Objective To investigate the expression of long non-coding RNA(lncRNA)CCAT2 and o-varian cancer domain-containing protease 1(OTUD1)in multiple myeloma(MM)tissue and their correlation with clinicopathological characteristics and prognosis of MM.Methods A total of 132 patients with MM(MM group)diagnosed and treated in this hospital from April 2018 to April 2020 were selected.Seventy patients with non-hematological disease who underwent bone marrow puncture without abnormal bone marrow func-tion during the same period served as the control group.The real-time fluorescence quantitative PCR was used to detect the expression levels of lncRNA CCAT2 and OTUD1 mRNA in bone marrow tissue.The Pearson correlation was performed to analyze the correlation between lncRNA CCAT2 and OTUD1 mRNA expression in bone marrow tissues.The expression differences of lncRNA CCAT2 and OTUD1 mRNA were compared a-mong the MM patients with different clinical and pathological characteristics.The Kaplan-Meier curve was used to analyze the difference of prognosis among the MM patients with different lncRNA CCAT2 and OTUD1 mRNA expressions.The Cox regression was performed to analyze the factors affecting the prognosis in MM patients.Results The expression level of lncRNA CCAT2 in the bone marrow tissue of the MM group was significantly higher than that of the control group(2.31±0.67 vs.0.85±0.24),while the expression level of OTUD1 mRNA in the MM group was lower than that of the control group(1.22±0.37 vs.2.54±0.75),and the differences were statistically significant(t=17.624,16.760,all P＜0.001).The lncRNA CCAT2 expression level in the bone marrow tissue of the MM group had significantly negative correlation with the OTUD1 mRNA expression level(r=-0.731,P＜0.001).The lncRNA CCAT2 and OTUD1 mRNA expression levels had statistical differences among the MM patients with different ISS stages and β2-micro-globulin levels(P＜0.001).The 3-year overall survival rates of the high and low expression groups of ln-cRNA CCAT2 were 42.19％(27/64)and 66.18％(45/68),respectively.The 3-year overall survival rates of the high and low expression groups of OTUD1 mRNA were 72.31％(47/65)and 37.31％(25/67)respective-ly.The 3-year cumulative survival rate of MM patients in the lncRNA CCAT2 low expression group was sig-nificantly higher than that in the lncRNA CCAT2 high expression group,and the difference was statistically significant(Log Rank X2=7.151,P=0.007).The 3-year cumulative survival rate of MM patients in the OTUD1 mRNA low expression group was significantly lower than that in the OTUD1 mRNAhigh expression group(Log Rank x2=13.667,P＜0.001).The ISS stage Ⅲ and lncRNA CCAT2 high expression were the risk factors affecting the prognosis of MM patients(P＜0.01),while the OTUD1 mRNA high expression was the protective factor.Conclusion The lncRNA CCAT2 expression level in bone marrow tissue of the MM pa-tients is increased and OTUD1 expression level is decreased,the both are associated with adverse clinical and pathological characteristics of MM and independent factors affecting the prognosis of MM patients.