Abstract:

Objective   To study the promoter methylation status of Wnt inhibitory factor-1 gene (WIF-1) and the protein expression of Wnt-5a in chondrosarcoma and then explore their clinicopathological significances. Methods   Methylation specific PCR(MSP) and immunohistochemical SP method were used respectively to investigate the methylation of WIF-1 gene and the expressions of Wif-1 protein and Wnt-5a protein in 61 chondrosarcoma samples and 40 matched chondroma samples. Results   The methylation of WIF-1 gene and the expression of Wnt-5a protein obviously increased in chondrosarcoma compared with chondroma(P<0.05). The expression of Wnt-5a protein was significantly higher in tumors with infiltration and/or metastasis than in that without any invasion and metastasis (P<0.05). The methylation of WIF-1 gene was related to the decreased expression of Wif-1 protein and the over-expression of Wnt-5a protein (KappaWif-1 Value 0.747，PWif-1<0.001；KappaWnt-5a Value 0.468, PWnt-5a<0.05). Conclusion   WIF-1 gene methylation may play an important role in the early stage of chondrosarcoma formation. The over-expression of Wnt-5a protein is positively related to the invasiveness of chondrosarcoma. Synergistic effects might exist between WIF-1 gene methylation and over-expression of Wnt-5a protein in the oncogenesis of chondrosarcoma.

Key words: Chondrosarcoma；WIF-1；Wnt-5a；Immunohistochemistry；Methylation specific PCR