Abstract: ObjectiveTo explore the expression of microRNA155 （miR155） in cervical cancer tissues and its effect on proliferation and invasion of cervical cancer cells. 
MethodsWe collected 76 cases of cervical cancer tissues， 63 cases of normal cervical tissue and 84 cases of cervical intraepithelial neoplasia tissues （22 cases of CIN Ⅰ， 29 cases of CIN Ⅱ and 33 cases of CIN Ⅲ） from May 2014 to December 2016 in our hospital. The miR155 levels in the above tissues were detected by realtime quantitative PCR （QPCR）， and the relationship between the miR155 level and the clinicopathological parameters of cervical cancer （age， FIGO staging， tumor size， histological grade， pathological type， vascular invasion and lymph node metastasis） was analyzed. HeLa cells were transfected with miR155 inhibitor （transfection group） and negative control （control group）， and the miR155 level of each group after transfection of 48 h was detected by QPCR. The proliferative rate and the cell number of penetrating membrane were detected by MTT and Transwell invasiveness test， respectively. 
ResultsQPCR detection showed that the miR155 level in cervical cancer tissues was 4270±1901， higher than that in normal cervical tissues and CIN tissues （P＜005）. The level of miR155 was not related to age， histological grade and pathological type of cervical cancer （P＞005）， but it was related to FIGO staging， tumor size， vascular invasion and lymph node metastasis （P＜005）. The miR155 level of cervical cancer cells transfected with miR155 inhibitor at 48 h was 0265±0034， lower than 1027±0158 of the control group （P＜005）. Compared with the control group， the proliferative rate and the number of penetrating membrane in the transfection group were lower （P＜005）. 
ConclusionMiR155 is highly expressed in cervical cancer tissues， and is associated with clinical stage， vascular invasion and lymph node metastasis. MiR155 is involved in the development of cervical cancer. Downregulating the level of miR155 can inhibit the proliferation and invasion process， and has a certain value in the prevention and treatment of cervical cancer.

Key words: Cervical cancer, MicroRNA155, Clinical significance, Proliferation, Invasion