Abstract：【Objective】To further investigate the mechanism involved in pathogenesis of osteosarcoma and to discuss the feasibility of methylation status in plasma as a biomarker for clinical detection of osteosarcoma.【Methods】 Methylationspecific PCR (MSP) was applied to determine RASSF1A methylation in 30 cases of osteosarcoma tissues and plasma from the same patient and 15 cases of normal bone tissues and plasma from healthy volunteers. The correlation between methylation of RASSF1A gene and clinicalpathological features such as gender, age, tumor location, tumor differentiation and tumor distant metastasis was analyzed. 【Results】 RASSF1A methylation was not detected in normal bone tissue and plasma. Hypermethylation of RASSF1A was present in 26.7% (8/30) of the osteosarcoma plasma samples and 40% (12/30) of the osteosarcoma tissues, and of the 12 cases of positive RASSF1A methylation, 8 cases were found with RASSF1A methylation both in the cancer tissues and plasma from the same patient, with a positive consistent rate of 66.7% (8/12), and 18 cases were observed with negative methylation both in the cancer tissues and plasma. Kappa consistency check showed that methylation of RASSF1A gene in osteosarcoma tissue and plasma had consistency (Kappa value was 0.133, P<0.05). In addition, analysis showed that RASSF1A methylation in osteosarcoma tissue and plasma was significantly higher than that in the normal tissue and plasma (P<0.05). The methylation of RASSF1A in plasma and cancer tissue had no obvious relationship with gender, age, or tumor location (P>0.05), but had relationship with tumor differentiation and tumor distant metastasis (P<0.05).【Conclusion】RASSF1A methylation in plasma can partly represent similar changes in cancer tissue from the same patient and may be a promising biomarker for clinical detection of osteosarcoma.
2016, Vol. 33 
