The Mast Cell-SCF-CB1 Interaction Is a Key Player in Seborrheic Keratosis.

Mast cell (MC) is an important player in the development of skin diseases, including atopic dermatitis, psoriasis, and urticaria. It is reported that MC infiltration and activation are observed around various types of tumors and speculated that MCs play key roles in their pathogenesis. As MCs in human seborrheic keratosis (SK) have not been well investigated, here we focused on the MCs in SK. The number of c-Kit and tryptase-positive MCs was significantly increased around the SK compared with the marginal lesion. Degranulated MCs were also increased around the tumors. Furthermore, MC growth factor, stem cell factor (SCF), expression within the SK was significantly upregulated compared with the marginal lesion. Interestingly, one of the cognitive regulators of SCF expression, cannabinoid receptor type 1 (CB1) immunoreactivity was downregulated within the SK. Our results suggest that MCs play important roles in the pathogenesis of SK and that SCF can be also deeply involved in the development of SKs. Our current results highlight the CB1-SCF-MC interaction as a novel mechanism of SK development and this also will be utilized for developing a novel treatment.

Stromal CD10 expression, as well as increased dermal macrophages and decreased Langerhans cells, are associated with malignant transformation of keratinocytes.

BACKGROUND: It has become evident that resident stromal cells, such as fibroblasts and inflammatory cells, are involved in the metastatic process, including proliferation or migration of malignant neoplasms. We analyzed CD10+ stromal cells, dermal macrophages and Langerhans cells (LCs) in skin tumors. METHODS: Immunohistological staining was performed with markers for macrophages (CD68), LC (CD1a), stromal fibroblasts (CD10) and cell proliferation (Ki67) in 12 normal skins (NSs) and 15 cases each of seborrheic keratosis (SK), actinic keratosis (AK), keratoacanthoma (KA), Bowen's disease (BD) and squamous cell carcinoma (SCC). RESULTS: All SCCs showed weak to strong stromal CD10 expression, while all NS, SK and AK were negative. Weak CD10 expression was observed in only 2 of 15 samples in both BD and KA. The number of CD68+ cells and Ki67 labeling index in SCC and BD were significantly higher than that in KA, AK and SK. In contrast, the number of LC was lower in SCC and BD. The stromal CD10 expression was significantly correlated with the Ki67 labeling indices and CD68+ cells and negatively correlated with decreased LC. CONCLUSIONS: The stromal CD10 expression is associated with malignant transformation of keratinocytes together with infiltration of dermal macrophages and loss of LC.

Local expression of antiinflammatory cytokines in cancer.

To characterize the nature of the local cytokine response to cancer, we chose to investigate cytokine patterns in biopsy specimens of basal cell carcinoma (BCC). We hypothesized that a distinct pattern of local cytokine production may be characteristic of BCC, a neoplasia of epidermis, in comparison to the pattern of seborrheic keratosis (SK), a benign growth of epidermis. We analyzed cytokine mRNAs in BCC versus SK by performing polymerase chain reaction on mRNA derived from biopsy specimens. The mRNAs encoding cytokines for IL-4, IL-5, IL-10, and granulocyte macrophage colony-stimulating factor were strongly expressed in BCC lesions and weakly expressed in SK lesions. Conversely, IL-2, IFN-gamma, and lymphotoxin mRNAs were strongly expressed in SK lesions and weakly expressed in BCC lesions. The response to malignancy, BCC, was typified by cytokines characteristic of murine TH2 cells. This cytokine pattern favors humoral immunity with concomitant immunosuppression of cell-mediated immune responses. In comparison, the response to the benign growth, SK, was typified by cytokines characteristic of murine TH1 cells that favor cell-mediated immune reactions. The findings of a distinct cytokine pattern in skin cancer provide a framework to develop strategies for immunologic intervention.

Clonal nature of seborrheic keratosis demonstrated by using the polymorphism of the human androgen receptor locus as a marker.

We evaluated the clonality of seborrheic keratoses using a polymorphism due to the random inactivation of one of two X chromosomes in females. Thirty-eight seborrheic keratoses obtained from the skin of females with polymorphism of the human androgen receptor (HUMARA) locus were examined by a fluorescent polymerase chain reaction procedure, which allowed accurate measurement of the peak intensities of each HUMARA allele. The epithelial portion of seborrheic keratosis and normal control epidermis adjacent to the seborrheic keratosis were removed by laser capture microdissection. As biopsied specimens of seborrheic keratoses contained small amounts of normal epidermis, the effect of digestion by a restriction enzyme (HhaI) recognizing the nonmethylated active sites was compared between seborrheic keratoses and normal control epidermis in only five seborrheic keratosis cases. Disappearance or significant reduction in intensity of one of two HUMARA alleles was observed after HhaI digestion in seborrheic keratoses, but not in the normal control epidermis. Although the skewing of the polymorphism was not corrected by the normal control epidermis in the remaining 33 seborrheic keratosis cases, one of two HUMARA peaks practically disappeared after HhaI digestion in 20 of 33 seborrheic keratosis cases. In total, 25 of 38 seborrheic keratoses were considered to be monoclonal. The histologic type of seborrheic keratoses did not affect clonality.

Detection and sequences of human papillomavirus DNA in nongenital seborrhoeic keratosis of immunopotent individuals.

BACKGROUND: The etiology of seborrhoeic keratosis (SK) is unknown. Its clinical and histopathological similarities to verrucae vulgaris and condyloma acuminatum prompted us to examine whether human papillomavirus (HPV) is present in SK lesions. In the present study, HPVs were frequently detected from genital lesions or hair follicle in immunocompromised host. OBJECTIVE: We analyzed 104 nongenital SK specimens diagnosed by clinical and histopathological examinations for HPV DNA in immunopotent individuals. METHOD: We analyzed SK specimens for HPV DNA using in situ hybridization (ISH), polymerase chain reaction (PCR), Southern blot hybridization, and sequencing of viral DNA of PCR-amplified fragments. And we also examined virion, which is the capsid protein of HPV in ISH-positive specimens by immunochemical examination. We identified eight mucosal and two cutaneous type HPVs. RESULT: ISH revealed that 30 of 104 (28.8%) SK samples contained HPV DNA. All ISH-positive specimens were demonstrated virion in the nuclei of the epidermal keratinocytes. PCR analysis showed that 87 (83.7%) samples contained HPV-18, 81 (77.9%) HPV-6, and 73 (70.2%) contained both HPV-18 and -6. The incidence of HPV-1 (7.7%) and HPV-2 (14.4%) was relatively low. All 20 normal controls were negative for HPV DNA by ISH but seven were positive by PCR sequencing. CONCLUSION: Our results suggest that HPV, possibly coinfection with HPV-6 and -18 and unknown type(s) of HPV, plays an important role in the pathogenesis of SK.

Squamous cell carcinomas in situ arising in seborrheic keratoses: an association with concomitant immunosuppression?

BACKGROUND: Seborrheic keratoses (SK) are the most common cutaneous neoplasm in humans. Given their numbers, a squamous cell carcinoma in situ (SCCIS) arising from an SK would not be unexpected, although this occurrence has not been widely reported. OBJECTIVE: This study compares the immune status of patients with a SCCIS arising contiguously from SK (SK/SCCIS) and the number of daily medications taken by these patients. The biopsy tissue was evaluated for the presence of human papillomavirus DNA. METHODS: Over a 5-year period at our institution, 13 cases of SK/SCCIS were diagnosed. For each case, age- and sex-matched control patients with a histologically diagnosed unremarkable SK were randomly selected. The number of patients taking immunosuppressing medications was determined from each group and compared statistically. In addition, polymerase chain reaction analysis of the 13 SK/SCCIS biopsies was performed. RESULTS: Five of the 13 study patients took immunosuppressive medications compared to none of the 39 control patients (P = 0.0005). None of the biopsies demonstrated the presence of human papillomavirus DNA by polymerase chain reaction. CONCLUSIONS: Immunocompromised patients with SKs appear to carry a greater risk of these otherwise innocuous lesions developing an SCCIS, although given the small number of patients evaluated, further research into this possible association is warranted.

Dendritic cell subsets and immunological milieu in inflammatory human papilloma virus-related skin lesions.

BACKGROUND: Human papilloma virus (HPV)-related warts persist, evading host immune surveillance, but sometimes disappear with inflammation. OBJECTIVES: To elucidate the immune evasion mechanisms of HPV, we have examined the density, dynamics, and subsets of dendritic cell (DC) types in non-inflammatory or inflammatory HPV-related skin lesions such as warts and Bowen's disease (HPV-Bowen), and compared the epidermal expression levels of macrophage inflammatory protein (MIP)-3α and E-cadherin. METHODS: The expression of various DC markers, MIP-3α, and E-cadherin in the tissue samples obtained from patients with warts, HPV-Bowen and HPV-unrelated skin diseases was evaluated by immunohistochemistry. MIP-3α gene expression levels were examined in warts and HPV-Bowen by in situ hybridization (ISH) and real-time quantitative polymerase chain reaction (RT-qPCR). RESULTS: The numbers of Langerhans cells (LCs) and the expression levels of MIP-3α and E-cadherin were decreased in non-inflammatory warts and HPV-Bowen, as compared with normal skin. Both epidermal LCs and MIP-3α expression reappeared in inflammatory warts, associated with dermal infiltrates composed of many cytotoxic T cells and various subsets of DCs, while cellular infiltrates in HPV-Bowen contained many B cells and plasma cells with sparse infiltration of DCs. The upregulation of MIP-3α gene expression was confirmed in the inflammatory warts and HPV-Bowen by ISH and RT-qPCR. CONCLUSIONS: The depletion of LCs in the non-inflammatory warts and HPV-Bowen is associated with a down-regulation of expression levels of MIP-3α and E-cadherin in the lesional keratinocytes. MIP-3α expression is upregulated in lesional keratinocytes of inflammatory warts, with the subsequent recruitment of various DC subsets and cytotoxic T cells, whereas plasma cell-rich infiltration was induced in HPV-Bowen.

CCR10 and CCL27 are overexpressed in cutaneous squamous cell carcinoma.

C-C chemokine receptor (CCR)10 is a specific receptor for chemokine ligand (CCL)27, a selective chemoattractant for skin-associated memory T cells to cutaneous sites. In melanoma, CCR10 increases the ability of neoplastic cells to grow, invade tissues, disseminate to lymph nodes, and escape the host immune responses. In this study, we investigated the expression of CCR10 and its ligand CCL27 in squamous cell carcinoma (SCC). CCR10 and CCL27 were expressed in SCC, actinic keratosis (AK), Bowen's disease, and seborrheic keratosis (predominantly prickle cell type), but not in seborrheic keratosis (predominantly basal cell type) and basal cell carcinoma. Furthermore, CCR10 and CCL27 were overexpressed in SCC relative to Bowen's disease, an early stage of SCC. Consistently, a human SCC cell line, A253 cells, and HaCaT cells exhibited CCL27 production that was strongly induced by tumor necrosis factor-α and interleukin-1ß. Finally, A253 cells expressed stronger intracellular CCR10 compared to HaCaT cells by flow cytometry. These results suggest that CCR10 and CCL27 overexpression in SCC is related to the progression of SCC and is useful for the diagnosis of SCC.

Cell-type related and spatial variation in the expression of integrins in cutaneous tumors.

Integrins constitute a group of transmembrane proteins which mediate cell-cell and cell-matrix interactions. Previous studies have shown both increased and decreased expression of integrins in relation to malignancy and invasion. In the present study, we investigated integrin distribution in cutaneous tumors by using monoclonal antibodies on frozen tissue sections. Antibodies to integrin subunits alpha v, alpha 3, alpha 4, alpha 5, alpha 6, beta 1 and beta 3 were used. The study was designed to explore (i) the association between integrin expression and the tumor type, and (ii) the effect on the integrin expression of the location of the tumor, i.e. whether it grows intraepidermally or within various compartments of the dermis (papillary or reticular). Beta 1, beta 3 and alpha 3 were strongly or moderately expressed in the epithelial and stromal cells of basal cell carcinomas (BCC), seborrheic keratoses, solar keratoses, dermatofibromas (DF), and showed a variable expression in the nevic cells of benign and dysplastic nevocellular nevi. alpha v and in alpha 5 appeared strongly expressed in the stromal cells of BCC and DF, while only a focal, often weak staining was seen in nevic cells and in the epithelial cells of BCCs. In some nevocellular nevi, they were only expressed, together with alpha 4, in the deep-seated nevic cells in the reticular dermis. alpha 6 was expressed by tumor cells of BCCs and nevocellular nevi only within the dermo-epidermal junction. In seborrheic keratosis and solar keratosis a basement membrane-associated staining pattern for alpha 6 was seen in the basal cell layer, with focal discontinuities in solar keratosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Spontaneous regression of multiple seborrheic keratoses associated with nasal carcinoma.

Seborrheic keratoses are very common epidermal neoplasms. We describe a patient with seborrheic keratoses presenting multifocal spontaneous regression. The patient had a concurrent nasal adenoid cystic carcinoma. The simultaneous regression of seborrheic keratoses ceased after total resection of the nasal carcinoma. Histological examination revealed marked infiltration of mononuclear cells, including CD4+, CD8+, CD68+ and cutaneous lymphocyte-associated antigen-positive cells, with profound accumulation of CD1a+ dendritic cells. Although apoptotic keratinocytes were not found in the lesional epidermis by histology, the majority of keratinocytes in the regressing seborrheic keratosis were positively stained by the TUNEL method. We postulate that the internal malignancy may induce spontaneous regression of seborrheic keratoses.

Expression of the antigen recognized by mAb GB36 in normal skin and in skin tumours.

GB36, a mouse monoclonal antibody (mAb) raised against an epithelial antigen of the human trophoblast, reacts with the epithelial basement membrane of chorionic villi; it does not react with the invasive extravillous cytotrophoblast. Expression and characterization of the antigen of GB36 (designated GBA36) were investigated in normal keratinocytes by immunoprecipitation, immunofluorescence and immunoelectron microscopic studies. Immunoprecipitation experiments demonstrated that the proteins identified on keratinocytes by mAb GB36 and a rat mAb anti-integrin alpha 6 (GoH3) were the same. Using immunofluorescence and immunoelectron microscopic methods, GBA36 was localized on the cell membrane facing the epithelial basal lamina of basal keratinocytes. GBA36 distribution in benign and malignant skin tumours was evaluated by immunostaining methods (immunofluorescence and immunoperoxidase). Analysis of tumours revealed that whereas benign epithelial tumours and intradermal naevi displayed high levels of GBA36, the expression of this antigen decreased progressively in spinocellular and basal cell carcinomas, and in cutaneous melanomas in relation to invasiveness. During cell transformation, GBA36 undergoes quantitative alterations, and expression is down-regulated. Although the functional relevance of these changes remains unknown, the correlation of decreased GBA36 expression with tumour progression may indicate a role for altered integrin expression in tissue invasion by human skin carcinoma and melanoma.

Partial loss of presenilins causes seborrheic keratosis and autoimmune disease in mice.

Presenilin (PS1) and (PS2) are the centers of gamma-secretase that release Abeta from APP in Alzheimer's disease (AD). They cleave signaling proteins like Notch and downregulate beta-catenin to modulate Wnt signaling. Inactivation of PS1 or PS1 and PS2 causes a prenatally lethal 'Notch phenotype,' which has hampered investigation of PS function in adulthood seriously. We have thus turned towards PS1+/-PS2-/- mice which carry the most severe reduction of PS alleles compatible with survival, to analyze the consequences of impaired PS function especially in adulthood. In these 'partial deficient' mice, PS1 protein concentration is considerably lowered, functionally reflected by reduced gamma-secretase activity and impaired beta-catenin downregulation. Their phenotype is normal up to approximately 6 months, when the majority of the mice develop an autoimmune disease characterized by dermatitis, glomerulonephritis, keratitis and vasculitis, as seen in human systemic lupus erythematosus. Besides B-cell dominated infiltrates, we observe a hypergammaglobulinemia with immune complex deposits in several tissues, high-titer nuclear autoantibodies and an increased CD4+/CD8+ ratio. The mice further develop a benign skin hyperplasia similar to human seborrheic keratosis as opposed to malignant keratocarcinomata observed in skin-specific PS1 'full' knockouts. A partial reduction of PS function in PS1+/-PS2-/- mice causes a novel phenotype in adulthood unrelated to the developmental defects of full knockouts. As PS1+/-PS2+/- mice remain healthy, this points towards a sharply defined minimum of PS function. Skin and immune system appear to be especially sensitive targets of impaired PS function and may need careful monitoring if gamma-secretase inhibitors are envisaged for treating AD.