnic, and gender diversity among chairs, VCs, and DCs in general surgery and 5 surgical specialties (neurosurgery, obstetrics and gynecology, ophthalmology, orthopedics, and otolaryngology). Results: A total of 2165 faculty (1815 males [83.8%] and 350 females [16.2%]; 109 [5.0%] African American or Black individuals; 347 [16.0%] Asian individuals; 83 [3.8%] Hispanic, Latino, or individuals of Spanish origin; and 1624 [75.0%] White individuals as well as 2 individuals [0.1%] of other race or ethnicity) at 154 surgical departments affiliated with 146 medical schools in the US and Puerto Rico were included in the analysis. There were more males than females in leadership positions at all levels-chairs (85.9% vs 14.1%), VCs (68.4% vs 31.6%), and DCs (87.1% vs 12.9%)-and only 192 leaders (8.9%) were from racial or ethnic groups that are underrepresented in medicine (URiM). Females occupied more VC than chair or DC positions both overall (31.6% vs 14.1% and 12.9%, respectively) and within racial and ethnic groups (African American or Black females, 4.0% VC vs 1.5% chair and 0.6% DC positions; P < .001). URiM individuals were most commonly VCs of diversity, equity, and inclusion (DEI, 51.6%) or faculty development (17.9%). Vice chairs of faculty development were split equally between males and females, while 64.5% of VCs for DEI were female. All other VCs were predominantly male. Among DC roles, URiM representation was greatest in transplant surgery (13.8%) and lowest in oral and maxillofacial surgery (5.0%). Except for breast and endocrine surgery (63.6% female), females comprised less than 20% of DC roles. Nearly half of DCs (6 of 13 [46.2%]) and VCs (4 of 9 [44.4%]) had no female URiM leaders, and notably, no American Indian, Alaska Native, or Native Hawaiian or Other Pacific Islander individuals were identified in any surgical leadership positions. Conclusions and Relevance: While it is unclear whether promotion from VC to chair or from DC to chair is more likely, these findings of similar gender distribution between chairs and DCs suggest the latter and may partially explain persistent nondiversity among surgical chairs. Female and URiM surgical leaders are disproportionately clustered in roles (eg, VCs of DEI or faculty development) that may not translate into future promotion to department chairs.

Functional reprogramming of peripheral blood monocytes by soluble mediators in patients with pancreatic cancer and intraductal papillary mucinous neoplasms.

Background: Monocytes and monocyte-derived tumor infiltrating cells have been implicated in the immunosuppression and immune evasion associated with pancreatic adenocarcinoma (PDAC). Yet, precisely how monocytes in the periphery and tumor microenvironment in patients with intraductal papillary mucinous neoplasm (IPMN), a precursor lesion to PDAC, change during disease progression has not been defined. Here we functionally profiled the peripheral immune system and characterized the tumor microenvironment of patients with both IPMN and PDAC. We also tested if sera from patients with IPMN and PDAC functionally reprogram monocytes relative to that of healthy donors. Methods: Pancreatic tissue and peripheral blood were collected at the time of resection from 16 patients with IPMN and 32 patients with PDAC. Peripheral blood and pancreatic tissue/tumor were immunophenotyped using flow cytometry. Whole blood was plated and incubated with R848 (a TLR 7/8 agonist) or LPS (a TLR4 agonist) for 6 hours and TNF expression in monocytes was measured by flow cytometry to measure monocyte activation. To test if TLR sensitivity is determined by factors in patient sera, we preconditioned healthy donor monocytes in serum from PDAC (n=23), IPMN (n=15), or age-matched healthy donors (n=10) followed by in vitro stimulation with R848 or LPS and multiplex cytokine measurements in the supernatant. Results: TNF expression in R848-stimulated peripheral blood monocytes was higher in patients with low grade vs high grade IPMN (65% vs 32%, p = 0.03) and stage 1 vs stage 2/3 PDAC (58% vs 42%, p = 0.03), this was not observed after LPS stimulation. TLR activation correlated with increasing grade of dysplasia from low grade IPMN to high grade IPMN. Serum from patients with IPMN and PDAC recapitulated suppression of TNF induction after R848 stimulation in naïve, healthy donor monocytes. Conclusion: Peripheral blood monocyte TNF secretion inversely correlates with the degree of dysplasia in IPMN and cancer stage in PDAC, suggesting innate immune reprogramming as IPMNs progress to invasive disease. These effects are, at least in part, mediated by soluble mediators in sera.

Timing of Adjuvant Immunotherapy in Stage III Melanoma, Does it Matter?

BACKGROUND: The optimal time to initiate adjuvant immune checkpoint inhibitors (ICI) following resection remains undefined. Herein, we investigated the impact of time to adjuvant ICI on survival in patients with stage III melanoma. METHODS: Patients with resected stage III melanoma receiving adjuvant immune therapy were identified within a multi-institutional retrospective cohort. Patients were stratified by time to adjuvant ICI: within 6 weeks, 6-12 weeks, and greater than 12 weeks from surgery. Recurrence-free survival (RFS) was compared among time strata with Kaplan-Meier and Cox proportional hazards methods in the multi-institutional cohort. RESULTS: Altogether, 626 patients were identified within the multi-institutional cohort: 39% of patients initiated adjuvant ICI within 6 weeks, 42.2% within 6-12 weeks, and 18.8% greater than 12 weeks from surgery. In a multivariate Cox model, adjusting for histology, nodal tumor burden, and pathologic stage, we found that increased time to adjuvant ICI was associated with improved RFS. Patients who initiated adjuvant ICI within 6 weeks of surgery had worse RFS. These findings were preserved in a conditional landmark analysis and separate subgroups of patients with (1) new melanoma diagnoses, (2) occult stage III disease, and (3) those receiving anti-PD-1 monotherapy. CONCLUSIONS: Outcomes for patients with stage III melanoma are not compromised when adjuvant ICI is initiated beyond 6 weeks from resection. Additional work is needed to better understand the underlying mechanisms and implications of timing of adjuvant ICI on long-term outcomes.

Survey Study of Clerkship Curriculum on Learner's Choice to Pursue Surgery: Positive Impact of Extracurricular Opportunities.

OBJECTIVE: Prior studies have focused on the role of the learning environment on students' decisions to pursue surgery, but few have analyzed the impact of the clerkship curriculum. This study assessed surgical clerkship curricula across United States (US) medical schools and their impact on students' likelihood of pursuing a surgical residency. DESIGN: A cross-sectional survey was developed to assess surgery clerkship characteristics. Questions included clerkship duration, number of offered and required surgical services, method of service assignment, and number of advanced clinical electives (e.g., fourth-year sub-internships) and additional surgical clinical opportunities (e.g., surgical elective rotations). Survey results were merged by the Association of American Medical Colleges with the percentages of students who matched into a surgical specialty. Linear regression models estimated the association of covariates with the percentage of students who (1) matched in surgical specialties, (2) were interested in surgery at medical school matriculation and ultimately matched into surgical residency (retention rate), and (3) were not interested in surgery at medical school matriculation but ultimately matched into surgical residency (recruitment rate). SETTING: The survey was distributed to clerkship directors and coordinators at 66 medical schools through the Association for Surgical Education (ASE) from 5/1/2021 to 8/1/2021. PARTICIPANTS: All US medical schools in the ASE. RESULTS: A total of 21 medical schools responded (34.8% response rate). The overall retention rate was 36.4%, and the overall recruitment rate was 25.0%. Clerkships were 4 to 12 weeks. In 81% of programs, students submitted preferences and were assigned services. The percentage of students applying to surgical specialties was not associated with clerkship duration (p=0.79) or the number of required services (p=0.15), subspecialty services offered (p=0.33), or advanced clinical electives (p=0.24) but was associated with a program's having additional surgical clinical opportunities (p=0.02). Most of these factors were not associated with retention or recruitment rates. CONCLUSIONS: Offering more extracurricular surgical clinical opportunities was associated with having more students pursue surgical careers. Though limited by a relatively small sample size, our findings suggest that having shorter clerkships or limited subspecialty offerings may not have a significant influence on students' career choices.

A SREBF2-dependent gene program drives an immunotolerant dendritic cell population during cancer progression.

Dendritic cells (cDCs) are essential mediators of anti-tumor immunity. Cancers have developed mechanisms to render DCs dysfunctional within the tumor microenvironment. Utilizing CD63 as a unique surface marker, we demonstrate that mature regulatory DCs (mregDCs) suppress DC antigen cross-presentation while driving T H 2 and regulatory T cell differentiation within tumor-draining lymph node tissues. Transcriptional and metabolic studies show that mregDC functionality is dependent upon the mevalonate biosynthetic pathway and the master transcription factor, SREBP2. Melanoma-derived lactate activates DC SREBP2 in the tumor microenvironment (TME) and drives mregDC development from conventional DCs. DC-specific genetic silencing and pharmacologic inhibition of SREBP2 promotes anti-tumor CD8 + T cell activation and suppresses melanoma progression. CD63 + mregDCs reside within the sentinel lymph nodes of melanoma patients. Collectively, this work describes a tumor-driven SREBP2-dependent program that promotes CD63 + mregDC development and function while serving as a promising therapeutic target for overcoming immune tolerance in the TME. One Sentence Summary: The metabolic transcription factor, SREBF2, regulates the development and tolerogenic function of the mregDC population within the tumor microenvironment.

Intratumor childhood vaccine-specific CD4+ T-cell recall coordinates antitumor CD8+ T cells and eosinophils.

BACKGROUND: Antitumor mechanisms of CD4+ T cells remain crudely defined, and means to effectively harness CD4+ T-cell help for cancer immunotherapy are lacking. Pre-existing memory CD4+ T cells hold potential to be leveraged for this purpose. Moreover, the role of pre-existing immunity in virotherapy, particularly recombinant poliovirus immunotherapy where childhood polio vaccine specific immunity is ubiquitous, remains unclear. Here we tested the hypothesis that childhood vaccine-specific memory T cells mediate antitumor immunotherapy and contribute to the antitumor efficacy of polio virotherapy. METHODS: The impact of polio immunization on polio virotherapy, and the antitumor effects of polio and tetanus recall were tested in syngeneic murine melanoma and breast cancer models. CD8+ T-cell and B-cell knockout, CD4+ T-cell depletion, CD4+ T-cell adoptive transfer, CD40L blockade, assessments of antitumor T-cell immunity, and eosinophil depletion defined antitumor mechanisms of recall antigens. Pan-cancer transcriptome data sets and polio virotherapy clinical trial correlates were used to assess the relevance of these findings in humans. RESULTS: Prior vaccination against poliovirus substantially bolstered the antitumor efficacy of polio virotherapy in mice, and intratumor recall of poliovirus or tetanus immunity delayed tumor growth. Intratumor recall antigens augmented antitumor T-cell function, caused marked tumor infiltration of type 2 innate lymphoid cells and eosinophils, and decreased proportions of regulatory T cells (Tregs). Antitumor effects of recall antigens were mediated by CD4+ T cells, limited by B cells, independent of CD40L, and dependent on eosinophils and CD8+ T cells. An inverse relationship between eosinophil and Treg signatures was observed across The Cancer Genome Atlas (TCGA) cancer types, and eosinophil depletion prevented Treg reductions after polio recall. Pretreatment polio neutralizing antibody titers were higher in patients living longer, and eosinophil levels increased in the majority of patients, after polio virotherapy. CONCLUSION: Pre-existing anti-polio immunity contributes to the antitumor efficacy of polio virotherapy. This work defines cancer immunotherapy potential of childhood vaccines, reveals their utility to engage CD4+ T-cell help for antitumor CD8+ T cells, and implicates eosinophils as antitumor effectors of CD4+ T cells.

Clinical Trials in Melanoma: Margins, Lymph Nodes, Targeted and Immunotherapy.

Multiple randomized controlled trials have influenced the current standard of care for patients with cutaneous melanoma. Since the development of targeted and immune therapy, studies of adjuvant therapy for patients with resected stage III/IV melanoma have led to the approval of combined B-raf proto-oncogene (BRAF) and mitogen-activated protein kinase kinase inhibitors for patients with a BRAF mutation, and cytotoxic T-lymphocyte associated protein-4 or antiprogrammed cell death-1 therapy for patients without a BRAF mutation. This article discusses the details of the trials that have influenced these treatment decisions, in addition to discussing ongoing trials and possible future directions.

Multicenter Experience with Neoadjuvant Therapy in Melanoma Highlights Heterogeneity in Contemporary Practice.

OBJECTIVE: To determine the feasibility and impact of neoadjuvant therapy (NT) in patients who present with advanced melanoma amenable to surgical resection. SUMMARY BACKGROUND DATA: Given current effective systemic therapy for melanoma, the use of NT is being explored in patients with advanced melanoma with disease amenable to surgical resection. METHODS: Prospective data from 3 institutions was obtained in patients with clinically evident Stage III/IV melanoma who underwent NT. The primary objective was to compare recurrence-free survival between patients who had pathologic complete response (pCR) to those with persistent disease. RESULTS: NT was offered to 45 patients, with 43 patients initiating various NT regimens including PD-1 antagonist (PD-1) therapy (N = 16), PD-1 plus ipilimumab (N = 10), BRAF/MEK inhibitor therapy (N = 14), a combination of those three (N = 1), and talimogene laherparepvec (TVEC) (N = 2). Thirty-two (74.1%) patients underwent surgery whereas 11 patients did not undergo surgery for these reasons: clinical CR (N = 7), progressive disease not amenable to resection (N = 3), and ongoing therapy (N = 1). 12 of 32 patients (37.5%) had pCR with these therapies: PD-1 (N = 4), PD-1 plus ipilimumab (N = 2), BRAF/MEK (N = 4), combination (N = 1), and TVEC (N = 1). At median follow-up of 16.4 months there was only 1 recurrence in the pCR group and patients with a pCR had significantly improved recurrence-free survival compared to patients without pCR (p = 0.004). CONCLUSIONS: Despite variability in NT regimens across institutions, NT for melanoma is feasible and associated with improved prognosis in patients who achieve a pCR. Maximizing rates of pCR could improve prognosis for patients with advanced melanoma.

International Center-Level Variation in Utilization of Completion Lymph Node Dissection and Adjuvant Systemic Therapy for Sentinel Lymph Node-Positive Melanoma at Major Referral Centers.

OBJECTIVE: The aim of this study was to determine overall trends and center-level variation in utilization of completion lymph node dissection (CLND) and adjuvant systemic therapy for sentinel lymph node (SLN)-positive melanoma. SUMMARY BACKGROUND DATA: Based on recent clinical trials, management options for SLN-positive melanoma now include effective adjuvant systemic therapy and nodal observation instead of CLND. It is unknown how these findings have shaped practice or how these contemporaneous developments have influenced their respective utilization. METHODS: We performed an international cohort study at 21 melanoma referral centers in Australia, Europe, and the United States that treated adults with SLN-positive melanoma and negative distant staging from July 2017 to June 2019. We used generalized linear and multinomial logistic regression models with random intercepts for each center to assess center-level variation in CLND and adjuvant systemic treatment, adjusting for patient and disease-specific characteristics. RESULTS: Among 1109 patients, performance of CLND decreased from 28% to 8% and adjuvant systemic therapy use increased from 29 to 60%. For both CLND and adjuvant systemic treatment, the most influential factors were nodal tumor size, stage, and location of treating center. There was notable variation among treating centers in management of stage IIIA patients and use of CLND with adjuvant systemic therapy versus nodal observation alone for similar risk patients. CONCLUSIONS: There has been an overall decline in CLND and simultaneous adoption of adjuvant systemic therapy for patients with SLN-positive melanoma though wide variation in practice remains. Accounting for differences in patient mix, location of care contributed significantly to the observed variation.

Survival and tumor characteristics of patients presenting with single primary versus second primary melanoma lesions.

BACKGROUND: Patients with single primary melanomas have an increased risk of developing subsequent melanomas. Secondary tumors diagnosed within and after 3 months are termed "synchronous" and "asynchronous," respectively. OBJECTIVE: To compare tumor distributions and survival characteristics between patients with second primary melanomas and those with single primary melanomas. METHODS: Retrospective cohort study. Data were collected from an institutional database from 14,029 patients with a diagnosis of a primary melanoma seen between 1970 and 2004. RESULTS: The synchronous and asynchronous cohorts demonstrated significantly improved survival probabilities compared with the single primary cohort (P = .04 and .002, respectively). Single primary lesions (2.2 ± 2.3 mm) were significantly thicker than the first-identified synchronous (2.0 ± 1.7 mm) and asynchronous (1.7 ± 1.3 mm) lesions. Synchronous lesions were more likely to be anatomically concordant compared with asynchronous lesions (55.7% vs 38.2%, P < .001). LIMITATIONS: Single-center study design and incomplete records for second primary melanoma Breslow depth and histopathology. CONCLUSION: Patients with second primary melanomas demonstrated a significant survival advantage and thinner lesions compared with those with single primary melanomas. Our reported tumor distributions support the role of full body skin examinations, with attention to the region of initial diagnosis.