Expression of CXCR4 in basal cell carcinoma. MT Wu and M LU, Taichung, Taiwan Beside the well-known role to regulate leukocyte trafficking, chemokines and their receptors also play important roles in the regulation of mitosis, apoptosis, survival and angiogenesis, which may enhance tumor growth or metastasis. Herein we investigated the possible involvements of chemokines and chemokine receptors in the carcinogenesis of basal cell carcinoma (BCC), the most common human cancer with unique clinical behaviors featuring local invasion and extremely rare metastasis. Real-time quantitative RT-PCR was used to measure the expression levels of several chemokine receptors (CXCR4, CCR7, CCR10) in various human skin cancer cell lines including BCC, squamous cell carcinoma and melanomas. The expression level of CXCR4 in BCC cell line was ~64-fold more than in other cancer cell lines and normal controls (cultured human keratinocytes and fibroblasts). The expression of CXCR4 in BCC cell line was further confirmed using conventional RT-PCR, immunofluorescent staining and western blotting. Immunohistochemistry studies using tissue samples from BCC lesions showed heterogeneous CXCR4 expression in 18 out of 26 (~69%) specimen. The up-regulation of CXCR4 in BCC suggests its possible role in tumor growth or invasion. Transgenic and xenograft studies are currently under way to determine whether overexpresson of CXCR4 in BCC may alter tumor behavior in nude mice.
