Modification in CLIC4 Expression is Associated with P53, TGF-β, TNF-α and Myofibroblasts in Lip Carcinogenesis

Chloride intracellular channel-4 (CLIC4) is regulated by p53 and tumor necrosis factor-α (TNF-α), it is linked to the increase of transforming growth factor-β (TGF-β), and myofibroblastic differentiation in skin carcinogenesis. This study analyzed the immunoexpression of CLIC4, p53, TGF-β, TNF-α, and α-SMA in 50 actinic cheilitis (AC) and 50 lower lip squamous cell carcinoma (LLSCC). AC and LLSCC immunoexpression were categorized as score 1 (<5% positive cells), 2 (5-50%) or 3 (>50%). For CLIC4, nuclear and cytoplasmic immunostaining of epithelial cells was considered individually. For morphologic analysis, the World Health Organization criteria were used to epithelial dysplasia grade of ACs, and Bryne grading of malignancy system was applied for LLSCC. Higher nuclear CLIC4 (CLIC4n) and TGF-β were observed in ACs with low-risk of transformation, while cytoplasmic CLIC4 (CLIC4c), p53 and TNF-α were higher in the high-risk cases (p<0.05). In LLSCCs, CLIC4c was higher in cases with lymph node metastasis, advanced clinical stages, and histological high-grade malignancy. p53 expression was higher in high-grade LLSCCs, whereas TGF-β decreased as the clinical stage and morphological grade progressed (p<0.05). ACs showed an increased expression of CLIC4n and TGF-β, while CLIC4c and α-SMA were higher in LLSCCs (p<0.0001). Both lesions showed negative correlation between CLIC4n and CLIC4c, while in LLSCCs, negative correlation was also verified between CLIC4c and p53, as well as CLIC4c and TGF-β (p<0.05). Change of CLIC4 from the nucleus to cytoplasm and alterations in p53, TGF-β, TNF-α, and α-SMA expression are involved in lip carcinogenesis.