Changes Of Peripheral Blood SPD-L1 In Patients With Small Cell Lung Cancer Before And After Chemotherapy And Its Clinical Significance

Objective:The expression of soluble programmed death ligand 1(s PD-L1)in lung squamous cell carcinoma and adenocarcinoma is related to the progression of the disease.Its expression in small cell lung cancer(SCLC)may be similar and become a potential target.The purpose of this study was to observe the expression change of s PD-L1 in the plasma of SCLC patients and its clinical significance.Methods:Ninety-four patients with small cell lung cancer diagnosed by pathological examination in Shanxi Cancer Hospital from March 2018 to November 2018 were selected as the test team,including 72 males and 22 females,aged 28-82(65+ 9)years.Nineteen healthy persons were selected from the physical examination center as control group,including 11 males and 8 females,aged 26-83(62 + 8)years.There was no significant difference in sex and age between the two groups(P>0.05).Selected chemotherapy regimens for small cell lung cancer were cisplatin+etoposide(EP)and carboplatin + etoposide(CE)for 4 cycles.The patient had complete medical records,including sex,age,smoking status,pathological type,TNM stage,distant metastasis and so on.Enzyme-linked immunosorbent assay(ELISA)was used to detect plasma s PD-L1 levels in 94 patients with small cell lung cancer before and after treatment,and to observe the correlation between plasma s PD-L1 levels and effect.Meanwhile,the levels of s PD-L1 were measured in 19 healthy subjects,and the correlation between the expression of sPD-L1 and tumor stage,distant metastasis,and pro-gastrin releasing peptide(Pro GRP)was analyzed.Results:The linear relationship between the concentration of s PD-L1 and OD450(r 2=0.9638).The level of s PD-L1 in peripheral blood of SCLC group was(1.59±1.02)ng/ml,and that of control group was(0.67 ± 0.21)ng/ml.The level of s PD-L1 in peripheral blood of lung cancer group was higher than that of control group(P=0.0013<0.01).Compared with the changes of s PD-L1 level in PR group,PD group and SD group during chemotherapy,the mean value of s PD-L1 content in PD group and PR group before and after chemotherapy was significantly different(P<0.01),but the difference of s PD-L1 content in SD group before and after chemotherapy was not significant(P>0.05).The dynamic changes of s PD-L1 showed a downward trend in PR group,an upward trend in PD group and a more stable trend in SD group.Compared with the changes of Pro GRP level during chemotherapy in PR group,PD group and SD group,the mean value of Pro GRP level in PD group and PR group was significantly different before and after chemotherapy(P<0.01),but there was no significant difference in Pro GRP level before and after chemotherapy in SD group(P>0.05).The dynamic changes of Pro GRP in PR group showed a downward trend;an upward trend in PD group and a more stable trend in SD group.The correlation between s PD-L1 and clinical characteristics of SCLC patients.According to the median level of s PD-L1 in SCLC patients,they were divided into high expression group(>2.14ng/ml)and low expression group(<2.14ng/ml).There was no significant correlation between the expression of s PD-L1 and sex,age,smoking history,tumor stage,lymphatic metastasis,liver or brain metastasis in SCLC patients(P>0.05).The ROC curve of s PD-L1 in SCLC patients and healthy controls was analyzed.Specificity was taken as abscissa and sensitivity as ordinate,the area under ROC curve was s PD-L1:0.941(95% CI: 0.8944-0.9873,P<0.01).According to the principle of selecting the best critical point,when s PD-L1 is 1.362ng/ml,it is the best critical point.At this time,the sensitivity and specificity of s PD-L1 are 95.0%and 79.6%,respectively,and the positive likelihood ratio was 4.66.Conclusion:The expression of s PD-L1 in peripheral plasma of SCLC patients is higher than that of healthy people,and it is closely related to the effect.The dynamic changes of plasma s PD-L1 were correlated with clinical efficacy.The changes of s PD-L1 and Pro GRP in SCLC patients during progression,remission and stabilization were basically the same,suggesting that the role of s PD-L1 in evaluating SCLC tumor load was similar to that of Pro GRP,a tumor marker.