Expression of tryptophan metabolizing enzymes (TMEs) and its transporter, LAT1, in metastatic melanoma (MM): Prognostic and therapeutic implications

e21014

Background: The ECHO-301/KEYNOTE-252 trial failed to show clinical benefit of adding epacadostat to pembrolizumab in PD-1 inhibitor-naïve MM. We reasoned that the expression of other TMEs and/or LAT1 by melanoma cells plays a more important role. Methods: Melanoma tissues from stage III/IV pts were stained for the 4 TMEs (TPH1, TPH2, TDO2, IDO1) and LAT1 by single-color immunohistochemistry. Tissues were scored for the status of tumor-infiltrating lymphocytes (TILs) and the expression of 5 proteins separately in melanoma cells and TILs (if present). Association between protein expression, TIL status, and melanoma-specific overall survival was performed. Results: Tissues from 87 pts (stage IV, n = 25) were available. Expression of all 4 TMEs and LAT1 was significantly higher in melanoma cells compared to TILs ( p< 0.001); TPH1, TPH2, and TDO2 expression in melanoma cells was significantly higher than IDO1 (p < 0.001). Lower TPH1 expression in melanoma cells was associated with presence of TILs. Multivariate analysis using a Cox proportional hazards model that included expression of the 5 proteins in melanoma cells showed that high IDO1 was a favorable and high LAT1 expression was an adverse prognostic factor. Conclusions: Expression of TMEs and LAT1 by melanoma cells may have more important role in metastatic melanoma by depleting an essential amino acid from the tumor microenvironment. Pharmacologic targeting of TPH1/TPH2 (e.g. telotristat) may be more clinically relevant in MM as opposed to IDO1 inhibition.

MC1R variants in childhood and adolescent melanoma: a retrospective pooled analysis of a multicentre cohort

BACKGROUND

Germline variants in the melanocortin 1 receptor gene (MC1R) might increase the risk of childhood and adolescent melanoma, but a clear conclusion is challenging because of the low number of studies and cases. We assessed the association of MC1R variants with childhood and adolescent melanoma in a large study comparing the prevalence of MC1R variants in child or adolescent patients with melanoma to that in adult patients with melanoma and in healthy adult controls.

METHODS

In this retrospective pooled analysis, we used the M-SKIP Project, the Italian Melanoma Intergroup, and other European groups (with participants from Australia, Canada, France, Greece, Italy, the Netherlands, Serbia, Spain, Sweden, Turkey, and the USA) to assemble an international multicentre cohort. We gathered phenotypic and genetic data from children or adolescents diagnosed with sporadic single-primary cutaneous melanoma at age 20 years or younger, adult patients with sporadic single-primary cutaneous melanoma diagnosed at age 35 years or older, and healthy adult individuals as controls. We calculated odds ratios (ORs) for childhood and adolescent melanoma associated with MC1R variants by multivariable logistic regression. Subgroup analysis was done for children aged 18 or younger and 14 years or younger.

FINDINGS

We analysed data from 233 young patients, 932 adult patients, and 932 healthy adult controls. Children and adolescents had higher odds of carrying MC1R r variants than did adult patients (OR 1·54, 95% CI 1·02-2·33), including when analysis was restricted to patients aged 18 years or younger (1·80, 1·06-3·07). All investigated variants, except Arg160Trp, tended, to varying degrees, to have higher frequencies in young patients than in adult patients, with significantly higher frequencies found for Val60Leu (OR 1·60, 95% CI 1·05-2·44; p=0·04) and Asp294His (2·15, 1·05-4·40; p=0·04). Compared with those of healthy controls, young patients with melanoma had significantly higher frequencies of any MC1R variants.

INTERPRETATION

Our pooled analysis of MC1R genetic data of young patients with melanoma showed that MC1R r variants were more prevalent in childhood and adolescent melanoma than in adult melanoma, especially in patients aged 18 years or younger. Our findings support the role of MC1R in childhood and adolescent melanoma susceptibility, with a potential clinical relevance for developing early melanoma detection and preventive strategies.

FUNDING

SPD-Pilot/Project-Award-2015; AIRC-MFAG-11831.

Utility of TERT Promoter Mutations for Cutaneous Primary Melanoma Diagnosis

Telomerase reverse transcriptase (TERT) promoter mutations are commonly found in malignant melanomas but rare in melanocytic nevi. To assess its potential diagnostic utility for the distinction of melanoma from nevus, we determined the TERT promoter mutation status of 86 primary melanomas, 72 melanocytic nevi, and 40 diagnostically problematic melanocytic proliferations. Of the 86 melanomas, 67 (77.9%) were TERT-positive, defined as harboring a hotspot TERT promoter mutation at positions -124C>T, -124_125CC>TT, -138_139CC>TT, or -146C>T. Of the 72 nevi, only 1 (1.4%) was TERT-positive. Of the 40 diagnostically uncertain melanocytic proliferations, 2 (5.0%) were TERT-positive. TERT positivity as a test for melanoma versus nevus had an accuracy of 87.3% [95% confidence interval (CI), 81.1-92.1], a sensitivity of 77.9% (95% CI, 68.9-85.4), a specificity of 98.6% (95% CI, 95.8-100), a positive predictive value of 98.5% (95% CI, 95.6-100), and a negative predictive value of 78.9% (95% CI, 72.6-85.4). Our results indicate that hotspot TERT promoter mutation status may be a useful ancillary parameter for the diagnosis of melanoma. In particular, the high specificity of these mutations for melanoma indicates the presence of a TERT promoter mutation in a melanocytic neoplasm associated with diagnostic controversy, or uncertainty should increase concern for a melanoma.

The Prognostic Significance of Low-Frequency Somatic Mutations in Metastatic Cutaneous Melanoma

Background: Little is known about the prognostic significance of somatically mutated genes in metastatic melanoma (MM). We have employed a combined clinical and bioinformatics approach on tumor samples from cutaneous melanoma (SKCM) as part of The Cancer Genome Atlas project (TCGA) to identify mutated genes with potential clinical relevance. Methods: After limiting our DNA sequencing analysis to MM samples (n = 356) and to the CANCER CENSUS gene list, we filtered out mutations with low functional significance (snpEFF). We performed Cox analysis on 53 genes that were mutated in ≥3% of samples, and had ≥50% difference in incidence of mutations in deceased subjects versus alive subjects. Results: Four genes were potentially prognostic [RAC1, FGFR1, CARD11, CIITA; false discovery rate (FDR) < 0.2]. We identified 18 additional genes (e.g., SPEN, PDGFRB, GNAS, MAP2K1, EGFR, TSC2) that were less likely to have prognostic value (FDR < 0.4). Most somatic mutations in these 22 genes were infrequent (< 10%), associated with high somatic mutation burden, and were evenly distributed across all exons, except for RAC1 and MAP2K1. Mutations in only 9 of these 22 genes were also identified by RNA sequencing in >75% of the samples that exhibited corresponding DNA mutations. The low frequency, UV signature type and RNA expression of the 22 genes in MM samples were confirmed in a separate multi-institution validation cohort (n = 413). An underpowered analysis within a subset of this validation cohort with available patient follow-up (n = 224) showed that somatic mutations in SPEN and RAC1 reached borderline prognostic significance [log-rank favorable (p = 0.09) and adverse (p = 0.07), respectively]. Somatic mutations in SPEN, and to a lesser extent RAC1, were not associated with definite gene copy number or RNA expression alterations. High (>2+) nuclear plus cytoplasmic expression intensity for SPEN was associated with longer melanoma-specific overall survival (OS) compared to lower (≤ 2+) nuclear intensity (p = 0.048). We conclude that expressed somatic mutations in infrequently mutated genes beyond the well-characterized ones (e.g., BRAF, RAS, CDKN2A, PTEN, TP53), such as RAC1 and SPEN, may have prognostic significance in MM.

Identification of a Robust Methylation Classifier for Cutaneous Melanoma Diagnosis

Early diagnosis improves melanoma survival, yet the histopathological diagnosis of cutaneous primary melanoma can be challenging, even for expert dermatopathologists. Analysis of epigenetic alterations, such as DNA methylation, that occur in melanoma can aid in its early diagnosis. Using a genome-wide methylation screening, we assessed CpG methylation in a diverse set of 89 primary invasive melanomas, 73 nevi, and 41 melanocytic proliferations of uncertain malignant potential, classified based on interobserver review by dermatopathologists. Melanomas and nevi were split into training and validation sets. Predictive modeling in the training set using ElasticNet identified a 40-CpG classifier distinguishing 60 melanomas from 48 nevi. High diagnostic accuracy (area under the receiver operator characteristic curve = 0.996, sensitivity = 96.6%, and specificity = 100.0%) was independently confirmed in the validation set (29 melanomas, 25 nevi) and other published sample sets. The 40-CpG melanoma classifier included homeobox transcription factors and genes with roles in stem cell pluripotency or the nervous system. Application of the 40-CpG melanoma classifier to the diagnostically uncertain samples assigned melanoma or nevus status, potentially offering a diagnostic tool to assist dermatopathologists. In summary, the robust, accurate 40-CpG melanoma classifier offers a promising assay for improving primary melanoma diagnosis.

Inherited Genetic Variants Associated with Melanoma BRAF/NRAS Subtypes

BRAF and NRAS mutations arise early in melanoma development, but their associations with low-penetrance melanoma susceptibility loci remain unknown. In the Genes, Environment and Melanoma Study, 1,223 European-origin participants had their incident invasive primary melanomas screened for BRAF/NRAS mutations and germline DNA genotyped for 47 single-nucleotide polymorphisms identified as low-penetrant melanoma-risk variants. We used multinomial logistic regression to simultaneously examine each single-nucleotide polymorphism's relationship to BRAF V600E, BRAF V600K, BRAF other, and NRAS+ relative to BRAF-/NRAS- melanoma adjusted for study features. IRF4 rs12203592*T was associated with BRAF V600E (odds ratio [OR] = 0.59, 95% confidence interval [CI] = 0.43-0.79) and V600K (OR = 0.65, 95% CI = 0.41-1.03), but not BRAF other or NRAS+ melanoma. A global test of etiologic heterogeneity (Pglobal = 0.001) passed false discovery (Pglobal = 0.0026). PLA2G6 rs132985*T was associated with BRAF V600E (OR = 1.32, 95% CI = 1.05-1.67) and BRAF other (OR = 1.82, 95% CI = 1.11-2.98), but not BRAF V600K or NRAS+ melanoma. The test for etiologic heterogeneity (Pglobal) was 0.005. The IRF4 rs12203592 associations were slightly attenuated after adjustment for melanoma-risk phenotypes. The PLA2G6 rs132985 associations were independent of phenotypes. IRF4 and PLA2G6 inherited genotypes may influence melanoma BRAF/NRAS subtype development.

A Leukocyte Infiltration Score Defined by a Gene Signature Predicts Melanoma Patient Prognosis

Melanoma is the most aggressive type of skin cancer in the United States with an increasing incidence. Melanoma lesions often exhibit high immunogenicity, with infiltrating immune cells playing important roles in regression of tumors occurring spontaneously or caused by therapeutic treatment. Computational and experimental methods have been used to estimate the abundance of immune cells in tumors, but their applications are limited by the requirement of large gene sets or multiple antibodies. Although the prognostic role of immune cells has been appreciated, a systematic investigation of their association with clinical factors, genomic features, prognosis and treatment response in melanoma is still lacking. This study, identifies a 25-gene signature based on RNA-seq data from The Cancer Genome Atlas (TCGA)-Skin Cutaneous Melanoma (TCGA-SKCM) dataset. This signature was used to calculate sample-specific Leukocyte Infiltration Scores (LIS) in six independent melanoma microarray datasets and scores were found to vary substantially between different melanoma lesion sites and molecular subtypes. For metastatic melanoma, LIS was prognostic in all datasets with high LIS being associated with good survival. The current approach provided additional prognostic information over established clinical factors, including age, tumor stage, and gender. In addition, LIS was predictive of patient survival in stage III melanoma, and treatment efficacy of tumor-specific antigen vaccine. IMPLICATIONS: This study identifies a 25-gene signature that effectively estimates the level of immune cell infiltration in melanoma, which provides a robust biomarker for predicting patient prognosis.

Abstract 3682: Expression levels of genes in primary melanoma associated with clinically meaningful characteristics

Melanoma survival appears to be improving; however, between 13-68% of individuals with melanoma diagnosed with Stages II-III ultimately die from their melanoma. Factors influencing melanoma survival include sex, age, clinical stage, lymph node involvement and several primary tumor characteristics, such as Breslow thickness, presence of infiltrating lymphocytes (TILs), mitotic rate and ulceration. Identification of genes whose expression in primary tumors is associated with these key tumor/patient characteristics can shed light on molecular mechanisms of melanoma survival. Here we show results from a gene expression analysis of 32 formalin-fixed, paraffin embedded (FFPE) primary melanomas with extensive clinical annotation. We extracted RNA, and measured the expression of 760 genes selected based on published evidence of association with melanoma initiation or outcome using NanoString. The Cancer Genome Atlas (TCGA) data on primary melanomas was used for validation of nominally significant associations. We identified 5 genes that were significantly associated with the presence of TILs in the combined analysis of both datasets after adjustment for multiple testing using the Benjamini-Hochberg false discovery rate method: IL1R2, PPL, PLA2G3, RASAL1, and SGK2. We also identified two genes significantly associated with lymph node status (PIK3CG and IL2RA), and two genes significantly associated with sex (KDM5C and KDM6A). We found that LEF1 was significantly associated with Breslow thickness and CCNA2 with mitosis. These results demonstrate that genetic expression in primary tumors is associated with clinically meaningful characteristics of cutaneous melanoma.

Citation Format: Marianne Berwick, Ivan P. Gorlov, Irene Orlow, Carol Ringelberg, Marc Ernstoff, Joel Parker, Meg Gerstenblith, Cheryl Thompson, Eva Hernando, Klaus Busam, Cecilia Lezcano, Sergio Corrales, Siok Leong, Nancy E. Thomas, Christopher I. Amos. Expression levels of genes in primary melanoma associated with clinically meaningful characteristics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3682.

Surgical re-excision vs. observation for histologically dysplastic naevi: a systematic review of associated clinical outcomes

BACKGROUND

The management of histologically dysplastic naevi (HDN) with re-excision vs. observation remains controversial because of lack of evidence about associated melanoma outcomes.

OBJECTIVES

To assess published data on the development of biopsy-site primary cutaneous melanoma among biopsy-proven HDN managed with either re-excision or observation.

METHODS

A systematic review of all published data: a total of 5293 records were screened, 18 articles were assessed in full text and 12 studies met inclusion criteria. No controlled trials were identified.

RESULTS

Most studies (11 of 12, 92%) were retrospective chart reviews, and one was both a cross-sectional and cohort study. Many studies (nine of 12, 75%) had no head-to-head comparison groups and either only reported HDN that were re-excised or observed. A total of 2673 (1535 observed vs. 1138 re-excised) HDN of various grades were included. Follow-up varied between 2 weeks and 30 years. Nine studies reported that no melanomas developed. Eleven biopsy-site melanomas developed across three of the studies, six among observed lesions (0·39%) and five among re-excised lesions (0·44%).

CONCLUSIONS

Based upon the available evidence the rates of biopsy-site primary melanoma were similarly low among observed lesions and re-excised lesions. This suggests that HDNs can be observed with minimal adverse melanoma-associated outcomes. However, all included articles were of low quality and further prospective trials could better guide clinical decision making.

Cash for carbon: A randomized trial of payments for ecosystem services to reduce deforestation

We evaluated a program of payments for ecosystem services in Uganda that offered forest-owning households annual payments of 70,000 Ugandan shillings per hectare if they conserved their forest. The program was implemented as a randomized controlled trial in 121 villages, 60 of which received the program for 2 years. The primary outcome was the change in land area covered by trees, measured by classifying high-resolution satellite imagery. We found that tree cover declined by 4.2% during the study period in treatment villages, compared to 9.1% in control villages. We found no evidence that enrollees shifted their deforestation to nearby land. We valued the delayed carbon dioxide emissions and found that this program benefit is 2.4 times as large as the program costs.

Associations of MC1R Genotype and Patient Phenotypes with BRAF and NRAS Mutations in Melanoma

Associations of MC1R with BRAF mutations in melanoma have been inconsistent between studies. We sought to determine for 1,227 participants in the international population-based Genes, Environment, and Melanoma (GEM) study whether MC1R and phenotypes were associated with melanoma BRAF/NRAS subtypes. We used logistic regression adjusted by age, sex, and study design features and examined effect modifications. BRAF+ were associated with younger age, blond/light brown hair, increased nevi, and less freckling, and NRAS+ with older age relative to the wild type (BRAF-/NRAS-) melanomas (all P < 0.05). Comparing specific BRAF subtypes to the wild type, BRAF V600E was associated with younger age, blond/light brown hair, and increased nevi and V600K with increased nevi and less freckling (all P < 0.05). MC1R was positively associated with BRAF V600E cases but only among individuals with darker phototypes or darker hair (Pinteraction < 0.05) but inversely associated with BRAF V600K (Ptrend = 0.006) with no significant effect modification by phenotypes. These results support distinct etiologies for BRAF V600E, BRAF V600K, NRAS+, and wild-type melanomas. MC1R's associations with BRAF V600E cases limited to individuals with darker phenotypes indicate that MC1R genotypes specifically provide information about BRAF V600E melanoma risk in those not considered high risk based on phenotype. Our results also suggest that melanin pathways deserve further study in BRAF V600E melanomagenesis.

Association of Delays in Surgery for Melanoma With Insurance Type

Importance

Timely receipt of treatment for cancer is an important aspect of health care quality. It is unknown how delays of surgery for melanoma vary by insurance type.

Objective

To analyze factors associated with delays between diagnosis and surgery for melanoma in patients with Medicare, Medicaid, or private insurance.

Design, Setting, and Participants

Retrospective cohort study of patients who received a diagnosis of melanoma between 2004 and 2011 in North Carolina using data from the North Carolina Cancer Registry linked to administrative claims from Medicare, Medicaid, and private insurance. Inclusion criteria were incident patients with a diagnosis of melanoma stage 0 to III and with continuous insurance enrollment from at least 1 month prior to the month of diagnosis to 12 months after diagnosis of melanoma.

Main Outcomes and Measures

Surgical delay, defined as definitive surgical excision occurring more than 6 weeks after melanoma diagnosis. Generalized linear models with log link, Poisson distributions, and robust standard errors were used to estimate adjusted risk ratios (RRs) to model risk of delay in definitive surgery.

Results

A total of 7629 patients were included (4210 [55%] female; mean [SD] age, 64 [15] years), 48% (n = 3631) Medicare, 48% (n = 3667) privately insured, and 4% (n = 331) Medicaid patients. Privately insured patients were least likely to experience a delay in definitive surgery, followed by Medicare and Medicaid patients (519 [14%], 609 [17%], and 79 [24%], respectively; P < .001). After demographic adjustment, the risk of surgical delay was significantly increased in patients with Medicaid compared with private insurance (RR, 1.36; 95% CI, 1.09-1.70). Delays were more likely in nonwhite patients (RR, 1.38; 95% CI, 1.02-1.87). Surgical delays were less likely if the physician performing the surgery (RR, 0.82; 95% CI, 0.72-0.93) or the diagnosing clinician (RR, 0.81; 95% CI, 0.71-0.93) was a dermatologist as compared with a nondermatologist.

Conclusion and Relevance

Surgical treatment delays were common but were less prevalent in patients diagnosed or surgically treated by a dermatologist. Medicaid patients experienced the most surgical delays. A reduction in delays in melanoma surgery could be achieved through better access to specialty care and cross-disciplinary coordination.

The interaction between vitamin D receptor polymorphisms and sun exposure around time of diagnosis influences melanoma survival

Evidence on the relationship between the vitamin D pathway and outcomes in melanoma is growing, although it is not always clear. We investigated the impact of measured levels of sun exposure at diagnosis on associations of vitamin D receptor gene (VDR) polymorphisms and melanoma death in 3336 incident primary melanoma cases. Interactions between six SNPs and a common 3'-end haplotype were significant (p < .05). These SNPs, and a haplotype, had a statistically significant association with survival among subjects exposed to high UVB in multivariable regression models and exerted their effect in the opposite direction among those with low UVB. SNPs rs1544410/BsmI and rs731236/TaqI remained significant after adjustment for multiple testing. These results suggest that the association between VDR and melanoma-specific survival is modified by sun exposure around diagnosis, and require validation in an independent study. Whether the observed effects are dependent or independent of vitamin D activation remains to be determined.

Association of Incident Amelanotic Melanoma With Phenotypic Characteristics, MC1R Status, and Prior Amelanotic Melanoma

Importance

We previously reported that survival is poorer from histopathologically amelanotic than pigmented melanoma because of more advanced stage at diagnosis. Identifying patients at risk of amelanotic melanoma might enable earlier diagnosis and improved survival; however, the phenotypic characteristics and underlying genetics associated with amelanotic melanoma are unknown.

Objective

To determine whether phenotypic characteristics, carriage of MC1R variants, and history of amelanotic melanoma are associated with histopathologically amelanotic melanoma.

Design, Setting, and Participants

The Genes, Environment, and Melanoma (GEM) study is an international cohort study that enrolled patients with incident primary cutaneous melanomas from population-based and hospital-based cancer registries (1998 to 2003). The GEM participants included here were 2387 patients with data for phenotypes, MC1R genotype, and primary melanomas scored for histopathologic pigmentation. Of these 2387 patients with incident melanomas scored for pigmentation, 527 had prior primary melanomas also scored for pigmentation.

Main Outcomes and Measures

Associations of phenotypic characteristics (freckles, nevi, phenotypic index) and MC1R status with incident amelanotic melanomas were evaluated using logistic regression models adjusted for age, sex, study center, and primary status (single or multiple primary melanoma); odds ratios (ORs) and 95% CIs are reported. Association of histopathologic pigmentation between incident and prior melanomas was analyzed using an exact logistic regression model.

Results

This study included 2387 patients (1065 women, 1322 men; mean [SD] age at diagnosis, 58.3 [16.1] years) and 2917 primary melanomas. In a multivariable model including phenotypic characteristics, absence of back nevi, presence of many freckles, and a sun-sensitive phenotypic index were independently associated with amelanotic melanoma. Carriage of MC1R variants was associated with amelanotic melanoma but lost statistical significance in a model with phenotype. Further, patients with incident primary amelanotic melanomas were more likely to have had a prior primary amelanotic melanoma (OR, 4.62; 95% CI, 1.25-14.13) than those with incident primary pigmented melanomas.

Conclusions and Relevance

Absence of back nevi, presence of many freckles, a sun-sensitive phenotypic index, and prior amelanotic melanoma increase odds for development of amelanotic melanoma. An increased index of suspicion for melanoma in presenting nonpigmented lesions and more careful examination for signs of amelanotic melanoma during periodic skin examination in patients at increased odds of amelanotic melanoma might lead to earlier diagnosis and improved survival.

Tumor Mitotic Rate and Association with Recurrence in Sentinel Lymph Node Negative Stage II Melanoma Patients

Tumor mitotic rate (TMR) is a known prognostic variable in thin melanoma patients. Its significance in stage II melanoma patients is yet to be demonstrated. Retrospective analysis of a prospective melanoma database from 9/1997 to 7/2015 was performed. All stage II melanoma, with documented TMR, and six months of follow-up were included. We evaluated the association of clinicopathologic variables, TMR, as a continuous and categorical variable with recurrence-free survival (RFS) and overall survival (OS) using Cox proportional hazards modeling. We used a statistical model, X-tile, to develop optimal categorizations of TMR. A total of 265 patient characteristics are included in this study. Recurrences occurred in 82 (30.9%) patients, including 5 local, 41 regional, and 36 distant patients. In multivariate model, ulceration, Breslow, and continuous TMR were associated with worse RFS\OS. Continuous TMR demonstrated worse RFS (hazards ratio [HR] 1.02 (1.00–1.05)) and OS (HR 1.02 (1.00–1.04)), whereas dichotomized TMR (≥1 vs <1) was not significant. TMR >10.4 mitoses/mm2 has a 5-year RFS\OS of 27.2 and 44.3 per cent, respectively, compared with 57.4 and 71.4 per cent, respectively, for TMR <3.2 mitoses/mm2. Continuous TMR predicts incidence of recurrence in stage II melanoma. We propose a new categorization method developed by statistical modeling for optimal stratification that may guide surveillance for this disparate patient population.

Tumor Mitotic Rate and Association with Recurrence in Sentinel Lymph Node Negative Stage II Melanoma Patients

Tumor mitotic rate (TMR) is a known prognostic variable in thin melanoma patients. Its significance in stage II melanoma patients is yet to be demonstrated. Retrospective analysis of a prospective melanoma database from 9/1997 to 7/2015 was performed. All stage II melanoma, with documented TMR, and six months of follow-up were included. We evaluated the association of clinicopathologic variables, TMR, as a continuous and categorical variable with recurrence-free survival (RFS) and overall survival (OS) using Cox proportional hazards modeling. We used a statistical model, X-tile, to develop optimal categorizations of TMR. A total of 265 patient characteristics are included in this study. Recurrences occurred in 82 (30.9%) patients, including 5 local, 41 regional, and 36 distant patients. In multivariate model, ulceration, Breslow, and continuous TMR were associated with worse RFS\OS. Continuous TMR demonstrated worse RFS (hazards ratio [HR] 1.02 (1.00-1.05)) and OS (HR 1.02 (1.00-1.04)), whereas dichotomized TMR (≥1 vs <1) was not significant. TMR >10.4 mitoses/mm2 has a 5-year RFS\OS of 27.2 and 44.3 per cent, respectively, compared with 57.4 and 71.4 per cent, respectively, for TMR <3.2 mitoses/mm2. Continuous TMR predicts incidence of recurrence in stage II melanoma. We propose a new categorization method developed by statistical modeling for optimal stratification that may guide surveillance for this disparate patient population.

NCI 9922: Phase 2 study of ibrutinib in treatment-refractory distant metastatic cutaneous melanoma (DMCM)

TPS9592

Background: We have previously shown that the IL-2 inducible kinase (ITK) is highly expressed in primary melanomas compared with nevi due to promoter hypomethylation (Conway PCMR 2011). We have also shown using 2-color immunofluorescence (2CIF) that ITK protein expression is increased even more in metastatic compared to primary melanomas (S100+) and that molecular targeting (shRNA) or pharmacologic inhibition of ITK (BI 10N) in various melanoma cell lines, various melanoma xenografts and an immunocompetent melanoma mouse model suppresses cell proliferation and retards tumor growth without inducing cell death (Carson CCR 2015). We have also shown by intracellular stain of peripheral blood mononuclear cells (PBMC) that ITK is expressed in PBMC obtained from patients (pts) treated with MAPK or CTLA-4 inhibitors. Other groups have shown that ITK and BTK are expressed in Th2 cells, myeloid-derived suppressor cells, and tumor-associated macrophages. We have also shown that ibrutinib suppresses proliferation of various melanoma cell lines in low nM concentrations depending on tumoral expression of ITK. We hypothesize that targeting DMCM with ibrutinib alone will induce antitumor responses and/or prolong survival if DMCM expresses high levels of melanoma-associated ITK by 2CIF (S100/ITK). Methods: This is an open-label, single-arm, multicenter, phase II study of DMCM refractory to or ineligible for PD-1 and MAPK inhibitors. Ibrutinib will be dosed at 840 mg p.o. qd. The null hypothesis is that an ineffective drug will confer a 5% response rate (RR) and 18% 6-month PFS (6m PFS), whereas ibrutinib will confer > = 20% RR and > = 35% 6m PFS (KEYNOTE-002). This trial accrues in two stages; if either the RR and/or 6m PFS endpoint are met after 18 patients, then 14 additional pts will be accrued for a total of 32. The Simon’s design will reject the null hypothesis if > = 4 responses are observed or > = 9 pts have PFS better than 6 months out of 32 patients. All pts are required to have baseline tumor tissue available for analysis of ITK expression by 2CIF. Immune monitoring will be performed on PBMC collected at baseline and various time points during treatment. Trial is currently recruiting pts (NCT02581930). Clinical trial information: NCT02581930.

Defining Cancer Subtypes With Distinctive Etiologic Profiles: An Application to the Epidemiology of Melanoma

We showcase a novel analytic strategy to identify sub-types of cancer that possess distinctive causal factors, i.e. sub-types that are "etiologically" distinct. The method involves the integrated analysis of two types of study design: an incident series of cases with double primary cancers with detailed information on tumor characteristics that can be used to define the sub-types; a case-series of incident cases with information on known risk factors that can be used to investigate the specific risk factors that distinguish the sub-types. The methods are applied to a rich melanoma dataset with detailed information on pathologic tumor factors, and comprehensive information on known genetic and environmental risk factors for melanoma. Identification of the optimal sub-typing solution is accomplished using a novel clustering analysis that seeks to maximize a measure that characterizes the distinctiveness of the distributions of risk factors across the sub-types and that is a function of the correlations of tumor factors in the case-specific tumor pairs. This analysis is challenged by the presence of extensive missing data. If successful, studies of this nature offer the opportunity for efficient study design to identify unknown risk factors whose effects are concentrated in defined sub-types.

No prognostic value added by vitamin D pathway SNPs to current prognostic system for melanoma survival

The prognostic improvement attributed to genetic markers over current prognostic system has not been well studied for melanoma. The goal of this study is to evaluate the added prognostic value of Vitamin D Pathway (VitD) SNPs to currently known clinical and demographic factors such as age, sex, Breslow thickness, mitosis and ulceration (CDF). We utilized two large independent well-characterized melanoma studies: the Genes, Environment, and Melanoma (GEM) and MD Anderson studies, and performed variable selection of VitD pathway SNPs and CDF using Random Survival Forest (RSF) method in addition to Cox proportional hazards models. The Harrell's C-index was used to compare the performance of model predictability. The population-based GEM study enrolled 3,578 incident cases of cutaneous melanoma (CM), and the hospital-based MD Anderson study consisted of 1,804 CM patients. Including both VitD SNPs and CDF yielded C-index of 0.85, which provided slight but not significant improvement by CDF alone (C-index = 0.83) in the GEM study. Similar results were observed in the independent MD Anderson study (C-index = 0.84 and 0.83, respectively). The Cox model identified no significant associations after adjusting for multiplicity. Our results do not support clinically significant prognostic improvements attributable to VitD pathway SNPs over current prognostic system for melanoma survival.

Abstract B07: The loss function of BP180 (Collagen type XVII) in skin, leads to a mast cell dependent pro-inflammatory microenvironment which promotes melanoma progression

BP180, also known as type 17 collagen, is a transmembrane glycoprotein located in the hemidesmosome of epidermal basal keratinocytes. BP180 is a critical cell/matrix adhesion molecule in dermal-epidermal junction of the skin. Various clinical reports indicated that the altered expression of hemidesmosomal protein BP180 is associated with melanoma progression. However, it is unclear whether BP180 is directly involved in melanoma progression. To investigate the role of BP180 in melanoma progression, we generated novel mouse strains lacking BP180 functions in whole body (by crossing floxed mice with germline Cre), in the local skin (tamoxifen-inducible Cre), or in basal keratinocytes (K14-driven Cre). These BP180 functional knockout mice showed dermal-epidermal junction separation in the skin, indicating that the cell/cell matrix adhesion mediated by BP180 is impaired. Loss of BP180 function also lead to a proinflammatory microenvironment in skin accompanied with an influx of immune cells including mast cells, neutrophils and T cells. When tested in B16 mouse melanoma model BP180 functional deficient mice (globally, in the local skin, or in basal keratinocytes) showed significantly increased melanoma progression. These results demonstrated that BP180 deficiency limited in local skin microenvironment or basal keratinocyte is sufficient to promote melanoma progression. To determine whether increased neutrophil or mast cells are required for the accelerated melanoma progression in BP180 functional deficient mice, we injected B16 melanoma cells into mice lacking both mast cells and BP180 function. Mast cell deficiency drastically reduced the inflammation, neutrophil influx into skin and melanoma progression caused by loss of BP180 function. These findings provide the first evidence suggesting that BP180, as a hemidesmosomal cell-cell matrix adhesion protein, plays a vital role in host defense against melanoma progression through modulating basal keratinocytes, neutrophil and mast cells in local tumor microenvironment.

Citation Format: Bin-Jin Hwang, Bin Peng, Yang Zhang, Jaime Marie Brozowski, Lin Lin, Scott E. Williams, Ning Li, Zhen Liu, Maureen Su, Nancy E. Thomas, Luis A. Diaz, Zhi Liu. The loss function of BP180 (Collagen type XVII) in skin, leads to a mast cell dependent pro-inflammatory microenvironment which promotes melanoma progression. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2016 Oct 20-23; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2017;5(3 Suppl):Abstract nr B07.

Variants in autophagy-related genes and clinical characteristics in melanoma: a population-based study

Autophagy has been linked with melanoma risk and survival, but no polymorphisms in autophagy‐related (ATG) genes have been investigated in relation to melanoma progression. We examined five single‐nucleotide polymorphisms (SNPs) in three ATG genes (ATG5;ATG10; and ATG16L) with known or suspected impact on autophagic flux in an international population‐based case–control study of melanoma. DNA from 911 melanoma patients was genotyped. An association was identified between (GG) (rs2241880) and earlier stage at diagnosis (OR 0.47; 95% Confidence Intervals (CI) = 0.27–0.81, P = 0.02) and a decrease in Breslow thickness (P = 0.03). The ATG16L heterozygous genotype (AG) (rs2241880) was associated with younger age at diagnosis (P = 0.02). Two SNPs in ATG5 were found to be associated with increased stage (rs2245214 CG, OR 1.47; 95% CI = 1.11–1.94, P = 0.03; rs510432 CC, OR 1.84; 95% CI = 1.12–3.02, P = 0.05). Finally, we identified inverse associations between ATG5 (GG rs2245214) and melanomas on the scalp or neck (OR 0.20, 95% CI = 0.05–0.86, P = 0.03); ATG10 (CC) (rs1864182) and brisk tumor infiltrating lymphocytes (TILs) (OR 0.42; 95% CI = 0.21–0.88, P = 0.02), and ATG5 (CC) (rs510432) with nonbrisk TILs (OR 0.55; 95% CI = 0.34–0.87, P = 0.01). Our data suggest that ATGSNPs might be differentially associated with specific host and tumor characteristics including age at diagnosis, TILs, and stage. These associations may be critical to understanding the role of autophagy in cancer, and further investigation will help characterize the contribution of these variants to melanoma progression.

Nevus count associations with pigmentary phenotype, histopathological melanoma characteristics and survival from melanoma

Although nevus count is an established risk factor for melanoma, relationships between nevus number and patient and tumor characteristics have not been well studied and the influence of nevus count on melanoma-specific survival is equivocal. Using data from the Genes, Environment and Melanoma (GEM) study, a large population-based study of primary cutaneous melanoma, we evaluated associations between number of nevi and patient features, including sun-sensitivity summarized in a phenotypic index, and tumor characteristics. We also assessed the association of nevus count with melanoma-specific survival. Higher nevus counts were independently and positively associated with male gender and younger age at diagnosis, and they were inversely associated with lentigo maligna histology. We observed a borderline significant trend of poorer melanoma-specific survival with increasing quartile of nevus count, but little or no association between number of nevi and pigmentary phenotypic characteristics or prognostic tumor features.