[Analysis of different protein expression levels in peripheral blood circulating tumor cells from patients with...

Objective: To analyze the expression levels of differentiation cluster 47 (CD47), signal regulatory protein α (SIRP-α), proto-oncogene (MYC) and proliferating cell associated antigen (Ki67) proteins in peripheral blood circulating tumor cells (CTC) from patients with diffuse large B-cell lymphoma and their predictive efficiency for tumor recurrence. Methods: The data of 82 patients with diffuse large B-cell lymphoma who were confirmed by histopathology and were in remission after chemotherapy in the Hematology Department of Linyi People's Hospital from January 2018 to January 2021 were retrospectively analyzed. There were 44 males and 38 females, and aged from 50 to 75 (63.8±4.6) years. The patients were divided into recurrent group (n=36) and non-recurrent group (n=46) according to their recurrence within 1 year after remission. The fasting peripheral venous blood samples (4 ml) from patients in the morning were collected, and the CTC were isolated. The expression levels of CD47, SIRP-α, MYC and Ki67 proteins in CTC were detected by Western blotting. The correlations between CD47 expression level and SIRP-α, MYC and Ki67 expression levels were analyzed by Pearson correlation analysis. The predictive efficiency of CD47, SIRP-α, MYC and Ki67 expression levels on tumor recurrence was evaluated by receiver operating characteristic (ROC) curves, and the areas under the curve (AUC) were calculated. Results: The expression levels of CD47, SIRP-α, MYC and Ki67 in recurrent group were 2.24±0.23, 1.17±0.12, 1.98±0.20 and 2.63±0.27, while those in non-recurrent group were 2.04±0.21, 1.31±0.13, 1.53±0.16 and 2.24±0.25. The expression levels of CD47, MYC and Ki67 in the recurrent group were higher than those in the non-recurrent group, while the expression levels of SIRP-α were lower than those in the non-recurrent group (all P<0.001). In 82 patients, the expression levels of CD47, SIRP-α, MYC and Ki67 were 2.13±0.22, 1.25±0.13, 1.73±0.18 and 2.41±0.26, respectively. The expression level of CD47 was negatively correlated with the expression level of SIRP-α (r=-0.308, P=0.005), but positively correlated with the expression level of MYC and Ki67 (r=0.484 and 0.332, P=0.012 and 0.003). The sensitivity of CD47, SIRP-α, MYC and Ki67 expression levels in predicting recurrence of diffuse large B-cell lymphoma was 66.7%, 72.2%, 72.2% and 66.7%, with the specificity of 67.4%, 71.7%, 67.4% and 71.7%, and AUC (95%CI) of 0.694 (0.582-0.791), 0.693 (0582-0.790), 0.714 (0.603-0.808) and 0.709 (0.598-0.804), respectively. The sensitivity of the combined detection of the above four indicators was 83.3%, with the specificity of 78.3% and the AUC (95%CI) of 0.864 (0.771-0.930), which was higher than those of the individual detection of each indicator (all P<0.05). Conclusions: The expression level of CD47 was negatively correlated with the expression level of SIRP-α, but positively correlated with the expression level of MYC and Ki67. The expression levels of CD47, SIRP-α, MYC and Ki67 have certain predictive value for tumor recurrence in patients with diffuse large B-cell lymphoma, and the predictive efficiency of combined detection is higher than single indicator detection.