Expression And Significance Of HMGB1, TLR4 And NF-κB P65in Human Epidermal Tumors

IntroductionHuman epidermal tumors mainly include seborrheic keratosis, precancerous lesions such as Bowen's disease or bowenoid papulosis, basal cell carcinoma and squamous cell carcinoma. Seborrheic keratosis is a benign hyperplasia of basaloid cells and keratinocytes in the epidermis. Bowen's disease is equivalent to squamous cell carcinoma in situ and atypical squamous cells proliferate through the whole thickness of the epidermis, but the tumor does not invade into the dermis. Bowenoid papulosis has a similar histological resemblance to Bowen's disease. Atypical keratinocytes are seen at all levels of the epidermis, together with suprabasal mitotic figures, and may have less cytologic atypia compared with Bowen's disease. Both Bowen's disease and bowenoid papulosis have the potential to grow into squamous cell carcinoma. Basal cell carcinoma is a slow-growing, locally invasive malignant skin tumor that begins in the deep basal cell layer of the epidermis and the basaloid cells form cancerous nests in the dermis. Its malignancy and the potential to metastasis is relatively low. Squamous cell carcinoma is also a locally invasive malignant skin tumor and there are cancerous nests of atypical squamous cell which arise from the different layer of the epidermis and extend into the dermis irregularly. Both the malignancy and metastasis potential of squamous cell carcinoma are relatively high.Many tunors are from inflammation.HMGB 1 is a DNA binding protein located in nucleus, but it can also leave the nucleus and be released into extracellular fluid by the stimulation of inflammation and some other stimuli. Extracellular HMGB1 is considered as an important proinflammatory cytokine. It can engage with TLR4 and transduce signals through the transcription factor NF-κB, inducing the expression of inflammatory genes, promoting cell proliferation.Up to now, the expression and role of HMGB1, TLR4 and NF-κB in epidermal tumors are not well defined. Thus, in this study we will observe the diverse expression of HMGB1, TLR4 and NF-κB p65 in the tumors to elucidate their involvement of tumor and investigate the relationship of HMGB1-TLR4 passage related inflammation with the tumors as well as its biology significance.1.The expression of HMGB1 in epidermal tumorsHMGB1 has different expressions in different epithelial intercellular space, and seborrheic keratosis is stronger in comparion with others while squamous cell carcinoma is the second, and almost no HMGB1 expression in the epithelial intercellular space of normal skin.IHC grading through a semi-quantitative scoring method was analyzed by using variation analysis. The expression of HMGB1 in epithelial intercellular space of seborrheic keratosis is significantly higher than that in normal skin (p<0.01), but there is no significant difference compared with squamous cell carcinoma.The result suggests that HMGB1 maybe is the promoter mediating the inflammation of epidermal tumors.2. The expression of TLR4 in epidermal tumorsTLR4 IHC has different expressions in squamous epithelial cell of normal skin and impaired squamous epithelial cell of different epidermal tumors, and its positive expression mainly localizes on the membrane. In seborrheic keratosis and precancerous lesions TLR4 mainly exhibits basal cell and acanthocyte of squamous epithelium membrane positive. In basal cell carcinoma, TLR4 can be found membrane positive in part of the cancerous epithelial cells. In squamous cell carcinoma, TLR4 could be found membrane positive in almost all of the cancerous epithelial cell. In normal skin TLR4 mainly exhibits basal cell of squamous epithelium membrane positive.IHC grading through a semi-quantitative scoring method was analyzed by using variation analysis. The expression of TLR4 in impaired epithelial cell of squamous cell carcinoma is significantly higher than that in seborrheic keratosis, precancerous lesions, basal cell carcinoma and normal skin (p<0.01).The result suggests that TLR4 signal passageway maybe participate in the local inflammation of the highly malignant epidermal tumors.3. The expression of NF-κB p65 in epidermal tumorsNF-κB p65 IHC positive expression mainly localizes in the epithelial cytoplasm and different level of epithelial nucleus expression can be found either. In seborrheic keratosis p65 exhibits relatively nucleus weak expression, while precancerous lesions and basal cell carcinoma exhibit nucleus weak expression, and squamous cell carcinoma exhibits nucleus relatively strong expression, but there is almost no epithelial nucleus p65 expression in normal skin.IHC grading was analyzed by using variation analysis. The expression of p65 in impaired squamous epithelial nucleus of different epidermal tumors is higher than that in normal skin. Along with the evolution from benign hyperplasia, precancerous lesions, low malignancy to high malignancy tumors, the level of p65 nucleus positive expression is elevated gradually, the difference has statistical signifinance (p<0.01).Western blot detection and analysis show that in the course of evolution from normal skin to different epidermal tumors, p65 positive expression in epithelial nucleus is elevated gradually along with the malignancy advanced. The result suggests the local inflammation is advanced along with the tumor malignant change.4. Variation analysis of IHCIHC grading through a semi-quantitative scoring method used by Spearman's rho correlation analysis shows that the expression of p65 in squamous epithelial nucleus of normal skin and impaired epithelial nucleus of different tumors is positively correlated with TLR4 in squamous epithelial cell of normal skin and impaired epithelial cell of different epidermal tumors (p<0.01).Conclusions1. The inflammation mediated by HMGB1-TLR4-NF-κB passageway maybe participate in the human epidermis tumorigenesis.2. Along with the evolution of epidermal tumors from benign hyperplasia, precancerous lesions, low malignancy to high malignancy, the expression of p65 in epithelial nucleus is increased gradually, suggesting the inflammation advanced in the meantime.3. HMGB1 maybe is the promoter which mediates the local inflammation in the epidermal tumors.4. TLR4 signal passageway maybe participate in the local inflammation of the highly malignant epidermal tumors.5. NF-κB p65 and TLR4 might play an important role in the malignant epidermal tumors. Combined detection of p65 in epithelial nucleus and TLR4 in epithelial cell is beneficial to the diagnosis of the epidermal malignant tumors.