Abstract: Objective To exploring the correlation between the expression level of serum carbohydrate antigen 211 (CA211) and the number of natural killer (NK) cells and prognosis in non-small cell lung cancer (NSCLC) patients. Methods 132 NSCLC patients admitted to the Affiliated Hospital of Hangzhou Normal University from June 2019 to July 2022 were selected as the test group, and 132 patients with benign lung lesions during the same period were selected as the control group. Data were collected from the laboratory to analyze the relationship between serum CA211 expression and NK cell count in NSCLC with clinical prognosis, as well as the related factors affecting the prognosis of NSCLC patients. Results The neutrophil to lymphocyte ratio(NLR) and serum CA211 expression in the test group were higher than those in the control group(P＜0.05), while the count of NK cells was less than that in the control group(P＜0.05); The expression level of serum CA211 in the test group was negatively correlated with the count of NK cells(r=-0.405, P＜0.001); There were significant differences in lymph node metastasis and TNM staging among patients with different levels of serum CA211 expression and NK cell count(P＜0.05); The one-year survival rate of patients with low expression of CA211 was significantly higher than that of patients with high expression of CA211(P＜0.05), and the one-year survival rate of patients with high count of NK cells was higher than that of patients with low count of NK cells(P＜0.05); Lymph node metastasis, TNM staging and CA211 level were all risk factors affecting the prognosis of NSCLC patients(P＜0.05), while counting of NK cells was protective factor for the prognosis of NSCLC patients(P＜0.05). Conclusions The level of serum CA211 and the number of NK cells in NSCLC patients are closely related to pathological characteristics and clinical prognosis.

Key words: non-small cell lung cancer, carbohydrate antigen 211, natural killer cell, prognosis