Role of COX-2 activity and CRP levels in patients with non-melanoma skin cancer. −765G>C PTGS2 polymorphism and NMSC risk

Abstract

Non-melanoma skin cancer is one of the most common of all cancers and the incidence has increased in the last years as a result of many factors including increased tanning, life style and possible global climate change. Inflammation plays an important role in cancer development and is frequently evaluated by serum C-reactive protein (CRP) levels. PTGS2 -765C allele coding for COX-2 has been found to be associated with lower plasma levels of CRP. The objectives of this study are: evaluation of the association between PTGS2 -765G>C polymorphism and the occurrence of non-melanoma skin cancer, the relationship between this polymorphism and cyclooxygenase-2 activity in skin tissue, as well as the correlation with serum CRP levels in patients with non-melanoma skin cancer. We used PCR-RFLP technique to explore -765G>C PTGS2 gene polymorphism, colorimetric analysis for cyclooxygenase-2 activity in skin tissue and immunoturbidimetric assay for CRP serum levels in 174 patients with non-melanoma skin cancer [54 patients with basal cell carcinoma (BCC) and 120 patients with squamous cell carcinoma (SCC)] and 80 healthy subjects. PTGS2 -765G>C polymorphism failed to show an association with non-melanoma skin cancer risk. We observed a significant increase in COX-2 activity in SCC and BCC patients compared to control tissue (0.58 ± 0.11 and 0.63 ± 0.09 U/mg protein, respectively vs. 0.16 ± 0.01 U/mg protein). BCC and SCC intra-group analysis showed lower COX-2 activity in C-allele carriers versus non-carriers (p < 0.001 and p < 0.0001, respectively). In BCC and SCC patients with GG genotype, CRP level is significantly increased compared to control group (p < 0.0001 and p < 0.0001, respectively). Intra-group comparison of CRP levels showed significantly lower CRP levels in patients carrying C-allele compared to GG homozygotes in BCC (p = 0.0001) and SCC patients (p < 0.0001). PTGS2 -765G>C polymorphism failed to show an association with non-melanoma skin cancer risk. Regarding prognostic indicators, no consistent association emerged between PTGS2 -765G>C polymorphism and COX-2 activity or CRP levels.