Clinical significance and expression of microRNA-21 in diffuse large B-cell lymphoma cell lines and serum of patients

Objective To study the expression of microRNA-21（miR-21）in serum of patient with diffuse large B cell lymphoma （DLBCL） and DLBCL cell lines and validate the significance of miR-21 in early diagnosis, genotyping and prognosis estimates of DLBCL. Methods miR-21 expression were detected by fluorescent quantity polymerase chain reaction （FQ-PCR）in 9 lymphoma cell lines (OCI-Ly1，OCI-Ly3，OCI-Ly4，OCI-Ly7，OCI-Ly8，OCI-Ly10，OCI-Ly18，OCI-Ly19 and HBL), the serum from DLBCL patients (n=62) and health controls (n=50).Kaplan-Meier survival analysis was carried out during the relapse-free survival period of DLBCL patients to explore the relationship between the prognosis and microRNA expression level. Results Real time FQ-PCR result indicated that miR-21 expression was higher in DLBCL cell lines than that in normal B cells (BC).miR-21 expression in normal B cell and 9 DLBCL cell lines separately were 1.04±0.02，2.30±0.35，237.97±56.19，5.27±0.83，3.40±0.30，11.22±2.70，133.55±16.78，6.63±0.24，4.91±0.37 and 81.59±6.64.Compared with BC, the expression of miR-21 were higher in all 9 DLBCL cell lines (t=7.3，13.7，21.0，6.2，8.8，13.6，6.5，39.5，18.1；P＜0.01). miR-21 expression segregates with specific molecular subgroups of DLBCL.The expression was higher in the ABC type cell lines (OCI-Ly3, OCI-Ly10, HBL) than GCB type cell lines (OCI-Ly1, OCI-Ly4, OCI-Ly7, OCI-Ly8, OCI-Ly18, OCI-Ly19；t=11.18，P＜0.01).Consistent with the cell line models, miR-21 expression levels were higher in serum from DLBCL patients ［21.38（10.26-45.21）］ than from controls ［1.87（1.05-3.97）, U=168, P=0.000］, and the levels were higher in DLBCL cases with an ABC-type ［28.68(14.92-98.44)］ than those in GCB-type ［18.30(7.32-33.46),U=336, P=0.043］.MiR-21 expression levels were different in sera from different clinical stage DLBCL patients.The miR-21 level in serum of patients with subgroup ABC and subgroup GCB in stage Ⅰ and Ⅱ were 47.49（25.65-295.41） and 24.74（16.08-50.38） respectively and in stage Ⅲ and Ⅳ were 16.66（5.35-44.30） and 11.96（4.10-21.05） respectively.The levels were higher in DLBCL cases with Ⅰ-Ⅱ stage than those with Ⅲ-Ⅳ stage (U=62, P=0.013 in GCB type；U=53, P=0.014 in ABC type).Moreover, compare with relapse-free survival in DLBCL patients, high miR-21 expression was associated with well prognosis (U=259, P=0.035). Conclusions MiR-21 is high expression in DLBCL cell lines and DLBCL patients serum.miR-21 level in sera from DLBCL patients is associated with clinical stage, molecular subgroup and prognosis estimates.MiR-21 may serve as a new biomarker to early detection, genotyping and prognosis estimates of DLBCL.（Chin J Lab Med，2012,35：431-435） Key words: Lymphoma，large B cell，diffuse; MicroRNAs; Early detection; Tumor markers，biological