Study on the correlation of LncRNA CASC2 and miR-155-5p with chemotherapy sensitivity and prognosis in patients with epithelial ovarian cancer

ObjectiveTo analyze the correlation between long chain non-coding RNA(LncRNA) cancer susceptibility candidate 2(CASC2), miR-155-5p and chemotherapy sensitivity and prognosis of patients with epithelial ovarian cancer.

MethodsThe expression levels of LncRNA CASC2 and miR-155-5p in 87 patients with epithelial ovarian cancer(epithelial ovarian cancer group) and 72 patients with benign ovarian cancer(control group) were detected by real-time quantitative PCR(QRT-PCR).The expression levels of LncRNA CASC2 and miR-155-5p between two groups were compared.The correlations between LncRNA CASC2, miR-155-5p expression levels and clinicopathological features were analyzed in the epithelial ovarian cancer group.The epithelial ovarian cancer group was subdivided into the chemotherapy-resistant group(n=32) and chemotherapy-sensitive group(n=55) according to the occurrence of secondary drug resistance after chemotherapy, and the relationship between the expression levels of LncRNA CASC2 and miR-155-5p and chemotherapy sensitivity were analyzed.Meanwhile, the Pearson method was used to analyze the correlation between LncRNA CASC2 and miR-155-5p in epithelial ovarian cancer tissues, and the Kaplan-Meier method was used to analyze the relationship between the LncRNA CASC2, miR-155-5p and 5-year survival of patients with epithelial ovarian cancer.

ResultsThe expression level of LncRNA CASC2 in epithelial ovarian cancer group was lower than that in control group, while the expression level of miR-155-5p in epithelial ovarian cancer group was higher than that in control group(P < 0.01).The expression levels of LncRNA CASC2 and miR-155-5p in epithelial ovarian cancer group were correlated with the abdominal metastasis, FIGO stage, differentiation degree and lymph node metastasis(P < 0.05 to P < 0.01), but not correlated with the age, tumor size, ascites and histological type(P>0.05).The expression level of miR-155-5p in chemotherapy-sensitive group was lower than that in chemotherapy-resistant group, while the expression level of LncRNA CASC2 in chemotherapy-sensitive group was higher than that in chemotherapy-resistant group(P < 0.01).The LncRNA CASC2 was negatively correlated with miR-155-5p in epithelial ovarian cancer group(r=-0.637, P < 0.05).The 5-year overall survival rate and median survival time in patients with high expression of miR-155-5p were lower than those in patients with low expression of miR-155-5p(P < 0.05), while the 5-year overall survival rate and median survival time in patients with high expression of LncRNA CASC2 were higher than those in patients with low expression of LncRNA CASC2(P < 0.05).

ConclusionsThe expression levels of LncRNA CASC2 and miR-155-5p in the cancer tissues of epithelial ovarian cancer patients are closely correlated with the chemotherapy sensitivity and prognosis, and can be used as the effective predictors.