Metastatic volume: an old oncologic concept and a new prognostic factor for stage IV melanoma patients

Ultra-High Frequency Ultrasound in Melanoma Management: A New Combined Ultrasonographic-Histopathological Approach

OBJECTIVES

The main aim of this study is to evaluate the correspondence between the ultrasonographic thickness and the Breslow thickness in melanoma using ultra-high frequency ultrasound and the intra- and inter-operator repeatability in the ultrasonographic measurements of melanoma depth. Moreover, we propose a new protocol based on a combined ultrasonographic-histopathological approach.

METHODS

We analyzed 27 melanomas in a population consisted of 27 patients (mean age 57.6 years, 51.8% males), who came at the Department of Dermatology (University of Pisa, Pisa, Italy) from April 2016 to March 2018 and had an ultrasonographic examination of a suspected lesion before the surgical removal using ultra-high frequency ultrasound (Vevo®MD, Fujifilm, Visualsonics, Toronto, Canada; 70 MHz probe). B-mode images were analyzed by two skilled and blinded operators, and the maximum depth of the lesions was measured using a dedicated graphical user interface developed in Matlab R2016b (MathWorks Inc., Natick, MA), to obtain repetitive measurements.

RESULTS

All melanomas appeared as band-like or oval/fusiform shaped hypoechoic inhomogeneous lesions. We observed an excellent agreement between the Breslow thickness of melanomas and the ultrasonographic thickness, as well as a reduced intra- and inter-operator variability in the ultrasonographic measurements of melanoma depth.

CONCLUSIONS

We propose a ultrasonographic-histopathological protocol which may help clinicians to reduce the diagnostic delay, improve prognosis and survival rates, perform a surgical excision with negative margins, and reduce the variability in the assessment of Breslow thickness.

Circulating tumour DNA in patients with advanced melanoma treated with dabrafenib or dabrafenib plus trametinib: a clinical validation study

BACKGROUND

Melanoma lacks validated blood-based biomarkers for monitoring and predicting treatment efficacy. Cell-free circulating tumour DNA (ctDNA) is a promising biomarker; however, various detection methods have been used, and, to date, no large studies have examined the association between serial changes in ctDNA and survival after BRAF, MEK, or BRAF plus MEK inhibitor therapy. We aimed to evaluate whether baseline ctDNA concentrations and kinetics could predict survival outcomes.

METHODS

In this clinical validation study, we used analytically validated droplet digital PCR assays to measure BRAFV600-mutant ctDNA in pretreatment and on-treatment plasma samples from patients aged 18 years or older enrolled in two clinical trials. COMBI-d (NCT01584648) was a double-blind, randomised phase 3 study of dabrafenib plus trametinib versus dabrafenib plus placebo in previously untreated patients with BRAFV600 mutation-positive unresectable or metastatic melanoma. Patients had an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. COMBI-MB (NCT02039947) was an open-label, non-randomised, phase 2 study evaluating dabrafenib plus trametinib in patients with BRAFV600 mutation-positive metastatic melanoma and brain metastases. Patients in cohort A of COMBI-MB had asymptomatic brain metastases, no previous local brain-directed therapy, and an ECOG performance status of 0 or 1. Biomarker analysis was a prespecified exploratory endpoint in both trials and performed in the intention-to-treat populations in COMBI-d and COMBI-MB. We investigated the association between mutant copy number (baseline or week 4 or zero conversion status) and efficacy endpoints (progression-free survival, overall survival, and best overall response). We used Cox models, Kaplan-Meier plots, and log-rank tests to explore the association of pretreatment ctDNA concentrations with progression-free survival and overall survival. The effect of additional prognostic variables such as lactate dehydrogenase was also investigated in addition to the mutant copy number.

FINDINGS

In COMBI-d, pretreatment plasma samples were available from 345 (82%) of 423 patients and on-treatment (week 4) plasma samples were available from 224 (53%) of 423 patients. In cohort A of COMBI-MB, pretreatment and on-treatment samples were available from 38 (50%) of 76 patients with intracranial and extracranial metastatic melanoma. ctDNA was detected in pretreatment samples from 320 (93%) of 345 patients (COMBI-d) and 34 (89%) of 38 patients (COMBI-MB). When assessed as a continuous variable, elevated baseline BRAFV600 mutation-positive ctDNA concentration was associated with worse overall survival outcome (hazard ratio [HR] 1·13 [95% CI 1·09-1·18], p<0·0001 by univariate analysis), independent of treatment group and baseline lactate dehydrogenase concentrations (1·08 [1·03-1·13], p=0·0020), in COMBI-d. A ctDNA cutoff point of 64 copies per mL of plasma stratified patients enrolled in COMBI-d as high risk or low risk with respect to survival outcomes (HR 1·74 [95% CI 1·37-2·21], p<0·0001 for progression-free survival; 2·23 [1·73-2·87], p<0·0001 for overall survival) and was validated in the COMBI-MB cohort (3·20 [1·39-7·34], p=0·0047 for progression-free survival; 2·94 [1·18-7·32], p=0·016 for overall survival). In COMBI-d, undetectable ctDNA at week 4 was significantly associated with extended progression-free and overall survival, particularly in patients with elevated lactate dehydrogenase concentrations (HR 1·99 [95% CI 1·08-3·64], p=0·027 for progression-free survival; 2·38 [1·24-4·54], p=0·0089 for overall survival).

INTERPRETATION

Pretreatment and on-treatment BRAFV600-mutant ctDNA measurements could serve as independent, predictive biomarkers of clinical outcome with targeted therapy.

FUNDING

Novartis.

Collapse of the Plasmacytoid Dendritic Cell Compartment in Advanced Cutaneous Melanomas by Components of the Tumor Cell Secretome

Melanoma is an immunogenic neoplasm infiltrated by T cells, although these adaptive T cells usually fail to eradicate the tumor. Plasmacytoid dendritic cells (PDCs) are potent regulators of the adaptive immune response and can eliminate melanoma cells via TLR-mediated effector functions. The PDC compartment is maintained by progressively restricted bone marrow progenitors. Terminally differentiated PDCs exit the bone marrow into the circulation, then home to lymph nodes and inflamed peripheral tissues. Infiltration by PDCs is documented in various cancers. However, their role within the melanoma immune contexture is not completely known. We found that in locoregional primary cutaneous melanoma (PCM), PDC infiltration was heterogeneous, occurred early, and was recurrently localized at the invasive margin, the site where PDCs interact with CD8+ T cells. A reduced PDC density was coupled with an increased Breslow thickness and somatic mutations at the NRAS p.Q61 codon. Compared with what was seen in PCM, high numbers of PDCs were found in regional lymph nodes, as also identified by in silico analysis. In contrast, in metastatic melanoma patients, PDCs were mostly absent in the tumor tissues and were significantly reduced in the circulation, particularly in the advanced M1c group. Exposure of circulating PDCs to melanoma cell supernatant (SN-mel) depleted of extracellular vesicles resulted in significant PDC death. SN-mel exposure also resulted in a defect of PDC differentiation from CD34+ progenitors. These findings indicate that soluble components released by melanoma cells support the collapse of the PDC compartment, with clinical implications for refining TLR agonist-based trials.

Blockade of MIF-CD74 Signalling on Macrophages and Dendritic Cells Restores the Antitumour Immune Response Against Metastatic Melanoma

Mounting an effective immune response against cancer requires the activation of innate and adaptive immune cells. Metastatic melanoma is the most aggressive form of skin cancer. While immunotherapies have shown a remarkable success in melanoma treatment, patients develop resistance by mechanisms that include the establishment of an immune suppressive tumor microenvironment. Thus, understanding how metastatic melanoma cells suppress the immune system is vital to develop effective immunotherapies against this disease. In this study, we find that macrophages (MOs) and dendritic cells (DCs) are suppressed in metastatic melanoma and that the Ig-CDR-based peptide C36L1 is able to restore MOs and DCs' antitumorigenic and immunogenic functions and to inhibit metastatic growth in lungs. Specifically, C36L1 treatment is able to repolarize M2-like immunosuppressive MOs into M1-like antitumorigenic MOs, and increase the number of immunogenic DCs, and activated cytotoxic T cells, while reducing the number of regulatory T cells and monocytic myeloid-derived suppressor cells in metastatic lungs. Mechanistically, we find that C36L1 directly binds to the MIF receptor CD74 which is expressed on MOs and DCs, disturbing CD74 structural dynamics and inhibiting MIF signaling on these cells. Interfering with MIF-CD74 signaling on MOs and DCs leads to a decrease in the expression of immunosuppressive factors from MOs and an increase in the capacity of DCs to activate cytotoxic T cells. Our findings suggest that interfering with MIF-CD74 immunosuppressive signaling in MOs and DCs, using peptide-based immunotherapy can restore the antitumor immune response in metastatic melanoma. Our study provides the rationale for further development of peptide-based therapies to restore the antitumor immune response in metastatic melanoma.

Computer-assisted measurement of primary tumor area is prognostic of recurrence-free survival in stage IB melanoma patients

Current staging guidelines are insufficient to predict which patients with thin primary melanoma are at high risk of recurrence. Computer-assisted image analysis may allow for more practical and objective histopathological analysis of primary tumors than traditional light microscopy. We studied a prospective cohort of stage IB melanoma patients treated at NYU Langone Medical Center from 2002 to 2014. Primary tumor width, manual area, digital area, and conformation were evaluated in a patient subset via computer-assisted image analysis. The associations between histologic variables and survival were evaluated using Cox proportional hazards model. Logistic regressions were used to build a classifier with clinicopathological characteristics to predict recurrence status. Of the 655 patients with stage IB melanoma studied, a subset of 149 patient tumors (63 recurred, 86 did not recur) underwent computer-assisted histopathological analysis. Increasing tumor width (hazard ratios (HR): 1.17, P=0.01) and digital area (HR: 1.08, P<0.01) were significantly associated with worse recurrence-free survival, whereas non-contiguous conformation (HR: 0.57, P=0.05) was significantly associated with better recurrence-free survival. The novel histopathological classifier composed of digital area, conformation, and baseline variables effectively distinguished recurrent cases from non-recurrent cases (AUC: 0.733, 95% confidence interval (CI): 0.647-0.818), compared to the baseline classifier alone (AUC: 0.635, 95% CI: 0.545-0.724). Primary tumor cross-sectional area, width, and conformation measured via computer-assisted analysis may help identify high-risk patients with stage IB melanoma.

TLR7 Gln11Leu single nucleotide polymorphism and susceptibility to cutaneous melanoma

Cutaneous melanoma is a life-threatening skin cancer. Its incidence is rapidly increasing, and early diagnosis is the main factor able to improve its poor prognosis. Toll-like receptors (TLRs) are transmembrane glycoproteins that recognize pathogen- and damage-associated molecular patterns, against which TLRs activate the innate immune response and initiate the adaptive immune response. Genetic variations of these receptors may alter the immune system, and are involved in evolution and susceptibility to various diseases, including cancer. The aim of the present study was to evaluate whether the presence of TLR7 glutamine (Gln) 11 leucine (Leu) polymorphism confers an increased susceptibility to cutaneous melanoma. For that purpose, a case-control study was performed with 182 melanoma cases and 89 controls. To highlight the possible association between the aforementioned polymorphism and the susceptibility to melanoma, 93 cases of single melanoma and 89 cases of multiple primary melanoma (MPM) were compared in the present study. Since the TLR7 gene is localized on the chromosome X, the allelic frequency of the Gln11Leu polymorphism was analyzed separately in males and females. The distribution of allele frequencies between melanoma cases and controls (P=0.245) and between single melanoma and MPM cases (P=0.482) was not significant. Therefore, the present results do not suggest an association between TLR7 Gln11Leu polymorphism and susceptibility to cutaneous melanoma. Further studies are required to analyze the influence of other TLR polymorphisms on the susceptibility to malignant melanoma and the involvement of innate immunity in this malignancy.

Giant Centrifugal and Necrotizing Cutaneous Metastases of Melanoma: A Brief Review of the Literature and a Case Report

BACKGROUND

Melanoma is a neoplasm derived from melanocytes of the skin and other sites. In the natural history of melanoma, cutaneous metastases occur relatively frequently and can arise in early or late stages of the disease.

OBJECTIVE AND METHODS

Melanoma skin metastases have a variable appearance. Several clinical appearances are described in the literature.

RESULTS AND CONCLUSION

We describe an unusual clinical pattern of cutaneous melanoma metastasis, defined as giant, centrifugal, and necrotizing, and we provide a brief review of the literature.

Circulating biomarkers in malignant melanoma

Melanoma is an aggressive tumor with increasing incidence worldwide. Biomarkers are valuable tools to minimize the cost and improve efficacy of treatment of this deadly disease. Serological markers have not widely been introduced in routine clinical practice due to their insufficient diagnostic sensitivity and specificity. It is likely that the lack of objective responses with traditional treatment hinder biomarker research and development in melanoma. Recently, new drugs and therapies have, however, emerged in advanced melanoma with noticeable objective response ratio and survival. In this new scenario, serological tumor markers should be revisited. In addition, other potential circulating biomarkers such as cell-free DNA, exosomes, microRNA, and circulating tumor cells have also been identified. In this review, we summarize classical and emerging tumor markers and discuss their possible roles in emerging therapeutics.