肢端型黑素瘤NRAS基因突变检测及预后分析

目的 分析肢端黑素瘤临床及病理特点,检测肢端型黑素瘤NRAS基因突变情况,探讨NRAS基因突变与疾病预后的关系。方法 收集经病理确诊的55例肢端型黑素瘤患者的临床及病理资料,提取其石蜡包埋组织及15例色素痣石蜡包埋组织DNA,采用PCR及DNA直接测序法检测NRAS基因突变。采用Cox比例风险回归模型进行单因素和多因素分析。结果 55例肢端型黑素瘤患者中,6例（10.9%）发生NRAS突变,突变位于61密码子,以Q61R为主。NRAS基因1、2外显子及15例色素痣组织未见上述突变。6例NRAS突变患者中,4例发生淋巴结转移。多因素Cox回归模型分析中,临床分期晚（RR = 2.54,95% CI：1.062 ~ 6.066）、未手术切除（RR = 2.98,95% CI：1.316 ~ 3.525）、存在NRAS突变（RR = 2.73,95% CI：0.932 ~ 3.257）为预后不良的独立影响因素（均P < 0.05）。结论 肢端型黑素瘤患者NRAS突变可能与淋巴结转移相关,临床分期、治疗方法、NRAS突变与预后有关。NRAS突变可能为肢端型黑素瘤提供一个新的预后评估指标。     

Usefulness of neuron-specific enolase as a serum marker of metastatic melanoma

Treatment strategies for advanced melanoma are dramatically changing, due to immune-checkpoint inhibitors and BRAF/MEK inhibitors. Nevertheless, reliable serum markers for evaluation of treatment responses and the outcome are still limited. Some previous reports suggested that serum neuron-specific enolase (sNSE) may be a useful marker for melanoma; however, its usefulness is controversial. Moreover, NSE has not been examined in vitro by using melanoma cell lines. We retrospectively evaluated sNSE and serum lactate dehydrogenase (sLDH) levels at the initial diagnosis and during therapy in 33 melanoma patients of various stages. We analyzed the NSE concentrations in cell lysates and supernatants from melanoma cell lines by enzyme-linked immunosorbent assay. The median sNSE was significantly higher in stage IV patients compared with stages I/II and III (16.3, 12.7 and 12.1 ng/mL, respectively). sNSE was elevated in 20% (2/10) of stage III and 61.1% (11/18) of stage IV patients but not in stages I/II. sNSE and sLDH tended to correspond to the total tumor volume (P = 0.48 and 0.58; 95% confidence intervals, 0.005–0172 and 0.776–0.836, respectively). The coincidence rate of sNSE and sLDH in stage IV at the initial diagnosis was 11 of 18 (61.1%). Of the remaining patients, elevated sNSE but not sLDH was observed in five patients (27.8%) and elevated sLDH but not sNSE was observed in two (11.1%). Four of the five patients showing elevated sNSE and normal sLDH were of the mucosal type. NSE was detected in both supernatant and cell lysate of all four melanoma cell lines (0.30–237.32 ng/mL and 137–483.04 ng/mg, respectively). Two cell lines with a high supernatant NSE level contained many dead cells in the supernatant. The combination of sNSE and sLDH could contribute to the early detection of distant metastasis and disease condition evaluations for advanced melanoma patients.     

Management and outcome of metastatic melanoma during pregnancy

Background Although metastatic melanoma occurrence during pregnancy challenges the physician in several ways, only a few studies have been published. Objectives Our aim was to investigate therapeutic management together with maternal and fetal outcomes in pregnant women with advanced melanoma. Methods A French national retrospective study was conducted in 34 departments of Dermatology or Oncology. All patients with American Joint Committee on Cancer (AJCC) stage III/IV melanoma diagnosed during pregnancy were included. Data regarding melanoma history, pregnancy, treatment, delivery, maternal and infant outcomes were collected. Results Twenty‐two women were included: 10 AJCC stage III and 12 stage IV. Abortion was performed in three patients. Therapeutic abstention during pregnancy was observed in three cases, 14 patients underwent surgery, four patients received chemotherapy and one patient was treated with brain radiotherapy alone. The median gestational age was 36 weeks amenorrhoea. Neither neonatal metastases nor deformities were observed. Placenta metastases were found in one case. Among 18 newborns, 17 are currently alive (median follow up, 17 months); one died of sudden infant death. The 2‐year maternal survival rates were 56% (stage III) and 17% (stage IV). Conclusions Faced with metastatic melanoma, a majority of women chose to continue with pregnancy, giving birth, based on our samples, to healthy, frequently premature infants. Except during the first trimester of pregnancy, conventional melanoma treatment was applied. No serious side effect was reported, except one case of miscarriage after surgery. Mortality rates do not suggest a worsened prognosis due to pregnancy but larger prospective controlled studies are necessary to assess this specific point.     

Mutated and amplified NRAS in a subset of cutaneous melanocytic lesions with dermal spitzoid morphology: report of two pediatric cases located on the ear

Extensive cytogenetic testing is slowly unveiling the complexity of the genomics of melanocytic tumors. NRAS mutations have been the first genetic abnormality described in malignant melanomas. We report the cases of two children, presenting a melanocytic lesion located on the ear. One appeared as a combined dermal clone inside a congenital nevus and the other as a centimetric purely dermal tumor. Both tumors were composed of spindled spitzoid melanocytes with atypical histologic features. aCGH and FISH revealed an amplification of the NRAS gene. Sequencing showed an exon 3 NRAS mutation. In the combined case, the amplification was limited to the spitzoid component, underscoring a possible phenotypic shift induced by the alteration. Similarly an overexpression of CyclinD1 and elevation of ki‐67 was found in the spitzoid component confirming a raise in proliferation. Such combination of mutation and copy number increase has been previously reported for the HRAS gene in a subset of Spitz nevi. Further studies must evaluate if mutated NRAS is also amplified in melanomas arising in this clinical setting. These combined alterations could represent an early event ultimately leading to malignancy.     

Tyrosine phosphate in melanoma progression

BACKGROUND: Cellular tyrosine phosphorylation is regulated by two large families of enzymes. Protein tyrosine kinases (PTK) mediate addition, and protein tyrosine phosphatases (PTP), removal of phosphate from protein substrates. PTKs are oncogenes and PTPs have been hypothesized to function as tumour suppressor genes. OBJECTIVES: To determine changes in tyrosine phosphate and PTP activity that occur during melanoma progression. METHODS: Immunohistochemistry was used to study phosphotyrosine in melanocytic lesions. In addition, PTP activity of normal melanocytes and melanoma cell lines was measured using an enzyme-linked immunosorbent assay-based system. RESULTS: Melanocytes in normal skin and most (67%) benign naevi were not immunostained. Neither were early malignant lesions (80% of malignant melanoma in situ and radial growth phase melanomas) stained. However, most advanced melanomas (100% of vertical growth phase, and 90% of metastatic melanomas) were immunoreactive. When total PTP enzyme activity was assayed in normal melanocytes and malignant melanoma cell lines, there was a significant increase in activity associated with melanoma progression. CONCLUSIONS: Taken together, the data suggest increased phosphotyrosine signalling occurs during melanoma progression at the stage when cells first become competent for metastasis.     

Clinical significance of BRAF mutation status in circulating tumor DNA of metastatic melanoma patients at baseline

Circulating tumor DNA is a promising non‐invasive tool for cancer monitoring. The main objective of our work was to investigate the relationship between mutant BRAF DNA in plasma and clinical response. Thirty‐eight stage IV patients with a V600 mutated BRAF melanoma were included prior to any treatment. DNA was extracted from plasma and mutant DNA was detected using the amplification‐refractory mutation system method. Before the beginning of any treatment, the corresponding BRAF mutation was detected in 29 of the 38 tested plasma samples (76.3% positive per cent agreement). We observed a strong correlation between the presence of circulating mutated DNA and overall survival (OS; P=.02), and with the number of metastatic sites (P=.01). The presence of circulating mutated DNA was also strongly correlated with serum LDH activity (P<.01) and S100 protein concentration (P<.01). Finally, seven patients presented discordant BRAF status in different tumor sites. In all these patients, the test performed on ctDNA was positive, suggesting that ctDNA analysis might be less sensitive to tumor heterogeneity. Altogether, these results suggest that plasmatic mutant BRAF DNA is a prognostic factor of OS, correlated with tumor burden. In addition, it represents an interesting alternative source of DNA to detect BRAF mutations before treatment.     

BRAF, NRAS and HRAS mutations in spitzoid tumours and their possible pathogenetic significance

Background The relationships between so‐called spitzoid tumours have proven difficult to understand. Objectives To address three questions: does spitzoid tumour morphological similarity reflect molecular similarity? Does Spitz naevus progress into spitzoid melanoma? Are ambiguous spitzoid tumours genuine entities? Methods BRAF, NRAS and HRAS mutations were analysed using single‐strand conformational polymorphism analysis and sequencing. Results Both Spitz naevi and spitzoid melanoma had a lower combined BRAF and NRAS mutation frequency compared with common acquired naevi (P = 0·0001) and common forms of melanoma (P = 0·0072), respectively. To look for evidence of progression from Spitz naevi to spitzoid melanoma, HRAS was analysed in 21 spitzoid melanomas, with no mutations identified. The binomial probability of this was 0·03 based on an assumption of a 15% mutation frequency in Spitz naevi with unbiased progression. Under these assumptions, HRAS mutations must be rare/absent in spitzoid melanoma. Thus, Spitz naevi seem unlikely to progress into spitzoid melanoma, implying that ambiguous spitzoid tumours cannot be intermediate degrees of progression. In addition, the data suggest that HRAS mutation is a potential marker of benign behaviour, in support of which none of three HRAS mutant spitzoid cases metastasized. Conclusions First, the morphological similarity of spitzoid tumours reflects an underlying molecular similarity, namely a relative lack of dependence on BRAF/NRAS mutations. Second, Spitz naevi do not appear to progress into spitzoid melanoma, and consequently ambiguous spitzoid tumours are likely to be unclassifiable Spitz naevi or spitzoid melanoma rather than genuine entities. Third, HRAS mutation may be a marker of Spitz naevus, raising the possibility that other molecular markers for discriminating Spitz naevi from spitzoid melanoma can be discovered.     

Dynamic interplay between autophagic flux and Akt during melanoma progression in vitro

Despite advances in cancer diagnosis and therapy, metastatic melanoma remains untreatable, due to its notorious resistance to apoptosis, deeming traditional therapies obsolete. Deregulated PI3K/Akt signalling is a common oncogenic event enabling melanocyte transformation and represents a significant and ‘druggable’ pathway in melanoma. Emerging data show that the ability of cancer cells to survive is also facilitated by alteration of vital homoeostatic mechanisms, such as autophagy. Although the role of autophagy in melanoma is still controversial, recent studies suggest that basal autophagy is down‐modulated in primary melanomas. However, the dynamic connection between pro‐tumorigenic PI3K/Akt and autophagy during melanoma progression has not been systematically studied. By using human primary melanocytes, incipient melanoma and metastatic melanoma cell lines, we show that early in melanomagenesis, increased Akt activity is associated with a low baseline autophagic flux. However, during melanoma progression, metastatic melanoma cells regain the ability to stimulate autophagic flux, supporting survival. Heightened autophagy is associated with an attenuated Akt activation status and can be suppressed by overexpressing a constitutive active mutant of Akt. On the other hand, blocking the higher Akt activity of primary melanoma is sufficient to incite autophagy. Interestingly, we found that although Akt supports survival of melanocytes and all melanoma cell lines, autophagy inhibition specifically targeted the metastatic melanoma cells, thus indicating a stage‐specific requirement for Akt and autophagic flux, throughout melanoma progression. Therefore, this study highlights a dynamic interplay between Akt signalling and autophagic rescue in melanoma, which should be considered in the design of therapeutic strategies targeting these pathways.     

过表达EphB6与BRAFi在抑制黑素瘤转移中的协同作用

目的：本研究旨在探讨EphB6过表达和BRAF抑制剂(BRAFi)治疗对抑制黑素瘤转移进展过程中的协同作用。方法：从Pubchem数据库中下载维莫非尼和达帕非尼靶向基因,通过GSE141484和GSE22838芯片中分析疾病表达具有差异的基因,鉴定出EphB6。通过CCK-8、克隆形成、伤口愈合和transwell实验检测过表达EphB6并且BRAFi处理分别对A375和1205Lu细胞活力和运动能力的独立效应和协同效应。结果：过表达EphB6可显著抑制A375和1205Lu细胞的增殖、克隆形成,明显阻碍细胞的增殖速度,促进维莫非尼和达帕非尼对A375和1205Lu细胞活力和运动能力的抑制作用。结论：过表达EphB6可显著抑制黑素瘤的转移进展,有利于黑素瘤的BRAFi治疗。     

Histologic progression of B16 F10 metastatic melanoma in C57BL/6 mice over a six week time period: distant metastases before local growth

B16F10 murine metastatic melanoma in the tails of C57BL/6 mice after subcutaneous injection is a well-established model. However, the histologic progression from injected cells to established local growth of melanoma has not been studied systematically. We therefore have investigated the histologic changes and growth of B16F10 melanoma at the injection site over a six-week time period. One million B16F10 melanoma cells were injected subcutaneously into the dorsal aspect of tails of C57/BL6 mice. Mice were sacrificed at zero, 12, 24, 48, 72 and 96 hours, and at one, two, three, four, five and six weeks. Sections were stained with Hematoxylin and Eosin and immunostained with antibodies to S100. Beginning at time zero, melanoma cells were detected between the dermis and the myofascial bundle of the tail. At week four, distant metastases were clinically evident in the inguinal region, though injection site tumors did not become evident until week six. Histological analysis showed melanoma cells at the injection site at all time periods and no injection site tumor until week six. Indeed, the injection site tumors arose two weeks after distant metastases were clinically apparent. A progression of S100 positivity was also observed. S100 immunostaining was negative in all injection site of B16F10 cells until the cells underwent a morphologic change from small and monomorphic at the injection site, to large, pleomorphic cells at week six in the clinically evident injection site tumors. Inguinal metastases were also S100 positive at week four, though injection site cells were still S100 negative. We conclude that in this particular established model for melanoma, local growth at the injection site may occur after the development of regional metastases. This may prove to be a good model for investigation of local growth of tumor cells and their interaction with metastatic lesions.     

A comparative study of Fas and Fas-ligand expression during melanoma progression

BACKGROUND: Impaired regulation of apoptosis is known to be associated with the development of various cancers. Fas receptor (APO-1/CD95) binding to its ligand, Fas-ligand (Fas-L), has been shown to trigger apoptosis in various cell types. OBJECTIVES: In this study, we examined CD95 and Fas-L expression on primary and metastatic melanoma cells from patients to investigate a potential correlation between these measures of apoptosis and different disease stages. PATIENTS AND METHODS: Primary melanoma cells were obtained after surgical resection from 19 patients and metastatic cells from fine-needle aspiration of lymph nodes or palpable subcutaneous lesions in 25 patients. Normal skin cells were obtained at skin biopsy of 10 healthy donors. RESULTS: Flow cytometric analysis revealed that CD95 and Fas-L expression was detected in all the kinds of cell studied. In whole cell suspensions, CD95 expression was significantly higher (P < 0.0001) in normal skin cells than in melanoma cells, whatever the stage studied. By contrast, we observed an increase in Fas-L expression in melanoma cells compared with normal ones. Subsequently, using a double staining method, we studied these measures on HMB45+ cells, a specific marker for melanoma cells, and found that CD95 expression was significantly higher (P = 0.0005) in primary than in metastatic cells while Fas-L expression was significantly increased (P = 0. 0004) in metastatic compared with primary cells. Furthermore, a relationship was found between CD95 or Fas-L expression and Breslow thickness; as primary melanoma thickness progressively increased, the percentage of HMB45+ CD95+ cells decreased while that of HMB45+ Fas-L+ cells concurrently increased. CONCLUSIONS: These results suggest that downregulation of CD95 and upregulation of Fas-L in melanoma might be considered as concomitant with disease progression.     

Epithelioid angiomyolipoma mimicking metastatic melanoma in a liver tumor

It is well known to pathologists that melanoma is “the great mimicker,” looking like almost any other tumor, and able to metastasize anywhere in the body. We report a case of a 48-year-old female with a history of metastatic melanoma 4 years before, who presented with a hepatic mass. Microscopic examination of the liver mass revealed sheets of pleomorphic, epithelioid cells, which expressed a pan-melanocytic cocktail (MART1, HMB45, and tyrosinase). These findings were initially interpreted as metastatic melanoma and the case was transferred for dermatopathology consultation. We compared the morphology of this tumor to the primary melanoma and noticed that the primary melanoma showed nevoid cytology, morphologically distinct from the liver lesion. Consequently, we performed additional immunohistochemical studies, which determined that the liver mass was negative for S100 and SOX10, and established a final diagnosis of epithelioid angiomyolipoma. The key for reaching the correct diagnosis was the morphologic comparison with the original lesion and the evaluation of a wider immunohistochemical profile. For appropriate management in patients with new lesions, even in the context of a patient with known metastatic disease, it is essential to consider other neoplasms in the differential diagnosis.     

A potential predictive marker for response to interferon in malignant melanoma

The methylthioadenosine phosphorylase (mtap) gene is localized on chromosome 9p21, a chromosomal region often affected by deletion in several kinds of malignant tumors. Studies on malignant melanoma have revealed loss of MTAP expression in vitro and in vivo; however, loss of MTAP expression is mainly regulated by promoter hypermethylation. Loss of MTAP was shown to have an effect on tumor invasion and metastasis. In a recent study, MTAP not only had a role as tumor suppressor but was also implicated in lack of therapeutic response of patients with recurrent malignant melanoma. There is evidence that loss of MTAP results in an inhibition of STAT signaling pathways regulated by interferon. This in turn leads to ineffectiveness of interferon therapy. Determination of the MTAP status in the primary tumor could, therefore, potentially lead to a selection of patients who benefit from interferon treatment.     

Increase in telomerase activity during progression of melanocytic cells from melanocytic naevi to malignant melanomas

Abstract During successive cell divisions of mortal cells the length of the telomeres (TTAGGG repeats in vertebrates) at the end of chromosomes decreases. It has been suggested that this process is responsible for cellular senescence. Expression of the ribonucleoprotein telomerase appears to prevent shortening of telomeres in germ-line cells and cancer cells. The purpose of this study was to investigate telomerase activity in melanocytic lesions and its possible role in the multistep tumor progression model of malignant melanoma. To quantify the level of telomerase activity both in cultured cells and in fresh tissue samples the TRAP (telomeric repeat amplification protocol) ELISA was used. Eight cell lines of malignant melanoma, 3 primary cultures of fibroblasts, 36 melanocytic naevi, 5 atypical melanocytic naevi, 3 Spitz’s naevi, 31 primary malignant melanomas and 13 metastases of malignant melanomas were investigated. Also 34 samples of skin (22 samples of perilesional skin and 12 samples of normal skin) were analysed. In our experiments all melanoma cell lines were strongly positive, whereas in fibroblasts telomerase activity could not be detected. Of the primary melanomas and metastatic melanomas, 90.3% and 92.3%, respectively, were strongly positive, and of the atypical melanocytic naevi, 80% were positive. Of the 36 common melanocytic naevi only 10 (27.7%) expressed weak telomerase activity and of the 34 samples of human skin, 4 (11.7%) expressed very weak telomerase activity. Our results indicate that telomerase activity increases from benign melanocytic naevi to atypical naevi and further to malignant melanoma and metastatic melanoma cells, and therefore may play a role in tumour initiation and progression. Received: 26 June 1998 / Received after revision: 28 October 1998 / Accepted: 2 November 1998     

Analysis of APAF-1 expression in human cutaneous melanoma progression

APAF-1 plays a pivotal role in mitochondria-dependent apoptosis, binding to cytochrome c and favoring activation of caspase-9. It has been shown that epigenetic silencing of the APAF-1 gene is a common event in several metastatic melanoma cells in vitro. We determined, by Western blot, variation in the level of expression of APAF-1 in several human melanoma cell lines and, by immunohistochemistry, in a group of 106 histological samples including benign and malignant melanocytic lesions. We observed APAF-1 down-regulation or loss of expression in two metastatic melanoma cell lines, compared to primary melanoma cell lines. The immunohistochemical analysis revealed a significant difference in APAF-1 staining between nevi and melanomas. In addition, we found a significant negative correlation between APAF-1 expression level and tumor thickness and between primary melanomas and metastases. We conclude that loss of APAF-1 expression can be considered as an indicator of malignant transformation in melanoma.