ABSTRACT
Objective:To explore the correlation of serum cystatin C (CysC), serum and glucocorticoid-regulated kinase 1 (SGK1) and homocysteine ??(Hcy) with postoperative lymph node metastasis in patients with lung cancer and their predictive values.Methods:One hundred and thirty-one patients with stage Ⅰ-Ⅲ A non-small cell lung cancer (NSCLC) who underwent tumor resection and systematic lymph node dissection in Meishan Hospital of Traditional Chinese Medicine from November 2016 to June 2018 were prospectively selected. Patients received a 3-year follow-up after surgery, and were classified into metastasis group (42 cases) and non-metastasis group (89 cases) according to the presence or absence of lymph node metastasis during the follow-up period. Serum CysC, SGK1 and Hcy levels were detected at the 1st day after surgery, and the levels of the three indicators were compared among patients with different TNM stages, differentiation degrees and histological types. Meantime, the clinicopathological characteristics and levels of the three indicators were also compared between metastasis group and non-metastasis group. Spearman analysis was conducted to discuss the correlation between the three indicators and clinicopathological characteristics of patients. Multivariate logistic regression analysis was performed to screen the factors affecting postoperative lymph node metastasis (the median levels of CysC, SGK1 and Hcy were used as the cut-off values, > the median level was a high level). Taking the pathological examination results as the gold standard, receiver operating characteristic (ROC) curve was applied to evaluate the predictive value of level of the three indicators alone or in combination for postoperative lymph node metastasis. Results:The serum levels of CysC, SGK1 and Hcy in patients with TNM stage Ⅲ A were higher than those in patients with stageⅠ-Ⅱ; the serum levels of CysC, SGK1 and Hcy in patients with poorly differentiated tumors were higher than those in patients with medium and well-differentiated tumors; the serum levels of CysC, SGK1 and Hcy in patients with non-squamous cell carcinoma were higher than those in patients with squamous cell carcinoma; the differences were statistically significant (all P < 0.05). Spearman correlation analysis showed that serum CysC, SGK1 and Hcy levels were correlated with TNM stage ( r values were 0.454, 0.672 and 0.645), differentiation degree ( r values were -0.399, -0.403 and -0.451), histological type ( r values were 0.528, 0.760 and 0.611) (all P < 0.001). Compared with non-metastasis group, an elevation was found in serum levels of CysC, SGK1 and Hcy in metastasis group [(1.37±0.30) mg/L vs. (1.16±0.25) mg/L, (53±4) pg/ml vs. (41±3) pg/ml, (18.3±2.3) mol/L vs. (15.4±1.8) mol/L] (all P < 0.001). Multivariate logistic regression analysis showed that TNM stage Ⅲ A ( OR = 2.944, 95% CI 1.556-6.847, P = 0.004) and high level of CysC (> 1.23 mg/L, OR = 2.431, 95% CI 1.402-5.226, P = 0.008), high level of SGK1 (>50 pg/ml, OR = 4.010, 95% CI 1.815-11.748, P = 0.004), high level of Hcy (> 16.8 μmol/L, OR = 3.742, 95% CI 1.747-9.142, P = 0.001) were independent risk factors for postoperative lymph node metastasis. ROC curve analysis showed that for predicting postoperative lymph node metastasis, the area under the curve (AUC) of serum CysC, SGK1 or Hcy level alone was 0.769, 0.808 and 0.816, the AUC of CysC+Hcy, CysC+SGK1 and Hcy+SGK1 was 0.889, 0.890 and 0.910, and the AUC of the three indicators was 0.936. Conclusions:Levels of serum CysC, SGK1 and Hcy in NSCLC patients with postoperative metastasis are higher than those in patients without metastasis, and the levels of the three are positively correlated with the TNM stage and histological type, and negatively correlated with the differentiation degree. The combined detection of the three has good predictive value for postoperative lymph node metastases in NSCLC patients.
