Objective:To analyze the expressions and clinical significance of serum heat shock protein 90 α(HSP90 α)and thymidine kinase 1(TK1)in patients with primary lung cancer.Methods:The medical records of 101 patients with primary lung canc-er,50 patients with benign pulmonary nodules and 50 healthy volunteers with physical examination were retrospectively analyzed,and they were included in groups A,B and C respectively.Serum levels of HSP90 α and TK1 were observed in the three groups.ROC curve was drawn to analyze the diagnostic efficiency of serum HSP90 α and TK1 on primary lung cancer.The levels of serum HSP90 α and TK1 were observed among primary lung cancer patients with different pathological features,and Spearman correlation analysis was per-formed.Results:Serum HSP90 α and TK1 levels in group A were higher than those in groups B and C(P＜0.05),but no obvious differences were shown between group B and group C(P＞0.05).The areas under ROC curves(AUCs)of serum HSP90 α and TK1 levels for the diagnosis of primary lung cancer were 0.951 and 0.879 respectively.According to correlation analysis,lymph node metas-tasis and tumor staging in patients with primary lung cancer were positively correlated with serum HSP90 α and TK1 levels(P＜0.05).Conclusion:Serum HSP90 α and TK1 are highly expressed in patients with primary lung cancer,and have high value in the diagnosis of primary lung cancer,and their levels are related to lymph node metastasis and tumor staging.