Mosaic neurofibromatosis type 1

A 24-year-old man presented with numerous lentigines and multiple cafe-au-lait macules on both sides of the face, neck, and trunk as well as on the proximal area of the upper extremities and in the axillae. The pigmented lesions had a Blaschko-linear distribution on the upper trunk and were limited to the left side of the abdomen, with a sharp demarcation at the midline. Multiple, cutaneous neurofibromas were found on the trunk, and ophthalmologic examination showed a Lisch nodule in the left iris. The clinical findings and their widespread but segmental distribution were consistent with a diagnosis of mosaic neurofibromatosis type 1.     

Intradermal transfer of caspase-1 (CASP1) DNA into mouse dissects: role of CASP1 in interleukin-1beta associated skin inflammation and apoptotic cell death.

Caspase-1 (CASP1) interleukin-1beta (IL-1beta) converting enzyme (ICE) has been cloned as a specific enzyme which activates the biologically inactive pro-form of IL-1beta into biological active IL-1beta. Based on the significant homology to Ced-3, Caenorhabditis elegans apoptotic gene and, proof of apoptotic activity of ICE in rat fibroblasts, ICE was renamed as CASP1. In contrast to in vitro functions, the in vivo significance of high expression of CASP1 in skin remains to be elucidated. We transferred plasmid DNA encoding murine CASP1 with beta-actin promoter into mouse skin. The CASP1 DNA-injected skin, but not skin injected with control plasmid without CASP1, developed localized erythema with subcutaneous nodules. The nodules were associated with marked inflammatory infiltrates. The apoptotic cells detected by the TUNEL method were distributed in and around the inflammatory foci. The plasma IL-1beta level of CASP1 DNA-injected mouse was elevated compared with that of the control DNA-injected mouse. These inflammatory reactions of CASP1 DNA-injected skin were suppressed by treatment with neutralizing anti-murine IL-1beta antibodies, but the TUNEL positive apoptotic cells were still detected. This study clearly demonstrate dual roles of CASP1 in causing IL-1beta associated granulomatous skin infiltration and inducing apoptotic cell death in vivo.     

Type 1 segmental cutaneous leiomyomatosis

Cutaneous leiomyomas are rare benign tumours of the skin, which present in multiple disseminated, segmental or solitary forms. The pathogenesis of segmental cutaneous leiomyomatosis is not yet fully known. Most recently two types of segmental manifestation of autosomal dominant inherited diseases were postulated. Type 1 reflects heterozygosity for the underlying mutation with a clinical picture similar to that in a non-mosaic phenotype. In type 2, loss of heterozygosity leads to homo- or hemizygosity with a pronounced segmental manifestation of lesions in the affected segment. In our patient the lesions were restricted to one segment and therefore she most probably has a type 1 segmental cutaneous leiomyomatosis.     

GSTM1 and GSTT1 null genotypes as possible heritable factors of rosacea

PURPOSE: Rosacea might be related to an increased activity of reactive oxygen species (ROS) and deficient function of the antioxidant system. Glutathione S-transferases (GSTs) play a primer role in cellular defense against electrophilic chemical species and radical oxygen species. We hypothesized that increased ROS activity or decreased antioxidant potential, possibly induced by GST gene polymorphism, might have a pathogenic role in rosacea. METHODS: The study group consisted of 45 patients with rosacea and 100 control subjects. DNA samples were isolated from blood samples using high pure polymerase chain reaction (PCR) Template preparation Kit. The GSTM1, GSTT1, and P1 polymorphisms were detected using a real-time PCR and fluorescence resonance energy transfer with a Light-Cycler Instrument. Associations between specific genotypes and the development of rosacea were examined using logistic regression analyses to calculate odds ratios (OR) and 95% confidence intervals (CI). RESULTS: GSTM1 and GSTT1 null genotypes were found to be statistically different from control (P=0.005, P=0.009, respectively), and associated with an increased risk of rosacea (OR [95% CI]: 2.84 [1.37-5.89]; OR [95% CI]: 2.68 [1.27-5.67], respectively). There was a statistically significant relationship between both null combination of the GSTM1 and GSTT1 genotype polymorphisms and rosacea (P=0.003, OR [95% CI]: 4.18 [1.57-11.13]). There were no statistically significant differences between patient and control groups for the GSTP1 Ile/Ile, Ile/Val, and Val/Val genotypes (P>0.05). CONCLUSION: We demonstrated a significant association between the GSTT1 and/or GSTM1 null genotypes and rosacea. However, the potential role of GSTs as markers of susceptibility to rosacea needs further studies in larger patient groups.     

Alpha-1-antitrypsin in leprosy

Estimation of Alpha-1-antitrypsin (AAT) levels was carried out in 52 patients of various types of leprosy. Fifty age and sex matched healthy individuals served as controls. The mean level of AAT in controls was 290.12 +/- 59.56 mg/dl. In patients of tuberculoid leprosy (TT), borderline tuberculoid leprosy (BT) and borderline leprosy (BB), the AAT levels were found to be 284 +/- 47.03, 314.37 +/- 31.56 and 324.44 +/- 32.05 mg/dl respectively. These were statistically insignificantly raised when compared with controls. In borderline lepromatous leprosy (BL), lepromatous leprosy without erythema nodosum leprosum (LL without ENL) and in LL with ENL there was a statistically significant rise in AAT levels. The maximum levels of AAT were observed in patients of LL with ENL (mean 500.8 +/- 93.44 mg/dl. P less than 0.001).     

New function for NF1 tumor suppressor

The expression and subcellular localization of neurofibromatosis type 1 tumor suppressor was studied in keratinocytes induced to differentiate by increased Ca2+ concentration of the culture medium. Differentiating keratinocytes became intensely immunoreactive for neurofibromatosis type 1 protein, which was apparently associated with cellular fibrils. Double immunolabeling with antibodies to cytokeratin 14 and neurofibromatosis type 1 protein suggested an association of intermediate type cytoskeleton and neurofibromatosis type 1 protein. The presence of neurofibromatosis type 1 protein in cell preparations treated with cytoskeletal buffer indicated a high affinity interaction between intermediate filaments and neurofibromatosis type 1 protein. Further studies utilizing double immunolabelings revealed that the intense neurofibromatosis type 1 tumor suppressor signal on intermediate filaments was temporally limited to the period in keratinocyte differentiation in which the formation of desmosomes takes place. Keratinocytes were also cultured from nine patients with type 1 neurofibromatosis and were studied with respect to cell morphology, and association of neurofibromatosis type 1 protein with intermediate cytoskeleton. The results showed that keratinocytes cultured from patients with neurofibromatosis type 1 displayed a highly variable cell size and morphology compared to controls. The latter findings represent predicted alterations in a situation where cytoskeletal organization is disturbed. Furthermore, differentiating neurofibromatosis type 1 keratinocytes were characterized by a reduced number of cytokeratin bundles that were decorated neurofibromatosis type 1 protein. The results of this study suggest that neurofibromatosis type 1 tumor suppressor exerts its effects in part by controlling organization of cytoskeleton during the formation of cellular contacts.     

Thrombospondin-1 promotes fibroblast-mediated collagen gel contraction caused by activation of latent transforming growth factor beta-1

BACKGROUND: Grafting of cultured epithelium has become a useful technique for the treatment of epithelial defects, since grafted epithelial cells secrete factors promoting wound healing. We identified one such factor produced by cultured oral epithelial cells as thrombospondin-1 (TSP-1). Recently, TSP-1 was reported to act as an activator of transforming growth factor-beta1 (TGF-beta1). OBJECTIVE: The role of TSP-1 in wound healing and its mechanism were investigated in vitro and in vivo. METHODS: The cultured oral epithelial cell-conditioned medium was harvested and applied to Heparin-Sepharose affinity chromatography. Proteins were analyzed by N-Terminal sequencer. TSP-1 and the other factors were applied to fibroblasts-mediated collagen gel contraction assay. The amount of TGF-beta1 (latent TGF-beta1 (LTGF) and active TGF-beta1) in collagen gels was quantified by ELISA and Western blotting analysis. Collagen sponges were soaked with TSP-1 and implanted subcutaneously into rats. RESULTS: A 38 kDa protein secreted from cultured oral epithelial cells was found to be human TSP-1. TSP-1 promoted collagen gel contraction activity, and anti-human TSP-1 and TGF-beta1 antibody inhibited the activity. The diameters of the gels treated with LTGF and TSP-1 were reduced to a greater extent than those of gels treated with either factor alone. Although there were no significant differences in the amounts of total TGF-beta1, which include LTGF, the amount of 25 kDa TGF-beta1 was 3.30-fold greater in TSP-1-treated samples than controls. In vivo, 7 days after implantation, increased numbers of fibroblasts were observed in the sponges treated with TSP-1. CONCLUSION: These findings suggested that TSP-1 causes collagen gel contraction by activation of LTGF. TSP-1 is expected to be especially suitable for regulating wound healing.     

Increased HMGB1 serum levels and altered HMGB1 expression in patients with psoriasis vulgaris

High mobility group box-1 (HMGB1) has been implicated as a pro-inflammatory cytokine in the pathogenesis of various inflammatory and autoimmune diseases. However, information about HMGB1 in inflammatory skin diseases is unknown. Herein, we investigated the serum HMGB1 levels and tissue HMGB1 expression in patients with psoriasis vulgaris (PV) and atopic dermatitis (AD). Serum levels of HMGB1 in patients with PV and AD were detected by enzyme-linked immunosorbent assay (ELISA). The expression of HMGB1 in lesional skin was evaluated by immunohistochemistry and immunofluorescence. Protein levels of HMGB1 in the nuclear fraction and cytoplasmic fraction were determined by western blot. Serum levels of HMGB1 in patients with PV but not AD were significantly higher than those in nornal controls. Moreover, serum HMGB1 levels were correlated with the severity of PV according to PASI socres. Furthermore, by immunohistochemistry and immunofluorescence, we showed that the expression of HMGB1 in normal skin was almost completely restricted to the nucleus. However, abundant cytoplasmic expression of HMGB1 was observed in the epidermis in lesional skin of PV patients. In addition, western blot data indicated that HMGB1 expression was in the nucleus protein and was absent in the cytoplasm protein in control group. In contrast, HMGB1 expression in the cytoplasmic fraction was detectable in AD patients and more distinct in PV patients. Taken together, this study provides first observations on the association of HMGB1 with PV, and showed the elevated HMGB1 serum levels and altered HMGB1 distribution in lesional skin in patients with PV. We suggest that HMGB1 might be involved in the pathogenesis of PV.     

Patched-1和Gli-1在银屑病皮损中的表达

目的 探讨Patched-1、Gli-1在银屑病皮损中的表达。方法 应用免疫组化和原位杂交的方法,检测银屑病皮损及正常人皮肤中Patched-1、Gli-1的表达和分布情况。结果 在银屑病皮损中Patched-1表达高于正常人皮肤(免疫组化χ²=6.53,P<0.05;原位杂交χ²=7.93,P<0.05),Gli-1表达显著高于正常人皮肤(免疫组化χ²=19.21,P<0.01;原位杂交χ²=14.34,P<0.01),主要分布于表皮细胞胞浆中,在毛囊、浸润的炎细胞及血管内皮细胞中也有阳性表达。结论 银屑病皮损表皮中Patched-1和Gli-1均处于高表达状态,Hedgehog信号转导通路可能在银屑病发病中起一定作用。     

1型神经纤维瘤病NF1基因突变检测

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

Effect of psoriasis activity on metalloproteinase-1 and tissue inhibitor of metalloproteinase-1 in plasma and lesional scales

The aim of this study was to evaluate the association between psoriasis severity and concentrations of matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in plasma and scales from psoriatic lesions, measured with an enzyme immunoassay in 24 patients and analysed with respect to psoriasis area and severity index (PASI). The mean plasma concentrations of both proteins in psoriatic patients significantly exceeded the control values. The proteins were also detectable in scales. There was a significant correlation between plasma MMP-1 concentration and the disease duration. The PASI values showed significant positive correlation with plasma TIMP-1 and significant negative correlation with MMP-1 content in scales. The highest plasma MMP-1 concentration was observed in patients with mild forms whereas the highest plasma TIMP-1 concentrations were demonstrated in severe forms of psoriasis. Our results confirm the role of these proteins in pathogenesis of psoriasis. In severe forms, a decrease in both MMP-1 and TIMP-1 was observed in scales, suggesting their insufficient tissue expression, which can be a crucial element of psoriasis aggravation.     

New Onset Guttate Psoriasis Following Pandemic H1N1 Influenza Vaccination

Since the introduction of H1N1 influenza vaccine in the wake of the 2009 H1N1 pandemic, many serious and non-serious vaccine-related adverse events have been reported. The vaccination could induce pain, erythema, tenderness, and induration on injected areas. These symptoms usually disappear in a few days after the vaccination. In this case, we observed a 26-year-old woman with multiple erythematous scaly macules scattered on the extremities and trunk. She was injected with an inactivated split-virus influenza A/H1N1 vaccine without adjuvant (Greenflu-S®, Green Corp.) on her left deltoid area 10 days earlier. The first lesion appeared on the injection site three days after the vaccination, and the following lesions spread to the trunk and extremities after a few days. Histopathological examinations showed neutrophilic collections within the parakeratotic cornified layer, moderate acanthosis, diminished granular layer, elongation and edema of the dermal papillae, and dilated capillaries. The lesions were successfully treated with topical steroids and ultraviolet B phototherapy within three weeks, and there was no relapse for the following fourteen months. We assumed that pandemic vaccination was an important trigger for the onset of guttate psoriasis in this case.     

UVA1 phototherapy for disseminated granuloma annulare

BACKGROUND/PURPOSE: Disseminated granuloma annulare is a benign granulomatous skin disease of unknown etiology. Recently, UVA1 (340-400 nm) phototherapy has been found effective in a small series of four patients. The purpose of this two-center study was to determine the rate and duration of clinical response to UVA1 phototherapy in a larger cohort of 20 patients with disseminated granuloma annulare. METHODS: Twenty patients with long-standing, stable disease (median 42 months, 95% CI 23-105) underwent UVA1 phototherapy. Sixteen patients were treated with a high-dose regimen (median single dose 110 J/cm2, 95% CI 103-121) and four patients with a medium-dose regimen (median single dose 50 J/cm2, CI 50-50). The clinical response was graded on a 5-point scale [0 = none, 1 = poor, 2 = moderate, 3 = substantial, 4 = (near) complete]. After cessation of therapy, patients with a clinical score of 3 or 4 were followed up to evaluate the duration of clinical improvement. RESULTS: At the end of treatment, five patients each had substantial improvement or (near) complete clearance. Another five patients had a moderate response, three patients were considered as poor responders and two patients as treatment failures. Out of the 10 patients with good or excellent response nine were available for follow up. Of these, two patients were still clear after 3 and 6 months, and seven patients relapsed after a median of 3 months (95% CI 1.68-6.46). CONCLUSIONS: UVA1 phototherapy provided good or excellent results in half of our 20 patients with disseminated granuloma annulare. In the majority of patients with a satisfactory response, however, discontinuation of treatment was followed by early recurrence of disease.     

Caveolin-1 is a negative regulator of MMP-1 gene expression in human dermal fibroblasts via inhibition of Erk1/2/Ets1 signaling pathway

Background

Caveolar raft domains, also termed caveolae, are flask shaped invaginations that require the expression of the structural protein caveolin-1 (cav-1). Matrix metalloproteinase 1 (MMP-1) is a collagenase capable of degrading insoluble triple helical collagens. Deregulation of MMP-1 contributes to various pathological processes, including tissue fibrosis and impaired wound healing.

Objective

In this study we investigated the role of cav-1 in MMP-1 gene regulation in human dermal fibroblasts.

Methods

Fibroblasts were isolated from healthy subjects. Western blot was used to analyze protein levels and quantitative real time RT-PCR was used to measure mRNA expression. Cells were transiently transfected with siRNA oligos against acid sphingomyelinase (ASMase) and cav-1, or transduced with adenoviruses overexpressing ASMase and cav-1. The specific pharmacological inhibitors UO126 and SP600125 were used to block Erk1/2 and JNK activity.

Results

This study shows that siRNA-mediated depletion of ASMase or cav-1, results in upregulation of MMP-1 gene expression. Similarly, MMP-1 expression was decreased after overexpresssion of cav-1 via an adenoviral vector. Depletion of cav-1 had no effect on JNK phosphorylation, while it resulted in an increase in Erk1/2 and Ets1 phosphorylation levels. Furthermore, in cav-1 depleted cells treated with the Erk inhibitor UO126, there was no increase in the levels of phospho-Erk1/2, phospho-Ets1, and MMP-1, suggesting that cav-1 mediated effects on MMP-1 and phospho-Ets1 are Erk1/2 dependent.

Conclusions

In conclusion, this study has revealed an important role for cav-1 as a negative regulator of MMP-1 gene expression via inhibition of Erk1/2/Ets1 signaling. Cav-1 could potentially be a therapeutic target in diseases with deregulated extracellular matrix (ECM) turnover.     

Association of estrogen receptor 1 intron 1 C/T polymorphism in Korean vitiligo patients

BACKGROUND: Vitiligo is a common disease characterized by cutaneous white maculae due to loss of melanocytes. It is a polygenic disease, however, the exact pathogenesis of vitiligo is not yet known. The estrogen receptor (ESR) 1 gene was selected as a candidate gene because some researchers treated vitiligo successfully with the steroid-thyroid hormone mixture containing estrogen. Furthermore ESR was expressed in the melanocytes which have an important role in the pigmentation. The polymorphisms of ESR1 gene in vitiligo patients was not reported yet. OBJECTIVE: To determine whether polymorphisms of ESR1 gene were associated with susceptibility to vitiligo patients in Korean population. METHODS: We conducted case-control association study of vitiligo patients (120) and healthy controls (254). Genotypes of ESR1 gene (intron 1 C/T, exon 4 C/G, and exon 8 A/G) were determined by polymerase chain reaction followed by restriction enzyme digestion. RESULTS: Intron 1 T/C allele frequency was significantly different between patients and controls (P = 0.034). Intron 1 T/C genotype distribution (P = 0.021) and allele frequency (P = 0.013) were different between female vitiligo patients and female controls. Intron 1 T/C allele frequency showed significantly difference between generalized type of vitiligo patients and controls (P = 0.044). Genotype distributions and allele frequencies of exon 4 C/G and exon 8 A/G polymorphisms were not different between patients and controls. CONCLUSION: The present study suggests that ESR1 may be a possible risk factor for female or generalized type of vitiligo patients.     

HLA-DQA1 and DQB1 alleles are associated with genetic susceptibility to psoriasis vulgaris in Chinese Han

BACKGROUND: Psoriasis vulgaris is a chronic skin disorder characterized by infiltration of inflammatory elements, keratinocyte hyperproliferation and altered differentiation. Although the pathogenesis of psoriasis is not fully understood, there is solid evidence of a susceptibility locus in the human leukocyte antigen (HLA) region. OBJECTIVES: To investigate whether HLA-DQA1 and DQB1 alleles are associated with genetic susceptibility to psoriasis vulgaris in Chinese Han. PATIENTS AND METHODS: The polymerase chain reaction-sequence-specific primer (PCR-SSP) method was used to analyse the distribution of HLA-DQA1 and DQB1 alleles in 189 patients with psoriasis and 273 healthy controls. RESULTS: The HLA-DQA1*0104 (OR = 2.33, P = 0.0001154, Pc = 2.0 x 10-3), DQA1*0201 (OR = 3.36, P < 1.0 x 10-7, Pc < 1.0 x 10-6), DQB1*0201 (OR = 1.64, P = 0.0192, Pc > 0.05) and DQB1*0303 (OR = 1.55, P = 0.0377, Pc > 0.05) alleles were more prevalent in patients with psoriasis vulgaris than in controls, and HLA-DQA1*0501 (OR = 0.30, P = 0.0000039, Pc < 4.0 x 10-5) alleles were less prevalent. The HLA-DQA1*0104 (OR = 2.42, P = 0.0001159, Pc < 2.0 x 10-3), DQA1*0201 (OR = 3.74, P < 1.0 x 10-7, Pc < 1.0 x 10-6) and DQA1*0501 (OR = 0.30, P = 0.0000374, Pc < 4.0 x 10-4) alleles were only associated with type I psoriasis. HLA-DQA1*0104 and DQA1*0201 were more prevalent in patients with or without a family history of psoriasis. However, the DQA1*0501 allele was only more prevalent in patients without a family history of psoriasis. CONCLUSION: HLA-DQA1*0104 and DQA1*0201 alleles may be psoriasis susceptibility genes or may be in close linkage with the susceptibility genes. The HLA-DQA1*0501 allele seems to have a protective effect against the development of psoriasis vulgaris in Chinese Han. There may be a difference in genetic background between psoriasis patients with and without a family history of psoriasis.     

Subcutaneous administration of collagen-polyvinylpyrrolidone down regulates IL-1beta, TNF-alpha, TGF-beta1, ELAM-1 and VCAM-1 expression in scleroderma skin lesions

In this study the effect of collagen-polyvinylpyrrolidone (collagen-PVP) vs. triamcinolone acetonide (Triam) in scleroderma (SSc) skin lesions was evaluated. Ten SSc patients were treated weekly with subcutaneous injections of 0.2 mL Triam (8 mg/mL) or 0.2 mL collagen-PVP (1.66 mg collagen). Skin biopsies were obtained from lesions before and after treatment. Tissue sections were evaluated by histology and immunohistochemistry (ELAM-1, VCAM-1, IL-1beta, TNF-alpha, TGF-beta1 and PDGF). The corticoid-treated group showed abnormal tissue architecture while the biodrug-treatment restored cutaneous appendages and type I/III collagen proportion. Cytokine and adhesion molecule expression was almost inhibited with Triam, while collagen-PVP down-regulated it. Collagen-PVP improved the tissue architecture of SSc lesions and down-regulated some proinflammatory parameters, without the side effects induced by corticoids.     

Neurofibromatosis type 1 (NF1) and pheochromocytoma: prevalence, clinical and cardiovascular aspects

The aim of the study was to evaluate the prevalence of pheochromocytoma (PHEO) in patients with neurofibromatosis type 1 (NF1), and to analyze the behavior of some anthropometric and cardiovascular parameters. In 48 consecutive NF1 patients, urinary metanephrines and vanillylmandelic acid excretion were assessed. The body mass index (BMI), waist circumference (WC), ambulatory blood pressure monitoring (ABPM), echocardiography and ultrasound carotid arterial wall evaluation were performed. In NF1 patients, 11 (29.3%) had arterial hypertension, 7 (14.6%) had a PHEO. Four (57%) NF1 patients with PHEO were symptomatic at the diagnosis. In PHEO-NF1 patients, we revealed a lower BMI and WC values with respect to NF1 patients without PHEO and normal subjects (NSs) (p?相似文献   

Importance of herpes simplex virus type-1 (HSV-1) in primary genital herpes

Herpes simplex virus type 1 (HSV-1) is increasingly reported in primary genital herpes. Its incidence was assessed among Rotterdam sexually transmitted diseases clinic attendees between 1996 and 2001, and demographic and sexual behaviour factors were evaluated. A retrospective record analysis was performed. All herpes diagnoses were based on cell culture techniques. A clinical scoring system was used to select "primary" cases. Demographic and sexual behaviour characteristics were analysed using logistic regression. The clinical scoring system showed 115 cases of primary genital herpes. HSV-1 (n = 60) was found in 52% and HSV-2 (n = 55) in 48% of cases. The multiple logistic regression model showed that HSV-1 was associated with "oro-genital contact" (p < 0.001) and "having a single partner in the last 2 months" (p = 0.054) and that HSV-2 was associated with "a higher number of sexual partners in the last 6 months" (p = 0.085). Our data confirm the growing importance of HSV-1 in primary genital herpes; oro-genital sex is the main risk factor.     

Fibroblasts surrounding melanoma express elevated levels of matrix metalloproteinase-1 (MMP-1) and intercellular adhesion molecule-1 (ICAM-1) in vitro

Tumour growth and metastasis involve the degradation of extracellular matrix components by matrix degrading enzymes produced by tumour cells and stromal fibroblasts. In this study, fibroblasts were obtained from biopsies on the border (TB) and 1 cm distant from the melanoma (TD) and cultured separately. Similar studies were performed with fibroblasts surrounding melanocytic nevi as control. The expression of matrix metalloproteinase-1 (MMP-1) mRNA and tissue matrix metalloproteinase inhibitor 1 (TIMP-1) were studied by Northern blot analysis. The activation antigen intercellular adhesion molecule-1 (ICAM-1) in TB-and TD-fibroblasts was investigated by flow cytometry. In melanoma, TB-fibroblasts showed an increased expression of MMP-1 mRNA mainly in fibroblasts obtained from tumours with extended invasive growth demonstrated by Clark level whereas the expression of the major specific inhibitor TIMP-1 was unaltered. In contrast, fibroblasts surrounding benign melanocytic nevi did not express elevated levels of MMP-1. The upregulation of MMP-1 in TB-fibroblasts compared to TD-fibroblasts was maintained during cultivation. Furthermore, MMP-1 mRNA expression and MMP-1 total protein amount in normal fibroblasts were increased by melanoma cell conditioned medium. We demonstrated an increased expression of ICAM-1 in TB-fibroblasts compared to TD-fibroblasts in vitro depending on the amount of inflammatory infiltrate in situ. The differences of ICAM expression disappeared during continued cell culture. These results support the idea that fibroblasts surrounding melanoma are activated and are possibly involved in the degradation of matrix proteins surrounding the tumour.