Expression of neurotrophins and their receptors in pigment cell lesions of the skin

The neurotrophins (NTs) are a group of growth factors involved in the development of the nervous system and presumed to play a role in neural crest-derived tumours. The expression of three NTs (NGF, BDNF, and NT-3) and their receptors (NTRs; i.e. low-affinity pan-NT receptor p75, Trk-B, and Trk-C) was studied in frozen sections of benign and malignant cutaneous pigment cell lesions, using immunohistochemistry. In order to understand the possible role of these growth factors and their receptors in the progression of primary cutaneous malignant melanomas (PCMMs), their distribution in the radial (RGP) and vertical (VGP) growth phases was particularly studied. While most of the common acquired naevi were unreactive, Spitz and blue naevi showed scattered immunoreactive cells, especially for the p75 NTR. Dysplastic naevi, but not common naevi, expressed NT-3 in their junctional component. PCMM and melanoma metastases often showed a diffuse pattern of immunostaining. NT-3 was significantly more frequently expressed in the RGP of PCMMs than in the junctional component of benign naevi, whereas more extensive immunoreactivity for NGF was found in the VGP of PCMMs, compared with the RGP; metastases more frequently expressed NGF, BDNF, and Trk-B than PCMMs. Interestingly, neurotropic melanoma expressed all NTs/NTRs except Trk-B. These immuunohistochemical data confirm suggestions from previous in vitro studies that autocrine loops of certain NTs and their respective receptors may be involved in melanoma progression; in addition, NT-3 may be involved in the junctional growth of dysplastic naevi. The precise role of these growth factors in melanoma, however, will await further functional studies.     

Expression of gelatinase B and the extracellular matrix metalloproteinase inducer EMMPRIN in benign and malignant pigment cell lesions of the skin.

By the degradative effect on basement membrane collagen type IV, matrix metalloproteinases (MMPs) or gelatinases are important in the early invasion of malignant tumors. These enzymes may be released by the tumor cells themselves or may be derived from nearby fibroblasts that have been stimulated by the extracellular MMP inducer EMMPRIN. We studied the distribution of 92-kd gelatinase B (MMP-9) and of EMMPRIN in 33 benign and 41 malignant, paraffin-embedded pigment cell lesions using immunohistochemistry and monoclonal antibodies. In benign pigment cell lesions, EMMPRIN but not gelatinase B was expressed in cellular blue nevi whereas all other benign lesions, including common blue nevi, were negative. In malignant melanomas (MMs), both gelatinase B and EMMPRIN were variably expressed in the pure and invasive radial growth phase but not in the vertical growth phase. All lentigo maligna cases and all metastatic lesions were negative. Of MMs with thickness < 1.6 mm, 63% expressed gelatinase B and 70% expressed EMMPRIN, whereas in MMs with > 1.6 mm thickness, only 10% expressed gelatinase B and only 25% expressed EMMPRIN. We conclude that early invasion of MM is associated with de novo expression of gelatinase B and EMMPRIN by neoplastic melanocytes. Expression of EMMPRIN and MMP-9 may be partly responsible for the stromal changes observed in thin MM. Their absence in the vertical growth phase and in metastatic lesions suggests that other factors are involved in tissue degradation during later stages of tumor progression in MM. The lack of both gelatinase B and EMMPRIN in lentigo maligna may contribute to the indolent behavior of this type of pigment cell lesion.     

Expression of vitamin D receptor decreases during progression of pigmented skin lesions

1,25-dihydroxyvitamin D3 affects proliferation, differentiation, and apoptosis and protects DNA against oxidative damage with a net tumorostatic and anticarcinogenic effect. It acts through a specific nuclear receptor that is widely distributed through the body. Although a beneficial role of vitamin D in melanoma patients has been suggested, there is lack of information on the changes in the expression pattern of vitamin D receptor during progression of pigmented lesions. Using immunohistochemistry, we analyzed the expression of vitamin D receptor in 140 samples obtained form 82 patients, including 25 benign nevi, 70 primary cutaneous melanomas, 35 metastases, 5 re-excisions, and 5 normal skin biopsies. The strongest expression was observed in normal skin that significantly decreased in melanocytic proliferations with the following order of expression: normal skin > melanocytic nevi > melanomas = metastases. The vitamin D receptor expression in skin surrounding nevi and melanoma was also significantly reduced as compared to normal skin. Tumor-infiltrating and lymph node lymphocytes retained high levels of vitamin D receptor. There was negative correlation between tumor progression and vitamin D receptor expression with a remarkable decrease of the immunoreactivity in nuclei of melanoma cells at vertical versus radial growth phases and with metastatic melanomas showing the lowest cytoplasmic receptor staining. Furthermore, lack of the receptor expression in primary melanomas and metastases was related to shorter overall patients' survival. In addition, the receptor expression decreased in melanized melanoma cells in comparison to amelanotic or poorly pigmented cells. Therefore, we propose that reduction or absence of vitamin D receptor is linked to progression of melanocytic lesions, that its lack affects survival of melanoma patients, and that melanogenesis can attenuate receptor expression. In conclusion, changes in vitamin D receptor expression pattern can serve as important variables for diagnosis, predicting clinical outcome of the disease, and/or as a guidance for novel therapy of melanomas based on use of vitamin D or its derivatives.     

Expression of p73 in normal skin and proliferative skin lesions

The p73 gene is a member of the p53 gene family and the structure and functions of p73 protein are similar to those of p53. However, these two proteins have different roles. In the present study, p73 protein was found immunohistochemically to be distributed in the basal cells of the epidermis, columnar basal cells in the hair follicle and peripheral cells without lipid droplets in the sebaceous and meibomian glands; it was expressed strongly in tumor cells in basal cell carcinomas and in the basal cell-like cells in seborrheic keratosis, and weakly or negatively in the squamous cell-like cells in seborrheic keratosis and in the tumor cells in squamous cell carcinomas. No relationship was detected between p73 and p53 protein distribution and between p73 protein expression and the proliferative potential, as shown by the Ki-67 immunopositive cell ratio. The present study shows that p73 protein is likely to play important roles in skin differentiation rather than proliferation or carcinogenesis of the skin.     

内皮素-B受体在脑缺血大鼠脑内小胶质细胞中的表达

目的 研究脑缺血后内皮素-B(ET-B)受体在脑内激活的小胶质细胞中的表达变化,探讨ET-B受体与脑缺血的关系.方法 应用微创开颅法建立大鼠大脑中动脉闭塞(MCAO)模型,81只大鼠随机分为2h、6h、12h、1d、2d、3d和1周7个缺血组,以及正常对照组和假手术组(n=9).用抗凝集素(lectin)和抗ET-B抗...     

Flexibility of pigment cell behavior permits the robustness of skin pattern formation

The striped pigmentation pattern of zebrafish is determined by the interaction between pigment cells with different colors. Recent studies show the behaviors of pigment cells are substantially different according to the environment. Interestingly, the resulting patterns are almost identical, suggesting a robustness of the patterning mechanism. To know how this robustness originates, we investigated the behavior of melanophores in various environments including different developmental stages, different body positions, and different genetic backgrounds. Normally, when embryonic melanophores are excluded from the yellow stripe region in the body trunk, two different cellular behaviors are observed. Melanophores migrate to join the black stripe or disappear (die) in the position. In environments where melanophore migration was restricted, we observed that most melanophores disappeared in their position, resulting in the complete exclusion of melanophores from the yellow stripe. In environments where melanophore cell death was restricted, most melanophores migrated to join the black stripes, also resulting in complete exclusion. When both migration and cell death were restricted, melanophores remained alive in the yellow stripes. These results show that migration and cell death complement each other to achieve the exclusion of melanophores. This flexibility may be the basis of the mechanistic robustness of skin pattern formation.     

Novel mutations of the endothelin-B receptor gene in isolated patients with Hirschsprung's disease

Hirschsprung's disease (HSCR) is characterized by the absence of autonomic ganglion cells in the terminal bowel and is a relatively common cause of intestinal obstruction in the newborn. The incidence of HSCR is estimated to be 1 in 5000 live births. Recently, the endothelin- B receptor (EDNRB) gene has been shown as a susceptibility gene for HSCR by the production of aganglionic colon in mice with a null mutation of this gene and by demonstrating a missense mutation in a large inbred kindred with a high incidence of HSCR (Mennonite pedigree). However, no further mutations have been demonstrated in other clinical cases. We analysed alterations of the EDNRB gene in 41 isolated patients of HSCR. Two novel mutations were detected: a G to A transition at nucleotide 824 and an insertion of T at nucleotide 878. Both mutations resulted in stop codons, predicted to produce a truncated and non-functional endothelin-B receptor. These observations indicate that dysfunction or loss of function of endothelin-B receptor may be involved in the aetiology of some isolated patients with HSCR.      

Expression analysis of proteases of Mycobacterium leprae in human skin lesions

Proteases are commonly involved in bacterial pathogenesis and their inhibition has represented a successful therapeutic approach to treat infectious diseases. However, there is little information on the role of proteases in the pathogenesis of Mycobacteria. Five of these genes, three coding for putative secreted proteases, were selected in the present study to investigate their expression in Mycobacterium leprae isolated from skin biopsies of multibacillary leprosy patients. Via nested-PCR, it was demonstrated that mycP1 or ML0041, htrA2 or ML0176, htrA4 or ML2659, gcp or ML0379 and clpC or ML0235 are transcribed in vivo during the course of human infection. Moreover, the expression of Gcp in leprosy lesions was further confirmed by immunohistochemistry using a specific hyperimmune serum. This observation reinforces the potential role of mycobacterial proteases in the context of leprosy pathogenesis.     

T cell and cytokine patterns in leprosy skin lesions

Conclusion The skin lesions of leprosy provide a window for directly studying immune responses to a pathogen. Analysis of the local immune responses in these lesions revealed distinct T cell and cytokine patterns which correlate with resistance versus susceptibility to infection. Similar information was not often obtainable from the study of blood, underscoring the importance of investigation of the immune response at the site of disease activity. The techniques employed in these investigations are generally useful for the study of other inflammatory diseases of skin.     

Expression of L-type amino acid transporter 1 in various skin lesions

L-type amino acid transporter 1 (LAT1) is a Na⁺-independent neutral amino acid transporter that has an essential role in cell proliferation. Although the involvement of LAT1 in human carcinogenesis has been investigated by immunohistochemistry in various organs, LAT1 expression in skin has not been reported yet. Therefore, in the present study, immunohistochemistry for LAT1 was performed in 15 keratoacanthoma (KA), 10 seborrheic keratosis, 16 Bowen's disease, 11 basal cell carcinoma (BCC), and 9 squamous cell carcinoma (SCC) cases as well as 61 normal epidermis as control. It was demonstrated that LAT1 expression limited to the basal layer was occasionally observed in normal epidermis while its expression was significantly decreased in the epithelium of seborrheic keratosis and Bowen's disease (P < 0.05). By contrast, a significantly higher rate of LAT1 expression was observed in the epithelium of KA, BCC, and SCC than in normal epidermis (P < 0.05). Although LAT1 expression was limited to the basal layer or rim of the nests in KA, LAT1 expression was also observed in the center of the nests in BCC and SCC (P < 0.001). Thus, LAT1 is differentially expressed in various skin lesions and may be an especially useful marker to distinguish KA from SCC.     

Novel nonsense mutation of the endothelin-B receptor gene in a family with Waardenburg-Hirschsprung disease

Waardenburg syndrome (WS) comprises sensorineural hearing loss, hypopigmentation of skin and hair, and pigmentary disturbances of the irides. Four types of WS have been classified to date; in WS type IV (WS4), patients additionally have colonic aganglionosis (Hirschsprung disease, HSCR). Mutations in the endothelin-3 (EDN3), endothelin-B receptor (EDNRB), and Sox10 genes have been identified as causative for WS type IV. We screened a family with a combined WS-HSCR phenotype for mutations in the EDNRB locus using standard DNA mutation analysis and sequencing techniques. We have identified a novel nonsense mutation at codon 253 (CGA→TGA, Arg→STOP). This mutation leads to a premature end of the translation of EDNRB at exon 3, and it is predicted to produce a truncated and nonfunctional endothelin-B receptor. All affected relatives were heterozygous for the Arg²⁵³→STOP mutation, whereas it was not observed in over 50 unrelated individuals used as controls. These data confirm the role of EDNRB in the cause of the Waardenburg-Hirschsprung syndrome and demonstrate that in WS-HSCR there is a lack of correlation between phenotype and genotype and a variable expression of disease even within the same family. Am. J. Med. Genet. 87:69–71, 1999. © 1999 Wiley-Liss, Inc.     

Interleukin-2 receptor expression in benign and malignant melanocytic skin lesions

The immunophenotype of the lymphocytic reaction of melanocytic skin lesions (12 cases of cutaneous malignant melanoma (CMM), three of Hutchinson's melanotic freckle (HMF), and eight naevocellular naevi) has been studied using monoclonal antibodies. CMM was associated with the most intense lymphocytic reaction, the lymphocytes being T cells of both CD-4 T helper/inducer and CD-8 suppressor/cytotoxic subsets which were present in varying proportions. Although less marked, the lymphocytic reaction to HMF and benign naevi showed similar features. An antibody to the interleukin-2 receptor (IL-2R; Tac, CD-25) was included in the panel and the earlier findings of positively stained cells in association with CMM were confirmed. In addition, the novel finding of these cells in association with HMF and naevocellular naevi is reported. The number of these CD-25 positive cells was extremely variable but they appeared most prominent in association with CMM. The findings presented here indicate that it is not possible to infer that CD-25 positive lymphocytes present in the host response to CMM necessarily indicates tumour specific activation of the cells of the host immune system.     

Specific skin lesions as the presenting symptom of hairy cell leukemia

A 68-year-old Japanese man with a chief complaint of eczema-like dermatosis was diagnosed as having B-cell hairy cell leukemia (HCL) by demonstration of hairy cells in the skin lesions as well as in blood and bone marrow. He was treated with alpha-interferon, resulting in disappearance of skin lesions and reduction of his massive splenomegaly from 18 to 5 cm in about 14 months. Although specific skin lesions in HCL, shown by a review of the literature to occur in about 8% of cases, are not as uncommon as generally assumed, it is rare for HCL to present with specific skin lesions, the present case being only the second of its type mentioned in the literature.     

Expression of androgen receptor and growth factors in premalignant lesions of the prostate

Analysis of growth factors and receptors in putative premalignant lesions of prostatic adenocarcinoma should aid our understanding of their growth pathways. Sixty prostatic TURP (transurethral resection of the prostate) specimens exhibiting atypical adenomatous hyperplasia (AAH) and/or prostatic intraepithelial neoplasia (PIN) lesions were assayed by immunohistochemistry for androgen receptor (AR), epidermal growth factor receptor (EGFR), c-erbB-2, transforming growth factor-alpha (TGF-α), vascular endothelial growth factor (VEGF), fibroblast growth factor-2 (FGF-2), MIB-1, E-cadherin, and high molecular weight keratin. Expression of these factors in the lesions was compared with that in the co-existing benign prostatic hyperplasia (BPH) or prostatic adenocarcinoma. Strong AR nuclear staining was observed in the luminal cells, but not the basal cells, of BPH and PIN lesions and in all the carcinomas examined. A similar growth factor and receptor profile was demonstrated in the secretory epithelium of high-grade PIN and carcinoma with a tendency to higher expression of membranous EGFR and c-erbB-2 and cytoplasmic TGF-α, and lower levels of FGF-2 than in low-grade PIN or BPH glands. Also, increased rates of proliferation, as estimated by MIB-1 stained cells, were observed in high-grade PIN in comparison with low-grade PIN and BPH and were not confined to the basal layer. AAH lesions resembled neither BPH nor carcinoma. Proliferation was virtually absent (MIB-1 expression); both AR and E-cadherin expression was significantly reduced; and, with the exception of FGF-2, all the other growth factors and receptors studied were absent. The results presented would support a premalignant role for high-grade PIN, whilst AAH would appear to represent a quiescent phenotype unlikely to progress to neoplasia. Copyright © 1998 John Wiley & Sons, Ltd.     

Augmented expression of endothelin-1, endothelin-3 and the endothelin-B receptor in breast carcinoma

AIMS: Endothelins (ETs) are peptides expressed in many tumours which may stimulate angiogenesis and desmoplasia. Because ETs have not been extensively studied mammary neoplasia, we assessed ET protein and mRNA expression and receptor mRNA expression in normal and neoplastic breast tissues. METHODS AND RESULTS: Tissues from five normal breasts, six fibroadenomas, seven ductal carcinomas in situ (DCIS) and 25 invasive carcinomas were stained with anti-ET-1 and anti-ET-3 antibodies and analysed using a grading system. ET-1, ET-3, ETA and ETB mRNA expression was assessed by quantitative RT-PCR from eight carcinomas and five normals. Weak staining for ET-1 and ET-3 was detected in all normals. Moderate to strong staining was seen in 72% and 64% of carcinomas for ET-1 and ET-3, respectively. Most fibroadenomas showed weak positivity for ET-1 (83%) and ET-3 (67%). ET-1 and ET-3 mRNA levels were upregulated in carcinomas compared with normal breast. No ETA mRNA was not detected in any tissue. ETB mRNA was detected in normal breast and was increased in carcinomas. CONCLUSION: These results suggest that the ET system is altered in breast carcinomas and this may be of importance in the progression from in-situ to invasive carcinoma.     

胎儿胸腺发育过程中T细胞抗原受体的表达

目的:检测不同胎龄胎儿胸腺组织内T细胞抗原受体(TCR)的表达及发育规律.方法:18～40周胎儿胸腺组织,采用免疫组织化学SP法检测TCRαβ和TCRγδ的表达. 结果:胚胎21周,胸腺组织开始出现TCRαβ和TCRγδ阳性细胞.TCRαβ阳性细胞主要分布被膜下及小叶间隔中,围绕血管成群分布.TCRγδ阳性细胞的分布与TCRαβ阳性细胞相似, 但细胞数量较TCRαβ阳性细胞少.38周以后胎儿胸腺内TCR阳性细胞主要分布在皮髓质交界处,被膜下及小叶间隔中的TCR阳性细胞较早期少.结论:TCR阳性细胞在胚胎早期开始出现,其分布部位提示局部微环境有利于这些细胞的分化发育.     

Lymphoproliferative lesions of the skin

Diagnosis and differential diagnosis of cutaneous lymphoproliferative disorders is one of the most difficult areas in dermatopathology, and biopsies are often taken to rule out a cutaneous lymphoma in patients with "unclear" or "therapy-resistant" skin lesions. Histopathological features alone often enable a given case to be classified to a diagnostic group (eg, epidermotropic lymphomas), but seldom allow a definitive diagnosis to be made. Performing several biopsies from morphologically different lesions is suggested, especially in patients with suspicion of mycosis fungoides. Immunohistochemistry is often crucial for proper classification of the cases, but in some instances is not helpful (eg, early lesions of mycosis fungoides). Although molecular techniques provide new, powerful tools for diagnosing cutaneous lymphoproliferative disorders, results of molecular methods should always be interpreted with the clinicopathological features, keeping in mind the possibility of false positivity and false negativity. In many cases, a definitive diagnosis can be made only on careful correlation of the clinical with the histopathological, immunophenotypical and molecular features.     

生存素在瘢痕疙瘩、皮肤瘢痕癌及鳞状细胞癌组织中的表达

目的:探讨凋亡抑制基因生存素在瘢痕疙瘩、皮肤瘢痕癌及皮肤鳞状细胞癌(简称鳞癌)组织中的表达。方法:应用免疫组化方法检测41例瘢痕疙瘩、35例皮肤瘢痕癌及46例鳞癌患者皮损中生存素蛋白的表达并进行统计学分析。结果:免疫组化示正常皮肤组织中未见生存素的表达;生存素在瘢痕疙瘩、皮肤瘢痕癌及鳞癌皮损中均呈阳性表达,表达阳性率分别为31.71%(13/41),54.29%(19/35)、60.87%(28/46);皮肤瘢痕癌与鳞癌的生存素蛋白表达阳性率均高于瘢痕疙瘩(P值均0.05),而皮肤瘢痕癌与鳞癌之间生存素蛋白表达差异无显著性(P0.05)。生存素蛋白在瘢痕疙瘩、皮肤瘢痕癌及鳞癌中的表达与性别、年龄均无关;生存素蛋白在皮肤瘢痕癌中的表达与原发病无关;生存素蛋白在皮肤瘢痕癌与鳞癌中的表达与组织病理分级无明显关系,与有无淋巴结转移密切相关。结论:生存素的高表达可能在瘢痕疙瘩、皮肤瘢痕癌及鳞癌的发病机制中起一定作用。     

A distinctive pigment of the skin in New Guinea indigenes

An unusual pigmentation of skin is described amongst indigenes of widely scattered areas in New Guinea. It is suggested that it is due to the accumulation of a red intermediary metabolite in the formation of melanin, and that it results from a metabolic error determined by an autosomal recessive gene. Pedigrees of thirty-three families with red skins are presented and analysed. The pigment could not be identified by histochemical studies of biopsy specimens and a portable reflectance spectrophotometer did not define its characteristics. The gene is present in high frequency in some areas in which it must possess a significant survival advantage.     

Expression of apoptosis-regulatory proteins in lesions of pulmonary Langerhans cell histiocytosis

AIMS: Pulmonary Langerhans cell histiocytosis (PLCH) is characterized by the presence of lesions containing numerous activated Langerhans cells (LCs). An uncontrolled immune response sustained by activated LCs seems to be involved in the pathogenesis of the disease. The aim of this study was to establish whether disruption of LC apoptosis related to the expression of the Bcl-2 family proteins is implicated in the maintenance of PLCH lesions. METHODS: Six patients with PLCH were evaluated by morphological and immunohistochemical techniques to explore the incidence of apoptosis in pathological LCs and to characterize the expression of Bcl-2-related proteins by these cells. RESULTS: Very few LCs present in PLCH lesions exhibited nuclear apoptotic changes or expressed cleaved caspase-3, whereas they all strongly expressed the anti-apoptotic molecule Bcl-x(L). Interestingly, pulmonary LCs present in intervening lung tissue not involved by the pathological process and known to be immature dendritic cells did not express Bcl-2 family proteins. CONCLUSIONS: These findings suggest that activated LCs present within PLCH lesions are poorly susceptible to apoptosis and, thus, are able to sustain the pathological process by causing continuous local stimulation of T cells. Functional studies are needed, however, to demonstrate that they are actually resistant to programmed cell death.