Increased expression of melanoma stem cell marker CD271 in metastatic melanoma to the brain

Human melanoma contains multipotent stem cells that express the neural crest stem cell marker CD271. CD271-expressing melanoma cells in murine xenografts give rise to metastatic tumor. However, a comprehensive clinical investigation of its role in different stages of melanomagenesis has not been well studied. We studied CD271 expression with immunohistochemistry in 11 cases of banal melanocytic nevus, 9 cases of primary cutaneous melanoma, 10 cases of primary mucosal melanoma, 5 cases of metastatic melanoma in regional lymph nodes, and 11 cases of metastatic melanoma in the brain. In addition, 9 cases of metastatic, high-grade adenocarcinomas from breast and lung to the brain were studied as controls. The staining was scored based on the number of positive cells and analyzed by student t-test. All banal melanocytic nevi showed negative to equivocal staining. Primary cutaneous melanomas showed variable patterns, mucosal melanomas were mostly negative, and metastases to lymph nodes ranged from negative to moderate positivity. In contrast, all 11 cases of metastatic melanoma to the brain showed moderate (4 cases) to strong positivity (7 cases). Metastases from lung and breast origin were used as controls and showed negative to weakly positive staining in all but one case. Statistically, CD271 has significantly increased expression in metastatic melanoma to the brain when compared to the other groups studied (P < 0.05). The findings suggest that CD271 expression is specifically increased in metastatic melanoma to the brain. Further prospective study for the role of CD271 in prediction of melanoma brain metastasis as well as prognosis assessment will be of great clinical significance.     

Versican is differentially expressed in human melanoma and may play a role in tumor development

Undifferentiated human melanoma cell lines produce a large chondroitin sulfate proteoglycan, different from the well-known melanoma-specific proteoglycan mel-PG (Heredia and colleagues, Arch Biochem Biophys, 333: 198-206, 1996). We have identified this proteoglycan as versican and analyzed the expression of versican in several human melanoma cell lines. Versican isoforms are expressed in undifferentiated cell lines but not in differentiated cells, and the isoform expression pattern depends on the degree of cell differentiation. The V0 and V1 isoforms are found on cells with an early degree of differentiation, whereas the V1 isoform is present in cells with an intermediate degree of differentiation. We have also characterized some functional properties of versican on human melanoma cells: the purified proteoglycan stimulates cell growth and inhibits cell adhesion when cells are grown on fibronectin or collagen type I as substrates, and thus may facilitate tumor cell detachment and proliferation. Furthermore, we have analyzed the expression of versican in human melanocytic nevi and melanoma: 10 benign melanocytic nevi, 10 dysplastic nevi, 11 primary malignant melanomas, and 8 metastatic melanomas were tested. Immunoreactivity for versican was negative in benign melanocytic nevi, weakly to strongly positive in dysplastic nevi, and intensely positive in primary malignant melanomas and metastatic melanomas. Our results indicate that versican is involved in the progression of melanomas and may be a reliable marker for clinical diagnosis.     

Divergent Cellular Differentiation Pathways during the Invasive Stage of Cutaneous Malignant Melanoma Progression

Melanocytic nevus cells in the dermis adopt many morphological features of Schwann cells. These differentiation-related changes typically are not observed in melanomas. However, nevus cells do not fully recapitulate a Schwann cell phenotype, because they lack expression of mature myelin-associated proteins. In this study, melanocytic nevi and malignant melanomas were examined by immunohistochemistry for expression of low-affinity nerve growth factor receptor (p75NGFR), neural cell adhesion molecule (CD56/N-CAM), and growth-associated phosphoprotein-43 (GAP-43). These three proteins define the earliest stages of Schwann cell development but are not expressed in myelinated Schwann cells or normal melanocytes. p75NGFR was expressed in 25 of 25 (100%) and CD56/N-CAM and GAP-43 in 23 of 25 (92%) nevi, predominantly in type C nevus cells and nevic corpuscles. Most (84%) of the nevi expressed all three proteins. In primary invasive and metastatic melanoma, expression of each of the three proteins was limited to 相似文献   

Melanoma-associated expression of transforming growth factor-beta isoforms.

Melanocytic neoplasia is characterized by the aberrant overproduction of multiple cytokines in vitro. However, it is largely unknown how cytokine expression relates to melanoma progression in vivo. Transforming growth factor beta (TGF-beta) is a multifunctional cytokine commonly produced by cultured melanoma cells. The in situ expression of all three TGF-beta isoforms (TGF-beta1, -2, and -3) was determined immunohistochemically in melanocytes and in 51 melanocytic lesions using isoform-specific antibodies. Significant linear trends of expression were observed from melanocytes through nevi and primary and metastatic melanomas for all three isoforms. TGF-beta1 was expressed by some melanocytes and almost uniformly by nevi and melanomas. TGF-beta2 and -3 were not expressed in normal melanocytes but were expressed in nevi and early and advanced primary (radial and vertical growth phase) and metastatic melanomas in a tumor-progression-related manner. TGF-beta2 was heterogeneously expressed in advanced primary and metastatic melanomas, whereas TGF-beta3 was uniformly and highly expressed in these lesions. Thus, expression of TGF-beta isoforms in melanocytes and melanocytic lesions is heterogeneous and related to tumor progression, and expression of TGF-beta2 and TGF-beta3 commences at critical junctures during progression of nevi to primary melanomas.     

Immunoreactivity with the anti-MAGE antibody 57B in malignant melanoma: frequency of expression and correlation with prognostic parameters.

The melanoma-associated antigen (MAGE) family consists of a number of antigens initially recognized by cytotoxic T lymphocytes, which are currently being investigated for immunotherapy of patients with metastatic melanoma and other tumor types. Expression of MAGE mRNA in melanocytic tumors is said to be restricted to invasive malignant tumors and absent in nevi. Recently, a monoclonal antibody (57B) has become available to examine MAGE protein expression in archival material. In this study, we performed immunohistochemical analysis on 132 melanocytic nevi and 205 melanomas (85 primary cutaneous melanomas and 120 metastatic tumors) to determine the frequency of MAGE expression and to explore a potential correlation with various prognostic parameters. None of the melanocytic nevi and none of the 20 in situ melanomas was immunopositive with the antibody 57B. Immunoreactivity was present in 17 of 65 (26%) primary invasive melanomas of the skin and in 30 of 120 (25%) metastatic tumors. Positive immunostaining did not correlate with tumor stage (P = .66), Breslow thickness (P = .39), Clark level (P = .5), or the histologic type of melanoma (P = .23) but was associated with a brisk infiltrate of lymphocytes involving the vertical growth phase of melanomas (P = .01). Because tumor-infiltrating lymphocytes in melanoma are associated with longer survival, our findings suggest a potential prognostic role for MAGE. Furthermore, the seeming restriction of immunopositivity to invasive malignant tumors suggests a potential diagnostic role for the antibody 57B in confirming the malignant potential of a melanocytic tumor.     

Expression of cell cycle inhibitor p27Kip1 and its inactivator Jab1 in melanocytic lesions.

Decreased expression of p27 (a cyclin-dependent kinase inhibitor) is an adverse prognostic marker in a diverse array of human cancers. The purpose of this study was to investigate the expression of p27 and Jab1 (a protein involved in p27 degradation) in melanocytic lesions, and to identify their possible participation in melanoma progression. A tissue microarray was constructed using formalin-fixed, paraffin-embedded archival tissue blocks of 94 melanocytic lesions including 19 benign nevi, 21 dysplastic nevi, 23 melanomas, and 31 metastatic melanomas. The expression of p27 and Jab1 was evaluated by immunohistochemistry. The association between p27, Jab1, and clinicopathological parameters was analyzed using chi2 and Fisher's exact tests. Nonparametric Pearson's rank correlation was applied to evaluate the relationship between p27 and Jab1 expression. p27 was expressed in 15 (88%) nevi, 18 (95%) dysplastic nevi, 11 (50%) melanomas, and only in four (13%) of the metastatic melanomas (P<0.001). Jab1 was expressed in 14 (82%) standard nevi, 18 (95%) dysplastic nevi, 17 (77%) melanomas, and 16 (53%) of the metastatic melanomas (P<0.01). In metastatic melanomas, there was a negative correlation between p27 and Jab1 expression (r=-0.166). The low levels of p27 in primary and metastatic melanoma cases may explain the high proliferation rate of such lesions. Also, the relative high expression of Jab1 in metastatic melanoma, associated with low levels of p27, suggests that Jab1 may be involved in survival and proliferation of metastatic melanoma cells.     

IMP-3 is a novel progression marker in malignant melanoma

Insulin-like growth factor-II messenger RNA (mRNA)-binding protein-3 (IMP-3), also known as K homology domain-containing protein overexpressed in cancer (KOC) and L523S, is a member of the insulin-like growth factor-II mRNA-binding protein family and is expressed during embryogenesis and in some malignancies. IMP-3 expression in melanocytic neoplasms has not been investigated. Fifty-six melanocytic neoplasms from 48 subjects were immunohistochemically studied using a monoclonal antibody against L523S/IMP-3. IMP-3 expression in melanoma was significantly higher than in Spitz nevi (P<0.05), and the staining intensity in the Spitz nevi was weak. IMP-3 expression in metastatic melanoma was significantly higher than in primary cutaneous melanoma with a Breslow depth 相似文献   

Cell cycle analysis can differentiate thin melanomas from dysplastic nevi and reveals accelerated replication in thick melanomas

Cell replication integrates aberrations of cell cycle regulation and diverse upstream pathways which all can contribute to melanoma development and progression. In this study, cell cycle regulatory proteins were detected in situ in benign and malignant melanocytic tumors to allow correlation of major cell cycle fractions (G1, S-G2, and G2-M) with melanoma evolution. Dysplastic nevi expressed early cell cycle markers (cyclin D1 and cyclin-dependent kinase 2; Cdk2) significantly more (p?<?0.05) than common nevi. Post-G1 phase markers such as cyclin A, geminin, topoisomerase IIα (peaking at S-G2) and aurora kinase B (peaking at G2-M) were expressed in thin (≤1 mm) melanomas but not in dysplastic nevi, suggesting that dysplastic melanocytes engaged in the cell cycle do not complete replication and remain arrested in G1 phase. In malignant melanomas, the expression of general and post-G1 phase markers correlated well with each other implying negligible cell cycle arrest. Post-G1 phase markers and Ki67 but none of the early markers cyclin D1, Cdk2 or minichromosome maintenance protein 6 (Mcm6) were expressed significantly more often in thick (>1 mm) than in thin melanomas. Marker expression did not differ between metastatic melanomas and thick melanomas, with the exception of aurora kinase A of which the expression was higher in metastatic melanomas. Combined detection of cyclin A (post-G1 phase) with Mcm6 (replication licensing) and Ki67 correctly classified thin melanomas and dysplastic nevi in 95.9 % of the original samples and in 93.2 % of cross-validated grouped cases at 89.5 % sensitivity and 92.6 % specificity. Therefore, cell cycle phase marker detection can indicate malignancy in early melanocytic lesions and accelerated cell cycle progression during vertical melanoma growth.     

Expression of microtubule-associated protein 2 in benign and malignant melanocytes: implications for differentiation and progression of cutaneous melanoma

Cutaneous melanocytic neoplasms are known to acquire variable characteristics of neural crest differentiation. Melanocytic nevus cells in the dermis and desmoplastic melanomas often display characteristics of nerve sheath differentiation. The extent and nature of neuronal differentiation characteristics displayed by primary and metastatic melanoma cells are not well understood. Here, we describe induction of a juvenile isoform of microtubule-associated protein 2 (MAP-2c) in cultured metastatic melanoma cells by the differentiation inducer hexamethylene bisacetamide. Up-regulation of this MAP-2 isoform, a marker for immature neurons, is accompanied by extended dendritic morphology and down-regulation of tyrosinase-related protein 1 (TYRP1/gp75), a melanocyte differentiation marker. In a panel of cell lines that represent melanoma tumor progression, MAP-2c mRNA and the corresponding approximately 70-kd protein could be detected predominantly in primary melanomas. Immunohistochemical analysis of 61 benign and malignant melanocytic lesions showed abundant expression of MAP-2 protein in melanocytic nevi and in the in situ and invasive components of primary melanoma, but only focal heterogeneous expression in a few metastatic melanomas. In contrast, MAP-2-positive dermal nevus cells and the invasive cells of primary melanomas were TYRP1-negative. This reciprocal staining pattern in vivo is similar to the in vitro observation that induction of the neuronal marker MAP-2 in metastatic melanoma cells is accompanied by selective extinction of the melanocytic marker TYRP1. Our data show that neoplastic melanocytes, particularly at early stages, retain the plasticity to express the neuron-specific marker MAP-2. These observations are consistent with the premise that both benign and malignant melanocytes in the dermis can express markers of neuronal differentiation.     

Fatty acid synthase expression in cutaneous melanocytic neoplasms.

Mammalian fatty acid synthase is a multifunctional enzyme complex involved in de novo synthesis of saturated fatty acids, and inhibitors of fatty acid synthase are being evaluated as potential therapeutic agents. Increased fatty acid synthase expression has been demonstrated in subsets of malignancies, including colon, breast, endometrium, prostate and ovarian carcinomas, and recently malignant melanomas. We evaluated the immunohistochemical expression of fatty acid synthase in 155 cutaneous melanocytic lesions. They included 30 congenital nevi, 19 compound nevi, 40 Spitz nevi, 48 primary melanomas, and 18 metastatic melanomas. Fatty acid synthase expression was stronger in malignant melanomas in comparison to conventional nevi and Spitz nevi, and was the highest for metastatic melanoma. Of the primary malignant melanomas, mean fatty acid synthase scores were significantly greater for Clark levels IV and V compared to Clark levels I and II (P<0.001). In addition, melanomas with Breslow thickness 0.75-1.50 mm and >1.50 mm showed significantly higher mean fatty acid synthase scores compared with those with Breslow thickness <0.75 mm (P=0.013 and <0.001, respectively). Of interest, congenital melanocytic nevi also showed strong fatty acid synthase expression, similar to that seen in metastatic melanoma. This may represent persistence of or regression to a fetal phenotype since normal fetal tissues are known to express high levels of fatty acid synthase.     

Proliferative activity of primary cutaneous melanocytic tumours

The expression of proliferating cell nuclear antigen (PCNA) was examined in formalin-fixed paraffin-embedded tissue sections from 41 lesions (27 melanocytic nevi, 3 atypical nevi and 11 malignant melanomas) to determine the proliferative activity of primary cutaneous melanocytic tumours. Most of the malignant melanomas had more than 7% PCNA-positive cells (9.2±0.5%), while the melanocytic nevi manifested less than 1% PCNA-positive cells (0.4±0.1%). Atypical nevi exhibited an intermediate, but still significantly lower, labelling ratio when compared with malignant melanomas (0.8±0.2%). The proliferative activity of the lesions was compared between portions at different depths in the skin (epidermal, upper dermal and lower dermal location). In cases of malignant melanoma, the proliferative activity was higher in the deeper portion of dermis whereas PCNA-positive cells in melanocytic nevi were located in the upper dermis predominantly. Thus the PCNA labelling ratio of malignant melanoma and/or melanocytic nevus cells located in the epidermodermal junction was not necessarily higher than that of malignant melanoma and/or melanocytic nevus cells in the dermis. These results indicate that staining with PCNA would be very useful in the differentiation of malignant melanoma from melanocytic nevi manifesting cellular and/or structural atypia by virtue of a significant difference in the proportion of PCNA-positive cells. Although malignant melanomas have higher proliferative activity than melanocytic nevi in the deeper dermis, junctional activity in melanocytic tumours does not indicate cell proliferation.     

DEK expression in melanocytic lesions

The diagnosis of malignant melanoma presents a clinical challenge and relies principally on histopathological evaluation. Previous studies have indicated that increased expression of the DEK oncogene, a chromatin-bound factor, could contribute to the development of melanoma and may be a frequent event in melanoma progression. Here, we investigated DEK expression by immunohistochemistry in a total of 147 melanocytic lesions, including ordinary nevi, dysplastic nevi, Spitz nevi, melanoma in situ, primary invasive melanomas, and metastatic melanomas. Most benign nevi (ordinary, dysplastic, and Spitz nevi) were negative or exhibited weak staining for DEK, with only 4 of 49 cases showing strong staining. Similar to benign nevi, melanoma in situ also demonstrated low levels of DEK expression. In contrast, the expression of DEK in primary invasive melanomas was significantly higher than benign nevi (P < .0001). Moreover, DEK expression was significantly increased in deep melanomas (Breslow depth >1 mm) and metastatic melanomas as compared with superficial melanomas (Breslow depth ≤1 mm) (P < .05). Our findings indicate that DEK overexpression may be a frequent event in invasive melanomas, and further augmentation of DEK expression may be associated with the acquisition of ominous features such as deep dermal invasion and metastasis. These data suggest a role of DEK in melanoma progression.     

The role of intermedial filament nestin in malignant melanoma progression

Nestin is one of intermedial filaments exprimed in proliferating progenitor cells of the CNS and PNS (central and peripheral nervous system). Postnatal reexpression of the protein occures mainly in CNS tumors and correlates with a high grade of malignancy. The aim of our study is assessment of the nestin expression in benign and malignant skin melanocytic lesions with respect to presume a prognostic role of this protein. We examined 127 bioptic specimens, including 42 nodular melanomas (NM), 32 superficial spreading melanomas (SSM), 10 dysplastic nevi and 43 common intradermal or dermoepidermal nevi. We proved significant increase in nestin expression in melanoma groups, especially in nodular melanomas, where nestin was localized mainly in the peripheral, invasive areas of the tumor mass. Conclusion: Detection of nestin expression might be used as an additional melanocytic tumour marker.     

Progression in melanoma is associated with decreased expression of death receptors for tumor necrosis factor-related apoptosis-inducing ligand

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in melanoma by interaction with death receptors TRAIL-R1 (DR4) or TRAIL-R2 (DR5) on melanoma cells or resists apoptosis by interaction with decoy receptors TRAIL-R3 (DcR1) or TRAIL-R4 (DcR2). Studies on cell lines suggest that there is a wide variation in TRAIL death receptor expression; however, their expression on excised human melanoma is not well documented. In view of this, we studied death receptor expression on melanomas using monoclonal antibodies specific for these receptors. Immunohistochemical staining for DR4, DR5, and DcR1/DcR2 was performed on formalin-fixed paraffin-embedded sections of 100 cases of primary melanoma, metastatic melanoma, and benign nevi. Percentage expressions of DR4 versus DR5 in benign nevi, primary melanoma, and melanoma metastases were 40% versus 90%, 69% versus 98%, and 55% versus 66%, respectively. There were significant differences in the mean percentage of DR5-positive cells between different groups of melanocytic lesions. Percent expression was higher in thin (< or =1.0 mm) compared with thick primary melanoma (88.9% versus 66.9%), and expression was less in subcutaneous metastases (49%) and lymph node metastases (30.6%) (P < .005). Expression was also higher in compound nevi (57%) than dysplastic nevi (49%). DcR1/DcR2 was found in 75% of benign nevi, 62% of primary melanomas, and 74% melanoma metastases. The results showed a wide variation in the expression of death receptors for TRAIL between and within primary and metastatic melanoma and a decreased expression on the thick primary melanoma and metastatic melanoma. This suggests that melanoma may not respond to treatment with TRAIL unless given with agents that increase the expression of TRAIL death receptors.