Clinical significance and detection of microRNA-21 in serum of patients with diffuse large B-cell lymphoma in Chinese population

Background Expression patterns of microRNAs in serum are involved in potentially non-invasive biomarkers for various diseases. The purpose of this study is to examine the expression of miR-21 in serum of patients with diffuse large B-cell lymphoma (DLBCL) and to validate the significance of miR-21 in early diagnosis, genotyping, treatment options as well as its prognosis estimates of Chinese DLBCL. Methods miR-21 expression was detected by fluorescent quantity polymerase chain reaction (qPCR) in 9 DLBCL cell lines (OCI-Ly1, OCI-Ly3, OCI-Ly4, OCI-Ly7, OCI-Ly8, OCI-Ly10, OCI-Ly18, OCI-Ly19, and HBL), as well as in tumor tissue and serum samples from patients with DLBCL (germinal center B-cell-like (GCB) DLBCL 32; activated B-cell-like (ABC) DLBCL 30) and 50 healthy subjects. Results Expression of miR-21 was increased in DLBCL cell lines. Compared with the miR-21 expression of GCB subgroup (OCI-Ly1, OCI-Ly4, OCI-Ly7, OCI-Ly8, OCI-Ly18, OCI-Ly19), ABC subgroup (OCI-Ly3, OCI-Ly10, and HBL) has higher expression (t=11.18, P<0.01). Circulating miR-21 level in sera from patients with DLBCLwas associated with matched tumor tissue (r(2)=0.931, P<0.0001). Consistent with the in vitro, miR-21 expression levels in serum of patients with DLBCL [21.38(10.26-45.21)] were higher than those in serum of control cases [1.87(1.05-3.97); U=168, P=0.000]. Moreover, miR-21 expression levels in serum of patients with subgroup ABC [28.68(14.92~98.44)] were higher than that of patients with subgroup GCB [18.3(7.32~33.46); U=336, P=0.043]. miR-21 expression in serum of DLBCL with stage I and II were higher than those in stage III and IV (U=62, P=0.013 in GCB type; U=53, P=0.014 in ABC type). Compared with relapse-free survival in patients with DLBCL, high expression of miR-21 was associated with well prognosis (U=259, P=0.035). Conclusion miR-21 expressed in the serum of patients with DLBCL from Chinese was associated with clinical stage, molecular subgroup, and prognosis estimates. miR-21 may be served as a biomarker in early diagnosis, genotyping, treatment options, and prognosis estimating of Chinese DLBCL.