Telocytes in Cutaneous Biology: A Reappraisal. / [Artículo traducido] Los telocitos en la biología cutánea: revaluación.

The telocytes (TCs) are novel interstitial cells that have been overlooked for a long time due to their histologic similarity to other stromal cells. TCs can be separated from the stromal cells based on their distinct immunohistochemical, ultrastructural, and molecular features. Functionally, TCs are involved in the tissue renewal, mechanical support, and immune modulation. These cells are also involved in the signal transduction either through their direct interactions with the neighboring cells or through the paracrine signaling via extracellular vesicles. TCs are damaged in several inflammatory and fibrotic conditions such as ulcerative colitis, Crohn's disease, hepatic fibrosis, psoriasis, and systemic sclerosis. The transplantation of TCs in the damaged tissue can promote tissue regeneration. Therefore, enhancing tissue TCs either by their transplantation or by promoting their survival and growth using novel medications represents novel therapeutic strategy in the future. In this review, we addressed several aspects of TCs including their origin, distribution, morphologic features, and functions. We also discussed their involvement of the cutaneous TCs in the development various pathologic conditions.

Telocytes in Cutaneous Biology: A Reappraisal.

The telocytes (TCs) are novel interstitial cells that have been overlooked for a long time due to their histologic similarity to other stromal cells. TCs can be separated from the stromal cells based on their distinct immunohistochemical, ultrastructural, and molecular features. Functionally, TCs are involved in the tissue renewal, mechanical support, and immune modulation. These cells are also involved in the signal transduction either through their direct interactions with the neighboring cells or through the paracrine signaling via extracellular vesicles. TCs are damaged in several inflammatory and fibrotic conditions such as ulcerative colitis, Crohn's disease, hepatic fibrosis, psoriasis, and systemic sclerosis. The transplantation of TCs in the damaged tissue can promote tissue regeneration. Therefore, enhancing tissue TCs either by their transplantation or by promoting their survival and growth using novel medications represents novel therapeutic strategy in the future. In this review, we addressed several aspects of TCs including their origin, distribution, morphologic features, and functions. We also discussed their involvement of the cutaneous TCs in the development various pathologic conditions.

Expression Profile of CD10, BCL-2, p63, and EMA in the Normal Skin and Basal Cell Carcinomas: An Immunohistochemical Reappraisal.

BACKGROUND: Basal cell carcinoma (BCC) is common cutaneous malignancy. AIMS: To examine the expression patterns of CD10, p63, BCL-2, and epithelial membrane antigen (EMA) proteins in BCC. MATERIALS AND METHODS: We used immunohistochemistry to evaluate the expression pattern of these proteins in 45 BCC specimens and their adjacent normal skin. RESULTS: We found variations in the expression pattern of these proteins among normal skins and BCC. In normal skins, we found strong EMA cytoplasmic expression (adnexal structures). A strong nuclear p63 protein expression was found in basal and some suprabasal keratinocytes, external root sheath cells of the hair follicles, basal cells of the sebaceous glands, and in sweat glands.CD10 protein expression was seen in peri-adnexal mesenchymal spindle cells and myoepithelial cells of sweat glands.BCL-2 protein expression was confined to the basal cell keratinocytes, epidermal melanocytes, outer root sheath, and infundibulum of the hair follicle. In BCC, we found p63 (diffuse, strong nuclear staining), CD10 (focal, moderate cytoplasmic reactivity), and BCL-2 (focal, moderate cytoplasmic reactivity) protein expression in the neoplastic cells. BCC was consistently negative for EMA (except in areas of squamous differentiation). CONCLUSIONS: There is an altered expression of these proteins in BCC. The underlying molecular mechanisms are open to further investigations.

Immunohistological Analysis of CD34-Positive Dermal Dendritic Cells and Microvessel Density in the Genital and Extragenital Lichen Sclerosus.

BACKGROUND: Lichen sclerosus (LiS) is a chronic scleroatrophic condition that usually affects the anogenital area and occasionally the extragenital sites. CD34-positive dermal dendritic cells (DDCs) contribute to the maintenance of the dermal microarchitecture and modulation of the immune response. p53 is a tumor suppressor gene important for the regulation of the cell cycle and apoptosis. Similar to morphea (a LiS-closely related scleroatrophic condition), dermal sclerosis, alterations of DDCs, and dermal microvasculature may be important underlying pathogenetic mechanisms in LiS. OBJECTIVES: To examine the profile of CD34-positive DDCs, microvessel density (MVD), and p53 protein in LiS. MATERIALS AND METHODS: The immunohistological profiles of DDCs, MVD, and p53 were examined in 19 cases of LiS and their age- and sex-matched normal skin (10 specimens), using antibodies against CD34 and p53. RESULTS: There was a markedly decreased counts (1.7 ± 0.5/mm2) or complete loss of CD34-positive DDCs in LiS against their abundance in the normal skin (23.4 ± 2.1/mm2, p = 0.000). MVD was markedly increased in LiS lesions (20 ± 0.47) as compared to normal skin (5.50 ± 0.20, p = 0.000). Discontinuous single-cell p53 weakly positive nuclear staining was seen in the epidermal basal cell keratinocytes in normal skin and LiS lesions. CONCLUSIONS: To the best of this author's knowledge, this is the first study analyzing DDCs, MVD, and p53 profiles together in LiS. The findings suggest that alterations of DDCs and MVD have roles in the pathogenesis of LiS.

Immunohistological Analysis of CD34-Positive Dermal Dendritic Cells and Microvessel Density in the Genital and Extragenital Lichen Sclerosus. / Análisis inmunohistológico de las células dendríticas dérmicas positivas para CD34 y de la densidad de microvasos en el liquen escleroso genital y extragenital.

BACKGROUND: Lichen sclerosus (LiS) is a chronic scleroatrophic condition that usually affects the anogenital area and occasionally the extragenital sites. CD34-positive dermal dendritic cells (DDCs) contribute to the maintenance of the dermal microarchitecture and modulation of the immune response. p53 is a tumor suppressor gene important for the regulation of the cell cycle and apoptosis. Similar to morphea (a LiS-closely related scleroatrophic condition), dermal sclerosis, alterations of DDCs, and dermal microvasculature may be important underlying pathogenetic mechanisms in LiS. OBJECTIVES: To examine the profile of CD34-positive DDCs, microvessel density (MVD), and p53 protein in LiS. MATERIALS AND METHODS: The immunohistological profiles of DDCs, MVD, and p53 were examined in 19 cases of LiS and their age- and sex-matched normal skin (10 specimens), using antibodies against CD34 and p53. RESULTS: There was a markedly decreased counts (1.7±0.5/mm2) or complete loss of CD34-positive DDCs in LiS against their abundance in the normal skin (23.4±2.1/mm2, p=0.000). MVD was markedly increased in LiS lesions (20±0.47) as compared to normal skin (5.50±0.20, p=0.000). Discontinuous single-cell p53 weakly positive nuclear staining was seen in the epidermal basal cell keratinocytes in normal skin and LiS lesions. CONCLUSIONS: To the best of this author's knowledge, this is the first study analyzing DDCs, MVD, and p53 profiles together in LiS. The findings suggest that alterations of DDCs and MVD have roles in the pathogenesis of LiS.

Melanocytic Nevi with Site-related Atypia: A Case Series and Characterization of their Immunohistochemical Profile. / Nevos melanocíticos con atipia relacionada con su localización: presentación de una serie de casos y caracterización de su perfil inmunohistoquímico.

BACKGROUND: Nevi of special sites (NOSS) are benign melanocytic lesions that occur at particular sites. Although the histological features of NOSS have been described, their immunophenotypic features have not been fully characterized. AIMS: To present the clinicopathological characteristics of a case series of NOSS and to characterize their immunohistochemical profile. MATERIALS AND METHODS: Thirty-five NOSS were assessed using immunoperoxidase staining techniques for the melanocytic (S100, Melan-A, and HMB45) and proliferation (Ki-67) markers RESULTS: All of the cases of NOSS showed concerning architectural changes (prominent lentiginous melanocytic proliferation, irregularities, crowdedness, and dyhesiveness of the nests), and cytological atypia (large nevomelanocytes with vesicular nuclei, clear cytoplasm, and dusty melanin pigment) that can lead to a misdiagnosis of atypical nevi or even melanomas. All of the cases of NOSS showed diffuse expression of S100 and Melan-A proteins. Ki-67 labeling index of the nevomelanocytes was extremely low. HMB45 protein expression was limited to the junctional and superficial dermal nevomelanocytes. CONCLUSIONS: NOSS can show histological features that can easily mimic atypical nevi or melanomas and this diagnostic consideration should be kept in mind to avoid their misdiagnosis. The expression of HMB45 protein in NOSS indicates that their nevomelanocytic cells have an activated phenotype. The decreased HMB45 protein expression following a gradient from junctional to deeper dermal localization in NOSS is indicative of their immunohistochemical maturation.

The first use of EaeI restriction enzyme in DNA diagnosis of Hb Q-India.

INTRODUCTION: The α-chain variant Hb Q-India (c.193G>C) is caused by a point mutation GAC→CAC at codon 64 of the α1 globin gene and is clinically silent. Point mutations can be diagnosed easily by many simple polymerase chain reaction (PCR) techniques including PCR-restriction digest, but for Hb Q-India the restriction digest has never been described. In this work we aimed to develop a restriction enzyme digestion assay for DNA diagnosis of Hb Q-India, in order to increase the panel of restriction enzymes used in DNA diagnosis of haemoglobinopathies and also as a simple cheap alternative to the ARMS-PCR method. METHODS: A restriction enzyme digestion assay was designed for diagnosis of Hb Q-India using the restriction enzyme EaeI enzyme as the Hb Q-India mutation abolishes the recognition site of this enzyme. Patients were screened for an abnormal haemoglobin by high performance liquid chromatography (HPLC) and those had an abnormal peak with a retention time between 4.7 and 4.8 minutes were selected for diagnosis at the molecular level. The α1 globin gene was amplified in 12 cases with a presumed diagnosis of Hb Q-India by HPLC and isoelectric focusing (IEF), and the amplified products were subjected to the EaeI digestion. RESULTS: All the 12 cases were diagnosed positive (100%) for Hb Q-India by the EaeI restriction enzyme digest. They were heterozygotes for the mutation. CONCLUSION: EaeI restriction enzyme digestion can be used as a simple and robust alternative method to ARMS-PCR for DNA diagnosis of Hb Q-India. The EaeI restriction enzyme can be added to the panel of restriction enzymes used in the DNA diagnosis of the abnormal Hb variants. Concomitant use of HPLC and IEF can be used efficiently for presumed diagnosis of this rare variant.

Haemoglobin (Hb) G-Philadelphia, Hb Stanleyville-II, Hb G-Norfolk, Hb Matsue-Oki and Hb Mizushi can form a panel of α-chain variants that overlap in their phenotype: the novel use of StyI to screen for Hb G-Philadelphia.

INTRODUCTION: Haemoglobin (Hb) G-Philadelphia mutation is a common alpha-globin chain variant [α68(E17)Asn > Lys]. Combined high performance liquid chromatography (HPLC) and isoelectric focusing (IEF) can be used in a presumptive diagnosis of Hb G-Philadelphia, but there are other α-chain variants with a similar phenotype that cannot be excluded. Our aim was to develop a novel StyI restriction enzyme assay to diagnose the common Hb G-Philadelphia mutation and to identify any other variants with a similar phenotype by DNA sequencing. METHODS: Thirty-one cases given a presumptive diagnosis as Hb G-Philadelphia by HPLC and IEF were subjected to DNA analysis by restriction enzyme digestion using StyI. Negative cases were then subjected to DNA sequencing. RESULTS: Twenty-two cases (78.6%) of 28 cases amplified were tested positive for Hb G-Philadelphia by StyI restriction digestion. Sequencing of the six negative cases revealed two cases of Hb G-Philadelphia with C→A mutation in codon 68 in α2 globin gene, plus one case each of Hb G-Norfolk Hb Stanleyville-II, Hb Matsue-Oki and Hb Mizushi. CONCLUSION: A novel StyI restriction enzyme can be used to confirm the commonest type of Hb G-Philadelphia. DNA sequencing identified four other α-chain variants with a similar HPLC and IEF phenotype.

Hurthle cell neoplasms of thyroid in south-western region of Saudi Arabia.

BACKGROUND: Thyroid Hurthle cell neoplasm (THCN) is relatively rare. OBJECTIVE: To describe the presentation, diagnostic approach and management of THCN in our institution. METHODS: This was a retrospective chart review of all thyroid Hurthle cell neoplasms diagnosed at Aseer Central Hospital (ACH), Saudi Arabia during the period from October 1998 to April 2007. Data including clinical, cytopathologic, radiologic, histopathologic and surgical treatment were extracted for analysis. RESULTS: Nine patients were diagnosed as THCN (eight females and one male). Their ages ranged from 24-49 years. Three cases were Hurthle cell carcinomas and six cases were Hurthle cell adenomas. Carcinomas presented as solitary nodules (two cases) and as multinodular goiter (one case). Adenomas presented as solitary nodules (two cases), as multinodular goiter (three cases) and as diffuse swelling (one case). Fine needle aspiration cytology (FNAC) was diagnostic for THCN in two cases of carcinoma that presented as solitary nodules and hence total thyroidectomy was performed. Total thyroidectomy was also done in one case of adenoma. Hemithyroidectomy was performed in two cases of adenoma in which FNAC showed benign lesion and in one case of carcinoma based on clinical and ultrasonographic impression of benign MNG in the involved lobe and inconclusive FNAC result. Subtotal thyroidectomy was performed in one case of adenoma. CONCLUSION: Preoperative diagnosis and management of THCN is still a dilemma. Neither clinical nor FNAC findings can exclude carcinoma. Therefore a combination of clinical, radiological, FNAC and histopathological results should be used for a more definitive subtyping and proper management.

Glomerular expression and elevated serum Bcl-2 and Fas proteins in lupus nephritis: preliminary findings.

Programmed cell death (apoptosis) is involved in glomerular injuries leading to glomerulonephritis. Bcl-2 and Fas are proteins that promote cell survival and death, respectively. This study tests the hypothesis that lupus nephritis is associated with alterations of Bcl-2 and Fas protein expression. Thirty-six patients with lupus nephritis and 10 controls (normal individuals) were included in this study. Bcl-2 and Fas positive cells were examined in kidney biopsies by immunohistochemistry. Bcl-2 and Fas serum levels were evaluated by enzyme-linked immunosorbent assay (ELISA). In the glomeruli of normal kidneys, Bcl-2 and Fas proteins were completely absent. In lupus nephritis patients, glomerular expression of Bcl-2 and Fas was seen in mesangial cells (1.3 +/- 0.1 and 2.0 +/- 0.1 for Bcl-2 and Fas, respectively). Similarly, a statistically significantly higher Bcl-2 (217.1 +/- 85.9) and Fas (767.9 +/- 271) serum levels were found in lupus patients compared to controls (148.6 +/- 87, 550.3 +/- 91 for Bcl-2 and Fas, P < 0.05). A direct correlation between serum Bcl-2 and Fas and chronicity index was also found. Compared to normal controls, lupus nephritis is associated with glomerular expression and elevated serum levels of Bcl-2 and Fas proteins. These findings suggest possible roles for Bcl-2 and Fas in glomerular injury during evolution of lupus nephritis. The diagnostic, prognostic and therapeutic ramifications of our findings are open to further investigation.

Analysis of the mononuclear inflammatory cell infiltrate in the normal breast, benign proliferative breast disease, in situ and infiltrating ductal breast carcinomas: preliminary observations.

BACKGROUND: Mammary carcinogenesis is a multistep process entailing the transition from normal breast to benign proliferative breast disease (ductal hyperplasia) to ductal carcinoma in situ to infiltrating ductal carcinoma. HYPOTHESIS: These transitions are associated with changes in the mononuclear inflammatory cell infiltrate. MATERIALS AND METHODS: A total of 53 mastectomy specimens of normal breast, benign proliferative breast disease, ductal carcinoma in situ and infiltrating ductal carcinoma were evaluated for mononuclear inflammatory cell infiltrate by using immunohistological methods and monoclonal antibodies including CD20, CD68, CD3 and granzyme B, histiocytes, T cells and cytotoxic T cells. RESULTS: Transitions from normal breast to the subsequent tissue with lesions (normal skin v benign proliferative breast disease v ductal carcinoma in situ v infiltrating ductal carcinoma) were associated with significantly (p<0.01) increased mean (SD) density of mononuclear inflammatory cell infiltrate at the parenchyma (3.2 (1.0) v 26.4 (7.8) v 33.6 (7.9) v 39.1 (4.7) for CD20+ B cells; 2.8 (1.0) v 81.5 (14.0) v 84.0 (14.9) v103.7 (3.9) for CD3; 1.3 (2.0) v 3.8 (4.0) v 12.7 (23) v 22.1 (25.0) for CD68+ macrophages; 2.0 (1.0) v 58.3 (5.0) v 60.0 (10.0) v 74.1 (28.0) for granzyme B+ cytotoxic T cells) and at the stroma (0.7 (1.0) v 3.0 (5.0) v 13.3 (20) v 16.7 (30.0) for CD20+ B cells; 1.0 (2.06) v 4.0 (2.5) v 16.7 (5.0) v 21.7 (15) for CD68+ macrophages; 1.4 (0.6) v 4.2 (1.2) v 46.6 (16.7) v 77.0 (5.0) for CD3+ cells and 0 (0) v 0.5 (1.0) v 0.7 (1.0) v 0.7 (1.0) for granzyme B+ cytotoxic T cells). CONCLUSIONS: The increased mononuclear inflammatory cell infiltrate during mammary carcinogenesis may reflect non-specific or specific immunological processes.

Age-associated decrease of CD1d protein production in normal human skin.

BACKGROUND: CD1d belongs to a family of antigen-presenting molecules structurally related to the classical major histocompatibility complex class I proteins. OBJECTIVES: To examine the expression pattern of CD1d protein in normal human skin with ageing. METHODS: Twenty normal human skin biopsy specimens were obtained from 20 healthy individuals. The latter were divided into three age groups: children (5-20 years), adults (21-50 years) and the elderly (51-81 years). The intensity of CD1d protein production was examined in human skin using immunofluorescent and immunoalkalinephosphatase staining methods. RESULTS: In the epidermis, CD1d protein production was strong in the skin of the children and declined gradually with age, being moderate in adults and weak in the elderly. As compared with values in children, there was a statistically significant decrease (P<0.05) in CD1d protein production in the elderly. In the dermis, CD1d protein production was strong in the fibroblasts, sweat glands, sebaceous glands, blood vessels and hair follicles regardless of age. CONCLUSIONS: Our study reports a decreased CD1d protein production in normal human skin with ageing. The clinical ramifications of these observations mandate further investigations.

Immunohistological characterisation of tumour infiltrating lymphocytes in melanocytic skin lesions.

BACKGROUND: Although the presence of tumour infiltrating lymphocytes (TIL) is a constant feature in melanomas, their immunophenotypic characterisation is still incomplete. We hypothesise that the transition from normal skin to benign naevi (BN) to melanocytic dysplastic naevi (MDN) to radial growth phase cutaneous malignant melanoma (RGP-CMM) to vertical growth phase cutaneous malignant melanoma (VGP-CMM) is associated with alterations in TIL. This study attempted to test this hypothesis and to characterise TIL in the melanocytic skin lesions. METHODS: In total, 74 lesions (12 BN, 12 MDN, 13 RGP-CMM, 26 VGP-CMM, and 11 metastatic melanomas) were examined using immunoperoxidase staining methods and antibodies targeting leukocyte common antigen (LCA+), T (CD3+) and B (CD20+) lymphocytes, and resting cytotoxic T cells (TIA-1+). RESULTS: Histologically, the transitions from normal skin to BN to MDN to RGP-CMM to VGP-CMM was associated with a gradual increase in the numbers of TIL (total, parenchymal, stromal, perivascular, and epidermal TIL, as well as TIL at the base of the lesions). The numbers of TIL were higher at the stroma than at the parenchyma. Similarly, immunostaining revealed that these transitions were associated with a gradual increase in the staining values (staining intensity, percentage of positive cells, and immunoreactivity score) for LCA+, CD20+, CD3+, and TIA-1+cells. The number of CD3+ cells was higher than that of CD20+ cells. All these differences between the normal skin and the lesional ones reached statistical significance (p<0.01). The majority of CD3+ cells were TIA-1+ T cells with cytotoxic potential. Compared with primary melanomas, there was a decrease in TIL in metastatic melanomas. CONCLUSIONS: The gradual increase in TIL during melanoma tumorigenesis may reflect increased antigenicity of the tumour cells. Although both humoral and cell mediated immunity are involved in melanomagenesis, the latter seems to have the major role. The immune profile of MDN suggests their intermediacy between BN and CMM.

Retinoic acid can induce markers of endocrine transdifferentiation in pancreatic ductal adenocarcinoma: preliminary observations from an in vitro cell line model.

BACKGROUND AND HYPOTHESIS: The pancreatic ductal adenocarcinoma (HPAF) cells have a multipotent stem cell potential. It was hypothesised that all-trans-retinoic acid (atRA) can induce transdifferentiation of these cells into cells with an endocrine phenotype. MATERIAL AND METHODS: To explore this hypothesis, an in vitro system of cells was established. Some cells were treated with atRA at concentrations of 100 nmol/l (non-apoptosis-inducing) and 5 micromol/l (apoptosis-inducing) and harvested. Cells were examined for cell cycle kinetics, apoptosis (terminal deoxynucleotidyl transferase assay and p53 protein expression) and immunomorphological features of redifferentiation (MUC1 and DUPAN-2) and endocrine transdifferentiation (insulin, somatostatin, glucagon, neurone-specific enolase) by using immunoperoxidase staining methods. Levels of insulin, transforming growth factor (TGF) beta2, TGFalpha and epidermal growth factor receptor (EGFR) were measured by enzyme-linked immunosorbent assay (ELISA). The vehicle-treated cells served as a control group. RESULTS: When compared with untreated cells, cells treated with 100 nmol/l and 5 micromol/l atRA were observed to show (1) decreased proliferative activity (cpm) as indicated by decreased incorporation of thymidine labelled with hydrogen-3; (2) cell cycle arrest; (3) increased apoptotic activity associated with p53 protein overexpression; (4) upregulated expression of the transdifferentiation and redifferentiation markers; (5) morphological changes indicative of transdifferentiation (increased cell size and appearance of dendrites); (6) decreased production of EGFR; (7) upregulation of TGFalpha and TGFbeta2; and (8) increase in basal and glucose-induced insulin secretion. CONCLUSIONS: Functional endocrine transdifferentiation can be induced in HPAF lines by atRA. Further investigations are mandated to explore the underlying mechanisms of this transdifferentiation and to explore its in vivo extrapolation.

Tumour-infiltrating lymphocytes and melanoma tumorigenesis: an insight.

The presence of tumour-infiltrating lymphocytes (TILs) amid the tumour cells in the stroma and overlying epidermis is a constant feature of melanoma, the deadliest skin cancer. These lymphocytes are mostly cytotoxic T cells (CTLs) that can be propagated in vitro by specific cytokines. Also, they can kill melanoma cells. This specific killing can be abrogated by monoclonal antibodies against CD3, CD8, T-cell receptors (TCRs) and against class I human leucocyte antigens (HLAs). This indicates that these CTLs can recognize the melanoma cells through the TCRs, in an HLA class I-restricted manner. Therefore, these cells and their products both are critical players in T cell-induced melanoma regression and are powerful predictors of survival. This review seeks to examine the characteristics, activation and role of TILs and their associated molecules in melanomas.

Analysis of fibronectin expression in the bilharzial granulomas and of laminin in the transformed urothelium in schistosoma haematobium infested patients.

UNLABELLED: The bilharzial granulomas and urothelial transformation are common findings in Schistosoma haematobium infested patients. We hypothesize that the distribution of extrinsic (fibronectin, FN) and intrinsic basement membrane (BM) proteins (laminin, LN) is altered during the evolution of these lesions. METHODS: To test this hypothesis, 70 cystectomy specimens, entailing variable associations of normal and dysplastic urothelium (all cases), and bilharzial granulomas were examined for FN and LN protein expression. RESULTS: The biharzial granulomas were formed of admixture of CD3+T cells, CD68+histiocytes and CD220B cells. The CD3+T cells and and CD68+histiocytes were the predominant cell populations. Increased deposition of FN occurred with the evolution from cellular (loose fibrillary network, 20 cases) to fibrocellualr (dense fibrillary network, 30 cases) to fibrotic (tight conglomerates, 20 cases) granulomas. Alternatively, BM staining for LN was linear and continuous underlying normal and metaplastic urothelium. In dysplastic urothelium (20 cases), it showed breaks in continuity. CONCLUSIONS: Alterations of FN and LN occur during the development of the bilharzial granuloma and urothelial transformation.

Melanocytic dysplastic naevi occupy the middle ground between benign melanocytic naevi and cutaneous malignant melanomas: emerging clues.

Although several studies have confirmed the aetiological importance of melanocytic dysplastic naevi (MDN) in the development of cutaneous malignant melanoma (CMM), the analysis of these lesions was directed mostly towards the study of melanomas. The underlying reasons include the relatively large size of CMMs, their direct lethal outcome, and the feasibility of establishing melanoma cell lines. In contrast, because of their relatively small size, questionable malignant potential, and the difficulty in establishing in vitro cultures, MDN have been studied less extensively. Hypothetically, transformed melanocytes can give rise to any lesion in the hierarchy of melanocytic tumours. Based on this hypothetical perspective, and on the epidemiological, morphological, immunohistochemical, and genetic characteristics of MDN, it is not surprising that these lesions occupy an intermediate position in the hierarchy of melanocytic lesions, and may be precursors of CMM. Although this argument appears to be straightforward, it is still controversial. This review explores the components of this argument and provides supporting evidence for this hypothesis.

Analysis of Bcl-2 protein expression in choroidal melanomas.

BACKGROUND: Bcl-2 protooncogene alterations are involved in tumorigenesis and may have prognostic ramifications. AIMS: To investigate normal ocular structures and choroidal melanoma for: (1) Bcl-2 protein expression (semiquantitative staining values: SI, staining intensity; PP, percentage of positive cells; and IRS, immunoreactivity score) and (2) any associations between the staining values and clinicopathological features in these lesions. MATERIALS/METHODS: Bcl-2 protein expression was analysed in 24 choroidal melanomas using immunoperoxidase staining methods. RESULTS: Bcl-2 protein expression was seen in corneal epithelium, lens epithelium, the ciliary body, and retinal cells. In these structures, the mean (SEM) values were: 1.1 (0.1), 1.6 (0.3), 1.1 (0.1), and 2.3 (0.3), respectively, for SI; 1.6 (0.2), 1.7 (0.1), 1.7 (0.2), and 1.7 (0.2) for PP, respectively; and 1.9 (0.4), 2.7 (0.5), 1.9 (0.1), and 4.0 (0.8), respectively, for IRS. Based on Bcl-2 immunoreactivity, the lesions were divided into two groups. The first group comprised 12 tumours with Bcl-2 expression. Bcl-2 expression was significantly higher in this group compared with normal ocular structures (1.5 (0.1) v 2.8 (0.2), 1.7 (0.1) v 3.5 (0.1), and 2.6 (0.3) v 9.3 (0.9) for mean (SEM) SI, PP, and IRS scores, respectively; p = 0.00). The second group comprised 12 tumours lacking Bcl-2 protein expression. There was no significant correlation between Bcl-2 protein expression and most of the clinicopathological features of these lesions. CONCLUSIONS: Bcl-2 protein expression is altered in choroidal melanomas.

Genomic instability in radial growth phase melanoma cell lines after ultraviolet irradiation.

BACKGROUND/AIMS: Although ultraviolet (UV) irradiation, apoptosis, and genomic instability are all potentially involved in the pathogenesis of melanoma, in vitro studies investigating these changes in the radial growth phase of this neoplasm are still lacking; therefore, this study was designed to investigate these changes. METHOD: An in vitro system consisting of three radial growth phase Wistar melanoma cell lines (WM35, WM3211, and WM1650) was established. Cells were UV irradiated (10 mJ/cm2 for UVB and 6 J/cm2 for UVA), harvested after UV exposure, and evaluated for viability and apoptosis using Trypan blue and terminal deoxynucleotidyl transferase mediated dUTP digoxigenin nick end labelling assays, respectively. Polymerase chain reaction based microsatellite assays were used to examine the cell lines for the presence of microsatellite instability (MSI) using 21 markers at the 1p, 2p, 3p, 4q, 9p, and 17p regions. RESULTS: Exposure to UV initiated progressive cell death associated with pronounced apoptosis, with UVA having a greater effect than UVB. MSI was found in UVB (WM35 and WM3211) and UVA (WM35) irradiated cell lines at 1p, 9p, and 17p, but not in non-irradiated cells. The prevalence of MSI was higher after UVB irradiation (14%) than UVA irradiation (4.7%), and was most frequently found at D1S233. CONCLUSIONS: The ability of erythemogenic UV irradiation to induce both apoptosis and MSI in radial growth phase melanoma cells is suggestive of its role in melanoma pathogenesis. This instability may reflect a hypermutability state, oxidative stress induced DNA damage, replication infidelity, or a combination of these factors.