Prognostic and Clinicopathologic Associations of BRAF Mutation in Primary Acral Lentiginous Melanoma in Korean Patients: A Preliminary Study

Curcumin Enhances the Anticancer Effects of Binimetinib on Melanoma Cells by Inducing Mitochondrial Dysfunction and Cell Apoptosis with Necroptosis

BACKGROUND

Recent studies suggest that MEK1/2 inhibitors, including binimetinib, significantly improve malignant melanoma (MM) patient survival. Growing evidence suggests that phytochemicals, especially curcumin, can overcome drug resistance in cancer cells through a variety of mechanisms.

OBJECTIVE

This study aims to examine curcumin's efficacy in vitro combined with binimetinib in human MM cells.

METHODS

We used 2D monolayer and 3D spheroid human epidermal melanocyte culture models, HEMn-MP (human epidermal melanocytes, neonatal, moderately pigmented), and two human MM cell lines, G361 and SK-MEL-2, to evaluate cell viability, proliferation, migration, death, and reactive oxygen species (ROS) production following single therapy treatment, with either curcumin or binimetinib, or a combination of both.

RESULTS

Compared to MM cells treated with single therapy, those with combination therapy showed significantly decreased cell viability and increased ROS production. We observed apoptosis following both single and combination therapies. However only those who had had combination therapy had necroptosis.

CONCLUSION

Collectively, our data demonstrates that curcumin exerts significant synergistic anticancer effects on MM cells by inducing ROS and necroptosis when combined with binimetinib. Therefore, a strategy of adding curcumin to conventional anticancer agents holds promise for treating MM.

Prognostic value of genetic aberrations and tumor immune microenvironment in primary acral melanoma

BACKGROUND

Acral melanoma (AM) is the most common subtype in Chinese melanoma patients with a very poor prognosis. However, our understanding of the disease pathogenesis and molecular landscape is limited by the few studies that have been conducted. Here, we profiled the clinical characteristics, mutational landscapes and tumor immune microenvironment of AM patients to gain insights into disease characteristics and potential treatment strategies.

METHODS

A total of 90 AM patients were enrolled and their tissue samples were subjected to next-generation sequencing and multiplexed immunohistochemistry tests. Kaplan-Meier curves and log-rank tests were used to analyze the prognostic potential of various genetic aberrations and immune cell compositions in AM.

RESULTS

The median disease-free survival was 21.3 months and estimated median overall survival (OS) was 60 months. More advanced stages, older ages and thickness of greater than 4 mm were associated with worse prognosis in AM patients (HR = 2.57, 95% CI 1.25-5.29, p = 0.01; HR = 2.77, 95% CI 1.22-6.28, p = 0.02; HR = 3.43, 95% CI 1.51-7.82, p < 0.01, respectively), while patients who received post-surgical treatments had better survival (HR = 0.36, 95% CI 0.17-0.76, p = 0.01). The most frequently altered genes included BRAF (14.5%), KIT (16.9%), NRAS (12%), NF1 (10.8%), APC (7.2%), and ARID2 (6%). Copy number variations (CNV) were commonly found in CCND1 (19.3%), CDK4 (19.3%), MDM2 (14.5%) and FGF19 (12%). CDK4 amplifications was independently associated with shorter OS in AM patients (HR = 3.61, 95% CI 1.38-9.46, p = 0.01). CD8 ⁺ T cells (p < 0.001) and M1 macrophages (p = 0.05) were more highly enriched in the invasive margin than in the tumor center. Patients with higher levels of M1 macrophage infiltration in the invasive margin derived markedly longer OS (HR = 0.43, 95% CI 0.20-0.95, p = 0.03). Interestingly, in CDK4-amplified patients, there tended to be a low level of M1 macrophage infiltration in the invasive margin (p = 0.06), which likely explains the poor prognosis in such patients.

CONCLUSIONS

Our study provided a comprehensive portrait of the clinicopathological features, genetic aberrations and tumor microenvironment profiles in AM patients and identified candidate prognostic factors, which may facilitate development of additional therapeutic options and better inform clinical management of AM patients. Based on these prognostic factors, further studies should focus on enhancing the infiltration of M1 macrophages, especially in CDK4-amplified AM patients.

Clinical features, molecular pathology, and immune microenvironmental characteristics of acral melanoma

Acral melanoma (AM) has unique biology as an aggressive subtype of melanoma. It is a common subtype of melanoma in races with darker skin tones usually diagnosed at a later stage, thereby presenting a worse prognosis compared to cutaneous melanoma. The pathogenesis of acral melanoma differs from cutaneous melanoma, and trauma promotes its development. Compared to cutaneous melanomas, acral melanomas have a significantly lighter mutational burden with more copy number variants. Most acral melanomas are classified as triple wild-type. In contrast to cutaneous melanomas, acral melanomas have a suppressive immune microenvironment. Herein, we reviewed the clinical features, genetic variants, and immune microenvironmental characteristics of limbic melanomas to summarise their unique features.

Frequency of mutations in BRAF, NRAS, and KIT in different populations and histological subtypes of melanoma: a systemic review

Supplemental Digital Content is available in the text.

The presence of mutations of BRAF, NRAS, and KIT genes is recognized as playing a role during carcinogenesis. Our study aims to evaluate and review other studies that present the frequency of mutations of BRAF, NRAS, and KIT genes for different populations, and analyse correlation to their clinical-pathological characteristics and to the demographics of melanoma. Thirty-two articles were selected from a collection of published literature studying 6299 patients. The parameters for correlation to different variables were calculated by odds ratio, for random and single effects. 38.5% of patients present BRAF gene mutations, 16.4% in NRAS, and 10% in KIT. Mutations of the BRAF gene were correlated to superficial spreading melanoma (odds ratio = 1.31), localization in the torso (odds ratio = 1.42) and presence of metastases. Mutations in NRAS were correlated to nodular melanoma (odds ratio = 1.57), localized in the limbs (odds ratio = 1.31). Mutations of the KIT gene were correlated to mucosal melanoma (odds ratio = 1.59). Populations in Brazil, the US, Sweden, Italian, and Australia were found to be correlated to mutations of BRAF and melanoma. Populations in Italy, Sweden, Spain, and the US were found to be correlated to mutations of NRAS. Populations in Japan, China, Turkey, Canada, and Russia were found to be correlated to mutations of KIT. Data correlated to the presence of melanoma and population type is due to the amount of studies performed across of globe.

The tumor genetics of acral melanoma: What should a dermatologist know?

Dermatologists stand at the gateway of individualization of classification, treatment, and outcomes of acral melanoma patients. The acral melanoma genetic landscape differs in vital ways from that of other cutaneous melanomas. These differences have important implications in understanding pathogenesis, treatment, and prognosis. The selection of molecularly targeted therapy must be adapted for acral melanoma. It is also critical to recognize that tumor development is far more complex than an isolated event, reliably treated by a medication acting on a single target. Tumors exhibit intratumor genetic heterogeneity, metastasis may have different genetic or epigenetic features than primary tumors, and tumor resistance may develop because of the activation of alternative genetic pathways. Microenvironmental, immune, and epigenetic events contribute and sustain tumors in complex ways. Treatment strategies with multiple targets are required to effectively disrupt the tumor ecosystem. This review attempts to translate the current molecular understanding of acral melanoma into digestible concepts relevant to the practice of dermatology. The focus is tumor genetics defining potentially treatable cancer pathways, contextualized within the relevant pathologic and molecular features.

A rare case of acral amelanotic melanoma, nodular type

Amelanotic melanoma is a rare melanoma subtype, and it is even more rare when it occurs at an acral site. We here present a case of a nodular amelanotic acral melanoma (NAAM) occurring on the heel of an 83-year old female. It presented as an ulcerated pink nodular growth on the heel, which clinically mimicked other nodular non-pigmented lesions, causing a delay in diagnosis until it was biopsied. This case is a demonstration of the critical importance to include NAAM in the differential diagnosis of nodular non-pigmented skin lesions as to avoid delay in diagnosis and disease progression, in which early detection can provide the most modifiable prognostic factor.

Targeted Genomic Profiling of Acral Melanoma

BACKGROUND

Acral melanoma is a rare type of melanoma that affects world populations irrespective of skin color and has worse survival than other cutaneous melanomas. It has relatively few single nucleotide mutations without the UV signature of cutaneous melanomas, but instead has a genetic landscape characterized by structural rearrangements and amplifications. BRAF mutations are less common than in other cutaneous melanomas, and knowledge about alternative therapeutic targets is incomplete.

METHODS

To identify alternative therapeutic targets, we performed targeted deep-sequencing on 122 acral melanomas. We confirmed the loss of the tumor suppressors p16 and NF1 by immunohistochemistry in select cases.

RESULTS

In addition to BRAF (21.3%), NRAS (27.9%), and KIT (11.5%) mutations, we identified a broad array of MAPK pathway activating alterations, including fusions of BRAF (2.5%), NTRK3 (2.5%), ALK (0.8%), and PRKCA (0.8%), which can be targeted by available inhibitors. Inactivation of NF1 occurred in 18 cases (14.8%). Inactivation of the NF1 cooperating factor SPRED1 occurred in eight cases (6.6%) as an alternative mechanism of disrupting the negative regulation of RAS. Amplifications recurrently affected narrow loci containing PAK1 and GAB2 (n = 27, 22.1%), CDK4 (n = 27, 22.1%), CCND1 (n = 24, 19.7%), EP300 (n = 20, 16.4%), YAP1 (n = 15, 12.3%), MDM2 (n = 13, 10.7%), and TERT (n = 13, 10.7%) providing additional and possibly complementary therapeutic targets. Acral melanomas with BRAFV600E mutations harbored fewer genomic amplifications and were more common in patients with European ancestry.

CONCLUSION

Our findings support a new, molecularly based subclassification of acral melanoma with potential therapeutic implications: BRAFV600E mutant acral melanomas with characteristics similar to nonacral melanomas that could benefit from BRAF inhibitor therapy, and non-BRAFV600E mutant acral melanomas. Acral melanomas without BRAFV600E mutations harbor a broad array of therapeutically relevant alterations. Expanded molecular profiling would increase the detection of potentially targetable alterations for this subtype of acral melanoma.

Acral Lentiginous Melanomas Harbour Intratumor Heterogeneity in BRAF Exon 15, With Mutations Distinct From V600E/V600K

The choice of appropriate therapeutic strategies may be influenced by intratumor heterogeneity and makes cancer treatment considerably more challenging. We aimed to evaluate the heterogeneity of BRAF exon 15 mutations in different areas of acral lentiginous melanoma (ALM). The entire exon 15 was sequenced in 4 different areas of paraffin-embedded samples from 26 patients with ALM. A total of 26 of 49 cases of ≥1 mm in depth of ALM identified by clinical, anatomical, and pathological data fulfilled the inclusion and exclusion criteria for this study. Tumors had a mean Breslow depth of 7.2 mm and an average mitotic index of 3 mitosis/mm. Mutations distinct from the common V600E and V600K were detected in 31%, and intratumor heterogeneity was observed in 31% of samples. Interestingly, 63.5% of all mutations had been previously associated with cancer. Most (62.5%) of the missense BRAF exon 15 mutations found in the ALM samples examined here were deemed "detrimental" for protein function according to at least 2 functional prediction programs, and 3 mutations (37.5%) were predicted to be "neutral," with no effect on protein function. BRAF exon 15 mutations were detected frequently in ALM and displayed heterogeneity, a finding to be further investigated.

Targeting the ERK Signaling Pathway in Melanoma

The discovery of the role of the RAS/RAF/MEK/ERK pathway in melanomagenesis and its progression have opened a new era in the treatment of this tumor. Vemurafenib was the first specific kinase inhibitor approved for therapy of advanced melanomas harboring BRAF-activating mutations, followed by dabrafenib and encorafenib. However, despite the excellent results of first-generation kinase inhibitors in terms of response rate, the average duration of the response was short, due to the onset of genetic and epigenetic resistance mechanisms. The combination therapy with MEK inhibitors is an excellent strategy to circumvent drug resistance, with the additional advantage of reducing side effects due to the paradoxical reactivation of the MAPK pathway. The recent development of RAS and extracellular signal-related kinases (ERK) inhibitors promises to add new players for the ultimate suppression of this signaling pathway and the control of pathway-related drug resistance. In this review, we analyze the pharmacological, preclinical, and clinical trial data of the various MAPK pathway inhibitors, with a keen interest for their clinical applicability in the management of advanced melanoma.

Local recurrence and metastasis in patients with malignant melanomas after surgery: A single-center analysis of 202 patients in South Korea

Malignant melanoma (MM) is a lethal skin cancer in Western countries. Although the incidence is low in Asians compared to that in Caucasians, it is increasing. However, literature regarding risk factors for prognosis of MM patients who have undergone surgical excision in Asian is limited. This study aimed to investigate the predictive factors for local recurrence and metastasis in MM patients who underwent surgical treatment at a single tertiary-level hospital in Korea. Patients who underwent surgery for MM at our institution between January 1998 and December 2014 were analyzed. We retrospectively investigated risk factors for local recurrence and metastasis after surgery. In cases with distant metastasis, tumor thickness (adjusted Hazard Ratio (HR), 6.139; 95% confidence interval (CI), 2.152 to 17.509; P = 0.001) and increased mitotic number [(0-1/mm² vs 2-6/mm²: adjusted HR, 4.483; 95% CI, 1.233 to 16.303; P = 0.023); (0-1/mm² vs > 6/mm²: adjusted HR, 10.316; 95% CI, 2.871 to 37.063; P < 0.001)] were associated with risk in multivariate analysis. Regarding local recurrence, tumor thickness (T4 [≥4mm] vs T1) was found to be a significant risk factor (adjusted HR, 8.461; 95% CI, 2.514 to 28.474; P = 0.001). Our data revealed tumor thickness and increased mitotic count were significant risk factors for local recurrence and distant metastasis in Korean patients with MM after surgery.

Molecular evaluation of BRAF V600 mutation and its association with clinicopathological characteristics: First findings from Indian malignant melanoma patients

Mutations in the BRAF gene have been described to occur in two-third of melanomas. The objective of the study was to establish the frequency of BRAF V600E/K/R mutation in a series of melanomas from Indian origin and to correlate mutation status with clinicopathological features. Seventy melanoma cases were evaluated for BRAF V600 mutation by pyrosequencing. Overall, BRAF mutations were detected in 30% of the patients. All mutations observed were missense type (GTG > GAG) resulting in p.V600E, while none showed V600K/R mutation. The frequency of BRAF V600E mutations were more in patients with onset age of 50 years. BRAF mutations were significantly associated with tumor site wherein more mutations were seen in tumors from head and neck and extremities region. Acral and mucosal tumor subtype showed a mutation frequency of 31% and 20%, respectively. Epithelial cell morphology tends to harbor frequent BRAF V600E mutation (36%) than other morphological subtypes. Tumors with ulceration and necrosis showed increased BRAF mutation rate (32.5% and 33%) respectively. In conclusion, this is the first study to report a mutation frequency of 30% in this cohort. Our results demonstrated that the BRAF V600E mutation is a frequent event in Indian melanomas, and represents an important molecular target for novel therapeutic approaches.

Sensitivity and Usefulness of VE1 Immunohistochemical Staining in Acral Melanomas with BRAF Mutation

Background

Acral melanomas are known to have a low frequency of BRAF mutation, in contrary to higher KIT mutation. Recently, VE1 immunostaining was reported to have a good correlation with BRAF mutation status.

Objective

We aimed to evaluate the clinicopathological features of BRAF-mutated acral melanomas and validate the correlation of the VE1 immunohistochemical stains in those cases.

Methods

The clinical features (age, sex, anatomical site), and histopathological characteristics of 41 patients with acral melanoma were evaluated. We performed a next-generation sequencing to detect BRAF mutation status. We also determined the correlation of VE1 immunohistochemical staining with BRAF mutation status.

Results

Among 19 acral melanomas with BRAF mutation, common histopathological subtype was acral lentiginous melanoma (8/19, 42%) and nodular melanoma (8/19, 42%) and superficial spreading melanoma (3/19, 16%) followed. VE1 immunostaining results were positive in all 15 cases with BRAF V600E mutation (sensitivity 100%), and negative in 4 cases of BRAF non-V600E mutation. However, VE1 immunostaining was negative in all 22 patients with BRAF wild-type.

Conclusion

VE1 immunostaining had a good correlation with BRAF V600E mutation status.

Prognostic role of the histological subtype of melanoma on the hands and feet in Caucasians

Acral melanoma (AM) is associated with a poor prognosis in part because of delayed diagnosis, but probably also because of other intrinsic characteristics of location. The aim of this study was to review the specific characteristics and outcome of AM in Caucasians. This was a cross-sectional retrospective clinical-pathological study of 274 patients identified with AM in the database of a referral unit in Europe from 1986 to 2010. The mean age of the patients was 56.6 (SD 17.7) years. 269 cases could be histologically classified and included in the study. In all, 222 (82.5%) were located on feet. According to melanoma subtype, 165 (61.3%) were acral lentiginous melanoma (ALM), 84 (31.2%) were superficial spreading melanoma (SSM), and 20 (7.5%) were nodular melanoma (NM). SSM patients were characterized by female predominance (77.4%), younger age, and classic melanoma-risk phenotype (fair skin and multiple nevi). Among the 198 invasive cases with a mean follow-up of 56.2 months, the mean (SD) Breslow's thickness was 3.1 (3.6) mm, being 1.4 (1.4) mm in SSM, 3.5 (4.1) mm in ALM and 4.9 (2.9) mm in NM (P<0.001). Ulceration was present in 33.3%, 2.9% in SSM, 38.6% in ALM, and 76.9% in NM (P<0.001). A total of 29.3% relapsed (7.3% of SSM, 35% of ALM and 55% of NM) and 24.2% died because of AM. In multivariate analysis, age at diagnosis, Breslow, and histopathological subtype were independent prognostic factors for both disease-free and AM-specific survival. The ALM and NM subtypes presented poorer outcome after weighting Breslow and age (P=0.02). Histological subtype of AM could have an impact on biological behavior, ALM and NM subtypes presenting a poorer prognosis after adjusting for age and Breslow's thickness.

MAP Kinase Pathways: Molecular Roads to Primary Acral Lentiginous Melanoma

The etiology and pathogenesis of lentiginous acral melanomas are poorly understood. Recent studies have postulated that DNA repair mechanisms and cell growth pathways are involved in the development of melanoma, particularly changes in the MAPK pathways (RAS, BRAF, MEK 1/2, and ERK 1/2). The aim of this study is to assess the status of the MAP kinase pathways in the pathogenesis of acral melanomas. The authors examined the components of the RAS–RAF–MEK–ERK cascades by immunohistochemistry in a series of 16 primary acral melanomas by tissue microarray. The expression of MAP kinase cascade proteins changed in most cases. The authors observed that 57.14% of cases were BRAF positive and that 61.53%, 71.42%, and 71.42% of cases were positive for MEK2, ERK1, and ERK2, respectively; RAS was not expressed in 92.31%, and all cases were negative for MEK1. The absence of RAS and positivity for MEK2, ERK1, and ERK2 were most seen in invasive cases with high thickness. These aspects of the MAPK pathway require further examination in acral melanomas between different populations. Nevertheless, the results highlight significant alterations in the MAP kinase cascades that are related to histological indicators of prognosis in primary acral melanomas.

A comparison of immunohistochemical and molecular methods used for analyzing the BRAF V600E gene mutation in malignant melanoma in Taiwan

AIMS

The BRAF V600 mutation has been shown to be clinically meaningful in terms of both the prognosis and sensitivity of BRAF inhibitors in patients with metastatic melanoma. Recently, a BRAF V600E mutation-specific antibody, VE1, was generated for the detection of tumors bearing BRAF V600E mutations. To determine the clinical value of immunohistochemical testing, we compared the prevalence of mutant BRAF detected by VE1 with direct sequencing results.

METHODS

Paraffin-embedded, formalin-fixed melanoma biopsies were analyzed for the BRAF mutation status by immunohistochemistry with the VE1 antibody. Sanger sequencing was applied to verify the immunohistochemical results.

RESULTS

A total of 73 melanoma cases with tumor samples from primary lymph nodes and metastatic sites were selected for this study. Direct sequencing demonstrated that 18 of 73 cases (24.6%) harbored the BRAF V600 mutation: 17 with V600E and one with V600K. All 18 tumors shown to harbor the BRAF V600E/K mutations were VE1-positive. One additional case was false-positive for VE1. The sensitivity and specificity of VE1 was 100% (18/18) and 98% (54/55), respectively. The overall concordance between the immunohistochemical method and direct sequencing was excellent (98.6%).

CONCLUSIONS

Our findings demonstrate that immunohistochemical analysis using VE1 constitutes a highly sensitive test for the detection of BRAF mutations and suggest that this cost-effective method is suitable as a rapid diagnostic approach complementary to molecular testing.

Prevalence of BRAF and NRAS mutations in cutaneous melanoma patients in Taiwan

BACKGROUND/PURPOSE

BRAF and NRAS mutations have been described in melanomas among Caucasians and some Asian populations. However, few large-scale studies have investigated the status and clinical significance of BRAF and NRAS mutations in a Taiwanese population.

METHODS

Melanoma samples (n = 119) were analyzed for mutations in exons 11 and 15 of the BRAF gene, and in exons 1 and 2 of the NRAS gene. The samples were studied in genomic DNA, using polymerase chain reaction amplification and Sanger sequencing. Mutations of the BRAF and NRAS genes were then correlated with clinicopathological features and patients' prognosis.

RESULTS

The incidence of somatic mutations within the BRAF and NRAS genes was 14.3% (17/119 patients) and 10.1% (12/119 patients), respectively. Among the 17 patients with BRAF mutations, 15 (88.2%) had V600E mutations. BRAF mutation was frequently detected in younger patients (p = 0.0035), in thin melanomas (p = 0.0181), and in melanomas with less ulceration (p = 0.0089). NRAS mutation was more often seen in patients with lymph node metastasis (p = 0.0332). Both BRAF and NRAS mutations were not significantly correlated with overall survival and disease-free survival.

CONCLUSION

As BRAF and NRAS mutations are rare in Taiwan, BRAF- or NRAS-targeted therapies may be effective only for selected Taiwanese melanoma patients.

Amelanotic Acral Melanoma Associated with KIT Mutation and Vitiligo

Amelanotic acral melanoma is rare and difficult to diagnose, both clinically and pathologically. KIT mutations are frequently found in acral melanomas and are considered a risk factor for poor prognosis. The presence of vitiligo in melanoma has been reported, and KIT is thought to be partly responsible for the dysfunction and loss of melanocytes observed in vitiligo. We report a case of amelanotic subungual melanoma with multiple metastases that was associated with KIT mutation and vitiligo. An 85-year-old man presented with a 3-year history of a tender erythematous ulcerated tumor on the left third fingertip and developed hypopigmented patches on the face and trunk. Histopathological examination of the ulcerative tumor showed aggregates of tumor cells that were pleomorphic epithelioid cells. Immunohistochemical staining of the tumor cells was positive for S100, HMB45, and c-Kit. Histopathological findings from the hypopigmented patch on the face were consistent with vitiligo. Mutation analysis showed a KIT mutation in exon 17 (Y823D). The patient had metastasis to the brain, liver, bone, and both lungs. The patient refused chemotherapy, and died 3 months after the first visit.

MTA1--a stress response protein: a master regulator of gene expression and cancer cell behavior

Gene mutation's role in initiating carcinogenesis has been controversial, but it is consensually accepted that both carcinogenesis and cancer metastasis are gene-regulated processes. MTA1, a metastasis-associated protein, has been extensively researched, especially regarding its role in cancer metastasis. In this review, I try to elucidate MTA1's role in both carcinogenesis and metastasis from a different angle. I propose that MTA1 is a stress response protein that is upregulated in various stress-related situations such as heat shock, hypoxia, and ironic radiation. Cancer cells are mostly living in a stressful environment of hypoxia, lack of nutrition, and immune reaction attacks. To cope with all these stresses, MTA1 expression is upregulated, plays a role of master regulator of gene expression, and helps cancer cells to survive and migrate out of their original dwelling.