Treatment of in-transit Merkel cell carcinoma by isolated limb infusion with cytotoxic drugs

Merkel cell carcinoma of the skin is a rare but aggressive malignancy, which predominantly affects older adults with fair skin. Isolated limb infusion (ILI) using melphalan and actinomycin D was first developed as a minimally invasive treatment option to treat unresectable metastatic melanoma confined to the limb. We report on a 62-year-old male with in-transit metastases (ITMs) treated with ILI to highlight the ongoing role this treatment has when all other therapies have been exhausted. At presentation, the patient had widespread ITMs in the right leg. Positron emission tomography scan demonstrated recurrent disease in the thigh and pelvis, and it was decided to treat the patient with ILI. The patient progressed well in the immediate post-operative period. The patient was able to mobilize from Day 6 post-ILI and was discharged on Day 10. There was an immediate clinical response seen in the lesions, with necrosis developing in the larger lesions.

Anatomic position determines oncogenic specificity in melanoma

Oncogenic alterations to DNA are not transforming in all cellular contexts1,2. This may be due to pre-existing transcriptional programmes in the cell of origin. Here we define anatomic position as a major determinant of why cells respond to specific oncogenes. Cutaneous melanoma arises throughout the body, whereas the acral subtype arises on the palms of the hands, soles of the feet or under the nails3. We sequenced the DNA of cutaneous and acral melanomas from a large cohort of human patients and found a specific enrichment for BRAF mutations in cutaneous melanoma and enrichment for CRKL amplifications in acral melanoma. We modelled these changes in transgenic zebrafish models and found that CRKL-driven tumours formed predominantly in the fins of the fish. The fins are the evolutionary precursors to tetrapod limbs, indicating that melanocytes in these acral locations may be uniquely susceptible to CRKL. RNA profiling of these fin and limb melanocytes, when compared with body melanocytes, revealed a positional identity gene programme typified by posterior HOX13 genes. This positional gene programme synergized with CRKL to amplify insulin-like growth factor (IGF) signalling and drive tumours at acral sites. Abrogation of this CRKL-driven programme eliminated the anatomic specificity of acral melanoma. These data suggest that the anatomic position of the cell of origin endows it with a unique transcriptional state that makes it susceptible to only certain oncogenic insults.

Effect of the time interval between melanoma diagnosis and sentinel node biopsy on the size of metastatic tumour deposits in node-positive patients

INTRODUCTION

This study sought to assess whether the interval between diagnostic excision-biopsy of a primary melanoma and definitive wide excision with sentinel node biopsy (SNB) influenced the size of SN metastatic deposits, which might have implications for management and prognosis.

METHODS

Data were collected for (i) a Dutch population-based cohort of patients treated between 2004 and 2014 who underwent SNB within 100 days of complete excision of their primary melanoma and who were SN-positive with known SN metastasis diameter (n = 1027) and (ii) a cohort from a large Australian melanoma treatment centre (n = 541) who presented in the same time period. The effects of SNB timing on the size of SN metastatic deposits were analysed.

RESULTS

Dutch patients whose SNB was performed in the second or third months after diagnosis had significantly larger SN metastasis diameters than patients who had their SNB in the first month (median increases of 17% (95%CI -14, 60%, p = 0.211) and 71% (95%CI 15, 119%, p = 0.004), respectively). No significant difference in tumour diameter for early and late SNB was found in the Australian cohort.

CONCLUSIONS

SN metastasis diameter became progressively greater with SN biopsy in the second and third months after primary melanoma diagnosis in the larger, population-based patient cohort. An increase in metastasis diameter was not observed in the smaller, institutional cohort, possibly due to detection of larger SN metastases by routine pre-operative ultrasound, with fine-needle biopsy confirmation. These patients did not proceed to SNB and were therefore not included in the study.

Cost-Effectiveness of PET/CT Surveillance Schedules to Detect Distant Recurrence of Resected Stage III Melanoma

Objective: To estimate the cost-effectiveness of three surveillance imaging strategies using whole-body positron emission tomography (PET) with computed tomography (CT) (PET/CT) in a follow-up program for adults with resected stage III melanoma. Methods: An analytic decision model was constructed to estimate the costs and benefits of PET/CT surveillance imaging performed 3-monthly, 6-monthly, or 12-monthly compared with no surveillance imaging. Results: At 5 years, 3-monthly PET/CT surveillance imaging incurred a total cost of AUD 88,387 per patient, versus AUD 77,998 for 6-monthly, AUD 52,560 for 12-monthly imaging, and AUD 51,149 for no surveillance imaging. When compared with no surveillance imaging, 12-monthly PET/CT imaging was associated with a 4% increase in correctly diagnosed and treated distant disease; a 0.5% increase with 6-monthly imaging and 1% increase with 3-monthly imaging. The incremental cost-effectiveness ratio (ICER) of 12-monthly PET/CT surveillance imaging was AUD 34,362 for each additional distant recurrence correctly diagnosed and treated, compared with no surveillance imaging. For the outcome of cost per diagnostic error avoided, the no surveillance imaging strategy was the least costly and most effective. Conclusion: With the ICER for this strategy less than AUD 50,000 per unit of health benefit, the 12-monthly surveillance imaging strategy is considered good value for money.

Residual melanoma in wide local excision specimens after 'complete' excision of primary cutaneous in situ and invasive melanomas

Wide local excision (WLE) to achieve adequate clearance margins is the standard initial definitive treatment for patients with biopsy-proven primary cutaneous melanoma. Residual melanoma in WLE specimens after prior complete excision-biopsy (CEB) is reported in 0-6.3% of cases. However, studies evaluating the prevalence, clinicopathological features and relevance of persistent disease in WLE specimens are limited. This study sought to determine the frequency of and clinicopathological characteristics associated with residual melanoma in WLE specimens performed after a CEB of primary cutaneous or acral melanoma (in situ or invasive) with clinically and histologically tumour-free margins, and assess its relevance. A review of the research database and pathology archives of a large Australian tertiary referral melanoma treatment centre was performed. Eligible patients were those for whom a definitive WLE was performed after CEB of a primary melanoma (in situ or invasive) with negative clinical and histological margins, between May 2013 and May 2015. All partial biopsies were excluded. Of 640 eligible patients, 510 (79.7%) had invasive melanoma and 130 (20.3%) had melanoma in situ. Residual disease was identified in 20 cases (20/640, 3.1%), of which three (15%) were melanoma in situ on CEB and 17 (85%) were invasive melanoma. On univariate analysis, the presence of residual disease in WLE specimens was associated with lentigo maligna (LM)/LM melanoma (LMM) subtype [odds ratio (OR) 10.33; 95% confidence interval (CI) 2.84-37.54; p=0.004], nodular melanoma (NM) subtype (OR 4.92; 95% CI 1.53-15.85; p=0.0076) and, for invasive tumours, higher tumour mitotic rate (mean 7.7, SD 7.51 vs 3.4, SD 4.83; OR 1.11; 95% CI 1.04-1.18; p=0.0014). Breslow thickness >4 mm was associated with a higher risk of residual disease (OR 7.30; 95% CI 1.88, 28.26; p=0.004). Cases with residual disease had primary tumours with a significantly larger diameter (median 14 mm, range 4-25) than those without residual disease (median 9 mm, range 2-60), (OR 1.07; 95% CI 1.03-1.11; p≤0.001) and were also more likely to be amelanotic (38% vs 14%), (OR 3.69; 95% CI 1.17, 11.60; p=0.026). Residual disease was associated with assessment of >3 slides of tissue (OR 6.98; 95% CI 1.54-31.62; p=0.0118) and complete blocking of the scar (OR 31.69; 95% CI 3.98-252.21; p=0.0011). Residual melanoma in WLE specimens is an infrequent occurrence. Risk factors for residual disease are LM/LMM and NM melanoma subtypes, higher mitotic rate, larger lesion diameter and amelanosis. Tumours with these features warrant more extensive pathological sampling. WLE after CEB for melanoma remains an important procedure to reduce local recurrence; however, limited pathological sampling of the WLE scar is probably appropriate for cases lacking high risk features.

Competing risks analysis with missing cause-of-failure-penalized likelihood estimation of cause-specific Cox models

Competing risks models are attractive tools to analyze time-to-event data where several causes of an event are competing. However, a complexity may arise when, for instance, some subjects experience the event of interest but the causes are not known. Assuming that unknown causes of events are missing at random, we developed a novel constrained maximum penalized likelihood method for fitting semi-parametric cause-specific Cox regression models. Here, penalty functions were used to smooth the baseline hazards. An appealing feature of this approach is that all the relevant estimands in competing risks models are estimated including cause-specific hazard ratios, cause-specific baseline hazards, and cumulative incidence functions. Asymptotic results for these estimators were also developed, allowing for direct inferences. The proposed method was compared with some existing methods through a simulation study. A real data example was analyzed using the new method to evaluate the association of age at diagnosis with melanoma-death and non-melanoma-death in patients diagnosed with thin melanoma (tumour thickness ≤1.0  mm). An R function for our proposed method is currently available on GitHub and will be included in the R package "survivalMPL" at CRAN.

Multiomic profiling of checkpoint inhibitor-treated melanoma: Identifying predictors of response and resistance, and markers of biological discordance

We concurrently examine the whole genome, transcriptome, methylome, and immune cell infiltrates in baseline tumors from 77 patients with advanced cutaneous melanoma treated with anti-PD-1 with or without anti-CTLA-4. We show that high tumor mutation burden (TMB), neoantigen load, expression of IFNγ-related genes, programmed death ligand expression, low PSMB8 methylation (therefore high expression), and T cells in the tumor microenvironment are associated with response to immunotherapy. No specific mutation correlates with therapy response. A multivariable model combining the TMB and IFNγ-related gene expression robustly predicts response (89% sensitivity, 53% specificity, area under the curve [AUC], 0.84); tumors with high TMB and a high IFNγ signature show the best response to immunotherapy. This model validates in an independent cohort (80% sensitivity, 59% specificity, AUC, 0.79). Except for a JAK3 loss-of-function mutation, for patients who did not respond as predicted there is no obvious biological mechanism that clearly explained their outlier status, consistent with intratumor and intertumor heterogeneity in response to immunotherapy.

Assessing the Potential for Patient-led Surveillance After Treatment of Localized Melanoma (MEL-SELF): A Pilot Randomized Clinical Trial

IMPORTANCE

Patient-led surveillance is a promising new model of follow-up care following excision of localized melanoma.

OBJECTIVE

To determine whether patient-led surveillance in patients with prior localized primary cutaneous melanoma is as safe, feasible, and acceptable as clinician-led surveillance.

DESIGN, SETTING, AND PARTICIPANTS

This was a pilot for a randomized clinical trial at 2 specialist-led clinics in metropolitan Sydney, Australia, and a primary care skin cancer clinic managed by general practitioners in metropolitan Newcastle, Australia. The participants were 100 patients who had been treated for localized melanoma, owned a smartphone, had a partner to assist with skin self-examination (SSE), and had been routinely attending scheduled follow-up visits. The study was conducted from November 1, 2018, to January 17, 2020, with analysis performed from September 1, 2020, to November 15, 2020.

INTERVENTION

Participants were randomized (1:1) to 6 months of patient-led surveillance (the intervention comprised usual care plus reminders to perform SSE, patient-performed dermoscopy, teledermatologist assessment, and fast-tracked unscheduled clinic visits) or clinician-led surveillance (the control was usual care).

MAIN OUTCOMES AND MEASURES

The primary outcome was the proportion of eligible and contacted patients who were randomized. Secondary outcomes included patient-reported outcomes (eg, SSE knowledge, attitudes, and practices, psychological outcomes, other health care use) and clinical outcomes (eg, clinic visits, skin surgeries, subsequent new primary or recurrent melanoma).

RESULTS

Of 326 patients who were eligible and contacted, 100 (31%) patients (mean [SD] age, 58.7 [12.0] years; 53 [53%] men) were randomized to patient-led (n = 49) or clinician-led (n = 51) surveillance. Data were available on patient-reported outcomes for 66 participants and on clinical outcomes for 100 participants. Compared with clinician-led surveillance, patient-led surveillance was associated with increased SSE frequency (odds ratio [OR], 3.5; 95% CI, 0.9 to 14.0) and thoroughness (OR, 2.2; 95% CI, 0.8 to 5.7), had no detectable adverse effect on psychological outcomes (fear of cancer recurrence subscale score; mean difference, -1.3; 95% CI, -3.1 to 0.5), and increased clinic visits (risk ratio [RR], 1.5; 95% CI, 1.1 to 2.1), skin lesion excisions (RR, 1.1; 95% CI, 0.6 to 2.0), and subsequent melanoma diagnoses and subsequent melanoma diagnoses (risk difference, 10%; 95% CI, -2% to 23%). New primary melanomas and 1 local recurrence were diagnosed in 8 (16%) of the participants in the intervention group, including 5 (10%) ahead of routinely scheduled visits; and in 3 (6%) of the participants in the control group, with none (0%) ahead of routinely scheduled visits (risk difference, 10%; 95% CI, 2% to 19%).

CONCLUSIONS AND RELEVANCE

This pilot of a randomized clinical trial found that patient-led surveillance after treatment of localized melanoma appears to be safe, feasible, and acceptable. Experiences from this pilot study have prompted improvements to the trial processes for the larger trial of the same intervention.

TRIAL REGISTRATION

http://anzctr.org.au Identifier: ACTRN12616001716459.

Association Between Melanoma Detected During Routine Skin Checks and Mortality

Importance

Early melanoma diagnosis is associated with better health outcomes, but there is insufficient evidence that screening, such as having routine skin checks, reduces mortality.

Objective

To assess melanoma-specific and all-cause mortality associated with melanomas detected through routine skin checks, incidentally or patient detected. A secondary aim was to examine patient, sociodemographic, and clinicopathologic factors associated with different modes of melanoma detection.

Design, Setting, and Participants

This prospective, population-based, cohort study included patients in New South Wales, Australia, who were diagnosed with melanoma over 1 year from October 23, 2006, to October 22, 2007, in the Melanoma Patterns of Care Study and followed up until 2018 (mean [SD] length of follow-up, 11.9 [0.3] years) by using linked mortality and cancer registry data. All patients who had invasive melanomas recorded at the cancer registry were eligible for the study, but the number of in situ melanomas was capped. The treating doctors recorded details of melanoma detection and patient and clinical characteristics in a baseline questionnaire. Histopathologic variables were obtained from pathology reports. Of 3932 recorded melanomas, data were available and analyzed for 2452 (62%; 1 per patient) with primary in situ (n = 291) or invasive (n = 2161) cutaneous melanoma. Data were analyzed from March 2020 to January 2021.

Main Outcomes and Measures

Melanoma-specific mortality and all-cause mortality.

Results

A total of 2452 patients were included in the analyses. The median age at diagnosis was 65 years (range, 16-98 years), and 1502 patients (61%) were men. A total of 858 patients (35%) had their melanoma detected during a routine skin check, 1148 (47%) self-detected their melanoma, 293 (12%) had their melanoma discovered incidentally when checking another skin lesion, and 153 (6%) reported "other" presentation. Routine skin-check detection of invasive melanomas was associated with 59% lower melanoma-specific mortality (subhazard ratio, 0.41; 95% CI, 0.28-0.60; P < .001) and 36% lower all-cause mortality (hazard ratio, 0.64; 95% CI, 0.54-0.76; P < .001), adjusted for age and sex, compared with patient-detected melanomas. After adjusting for prognostic factors including ulceration and mitotic rate, the associations were 0.68 (95% CI, 0.44-1.03; P = .13), and 0.75 (95% CI, 0.63-0.90; P = .006), respectively. Factors associated with higher odds of routine skin-check melanoma detection included being male (female vs male, odds ratio [OR], 0.73; 95% CI, 0.60-0.89; P = .003), having previous melanoma (vs none, OR, 2.36; 95% CI, 1.77-3.15; P < .001), having many moles (vs not, OR, 1.39; 95% CI, 1.10-1.77; P = .02), being 50 years or older (eg, 50-59 years vs <40 years, OR, 2.89; 95% CI, 1.92-4.34; P < .001), and living in nonremote areas (eg, remote or very remote vs major cities, OR, 0.23; 95% CI, 0.05-1.04; P = .003).

Conclusions and Relevance

In this cohort study, melanomas diagnosed through routine skin checks were associated with significantly lower all-cause mortality, but not melanoma-specific mortality, after adjustment for patient, sociodemographic, and clinicopathologic factors.

Association of Histologic Regression With a Favorable Outcome in Patients With Stage 1 and Stage 2 Cutaneous Melanoma

Importance

Although regression is commonly observed in cutaneous melanoma, it is uncertain whether it is associated with patient prognosis.

Objective

To determine whether histologically confirmed regression was associated with better or worse survival in patients with primary cutaneous melanoma.

Design, Setting, and Participants

This cohort study analyzed data from 2 large cohorts of adults (one in the Netherlands and the other in Australia) with histologically proven, stage 1 and 2 primary, invasive cutaneous melanoma with known regression status treated between 2000 and 2014, with median follow-up times of 4.5 and 11.1 years for the Dutch and Australian cohorts, respectively. For the Dutch patients, population-based data from PALGA, the Dutch Pathology Registry, were used, and follow-up data were retrieved from the Netherlands Cancer Registry. For the Australian patients, data from the database of a large, specialized melanoma treatment center were used.

Main Outcomes and Measures

Multivariable Cox proportional hazards analyses were performed per cohort to assess recurrence-free survival (RFS) and overall survival (OS), and subgroup analyses according to Breslow thickness category and melanoma subtype were performed.

Results

A total of 17 271 Dutch patients and 4980 Australian patients were included. In both cohorts, survival outcomes were better for patients with disease regression. For Dutch patients, the hazard ratio (HR) for those with disease regression was 0.55 (95% CI, 0.48-0.63; P < .001) for RFS and 0.87 (95% CI, 0.79-0.96; P = .004) for OS; for the Australian patients, the HR was 0.61 (95% CI, 0.52-0.72; P < .001) for RFS and 0.73 (95% CI, 0.64-0.84; P < .001) for OS. Subgroup analyses showed that the presence of regression improved RFS within thin and intermediate Breslow thickness melanomas in both cohorts. For patients with superficial spreading melanoma (SSM) subtype, regression improved RFS and OS in both cohorts. For Dutch patients with SSM, the HR for those with disease regression was 0.54 (95% CI, 0.46-0.63; P < .001) for RFS and 0.86 (95% CI, 0.76-0.96; P = .009) for OS; for the Australian patients with SSM, the HR was 0.67 (95% CI, 0.52-0.85; P = .001) for RFS and 0.72 (95% CI, 0.59-0.88; P = .001) for OS.

Conclusions and Relevance

In 2 large patient cohorts from 2 different continents, regression was a favorable prognostic factor for patients with stage 1 and 2 melanomas, especially in those with thin and intermediate thickness tumors and those with SSM subtype.

Contemporary management of locoregionally advanced melanoma in Australia and New Zealand and the role of adjuvant systemic therapy

Australia and New Zealand have the highest incidence and mortality rates for melanoma in the world. Local surgery is still the standard treatment of primary cutaneous melanoma, and it is therefore important that surgeons understand the optimal care pathways for patients with melanoma. Accurate staging is critical to ensure a reliable assessment of prognosis and to guide treatment selection. Sentinel node biopsy (SNB) plays an important role in staging and the provision of reliable prognostic estimates for patients with cutaneous melanoma. Patients with stage III melanoma have a substantial risk of disease recurrence following surgery, leading to poor long-term outcomes. Systemic immunotherapies and targeted therapies, known to be effective for stage IV melanoma, have now also been shown to be effective as adjuvant post-surgical treatments for resected stage III melanoma. These patients should be made aware of this and preferably managed in an integrated multidisciplinary model of care, involving the surgeon, medical oncologists and radiation oncologists. This review considers the impact of a recent update to the American Joint Committee on Cancer (AJCC) staging system, the role of SNB for patients with high-risk primary melanoma and recent advances in adjuvant systemic therapies for high-risk patients.

Survival Outcomes of Salvage Metastasectomy After Failure of Modern-Era Systemic Therapy for Melanoma

BACKGROUND

Metastasectomy for selected patients with melanoma was associated with improved survival in the era before effective systemic therapy. Emerging evidence shows that these benefits persist even in this era of BRAF-targeted therapy and immune checkpoint inhibitor immunotherapy. This study aimed to evaluate the outcomes of salvage metastasectomy after failure of systemic therapy.

METHODS

Stage 3 or 4 melanoma patients with extracranial disease progression after at least 4 weeks of systemic treatment between 2009 and 2020 were identified and categorized as resected to no evidence of disease (NED), non-progressive residual disease (NPRD), or progressive residual disease (PRD). Systemic therapy was stratified into BRAF-targeted therapy, immune checkpoint inhibitor immunotherapy, or both. The end points of overall survival (OS), progression-free survival (PFS), and locoregional disease control (LRC) were assessed using Kaplan-Meier curves. Uni- and multivariable Cox regression procedures were used to examine factors associated with OS, PFS and LRC.

RESULTS

The study enrolled 190 patients. Among all the patients, the 5-year OS from metastatectomy was 52%, the 3-year PFS was 21%, and the 5-year LRC was 61%. After resection to NED, NPRD, and PRD, the 5-year OS values were 69%, 62% and 8%, respectively. Fewer lines of preoperative therapy, use of preoperative immunotherapy, and resection to NED were predictors of improved OS. After resection to NED, NPRD, and PRD, the 3-year PFS values were 23%, 24% and 10%, and the 5-year LRC values were 61%, 72% and 34%, respectively.

CONCLUSIONS

Salvage metastasectomy was associated with durable survival and disease control, particularly after resection to NED, preoperative immunotherapy, and fewer lines of preoperative systemic therapy.

The role of regional chemotherapy for advanced limb melanoma in the era of potentially effective systemic therapies

To review the current role of regional chemotherapy in the management of advanced limb melanoma. Articles reporting the results of isolated limb infusion (ILI) were identified by performing a comprehensive literature search using the PubMed database. Keywords included isolated limb infusion, in-transit melanoma and melphalan. No publication date restrictions were applied. ILI data were compared with those from current systemic therapy clinical trials and the previously reviewed isolated limb perfusion (ILP) literature. Regional chemotherapy is today required in fewer patients because effective systemic therapies now provide an alternative treatment for those who develop extensive local melanoma recurrence or in-transit metastases (ITMs). However, regional chemotherapy may be a valuable treatment option when the side-effects of systemic therapies are of concern, or after systemic treatment failure. ILP achieves overall response rates (ORRs) of 64-100% and complete response rates (CRRs) of 25-89%. ILI achieves ORRs of 41-91% and CRRs of 6-39%. ILP and ILI can have a low risk of serious morbidity. Early results from treatment with ILP or ILI in conjunction with systemic immune therapies suggest that these modalities can be safely combined, which may be useful in patients with refractory limb disease. Regional chemotherapy remains important in the armamentarium of clinicians managing patients with unresectable limb melanoma and may be preferable in those who are frail, elderly or who are at high risk from complications of systemic therapies. The efficacy of combining regional chemotherapy with systemic immune therapy is currently being assessed.

Abstract 2609: Hypoxia-mediated downregulation of GCNT2/I-antigen in metastatic melanoma accelerates disease progression and mortality

Metastatic melanoma is a lethal disease with a dismal 5-year survival rate. Thus, intense efforts to boost novel therapeutic strategies are underway to identify early detection of melanomas with a high propensity to metastasize. We recently discovered that the loss of cell surface glycan, I-antigen, corresponds with the transition of primary melanoma to metastatic melanoma. I-antigen or I-branched glycans are synthesized by β16, N-acetylglucosaminyltransferase 2 (GCNT2) and inversely correlate with the growth and signaling potential of metastatic melanoma cells. Moreover, compared with high GCNT2 expression in normal melanocytes, nevi, and early-stage primary melanomas, GCNT2 is conspicuously lost in metastatic melanomas. We anticipate the potential utilization of GCNT2 expression as a biomarker to predict melanoma metastasis. Further, metastasis and aggressive disease progression are key phenotypes of tumor-initiating cells (TIC), which are preferentially generated in areas of hypoxia. In the vertical growth phase of primary melanomas and melanoma metastases, the tumor microenvironment is typically hypoxic (1.5% oxygen). We hypothesize that the hypoxic microenvironment aids in metastatic melanoma progression through TIC generation and immune evasion, by downregulating GCNT2 and switching I-branched glycans to linear glycans. In this study, metastatic melanoma cells grown under hypoxic conditions had reduced GCNT2 and MITF with upregulated stem cell marker KLF4 expression. Importantly, in the in vivo TIC assay, we found significantly decreased tumor formation with increased GCNT2 expression while low GCNT2 levels enabled tumor formation even when 103 cells were injected in immunocompromised mice. Since TICs are thought to evade immune clearance, we investigated whether loss of GCNT2 increased TIC characteristics and also enabled immunosuppressive features. In human PBMC - metastatic melanoma co-cultures, there was an increase in T regulatory cell generation associated with low GCNT2 compared to high GCNT2 expression in melanoma cells, suggesting that loss of GCNT2 associates with increased TIC generation, tumor formation, and immunoevasion potential. Using melanoma patient specimens, immunohistochemical analysis of GCNT2 corresponded with a significant increase in mortality with the loss of GCNT2 staining. Altogether, these findings highlight GCNT2/I-branching not only as a biomarker of melanoma virulence but reveal malignancy-associated pathways functioning in parallel with loss of GCNT2/I-branching that could offer additional targets for the treatment of metastatic melanoma.

Citation Format: Asmi Chakraborty, Mariana Perez, Norhan B. B Mohammed, Michael Wells, James S. Wilmott, John F. Thompson, Stuart M. Haslam, Wei Wang, Richard A. Scolyer, George F. Murphy, Charles J. Dimitroff. Hypoxia-mediated downregulation of GCNT2/I-antigen in metastatic melanoma accelerates disease progression and mortality [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2609.