PTEN expression in normal skin, acquired melanocytic nevi, and cutaneous melanoma

BACKGROUND: Although various studies have shown mutations of the tumor suppressor gene, PTEN/MMAC1, in primary, metastatic, and cultured cutaneous melanoma specimens, little is known about the pattern of PTEN protein expression in early melanocytic tumor progression. OBJECTIVE: To further investigate the role of PTEN in melanocytic tumor development. METHODS: We assessed the level and distribution of PTEN in normal skin, 39 acquired melanocytic nevi, and 30 primary cutaneous melanomas, including lentigo malignas, by immunostaining. RESULTS: We found high levels of PTEN expression in cutaneous muscles, nerves, and muscular arteries, and moderate-to-high amounts of PTEN in the epidermis, follicular epithelium, and sebaceous and eccrine glands. PTEN staining in cutaneous lymphatics, dermal and periadnexal adventitial fibroblasts, and chondrocytes were variably absent. Junctional melanocytes and chondrocytes frequently exhibited preferential nuclear staining. We found uniformly strong PTEN expression in the cytoplasm of almost all benign and dysplastic nevi. However, there was some evidence of nuclear PTEN loss even in the benign melanocytic proliferations. In addition, out of 30 primary cutaneous melanomas and lentigo malignas, we detected diffuse expression of PTEN in 11 (37%) tumors, widespread loss of PTEN in 11 (37%) tumors and mixed PTEN expression in 8 (27%) lesions. In the primary cutaneous melanomas, PTEN was largely localized to the cytoplasm. CONCLUSIONS: The presence of PTEN in benign melanocytic tumors and the absence of PTEN in a significant proportion of primary cutaneous melanomas support a role for PTEN loss in the pathogenesis of melanoma.     

Nerve growth and expression of receptors for nerve growth factor in tumors of melanocyte origin.

Nerve growth factor (NGF) stimulates growth and differentiation of sensory and sympathetic neurons. It is not known what role NGF plays in melanoma development, but nevus and malignant melanoma cells express NGF-receptor (NGF-R). We counted nerve fibers within melanocytic nevi, primary cutaneous melanomas, and cutaneous melanoma metastases using a monoclonal antibody (MoAb) as marker against a 200-kD glycoprotein that is expressed on human nerves. The expression of NGF-R was studied in serial cryostat sections using a MoAb against the NGF-R. Compared to normal skin, increased numbers of nerve fibers were found in 72 melanocytic nevi. In congenital nevi their number significantly increased with age. In 47 primary cutaneous melanomas the number of nerve fibers decreased in proportion to tumor thickness. In 33 cutaneous melanoma metastases no accumulation of nerve fibers was found. NGF-R was not expressed in normal skin melanocytes and in the majority of nevus cells in melanocytic nevi. Considerable numbers of NGF-R-positive nervus cells were found only in some congenital nevi and few acquired nevi with dysplastic features. By contrast, in primary and metastatic melanomas higher expression of NGF-R was observed. The increased number of nerve fibers in melanocytic nevi suggests that neurite-promoting factors are produced in situ. Production of such factors appears to be lost in malignant melanoma cells. The finding of an inverse correlation between an abundance of nerve fibers in NGF-R-poor nevi and a high expression of NGF-R in melanomas that show no evidence of nerve growth suggest a role of NGF and its receptor in malignant melanocytic tumors.     

Expression of galanin in melanocytic tumors

IntroductionGalanin is a neuropeptide with wide-ranging effects, especially within the endocrine and nervous systems. Galanin and its receptors are present in human skin. Galanin is expressed in different neural, endocrine and neuroendocrine tumors and, on the other hand, several neuropeptides, particularly α-MSH, seem to play a role in the pathogenesis of melanoma.ObjectiveTo investigate the expression of galanin in cutaneous melanomas and melanocytic nevi and correlate it with α-MSH expression and several prognostic factors for melanoma.Material and methodsWe performed an observational and retrospective study of the immunohistochemical expression of galanin and α-MSH in samples of cutaneous melanomas diagnosed in the last 5 years in the San Jorge Hospital, Huesca (Spain). Different types of melanocytic nevi were also analyzed.ResultsA total of 130 pigmented lesions were studied: 38 primary cutaneous melanomas, 6 cutaneous melanoma metastases and 86 melanocytic nevi. Immunostaining with galanin and α-MSH was significantly higher in melanomas than in melanocytic nevi (p < 0.001), although spindle cell and blue nevi showed significant expression of α-MSH. More than 50 % of nodular melanomas and 90 % of superficial spreading melanomas were positive for galanin and α-MSH, and the latter also showed the highest percentage of positive cells for galanin (mean 35.09 ± 28.16) as well as for α-MSH (mean 67.64% ± 35.38). A positive correlation of 71 % was found for immunostaining of both neuropeptides in melanomas. No significant correlation was observed between galanin expression and age, gender, location of the lesions, Breslow index, Clark level and mitotic index.ConclusionOur study shows the expression of galanin in cutaneous melanoma and its significant correlation with α-MSH immunostaining.     

The neuropeptide/mast cell secretagogue substance P is expressed in cutaneous melanocytic lesions

Substance P (SP) is a neuropeptide found in both the central and peripheral nervous system. In the skin, SP-containing neurons stimulate the release of histamine from connective tissue mast cells (MC). SP also can potentiate neoangiogenesis and induce dermal fibrosis. MC-derived histamine has potent vasoactive effects, is angiogenic, and promotes tissue fibroplasia. In addition to histamine, MC contain many other angiogenic factors and a variety of cytokines, growth factors, and proteolytic enzymes implicated in tissue remodeling, and normal as well as tumor-associated neoangiogenesis. Many MC-derived factors, including histamine, can enhance melanoma cell growth directly. MC often concentrate around cutaneous melanomas which also frequently are associated with angiogenesis and peritumoral fibrosis. The precise mediators of these responses have not been well defined. We evaluated by immunohistochemistry cutaneous lesions representing stages of progression of malignant melanoma and its precursor lesions for the expression of SP. SP was expressed in 17/25 (68%) primary invasive malignant melanomas, 2/5 (40%) metastatic melanomas, 6/10 (60%) melanomas in situ , 7/12 (58%) atypical (dysplastic) nevi, and 4/10 (40%) spindle and epithelioid cell (Spitz) nevi, but was not detected in any (0/11, 0%) acquired benign melanocytic nevi (p<0.05). Invasive melanomas were immunolabeled in both the intraepidermal and the dermal components of the lesions. For those atypical and Spitz nevi which expressed SP, most of the immunoreactive melanocytes were located at the dermal-epidermal junction overlying areas of papillary dermal fibrosis. The results show differential expression of SP among cutaneous melanocytic lesions and suggest that the expression of this neuropeptide together with other factors may contribute to some of the host responses associated with these lesions.     

Antiapoptotic bcl-2 and bcl-xL in advanced malignant melanoma

Apoptosis is an important cofactor in the pathogenesis of a plethora of malignancies. However, little is known about modulation of the expression of bcl gene family in melanocytic tumors. To determine the role of bcl-2, bcl-x and bax in melanocytic tumors we investigated the differential expression of these genes via RT-PCR in tissue samples from human benign nevi, primary melanomas and melanoma metastases in comparison with normal skin. Bcl-2 was strongly expressed in 14/16 metastases (87.5%), whereas only 7/13 primary melanomas (53%), 7/15 nevi (46%) and 7/16 normal tissue samples (43%) showed expression of bcl-2 (P < 0.05). There was a strong indication of a correlation between tumor thickness and bcl-2 expression in nodular malignant melanomas. Expression of bcl-x was found in 16/16 melanoma metastases (100%), 11/13 primary melanomas (84%), 12/15 nevi (80%) and 10/16 normal tissue samples (62%) (P < 0.05). Bcl-xL expression increased from primary melanoma to melanoma metastases, whereas bcl-xS showed a decreasing expression level during melanoma progression. No differences in bax expression were seen between melanoma metastases, primary melanoma, nevi and normal tissue. Immunohistochemical investigations of another 53 tissue samples showed similar results. Our results strongly indicate that bcl-2 and bcl-xL gene expression increases with progression of malignant melanoma. Bcl-2 and bcl-xL expression could reflect an increased malignant potential caused by an inhibition of apoptosis and growth advantage for metastatic melanoma cells.     

Protein expression of melanocyte growth factors (bFGF, SCF) and their receptors (FGFR-1, c-kit) in nevi and melanoma

BACKGROUND: Basic fibroblast growth factor (bFGF) and stem cell factor (SCF) are essential growth factors for melanocytes which carry the receptors FGFR-1 for bFGF and c-kit for SCF. Because both factors may be involved in melanoma development, the expression of bFGF/FGFR-1 and SCF/c-kit was investigated in melanocytic tumors of different progression stages. METHODS: Fifty primary melanomas and 44 melanocytic nevi were analyzed for the expression of SCF, c-kit, bFGF, and FGFR-1 by immunohistochemistry. RESULTS: In melanoma, SCF and c-kit were expressed in 76 and 84%, respectively, and coexpressed in 66%. bFGF and FGFR-1 were expressed in 45 and 86%, respectively, and coexpressed in 46%. In melanocytic nevi, SCF was expressed in 23% and c-kit in 70% while coexpression was more common in dysplastic (39%) than non-dysplastic subtypes (8%). bFGF and FGFR-1 were expressed in 55 and 67%, respectively, while coexpression was found in 47% but varied considerably between different histological subtypes. CONCLUSIONS: SCF and c-kit were frequently expressed by melanomas and dysplastic nevi suggesting an autocrine growth mechanism as described for bFGF. In both nevi and melanoma, c-kit was almost exclusively found in the epidermis while bFGF was more common in the dermis. Thus the growth factor/receptor expression seems to depend on the cutaneous localization of the melanocytic tumors.     

Cyclin D1 and D3 expression in melanocytic skin lesions

Cyclins, cyclin-dependent kinases, as well as proteins cooperating with them are responsible for cell cycle regulation which is crucial for normal development, injury repair, and tumorigenesis. D-type cyclins regulate G1 cell cycle progression by enhancing the activities of cyclin-dependent kinases, and their expression is frequently altered in tumors. Disturbances in cyclin expression were also reported in melanocytic skin lesions. The objective of the study was to evaluate the expression of cyclins D1 and D3 in common, dysplastic, and malignant melanocytic skin lesions. Forty-eight melanocytic skin lesions including common nevi (10), dysplastic nevi (24), and melanomas (14) were diagnosed by dermoscopy and excised. Expression of cyclin D1 and D3 was detected by immunohistochemistry and quantified as percentage of immunostained cell nuclei in each sample. In normal skin, expression of cyclins D1 and D3 was not detected. The mean percentage of cyclin D1-positive nuclei was 7.75% for melanoma samples, 5% for dysplastic nevi samples, and 0.34% for common nevi samples. For cyclin D3, the respective values were 17.8, 6.4, and 1.8%. Statistically significant differences in cyclin D1 expression were observed between melanomas and common nevi as well as between dysplastic and common nevi (p = 0.0001), but not between melanomas and dysplastic nevi. Cyclin D3 expression revealed significant differences between all investigated lesion types (p = 0.0000). The mean cyclin D1 and D3 scores of melanomas with Breslow thickness <1 mm and >1 mm were not significantly different. G1/S abnormalities are crucial for the progression of malignant melanoma, and enhanced cyclin D1 and D3 expression leading to increased melanocyte proliferation is observed in both melanoma and dysplastic nevi. In histopathologically ambiguous cases, lower cyclin D3 expression in dysplastic nevi can be a diagnostic marker for that lesion type.     

Overexpression of the cyclin-dependent kinase inhibitor p21WAF1/GIP1 in human cutaneous malignant melanoma

p2l^WAFI/CIPI (p21) is an inhibitor of cyclin-dependent kinases recently identified as the downstream effector of wild-type p53-me-diated cell cycle arrest. The gene coding for p21 may function as a negative regulator of melanoma growth, progression, and metastasis. Using immunohistochemistry and Western blotting, we investigated the expression of p21 in human melanocytic proliferations. Immunohistochemical staining was performed on 13 common acquired nevi, 12 dysplastic nevi, 23 primary malignant melanomas, and 12 metastatic melanomas. Common acquired nevi showed minimal p21 staining (1.8±0.3%, mean±SEM). The percentage of positive nuclei was slightly elevated in dysplastic nevi (8.9±1.7%). Both primary malignant melanoma (29±3%) and metastatic melanoma (33±5%) demonstrated a significantly increased number of p21-positive nuclei compared to benign lesions (p<0.001). p21 was strongly expressed even in actively proliferating lesions as confirmed by MIB-1 labelling, and although the majority of p21-positive cells likely represent a non-proliferating population, staining was occasionally observed in cells undergoing mitosis, suggesting abnormal function of this cell cycle inhibitor in malignant melanoma. Overexpression of p21 in metastatic melanoma compared to common acquired nevi was confirmed by Western blot analysis of human tumor samples. These findings suggest that increased p21 expression relative to benign nevi is not sufficient to control melanoma growth in vivo.     

Fibroblast activation protein: differential expression and serine protease activity in reactive stromal fibroblasts of melanocytic skin tumors

Growth and metastasis of solid neoplasms require the recruitment of a supporting tumor stroma. A highly consistent trait of tumor stromal fibroblasts in most epithelial cancers is the induction of fibroblast activation protein (FAP), a member of the serine protease family. Recently it was demonstrated that FAP has both dipeptidyl peptidase and collagenolytic activity capable of degrading gelatin and type I collagen. In this study, we describe the expression and enzyme activity of FAP in benign and malignant melanocytic skin tumors. FAP-positive fibroblasts were detected immunohistochemically in the reactive stroma of all melanocytic nevi tested. In primary and metastatic melanomas an upregulation of FAP expression in the reactive mesenchyme could be observed. Whereas 30% of the nevi revealed additional FAP expression on subsets of melanocytic cells, melanoma cells from primary and metastatic melanomas were FAP negative. This may indicate a possible role for FAP in the control of tumor cell growth and proliferation during melanoma carcinogenesis. Consistent with this in vivo expression pattern FAP enzyme activity could be detected by a specific immunocapture assay in extracts of melanocytic nevi and melanoma metastases, whereas no significant activity was detectable in normal adult skin. Strong protein expression of FAP was observed in patterned structures restricted to a subset of the melanoma metastases. Our findings that these FAP-positive structures showed no overlap with endothelial cell surface markers, nor with various melanoma antigens, suggest that FAP is a marker for specific stromal-cell-derived patterns in cutaneous melanoma metastases.     

Staining of melanocytic neoplasms by melanoma antigen recognized by T cells

We stained benign melanocytic nevi and malignant melanoma with antibodies to melanoma antigen recognized by T cells (Mart-1) to determine if this was useful in differentiating benign from malignant melanocytic neoplasms. Forty-five primary malignant melanomas and 71 benign melanocytic nevi were stained with antibodies to Mart-1. Two cases of malignant melanoma metastatic to lymph node and three cutaneous metastases of malignant melanoma were also stained. The degree of staining was graded into diffuse positive staining, focal positive staining, and negative staining. Thirty-six of 45 primary malignant melanomas stained diffusely positive with antibodies to Mart-1. This included three of five desmoplastic malignant melanomas that showed positive staining. Four melanomas showed faint or focal positive staining. One of two metastases to lymph node showed strong positive staining and one showed no staining. All three cutaneous metastases showed diffuse positive staining. Sixty-one of 71 melanocytic nevi showed no staining or faint staining with antibodies to Mart-1. Ten of 71 melanocytic nevi showed strong positive staining. The majority of these were congenital nevi. Staining with antibodies to Mart-1 antigen was a useful marker of malignant melanoma. However, staining may also be seen in benign melanocytic neoplasms. The presence or absence of staining for Mart-1 antigen cannot be used to differentiate benign melanocytic nevi from malignant melanocytic tumors.     

Quantification of vascularity in nodular melanoma and Spitz's nevus

Spitz's nevi are acquired benign melanocytic skin tumors. Usually they are differentiated from nodular melanoma by clinical and histopathological criteria. Since Spitz's nevi are one of the most common simulators of nodular melanomas their bizarre histopathology may cause diagnostic confusion and make it difficult to differentiate these two melanocytic tumors. One of the histologic features shared by Spitz's nevus and nodular melanoma is prominent vascularity. The ability of malignant melanoma to induce angiogenesis is well established whereas benign melanocytic tumors do not have a prominent overall vascularity. The purpose of this study was to find out whether the degree of vascularity of nodular melanomas differs significantly from that of benign Spitz's nevi. In this study the number of microvessels and the vessel area were determined in 23 Spitz's nevi and 16 nodular melanomas. The number of microvessels and the vessel area were determined on Ulex Europacus agglutinin I-stained sections by computer-assisted image analysis. Two methods of measurement were used, namely systematic and selective sampling. Measurement of the whole tumor specimen (systematic sampling) revealed a vessel count of 10.83/field (SD±5.97) for Spitz's nevi whereas nodular melanomas exhibited a significantly lower (p=0.04) vessel count of 6.44/field (SD±3.85). This difference was even more pronounced when the vessel area (Spitz's nevi: 17.85×10–4mm², SD±10.32; nodular melanomas: 7.88×10-mm², SD×5.23) was investigated (p < 0.001). The difference in vessel area and vessel count was insignificant for areas exhibiting the greatest vascularity (selective sampling). Measurement of vessel count and vessel area lead us to conclude that Spitz's nevi have a significantly higher vascularity than do nodular melanomas. Our results thus indicate that angiogenesis in these pigmented lesions is not correlated with malignancy.     

Human monoclonal antibodies that distinguish cutaneous malignant melanomas from benign nevi in fixed tissue sections

Human monoclonal antibodies were generated by fusing a nonsecretory variant of murine myeloma cells with lymphocytes obtained from the lymph nodes of patients with metastatic cutaneous malignant melanoma. Two human IgG monoclonal antibodies, designated 2-139-1 and 6-26-3, were extensively studied for their patterns of binding to cells in 64 specimens of formalin-fixed, paraffin-embedded tissue sections. These comprised: 23 cutaneous and 2 ocular melanomas; 4 specimens of lentigo maligna; 27 benign nevi; 2 basal and 2 squamous cell neoplasms of the skin; and 4 specimens of normal skin. A direct avidin-biotin-immunoperoxidase staining method was used. Under these conditions, the antibodies reacted with variable intensity to all 18 primary cutaneous malignant melanomas, 5 metastatic cutaneous melanomas, and both ocular melanomas. Antibody 2-139-1 reacted with 1 of 4 specimens and 6-26-3 with 3 of 4 specimens of lentigo maligna. Two of 5 dysplastic nevi reacted with both antibodies, each with a smaller proportion of cells than with melanomas. There was no reactivity with the 22 other nevi representing a spectrum of histologic types or with normal melanocytes. Basal cell and squamous cell carcinomas of the skin also were not stained. These human monoclonal antibodies appear to be useful in distinguishing malignant melanomas from benign nevi, with the exception of dysplastic nevi, and from basal and squamous cancers of the skin in routinely prepared tissue sections. They may also help to identify the cytoplasmic antigens that are immunogenic in humans.     

Cdc7 expression in melanomas, Spitz tumors and melanocytic nevi

Background:  Cdc7 is a serine-threonine kinase required for initiation of DNA replication that may play a role in the development and progression of melanoma.
Materials and Methods:  Tissue microarrays containing 40 melanomas, 40 Spitz tumors and 30 nevi were constructed. Staining for Cdc7 was scored semiquantitatively according to intensity and extent, and the values were converted into composite scores.
Results:  Nodular melanomas, atypical Spitz tumors and superficial spreading melanomas had the highest scores (nodular melanomas, 3.67; atypical Spitz tumors, 2.78 and superficial spreading melanomas, 2.44). Typical Spitz nevi, dysplastic nevi and ordinary nevi had the lowest scores. Cdc7 expression in melanomas differed significantly from non-Spitz nevi (p < 0.001). The difference was also significant when invasive melanomas were compared with dysplastic nevi (p < 0.005) and when invasive melanomas were compared with non-atypical Spitz nevi (p < 0.001). However, there was no significant difference between invasive melanomas and atypical Spitz tumors (p = 0.69) or between dysplastic nevi and ordinary nevi (p = 0.73).
Conclusion:  Cdc7 expression differs significantly among cutaneous melanocytic neoplasms and can be evaluated by routine immunohistochemical methods. The results suggest that differences in Cdc7 expression may account for some of the differences between malignant melanomas and benign melanocytic nevi.     

Expression of stromal cell markers in distinct compartments of human skin cancers

BACKGROUND: The importance of changes in the supporting tumor stroma for cancer initiation and progression is well established. The characteristics of an activated tumor stroma, however, are not completely understood. In an effort to better characterize the desmoplastic response to human skin tumors, we evaluated the expression pattern of three stromal cell markers, fibroblast-activation protein (FAP), endoglyx-1, and endosialin, in a series of melanocytic and epithelial skin tumors. METHODS: Immunohistochemistry using antibodies against FAP, endoglyx-1, and endosialin was carried out in skin samples obtained from 43 patients. Furthermore, microarray data from an independent set of human skin cancers were analyzed. RESULTS: FAP-positive fibroblasts were detected in all tumor tissues tested, including cases of melanocytic nevi, melanoma metastases, basal cell carcinomas, and squamous cell carcinomas. In cutaneous melanoma metastases, we identified different compartments within the stromal response on the basis of the regions of FAP expression. Endoglyx-1 expression was confined to normal and tumor blood vessel endothelium including 'hot spots' of neoangiogenesis within the cutaneous melanoma metastases. Endosialin was selectively induced in subsets of small- and medium-sized tumor blood vessels in melanoma metastases and squamous cell carcinomas. CONCLUSIONS: These data describe novel aspects of stromal marker expression in distinct compartments of human skin tumors and may point to potential targets for novel therapeutic strategies aimed at the tumor stroma.     

Loss of p14<Superscript>ARF</Superscript> expression in melanoma

Lack of p14ARF expression or its functional inactivation has been observed in human and murine carcinomas. Although very few mutations of p14ARF have been detected in some cancer types, changes in expression seem to play an important role in the development of other human cancers such as mesotheliomas. To examine the p14ARF gene and expression of p14ARF protein in melanomas, we screened eight human melanoma cell lines and primary human melanocytes by RT-PCR, sequencing and immunoblotting. All melanoma cell lines analyzed expressed wild-type p14ARF mRNA as well as protein. P14ARF expression was investigated by immunohistochemical staining of 32 tissue samples of benign melanocytic nevi (n=14), melanomas (n=12) and melanoma metastases (n=6). In contrast to the results obtained from cell lines in vitro the immunohistochemical stainings revealed a correlation between the progression of melanoma and the lack of the p14ARF protein expression. Positive p14ARF protein staining was observed in 11 of 14 benign nevi, in 3 of 12 melanomas and in 0 of 6 melanoma metastases. In summary, we demonstrated a significant inverse correlation between p14ARF protein expression and progression of melanocytic tumors since the amount of p14ARF protein staining decreased from benign melanocytic nevi to metastatic melanoma in situ. These results suggest that p14ARF inactivation is important in the development of melanomas.     

Apoptosis, Fas and Fas-ligand expression in melanocytic tumors

Impaired regulation of apoptosis is known to be associated with the development of various forms of cancer. Fas binding to its ligand, Fas ligand (Fas-L), has been shown to trigger apoptosis in various cell types. Fas-L is expressed by melanoma cells and has been suggested to play a role in melanoma escape from immune surveillance. In the present study, we assessed apoptotic activity and examined Fas and Fas-L expression in malignant melanomas, Spitz nevi and ordinary melanocytic nevi. We evaluated apoptotic activity using terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling. Apoptotic activity was found to be minimal in melanomas and moderate in Spitz nevi. In contrast, common nevi demonstrated significant levels of apoptosis in the deep parts of the tumor. Fas was found to be expressed by all Spitz nevi, most melanocytic nevi and approximately half of the malignant melanoma specimens. Fas expression was also significantly more pronounced in Spitz nevus cells as compared with the two other tumors. The anti-Fas-L antibody was found to stain all three melanocytic tumors. Staining was shown to be stronger and more frequent in melanoma cells as compared to the nevus cells. Using the Spearman test, no significant correlation between Fas-L expression in melanoma cells and apoptosis in MM-infiltrating mononuclear cells was found, suggesting that Fas-L expression in melanoma cells may not be instrumental in their ability to escape immune mechanisms of defense. In contrast, increased levels of apoptosis in the deep parts of melanocytic nevi may reflect and possibly contribute to their benign nature.     

Laminin‐5 Expression in Melanocytic Lesions of the Skin

Background: Laminin‐5 is a basement membrane constituent that functions as an anchoring filament to integrin‐derived hemidesmosomes, and has been detected at the invasive front (tumor‐stromal interface) in many types of carcinomas. Our goal was to analyze laminin‐5 expression in melanocytic lesions and evaluate its role in tumor progression. Design: Immunohistochemical staining for laminin‐5 was performed on 101 cutaneous melanocytic lesions including 41 nevi, 31 primary melanomas, and 29 metastatic melanomas. A standard immunoperoxidase technique (ABC) was used with DAB chromagen and a primary monoclonal antibody to the laminin‐5 gamma2 chain (clone D4B5, 1:50, Chemicon International, Temecula, CA). Any degree of staining in melanoma cells or at the tumor‐stromal interface was considered positive. Results: Positive staining for laminin‐5 was observed in three of the primary melanomas (10.7%), three of the metastatic melanomas (10.3%), and none of the nevi. In primary melanomas, staining was observed predominately at the tumor‐stromal interface. In metastatic lesions, staining was observed around individual melanoma cells and melanoma cell nests.Conclusion: Expression of laminin‐5 was detected in a small percentage of primary and metastatic melanomas and in none of the nevi studied. Laminin‐5 expression does not appear to be essential for the development of melanomas or their metastases.     

Cutaneous Rhizopus in an Immunosuppressed Patient

Background: Progression through the cell cycle is controlled by cyclins, cyclin‐dependent kinases and cyclin‐dependent kinase‐inhibitory proteins. The role of cyclin D1 in the development, progression and prognosis of melanomas is controversial. The goal of this study is to evaluate the role of cyclin D1 in benign and malignant melanocytic lesions of the skin. Methods: A total of 101 melanocytic lesions of the skin including compound nevi (21), intradermal nevi (18), melanoma in situ (3), primary invasive melanoma (30), and metastatic melanoma (29) were evaluated for cyclin D1 overexpression by immunohistochemistry. The following tiered system was used for scoring: 0% of cells with nuclear staining (score 0), 1–19% nuclear staining (score 1), 20–49% nuclear staining (score 2), and 50% or greater nuclear staining (score 3). Results: The average score for primary melanomas was significantly higher compared to nevi (p = 0.0046), and for in situ melanomas compared to primary invasive melanomas (p = 0.011). There was slightly higher level of expression in compound nevi versus intradermal nevi. Conclusion: Our study indicates that cyclin D1 expression is increased in malignant compared to benign melanocytic lesions. Further studies are needed to ascertain the biological role of cyclin D1 in melanocytic lesions of the skin.     

Immunohistochemical expression of BCL-2 in melanomas and intradermal nevi

The BCL-2 gene is the prototype of a newly described family of oncogenes involved in tumorigenesis by blocking apoptosis, or programmed cell death. Overexpression of BCL-2 protein was originally described in follicular B-cell lymphomas bearing the 14;18 translocation. BCL-2 overexpression has also been described in other lymphomas and more rarely in neoplasms outside the lymphoid tissue. The aim of this paper is to determine the immunohistochemical expression of BCL-2 in intradermal nevi and primary invasive and metastatic melanoma. Formalin-fixed and paraffin-embedded tissues from 4 cutaneous melanoma metastases, 10 primary invasive melanomas, and 10 intradermal melanocytic nevi were immimolabeled with monoclonal antibodies directed against BCL-2 protein (Dako, clone 124) and Ki-67 antigen (Amac, clone MIB-1), after antigen retrieval techniques. Morphologically normal epidermal melanocytes expressed BCL-2, as did nevi and melanomas in virtually all cells. However, whereas the labeling in normal melanocytes and nevus cells showed a uniformly strong reactivity, melanoma cells showed a variable but mainly weak reactivity. Ki-67 antigen expression was restricted to melanomas. The widespread expression of BCL-2 suggests that this onco-protein cannot be involved in the malignant transformation of melanocytic cells. It seems likely that the decreased BCL-2 expression detected in melanomas may reflect one further step of tumor progression in melanocytic neoplasms.