BRAF V600E mutation as a prognostic factor in cutaneous melanoma patients

The prognostic significance of BRAF mutations in the natural course of melanoma is controversial. The aim of study was to assess the prognostic significance of BRAF V600E mutation in cutaneous melanoma patients. A total of 151 melanomas were included in the study. BRAF V600E mutation was detected using the real‐time PCR. BRAF V600E mutation rate was 51%. BRAF mutation rate was higher for young patients (61.4%) and upper limbs (63.2%), trunk (59.3%) and head and neck (59.2%) were the most frequently afflicted sites in BRAF‐mutant patients, whereas lower limbs were mostly affected in BRAF‐wild patients (77.8%). Likewise, acral melanomas rarely harbored BRAF mutation (17.1%). The disease‐free survivals regarding the entire and Stage III cohorts were longer in the BRAF‐mutant group than in the BRAF‐wild group (p = .006 and p = .004, respectively), whereas Stage I–II patients had no survival differences between BRAF statuses (p = .2). Likewise, BRAF‐mutant patients had better overall survival (OS) time compared to BRAF‐wild patients in all stages (p = .01), in Stage III (p = .01), and in Stage IV patients (p = .001). However, no differences between BRAF statuses were observed in Stage I–II melanomas (p = .3). In conclusion, BRAF V600E‐mutant melanomas show favorable prognostic impact on both disease‐free and OSs in all staged melanomas except local disease.     

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

Background

In the majority of melanomas, the RAS/RAF/MEK/ERK signaling pathway is constitutively activated, due to oncogenic mutations in the BRAF and NRAS genes. The BRAF mutation has been mainly described in Caucasian melanomas. However, there is a lack of study evaluating the status, and the clinical significance, of BRAF mutation in the Asian population.

Objective

This study was aimed to determine the frequency of BRAF mutation, and to evaluate the correlation of BRAF status with clinicopathologic features and outcomes, in Korean primary acral lentiginous melanoma (ALM) patients.

Methods

ALM samples (n=36) were analyzed for the BRAF V600E mutation, by dual-priming oligonucleotide (DPO) based real-time polymerase chain reaction. The clinicopathologic features and prognosis of the patients were analyzed with BRAF mutation status.

Results

The incidence of BRAF V600E mutation was 19.4% (7/36). The BRAF V600E mutations were not associated with clinicopathologic features, except for the age factor. All of the BRAF-mutant patients survived without recurrence or metastasis, and have a better clinical outcome than BRAF wild-type patients.

Conclusion

In Korean primary ALM, a low frequency of BRAF mutation was shown; and BRAF mutation presented with a favorable prognosis. These results indicate that other distinctive genetic mechanisms may have more important roles in the development and progression of disease. Further multicenter study with large sample size is firmly needed, to confirm the results of our preliminary study.     

BRAF V600E mutation and the tumour suppressor IGFBP7 in atypical genital naevi

Background Atypical genital naevi (AGN) are naevi of special sites with atypical histological features that overlap with those of malignant melanoma. Activating BRAF mutations, identified in the majority of banal melanocytic naevi and cutaneous melanomas, are reportedly uncommon in naevomelanocytic proliferations in nonsun‐exposed sites. We have recently shown that constitutive activation of the BRAF‐MEK‐ERK signalling pathway in oncogenic BRAF‐positive naevi increases expression and secretion of IGFBP7, which induces senescence and apoptosis. Objectives To ascertain the frequency of BRAF V600E mutations in AGN compared with banal naevi without atypia. An additional aim was to assess the expression of IGFBP7 in oncogenic BRAF‐positive AGN. Methods Genomic DNA was isolated per protocol from seven genital naevi without atypia and 13 AGN for BRAF genotyping. Immunohistochemical staining for IGFBP7 was performed on all cases. Results The BRAF V600E mutation was identified in 43% of genital naevi without atypia and 23% of AGN (P = 0·61). In both groups, IGFBP7 expression was maintained in 67% of BRAF V600E‐positive cases. Conclusions The prevalence of BRAF V600E in AGN suggests that ultraviolet exposure is not essential for generating the mutation. The BRAF V600E mutational status appears to be of limited diagnostic utility in distinguishing genital naevi that exhibit atypia from those that do not. Similar to oncogenic BRAF‐positive common naevi without atypia, enhanced expression of the tumour suppressor IGFBP7 in oncogenic BRAF‐positive AGN supports that they are biologically inert.     

SERPINB8 and furin regulate ITGAX expression and affect the proliferation and invasion of melanoma cells

In the past 10 years, the systemic treatment of advanced melanoma has undergone tremendous changes through the development of targeted therapy. However, there is still a long way to go. This study aims to characterize the function and interaction of ITGAX, SERPINB8 and furin in BRAF V600E mutant melanoma. Differentially expressed genes related to BRAF V600E mutation and BRAFi treatment were obtained by analysing GSE141484 and GSE22838. two kinds of BRAFi (Vemurafenib, 10 μM; Dabrafenib, 1 μM) were used to treat A375 and 1205Lu cells, respectively. The expression of ITGAX, SERPINB8 and Furin in A375 and 1205Lu cells was down-regulated by specific siRNAs, and cell proliferation, clone formation and invasion were detected by CCK-8, colony formation and transwell assays. The physical binding of furin and SERPINB8 was detected by immunoprecipitation. BRAFi treatment down-regulated the ITGAX and SERPINB8 expression and did not change furin expression. Knockdown of ITGAX and SERPINB8 both inhibited the proliferation and invasion of A375 and 1205Lu cells. Knocking down SERPINB8 down-regulated the expression of ITGAX. Furin knockdown and inhibitors all up-regulated the protein level of ITGAX. SERPINB8 can physically bind to furin. In summary, SERPINB8 and furin regulate the expression of ITGAX in melanoma cells, and ITGAX significantly promotes the proliferation and invasion of melanoma cells.     

恶性黑素瘤中BRAF癌基因突变研究新进展

恶性黑素瘤是死亡率较高的皮肤肿瘤之一,研究发现恶性黑素瘤中存在高频BRAF癌基因突变.紫外线是引起突变的高危因素,不同种族、发病部位以及病理类型的恶性黑素瘤间BRAF突变率存在差异.此突变与遗传、预先存在的色素痣、肿瘤侵袭性及预后之间的关系还存在争论.BRAF突变相关的MAPK信号传导分子是治疗恶性黑素瘤的靶点.综述近几年的研究,以认识BRAF突变与恶性黑素瘤的关系.     

BRAF(V600E)基因突变与儿童先天性色素痣的增殖活性及组织病理学特征的相关性研究

目的:明确先天性色素痣(congenital melanocytic nevi, CMN)中BRAF(V600E)基因突变对其增殖活性和组织病理学的影响。方法:回顾分析2018年12月至2020年12月我院皮肤科诊治的185例CMN患儿,所有患儿均进行基因检测、病理检查和Ki67免疫组化检测。根据基因检测结果是否存在BRAFV600E突变,将入选患儿分为突变组和对照组,然后再根据性别、年龄、皮损大小和皮损部位进行配对后进一步研究。结果:突变组Ki67指数、痣细胞累及深度、痣细胞巢个数、痣细胞巢大小与对照组比较差异均有统计学意义(均P<0.05)。与BRAF V600E阴性的CMN相比,BRAF(V600E)阳性CMN通常在表真皮交界部位形成黑素细胞巢,且巢较大。痣细胞累及深度和痣细胞巢个数与Ki67指数之间成正相关(均P<0.05)。结论:BRAF(V600E)基因突变使CMN的增殖活性明显升高,并对其组织病理学有特殊的影响。     

Frequency of Trauma,Physical Stress,and Occupation in Acral Melanoma: Analysis of 313 Acral Melanoma Patients in Korea

BackgroundTraumatic events are thought to be a cause of acral melanoma. However, little is known about the role of mechanical trauma or physical stress in the development of acral melanoma.ObjectiveIn our study, we evaluated the frequency of trauma, physical stress, and occupation in patients with acral melanoma and aimed to identify any pathological correlates of these factors.MethodsWe conducted a retrospective study of 313 acral melanoma patients from Chonnam National University Hospital. We mapped melanoma-developed anatomical sites of acral areas and assessed patients'' history of trauma, physical stress, and occupation.ResultsAmong the 313 acral melanoma patients, many reported a traumatic event (84 of 313; 26.8%) or physical stress (91 of 313; 29.1%) before the melanoma developed. The most common anatomical sites in these patients were on the borders of the foot (136 of 313; 43.5%). Trauma was more commonly associated with the fingernails and toenails than other sites. The frequency of each type of physical stress depended on the site of the lesion. Farmer and fisherman were the most common occupations (130 of 313; 41.5%) of the acral melanoma patients.ConclusionOur results demonstrate that traumatic events, physical stress, and certain occupations are common in acral melanomas. Further studies are needed to establish whether these are risk factors for acral melanomas.     

Distant metastasis due to heavily pigmented epithelioid melanoma with underlying BRAF V600E,NOTCH1, ERBB3, and PTEN mutations

Pigment‐synthesizing melanoma (PSM) describes a morphologically and genetically diverse group of melanomas. In contrast, pigmented epithelioid melanocytoma (PEM) encompasses a spectrum of indolent tumors now classified as borderline/intermediate melanocytic tumors. Herein, we report a case of widely metastatic heavily pigmented epithelioid melanoma with fatal outcome in a 36‐year‐old woman. Next‐generation sequencing identified somatic (tumoral) mutations in BRAF V600E, PTEN, NOTCH1, and ERBB3. By contrast, GNAQ and GNA11 were wild type. Prkar1α and p16 expression were maintained. Identification of mutations in NOTCH1 and ERBB3 may support the diagnosis of heavily pigmented epithelioid melanoma. In contrast, PRKCA fusion genes and PRKAR1A mutations support the diagnosis of PEM. Given the heterogeneity, potential overlap (loss of Prkar1α expression), and evolving genetic profiles of these two distinct groups of tumors, careful appraisal of molecular profiles in the light of histomorphology and clinical history is necessary for distinction between PEM and PSMs including heavily pigmented epithelioid melanomas, with significant potential impact on prognosis and therapy.     

Expression of Phosphatase and Tensin Homologue,phospho-Akt,and p53 in Acral Benign and Malignant Melanocytic Neoplasms (Benign Nevi,Dysplastic Nevi,and Acral Melanomas)

BackgroundThe role of the phosphatidylinositol-3 kinase signaling pathway in the development of acral melanoma has recently gained evidence. Phosphatase and tensin homologue (PTEN), one of the key molecules in the pathway, acts as a tumor suppressor through either an Akt-dependent or Akt-independent pathway. Akt accelerates degradation of p53.ObjectiveWe assessed the expression of PTEN, phospho-Akt (p-Akt), and p53 by immunohistochemistry in benign acral nevi, acral dysplastic nevi, and acral melanomas in the radial growth phase and with a vertical growth component.MethodsTen specimens in each group were included. Paraffin-embedded specimens were immunostained with antibodies for PTEN, p-Akt, and p53. We scored both the staining intensity and the proportion of positive cells. The final score was calculated by multiplying the intensity score by the proportion score.ResultsAll specimens of benign acral nevi except one showed some degree of PTEN-negative cells. The numbers of p-Akt and p53-positive cells were higher in acral dysplastic nevi and melanoma than in benign nevi. P-Akt scores were 1.7, 1.8, 2.6, and 4.4, and p53 scores were 2.0, 2.1, 3.8, and 4.1 in each group. PTEN and p-Akt scores in advanced acral melanoma were higher than in the other neoplasms.ConclusionThe expression of PTEN was decreased and the expression of p-Akt was increased in acral melanoma, especially in advanced cases. The PTEN-induced pathway appears to affect the late stage of melanomagenesis. Altered expression of p-Akt is thought to be due to secondary changes following the loss of PTEN.     

The Clinical Significance of Tumor-Infiltrating Lymphocytes and Microscopic Satellites in Acral Melanoma in a Korean Population

Background

There are various histological prognostic parameters of cutaneous malignant melanoma, including tumor thickness and ulceration. Tumor-infiltrating lymphocytes (TIL) are among these parameters and can be further classified into three categories: ''absent'', ''non-brisk'' and ''brisk''. Brisk TIL usually indicates better clinical prognosis. Microscopic satellite (Ms) is defined as a nest of tumor cells that is greater than 0.05 mm in diameter and definitely separated from the main tumor. Even though the incidence of Ms varies according to Breslow thickness, the presence of Ms generally indicates poor prognosis.

Objective

Clinical significance of both TIL and Ms has been extensively studied in western populations but much less so in Asian countries, including Korea, where acral melanoma is the most common subtype.

Methods

We reviewed 90 patients with acral melanoma diagnosed at Kyungpook National University Hospital in Korea. Tissue specimens were examined using hematoxylin-eosin and HMB45 immunohistochemical staining. They were also evaluated by the presence and categorization of TIL (absent, non-brisk and brisk) and the presence of Ms. We further evaluated their impact on survival events (recurrence, distant metastasis and death).

Results

The number of survival events by TIL type was 22 in the absent category (22/64, 34.4%), 3 in the non-brisk category (3/25, 12.0%) and 0 in the brisk category. For Ms, survival events were present in 7 patients in Ms-present group (7/11, 63.6%) and 21 patients in Ms-absent group (21/79, 26.6%).

Conclusion

We suggest the possibility of TIL and Ms as prognostic indicators for acral melanoma in Korean population.     

Oncogenic BRAF signalling increases Mcl‐1 expression in cutaneous metastatic melanoma

The Bcl‐2 family member Mcl‐1 is essential for melanoma survival; however, the influence of oncogenic BRAF signalling remains elusive. In this study, Mcl‐1 splice variant expression was determined in a panel of melanoma cell lines in relation to BRAF mutational status. Mcl‐1L mRNA expression was increased in melanoma cells compared with primary melanocytes with significantly increased mRNA and protein expression observed in BRAF^V600E mutant melanoma cells. Although no change in Mcl‐1S mRNA was observed, Mcl‐1S protein expression also increased in BRAF mutant melanoma cells. Additionally, while over‐expression of mutant BRAF^V600E increased both Mcl‐1L and Mcl‐1S expression, inhibition of hyperactive BRAF signalling resulted in decreased Mcl‐1L expression. These studies suggest that the regulation of Mcl‐1 expression by BRAF signalling is increased by oncogenic activation of BRAF, revealing a mechanism of apoptotic resistance which may be overcome by the use of more specifically targeted Mcl‐1 inhibitors.     

Treatment of congenital Langerhans cell histiocytosis with cobimetinib

We report a case of congenital multisystem Langerhans cell histiocytosis with cutaneous and hematopoietic involvement. After the failure of first-line (vinblastine and prednisolone) and second-line (vincristine and cytarabine) therapies, treatment with cobimetinib, a mitogen-activated protein kinase (MEK) inhibitor, led to the remission of disease and a sustained response after 11 months of ongoing treatment. Protein kinase inhibitors targeting BRAF or MEK could represent a promising future therapeutic option, also in children with LCH.     

新疆80例恶性黑素瘤BRAF基因突变分析

目的 探讨BRAF基因突变与恶性黑素瘤临床表现的关系。方法 PCR及DNA直接测序法对新疆80例恶性黑素瘤及30例正常皮肤石蜡包埋组织BRAF基因11、15外显子进行检测。结果 80例恶性黑素瘤19例发生BRAF基因突变,突变率为23.8%（19/80）;有17例突变发生于15外显子,突变率为89.5% （17/19）,其中V600E突变占BRAF基因15外显子突变的88.2% （15/17）;2例突变位于11外显子,突变率10.5%（2/19）;30例正常皮肤组织均未发现BRAF基因突变。患者平均发病年龄为57.5岁,年龄在60岁以下患者BRAF基因突变率显著高于60岁以上（χ2 = 6.613,P < 0.05）。黏膜、肢端、非肢端突变率分别为：18.2%（4/21）,14.7%（5/34）,41.7%（10/24）,差异具有统计学意义（χ2 = 6.167,P < 0.05）。BRAF基因突变与恶性黑素瘤患者性别、民族、有无淋巴结转移无明显相关性（P > 0.05）。结论 BRAF基因仍为新疆地区恶性黑素瘤热点突变基因,且以该基因15外显子V600E突变为主。BRAF基因突变与恶性黑素瘤患者发病年龄、发病部位密切相关,而与民族、性别、有无淋巴结转移无相关性。     

1型神经纤维瘤病NF1基因突变检测

目的 检测1例1型神经纤维瘤病(NF1)患者NF1基因的突变.方法 采用PCR和DNA测序法检测1例NF1患者、2例直系亲属及100例无亲缘关系的正常人NF1基因突变.结果 在NF1患儿中检测到1个移码突变c.3822delC,患者直系亲属及100例无亲缘关系的正常对照均未检测到上述突变.结论 在该例NF1患儿中新发现1个NF1基因移码突变c.3822delC不是罕见的单核苷酸多态性,可能是致病突变,通过影响NF1基因的功能致病.