Common Subtype Of Melanoma Research Articles

CDK4 gene copy number increase and concurrent genetic changes in acral melanoma of a Chinese cohort

Acral melanoma (AM) is the most common subtype of melanoma in the Asian population. Abnormalities in the p16-cyclin D1-CDK4 signalling pathway play a crucial role in the development and progression of AM. However, the CDK4 copy number variations (CNVs) in AM are under-reported. In this study, we investigated CDK4 gene copy number and concurrent molecular changes in a Chinese cohort with AM, to explore CDK4 CNVs and their significance in AM. We examined CDK4 CNVs with fluorescence in situ hybridisation (FISH) in 31 patients with AM. Six patients with CDK4 high-level copy number increase were examined by next-generation sequencing to detect concurrent molecular changes. Using FISH, 12 (12/31, 38.7%) cases showed CDK4 copy number increase, with six (6/31, 19.4%) low-level copy number increase and six (6/31, 19.4%) high-level copy number increase. Five of six CDK4 low-level copy number increase cases were accompanied by polysomy of chromosome 12, while one case was not. Two of six CDK4 high-level copy number increase cases were accompanied by polysomy of chromosome 12, while four cases were not. CDK4 copy number increase was significantly correlated with younger patient age. In six CDK4 high-level copy number increase cases, one case was found to be accompanied by NRAS mutation, one case was accompanied by HER2 mutation, one case was accompanied by BCL2L11 mutation ​and one case was accompanied by BRAF, HER2 and BCL2L11 mutations. Our study confirmed the presence of CDK4 copy number increase in AM cases. Detecting CDK4 copy number increase by FISH can be reliable in the diagnosis of AM. Some CDK4 copy number increases are the results of polysomy of chromosome 12. CDK4 high-level copy number increase coexists with other pathogenic mutations in AM. CDK4 appears to be a promising target for AM treatment and is expected to be combined with other targeted therapies.

YAP Activation in Promoting Negative Durotaxis and Acral Melanoma Progression.

Directed cell migration towards a softer environment is called negative durotaxis. The mechanism and pathological relevance of negative durotaxis in tumor progression still requires in-depth investigation. Here, we report that YAP promotes the negative durotaxis of melanoma. We uncovered that the RhoA-myosin II pathway may underlie the YAP enhanced negative durotaxis of melanoma cells. Acral melanoma is the most common subtype of melanoma in non-Caucasians and tends to develop in a stress-bearing area. We report that acral melanoma patients exhibit YAP amplification and increased YAP activity. We detected a decreasing stiffness gradient from the tumor to the surrounding area in the acral melanoma microenvironment. We further identified that this stiffness gradient could facilitate the negative durotaxis of melanoma cells. Our study advanced the understanding of mechanical force and YAP in acral melanoma and we proposed negative durotaxis as a new mechanism for melanoma dissemination.

Comparative Genomics Provides Etiologic and Biological Insight into Melanoma Subtypes.

This is the largest whole-genome analysis of melanoma to date, comprehensively comparing the genomics of the four major melanoma subtypes. This study highlights both similarities and differences between the subtypes, providing insights into the etiology and biology of melanoma. This article is highlighted in the In This Issue feature, p. 2711.

Clinicopathological Characteristics Predicting Further Recurrence and Survival Following Resection of In-Transit Melanoma Metastases

BackgroundIn-transit metastases (ITMs) affect approximately 4% of patients with cutaneous melanoma. This study sought to identify clinical and pathological characteristics that predict further recurrence and survival following resection of ITMs.Patients and MethodsPatients (n = 573) who underwent surgical resection of their first presentation of ITM following previous surgical treatment of an American Joint Committee on Cancer (AJCC) stage I–II melanoma between 1969 and 2017 were identified from an institutional database. Clinicopathological predictors of patterns of recurrence and survival following ITM resection were sought.ResultsThe median time of ITM development was 2.4 years after primary melanoma resection. ITMs were most frequently located on the lower limb (51.0%). The most common melanoma subtype associated with ITM development was nodular melanoma (44.1%). After surgical resection of a first ITM, 65.4% of patients experienced recurrent disease. Most recurrences were locoregional (44.7%), with distant metastasis occurring in 23.9% of patients. Lower limb ITMs were more frequently associated with subsequent ITMs [odds ratio (OR) 2.41, p = 0.0002], and the lowest risk of distant metastasis (p < 0.0001) compared with other primary sites. Primary melanomas and ITM on head and neck, as well as the presence of ulceration, were associated with worse survival.ConclusionsRecurrence after surgical resection of a first ITM was common. Patterns of recurrence differed according to anatomical site; further ITM recurrences were more likely for lower limb ITMs, which were also associated with longer distant recurrence-free survival. Distant metastasis was more common for ITM on the head and neck, with worse survival.

Integrative molecular and clinical profiling of acral melanoma links focal amplification of 22q11.21 to metastasis

Acral melanoma, the most common melanoma subtype among non-White individuals, is associated with poor prognosis. However, its key molecular drivers remain obscure. Here, we perform integrative genomic and clinical profiling of acral melanomas from 104 patients treated in North America (n = 37) or China (n = 67). We find that recurrent, late-arising focal amplifications of cytoband 22q11.21 are a leading determinant of inferior survival, strongly associated with metastasis, and linked to downregulation of immunomodulatory genes associated with response to immune checkpoint blockade. Unexpectedly, LZTR1 – a known tumor suppressor in other cancers – is a key candidate oncogene in this cytoband. Silencing of LZTR1 in melanoma cell lines causes apoptotic cell death independent of major hotspot mutations or melanoma subtypes. Conversely, overexpression of LZTR1 in normal human melanocytes initiates processes associated with metastasis, including anchorage-independent growth, formation of spheroids, and an increase in MAPK and SRC activities. Our results provide insights into the etiology of acral melanoma and implicate LZTR1 as a key tumor promoter and therapeutic target.

Nodular Melanoma: A Review of Pathogenesis, Presentation, Diagnosis, and Treatment

Nodular melanoma is the second most common subtype of melanoma. Unlike other subtypes, nodular melanoma is characterized by early vertical growth rather than the typical initial radial growth of most melanomas. As a result, nodular melanoma presents clinically in a more aggressive phenotype. Given its more aggressive nature and intrinsic ability to mimic benign lesions, a modified acronym has been developed to allow clinicians to better evaluate, diagnose and treat nodular melanoma in earlier stages. Surgical excision with wide margins is the gold standard of nodular melanoma therapy; however, an emphasis in early detection, diagnosis, staging, and treatment needs to be emphasized among clinicians due to its dismal prognosis in later stages, as compared to other subtypes. A better understanding of the molecular pathophysiology that allows nodular melanoma to act aggressively very early in diagnosis is necessary for the development of therapeutics that may effectively target lesions in more advanced stages.

Gene mutations and clinical prognosis of mucosal melanoma in different locations of head and neck

Background Mucosal melanoma is the second most common subtype of melanoma in China and head and neck region is one of the main sites of this disease. Aims/Objectives Analyzed the phenotypes of C-Kit, NRAS, PDGFRA and BRAF genes in patients with in different locations to explore the characteristics of gene mutations. Material and Methods 96 patients were included in this study. C-Kit (exons 9, 11, 13, 17 and 18), NRAS (exons 1 and 2), PDGFRA (exons 12, 14 and 18) and BRAF (exons 11 and 15) were analyzed by PCR amplification and Sanger sequencing. Results 14 (14.58%) patients had C-Kit mutation, 6 (6.25%) had BRAF mutation, 23 (23.96%) had PDGFRA mutation, and 12 (12.50%) had NRAS mutation. The NRAS mutation (p = 0.037, 95%CI: 1.050–4.572) was an independent factor affecting distant metastasis and was most commonly found in the nasal cavity/paranasal sinuses (p = .043) while the BRAF mutation was more common in locations other than the nasal cavity/paranasal sinus (p = .008) and was associated with local recurrence. Conclusions and Significance Gene phenotypes of mucosal melanoma in different locations has differences. Lesions in the nasal cavity and paranasal sinus should be assessed separately from other parts such as the nasopharynx.

Abstract 2222: The molecular landscape of acral lentiginous melanoma in Mexican patients

Abstract Acral lentiginous melanoma (ALM) is the most common melanoma subtype in several countries in Africa, Asia, and Latin America, including Mexico. Comparatively fewer studies have been published of ALM than other subtypes of the disease. However, it is becoming clear that complex DNA structural aberrations, as well as several genes, such as NOTCH2, KIT, PTEN and TYRP1, in addition to the established melanoma drivers, play a role in its development. To date, no comprehensive genomic characterization has been performed on tumors from Latin American patients. The causes of ALM are unknown, and little is known about its transcriptomic profile and immune landscape. Because of these factors, therapeutic options are limited, while approaches such as immunotherapy are too costly for most patients in Latin American countries, and are of unknown efficacy in rarer forms of melanoma such as ALM. A better understanding of the molecular and immune profile of ALM would allow us to identify potential therapeutic targets and treatment strategies in this population. We have sequenced the exomes and transcriptomes of 113 ALM tumors (primaries, metastases and recurrences) from 86 patients being treated at the National Cancer Institute of Mexico, a national reference hospital. We have performed analyses to define the genomic landscape of the disease, its mutational signatures, the biological pathways involved in its development, and its immune profile. From these analyses, we have identified recurrently amplified and deleted genomic regions, potential causal agents, and the involvement of specific interleukins and cell-adhesion proteins in ulcerated and metastatic tumors. This study is one of the first to profile the molecular landscape of ALM in a Latin American population. We hope that it will contribute to increasing the diversity of cancer genomics datasets, help highlight differences in disease biology, and provide insights that may inform therapeutic strategies for all patients with this lethal malignancy. Citation Format: Martha E. Vázquez-Cruz, Patricia Basurto-Lozada, Christian Molina-Aguilar, Carolina Castaneda-Garcia, Ingrid Ferreira, Héctor Martínez-Said, Alethia Álvarez-Cano, Luis Alberto Tavares-de la Paz, Diego Hinojosa-Ugarte, Dorian Y. García-Ortega, Julia M. Martínez-Gómez, Mitchell P. Levesque, David J. Adams, Carla D. Robles-Espinoza. The molecular landscape of acral lentiginous melanoma in Mexican patients [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 2222.

568 CK2 inhibition synergizes with MAPK inhibition to overcome resistance in acral melanoma

Acral melanoma (AM) occurs on the palms, soles and subungual sites and occurs in a much higher proportion in darker-skinned individuals compared to cutaneous melanoma. AM is the most common subtype of melanoma in patients of African and Asian descent. AM is associated with activation mutations in the KIT gene and/or inactivating mutations in NF1 (neurofibromin1). These tumors respond poorly to currently available targeted therapies and immune checkpoint inhibition, underscoring the urgent need for treatment alternatives that improve overall survival of patients with metastatic disease. The protein kinase CK2 (casein kinase II) is upregulated in several types of cancer, including melanoma, and especially in AM. CK2 over-expression contributes to maintenance of the malignant phenotype and is associated with resistance to targeted therapies. Here, we investigated the potential of CK2 inhibition to overcome resistance to MEK inhibitors (MEKi) in preclinical models of AM. We found that in vitro treatment of NF1-null human melanoma cells with a small-molecule CK2 inhibitor (CX4945, silmitasertib) resulted in inhibition of cell proliferation. This was accompanied by downregulation of PI3K and ERK-MAPK signaling, as demonstrated by dephosphorylation of AKT (S129 and S473) and ERK (p44/42 MAPK; Thr202/Tyr204). CX4945 also showed a synergistic anti-proliferative effect with the MEKi trametinib in MTS viability assays, and an increase in apoptosis. Further, in colony formation assays, CX4945 significantly reduced the appearance of trametinib resistant colonies. To translate these findings, we treated NF1-null human melanoma cells grown as xenografts in nude mice with CX4945, and noted a significant reduction in tumor growth that resulted in stable disease. Together, our results suggest that the combination of CK2 inhibitors with MEK inhibitors, and potentially other tyrosine kinase inhibitors, may improve therapeutic outcomes in difficult to treat malignant melanomas of acral origin.

Molecular profiling of Asian patients with advanced melanoma receiving check-point inhibitor treatment

ObjectiveMelanoma is major medical challenge and being able to monitor treatment response is critical. This study aimed to use molecular profiling of Asian patients with advanced melanoma who were receiving treatment with check-point inhibitors (CPIs) to identify novel biomarkers of tumor response.MethodsNext-generation sequencing (NGS) was performed using tumor specimens collected from 178 Asian patients with metastatic melanoma receiving CPIs. The NGS data and clinical-pathological factors were analyzed for potential genetic biomarkers of tumor response to CPI treatment.ResultsThe most common melanoma subtype was acral melanoma (40%), followed by cutaneous melanoma (32%), mucosal melanoma (26%), and others (2%). For calculation of treatment efficacy, 164 of the patients could be evaluated. The overall response rate was 45.7%, of which 41 cases exhibited complete responses (25.0%) and 34 showed partial responses (20.7%). There were no significant differences in tumor responses based on melanoma subtype (P = 0.295). Genetically, NRAS mutations, TP53 mutations, and NF2 deletions were significantly associated with resistance to CPIs (P < 0.05). In contrast, MYC and RPS6KB1 amplifications were associated with responsiveness to CPIs (P < 0.05). Median progression-free survival (PFS) for patients treated with CPIs was 5.9 months (95% CI, 3.8-8.05 months). Univariate analysis identified TP53 and BRAF mutations, NF2 deletions, and BIRC2 amplifications as poor prognostic factors for PFS (P < 0.05).ConclusionsThis study determined the integrated genomic profiles of Asian patients with metastatic melanoma receiving CPIs and identified candidate biomarkers that reflected treatment outcomes.

Comparative Analysis of Acral Melanoma in Chinese and Caucasian Patients

Background Acral melanoma (AM) is a rare subtype of melanoma, which is one of the least common in Caucasian patients but is a common subtype of melanoma in Chinese patients. It is unclear if prognosis differs between Chinese and Caucasian patients diagnosed with AM. The aim of our study is to investigate patient characteristics and survival differences between Chinese and Caucasian AM patients. Methods Two large institutional melanoma databases from Fudan University Shanghai Cancer Center (FUSCC) and Mayo Clinic enterprise were retrospectively reviewed from 2009 to 2015. Clinicopathologic and survival data were collected and analyzed between the two groups. The primary outcome was disease-specific survival (DSS) and was calculated using the Kaplan Meier (KM) method. Results The Chinese group presented with more advanced disease compared with Caucasians: thicker Breslow depth (median 3.0 mm vs. 1.2 mm, p=0.003), more ulcerated disease (66.1% vs. 29%; p < 0.001), and advanced stages (stage II/III 84.3% vs. 37.1%; p < 0.001). No significant difference was identified in terms of age at diagnosis, location, histologic subtypes, or node positive rate. The 5-year DSS rate was 68.4% and 73% (p=0.56) in Chinese and Caucasians AM patients, respectively. Male gender, Breslow thickness, ulceration, and positive sentinel lymph nodes were independent poor prognostic factors on multivariate analysis. Conclusions There appears to be no difference in stage-stratified survival between Chinese and Caucasians, supporting the implementation of clinical trials for AM that could include both Chinese and Caucasian patients.

665 Associations of BIRC2/3/5 copy number gains with clinicopathological features of acral melanomas in Taiwan

Anti-apoptotic molecules can protect melanoma cells from apoptosis, thus enhancing their aggression. One of the factors responsible for the difficulties in engaging the apoptotic cascade efficiently in melanoma is the up-regulation of conserved inhibitor of apoptosis proteins (IAPs). All IAPs share up to three conserved zinc-binding baculoviral IAP repeats domains. The best described members are cIAP1, cIAP2, X-linked IAP, and surviving, which are encoded by Baculovirus inhibitor of apoptosis repeat containing genes (BIRC2, BIRC3, BIRC4, and BIRC5). These proteins are associated with chemoresistance and poor outcome in many cancer types. Acral melanoma is the most common subtype of melanoma in Asians. Our previous report found that frequencies of NRAS/KRAS mutations, altered cell cycle regulation, BIRC2/3/5 copy number gain, and amplification of receptor tyrosine kinase genes were significantly enriched in acral melanomas. In addition, BIRC2/3 copy number gain was only detected in the acral melanomas, and acral melanomas had significantly more BIRC2/3/5 copy number gain than the cutaneous melanomas. Most of BIRC2/3/5 copy number gains were detected in acral melanomas developed in stress-bearing areas. Moreover, the melanomas with BIRC2/3/5 gain were associated with ulceration and greater Breslow thickness. Our further analysis found that cell cycle alteration, BIRC2/3/5 copy number gain, and lymph node status were significant prognostic factors in 45 acral melanoma in a univariate analysis. In a multivariate analysis, altered cell cycle and lymph node status remained the most crucial independent prognostic factors in acral melanomas. We identified BIRC2/3/5 might be a critical determinant of survival in the acral melanoma patients.

Genetic alterations in primary melanoma in Taiwan

Acral melanoma (AM) is the most common histopathological subtype of malignant melanoma in Asians. However, differences in the mutational profiles underlying AM and nonacral cutaneous melanoma (NAM) in Asians are not well understood. To augment the understanding of the prevalence, patterns and associations of various mutations between different subtypes of melanoma. We performed comprehensive genomic profiling of 409 cancer-associated genes, using next-generation sequencing, in 66 primary melanomas comprised of 45 AMs and 21 NAMs. Most of the AMs (n = 27/45; 60%), but only five of 21 (24%) NAMs, were triple wild-type (triple-WT) tumours. Compared with AMs, NAMs exhibited a significantly higher frequency of BRAF mutations. The frequencies of NRAS/KRAS mutations, cell-cycle aberrations, copy number gains in BIRC2, BIRC3 and BIRC5, and gains of receptor tyrosine kinase genes were significantly higher in AMs. Ulceration was found at significantly higher rates in the AMs and NAMs with cell-cycle aberrations and gains of receptor tyrosine kinase genes. Notably, cell-cycle aberrations and copy number gains in BIRC2, BIRC3 and BIRC5 were significantly associated with poor melanoma-specific survival in the 66 patients with melanoma and especially in the 45 patients with AM. Multivariate analysis showed that lymph node metastasis and cell-cycle aberrations were independent prognostic factors of melanoma-specific survival. This study strengthens our understanding of the patterns and clinical associations of oncogenic mutations in AMs and NAMs in Asians. What's already known about this topic? Mutation frequencies of driver genes vary between melanoma subtypes. Acral melanoma is the most common subtype of melanoma in Asians. KIT mutations and copy number variations occur more frequently in the acral subtype of melanoma than in the nonacral subtype What does this study add? NRAS/KRAS mutations, cell-cycle aberrations, copy number gains in BIRC2, BIRC3 and BIRC5, and amplifications of receptor tyrosine kinase genes were significantly enriched in acral melanoma and could be potential targets for treatment. Melanomas with cell-cycle aberrations and gains in receptor tyrosine kinase genes were significantly more likely to contain ulceration. What is the translational message? Cell-cycle aberrations and copy number gains in BIRC2, BIRC3 and BIRC5 were significantly associated with poor melanoma-specific survival. These observations should be explored further for future drug development.

MicroRNA-23a-3p Inhibits Mucosal Melanoma Growth and Progression through Targeting Adenylate Cyclase 1 and Attenuating cAMP and MAPK Pathways.

Mucosal melanoma (MM) is the second most common melanoma subtype in Asian populations. Deregulation of microRNAs (miRNAs) has been extensively investigated in various cancers, including cutaneous melanoma. However, the roles of miRNAs in MM are unclear. In this study, we carried out miRNA profiling in MM, and we investigated the clinical and biological roles of miR-23a-3p in MM.Methods: miRNA expression in MM was profiled by miRNA microarray analysis. The expression of miR-23a-3p was quantitated by qRT-PCR in a cohort of 117 patients with MM, and its prognostic significance was evaluated. The biological effect of miR-23a-3p was demonstrated by both in vitro and in vivo studies through ectopic expression of miR-23a-3p. The target gene of miR-23a-3p and molecular pathway influenced by it was characterized using in silico target prediction tools, dual luciferase reporter assays, knockdown, and rescue experiments.Results: Microarray and qRT-PCR results showed that the miR-23a-3p level was substantially lower in MM, and low miR-23a-3p expression was significantly associated with poor outcomes. Ectopic expression of miR-23a-3p suppressed MM cell proliferation, migration, invasion, and tumorigenicity, indicating that miR-23a-3p has a tumor-suppressive role in MM. Mechanistic investigations identified adenylate cyclase 1 (ADCY1) as a direct target of miR-23a-3p in MM, and knockdown of ADCY1 recapitulated all the phenotypic characteristics of miR-23a-3p overexpression. Targeting of ADCY1 by miR-23a-3p resulted in the suppression of cyclic adenosine monophosphate (cAMP) and mitogen-activated protein kinase (MAPK) signaling pathways.Conclusions: Our data highlight the molecular etiology and clinical significance of miR-23a-3p in MM and reveal its major target and biological function. miR-23a-3p may represent a new prognostic biomarker or therapeutic target in MM.

Increasing incidence of lentigo maligna and lentigo maligna melanoma in Catalonia.

Recent epidemiological studies suggest that past data where superficial spreading melanoma was by far the most common subtype of melanoma may not reflect current patterns of sun exposure or other risk factors more involved in other subtypes of melanoma as lentigo maligna (LM) or lentigo maligna melanoma (LMM). In order to measure the current situation in our country, all cases of LM and LMM diagnosed in 23 hospitals in Catalonia, from 2000 to 2007, were recorded. Although for the global period LM/LMM represented only 8.4% of cases, an increasing trend in this percentage was observed throughout the study period (from 6.9% [27 cases] in 2000 to 13.1% [94 cases] in 2007). Also, an increasing incidence of LM/LMM was observed, especially in chronically sun-exposed areas (85.5% involving the head and neck region). During the 8years of the registry, the mean Breslow thickness of LMM remained stable. However, the increase in the number of LM (insitu) cases was significantly higher than the increase of the invasive ones. An important observation from this data is that aging of population and current sun exposure patterns could keep increasing the incidence of LM/LMM, which may become an important public healthcare problem, over the other histological subtypes. In order to establish primary or secondary preventive measures to the LM/LMM risk-population, it is imperative to highlight the importance of chronic sun damage as a melanoma risk factor, and not only sunburn, most commonly addressed in melanoma prevention campaigns.

ANALYSIS OF EPIDEMIOLOGICAL CHARACTERISTICS OF MELANOMA PATIENTS

Melanoma is malignant disease and the incidence of melanoma has been increasing worldwide, resulting in an important socio-economic problem especially in not well development countries. At the time when the incidence of many tumors is decreasing, melanoma incidence continues to increase. Incidence in Southern Europe is ranging from 1,9/100.00 in Albania across 3,3/100.000 in Bulgaria to 14,5/100.000 in Slovenia and in Serbia 8,5/100.000 for male and 5,9/100.000for female (ASR-W, 2012). In Serbia, during 2007 to 2012, according to Cancer Registry of Central Serbia, there are about 622 new melanoma diagnoses, 320 male and 302 female. During 2012, in Republic of Serbia melanoma was the 10th most common diagnosed cancer and 12th most common cancer caused death, in both, females and males. The aim of this study was to analyzed clinical and epidemiological characteristic of melanoma. Retrospective study, data analysis, all patients referred and treated in two year period in Clinic for Burns, plastic and reconstructive surgery, Clinical Center of Serbia, Belgrade. All data are collected in hospital based registry The analyzed characteristics of interest: sex, age, subtype of melanoma, primary location of melanoma, Breslow thickness and Clark level of invasion, number of mitosis, ulceration, TNM stadium, the presents of microsatellites, metastases, level of Protein S and LDH and decision of future treatment . Decision about future treatment are made according AJCC (re-excision and SLNB – Sentinel Lymph Node Biopsy ) and follow-up of patients after SLNB is still lasting. In two year period, 201 patients were treated in our hospital, all patients in this study were with pathohistologically verified diagnoses of melanoma. The average age of patients was 61, 47 ( 25 - 87). The most common primary location of melanoma was trunk with some differences between sexes. The most common subtype of melanoma was superficial subtype in 69% of patients. Ulceration were present in 22% of all primary melanomas and mitosis in 47, 5% and microsatellites in 3, 5%. Protein S and LDH level were elevated in patients with higher Breslow thickness. According to the AJCC protocol we made a decision about future treatment, re-excision and SLNB. The follow-up after SLNB is still lasting and we are still collecting data. The study showed the correlation between subtype of melanoma, higher Breslow thickness and the level of invasion by Clark, as well as elevated level of protein S and LDH and the presents of ulcerations and mitosis with decision about future treatment according to AJCC protocol.

CMET-N375S germline mutation is associated with poor prognosis of melanoma in Chinese patients

Background: cMET has been known to play an essential role in malignant melanoma tumor progression. Recent studies have shown that a germline missense variant in exon 2 of the cMET , N375S (rs33917957 A>G) occurred at a much higher frequency in East Asian patients with lung cancer. However, the status of this mutation in melanoma is unclear. In this study, we examined the mutation frequency of cMET-N375S in 181 melanoma samples and analyzed its clinicopathological significance. Methods: Tissue samples (n=181) were analyzed for cMET-N375S, BRAF, NRAS , and CKIT mutation in genomic DNA by polymerase chain reaction amplification and Sanger sequencing. The levels of p-cMET protein were determined by immunohistochemistry. Clinical data of patients were also collected. Results: We identified a highly frequent variant (N375S) of cMET in 13.26% (24/181) of the patients with melanoma. This mutation was relatively more frequent in acral (22.8%) and mucosal (12.7%) melanomas (the two most common melanoma subtypes in Asian, but not in Caucasians) than in non-chronic sun induced damage (non-CSD; 5.9%) and CSD (8.3%) melanomas. Among the 24 cases with cMET-N375S mutations, six cases were found to harbor the BRAF mutation, four cases harbored NRAS mutations, and two cases harbored CKIT mutations. And there was no correlation between this mutation and p-cMET levels. Kaplan- Meier analysis showed significant differences in overall survival (OS) and disease-free survival (DFS) between the N375S mutation group and non-N375S mutation group (P=0.039; P=0.030). The Cox proportional hazards model revealed that cMET-N375S mutation was an independent adverse prognostic factor for OS [P=0.003, hazard ratio (HR) =3.577]. Conclusions: Our findings suggested that the cMET-N375S mutation was an adverse prognostic factor for melanoma in a Chinese cohort.

Acral melanoma foot lesions. Part 2: clinical presentation, diagnosis, and management.

Acral melanoma (AM) is a rare subtype of cutaneous malignant melanoma found on acral skin, primarily on the soles of the feet. Although rare, it is the most common subtype of melanoma found in patients of African or Asian ethnicity and has a poor prognosis, often because of the more advanced stage of presentation at diagnosis. In the second of this two-part series, we review the clinical presentation, histopathology, diagnosis and management of AM. Clinically, AM presents as a variegated lesion with blue-black pigment and irregular borders on acral skin. A parallel-ridge pattern is a very specific dermoscopic finding for AM. The differential diagnoses of AM include acral naevus, pyoderma gangrenosum, pyogenic granuloma, verrucous carcinoma and peripheral neuropathy-induced foot ulcers. If there is a clinical suspicion of AM, an excisional biopsy should be taken. Once diagnosis is confirmed by histology, surgical excision is the standard treatment. Overall, dermoscopy and histopathology are key tools in the diagnosis of AM. A greater emphasis on melanoma screening and awareness is essential in minority populations to improve survival outcomes in AM.

Whole genome and RNA sequencing reveal the distinct genomic landscape of acral melanoma.

9589 Background: Acral melanoma is a common subtype of melanoma in Asians with extremely poor prognosis, and therapy strategy has not been clearly established for acral melanoma. The aim of this study is to perform genomic and RNA profiling of acral melanoma to obtain the comprehensive genomic view of this subtype of melanoma. Methods: Genomic DNA was extracted with Qiagen DNeasy Blood or Tissue Kit . DNA libraries were prepared using a CancerPROTM-P88 BOX library Prep kit and sequencing was performed using the Illumina HiSeq X10. RNA was isolated with Qiagen RNeasy mini-spin column. cDNA was synthesized from total RNA using the SuperScript III first-strand synthesis system . RNA libraries were prepared using the NEBNext Ultra II Directional RNA Library Prep Kit and sequencing was performed using the Illumina HiSeq X10. Results: To obtain a comprehensive genomic and functional genomic view of acral melanoma, we sequenced the genomes of 14 acral melanoma and transcriptomes of 11 of these melanoma samples. We found a new mutation in the V28 codon of BRAF in three patients. Furthermore, we identified recurrent non-synonymous single nucleotide variants in previously described oncogene NRAS, as well as in genes encoding keratin associated proteins (KRTAP4-7, KRTAP4-5) and mucin (MUC2, MUC21). Notably, a recurrent noncoding hotspot mutation was discovered in 4 of 11 cases. By analyzing the RNA sequencing data, we found significant divergence on transcriptome between patients with or without ulcer. In total, we identified 201 genes were significantly up-regulated and 386 genes significantly down-regulated in acral melanoma patients with ulcer. Differentially expressed genes were enriched in pathways associated with cancers, melanogenesis, cell death signaling, skin diseases, etc. Conclusions: Our study reveals potentially different driver mutations and distinct transcriptome in acral melanoma patients compared with cutaneous melanoma patients and sheds lights to the further personalized medicine for acral melanoma patients.

Melanoma in Mexico: Clinicopathologic Features in a Population with Predominance of Acral Lentiginous Subtype.

The aim of this study was to analyze the clinicopathologic features of melanoma in México as the demographics of melanoma are not well known in Mexican and Latin American people. A total of 1219 patients with cutaneous melanoma were analyzed through a retrospective database collected from a cancer referral institute, and the results were compared with developed countries. Median age was 57years, and 713 (58.5%) were females. The most common melanoma subtype was acral lentiginous melanoma (ALM), which was observed in 538 (44.1%) patients. Median Breslow thickness was 5.2mm. Among 837 patients with complete data, the 5-year disease-specific survival (DSS) was 52.3%. Factors associated with worse DSS on univariate analysis were Breslow thickness (p<0.001), recurrence (p<0.001), ulceration (p<0.001), positive margin (p<0.001), ALM (p=0.001), and male sex (p=0.001). Multivariate analysis demonstrated Breslow thickness [hazard ratio (HR) 1.45, 95% confidence interval (CI) 1.27-1.65; p<0.001], positive margin (HR 1.25, 95% CI 1.03-1.57; p=0.018), recurrence (HR 9.56, 95% CI 6.89-9.87; p=0.002), ALM (HR 8.07, 95% CI 6.77-8.95; p=0.004), and male sex (HR 1.33, 95% CI 1.06-1.68; p=0.013) as independent risk factors for DSS. Our patients had worse prognosis compared with data from the US Surveillance, Epidemiology, and End Results database. We found male sex and ALM as independent risk factors for worse survival, in addition to known risk factors.