Objective To investigate the expression of SFRP1 gene methylation and SFRP1 protein in lung adenocarcinoma tissues.

Methods There were 60 lung adenocarcinoma patients who underwent a completely surgical excision from May 2015 to May 2016. The expression of SFRP1 gene methylation, SFRP1 mRNA and SFRP1 protein in lung adenocarcinoma tissues and adjacent tissues were detected respectively by methylation specific PCR, real-time PCR and immunohistochemistry.

Results SFRP1 gene methylation rate was higher in tumor tissues than that in adjacent tissues (58.3% vs. 20.0%, P=0.001). The relative expression of SFRP1 mRNA in tumor tissues and adjacent tissues were (0.847±0.297) and (2.019±0.445) (P < 0.01). The positive expression rate of SFRP1 protein in tumor tissues was significantly lower than that in adjacent tissues (38.3%(23/60) vs. 83.3%(25/30), (P < 0.001)). SFRP1 protein expression was correlated with differentiation degree, clinical stage and lymph node metastasis (P < 0.05). SFRP1 gene methylation was closely correlated with SFRP1 protein expression deficiency in lung adenocarcinoma tissues (r=-0.585, P < 0.001).

Conclusion The expression of SFRP1 gene methylation and protein are associated with the degree of differentiation and lymph node metastasis. The decrease of SFRP1 protein expression may be due to SFRP1 gene methylation.