Background Ovarian cancer has greatly endangered and deteriorated female health conditions worldwide. Refinement of predictive biomarkers could enable patient stratification and help optimize disease management. Methods RAD51 expression profile, target-disease associations, and fitness scores of RAD51 were analyzed in ovarian cancer using bioinformatic analysis. To further identify its role, gene enrichment analysis was performed, and a regulatory network was constructed. Survival analysis and drug sensitivity assay were performed to evaluate the effect of RAD51 expression on ovarian cancer prognosis. The predictive value of RAD51 was then confirmed in a validation cohort immunohistochemically. Results Ovarian cancer expressed more RAD51 than normal ovary. RAD51 conferred ovarian cancer dependency and was associated with ovarian cancer. RAD51 had extensive target-disease associations with various diseases, including ovarian cancer. Genes that correlate with and interact with RAD51 were involved in DNA damage repair and drug responsiveness. High RAD51 expression indicated unfavorable survival outcomes and resistance to platinum, taxane, and PARP inhibitors in ovarian cancer. In the validation cohort (126 patients), high RAD51 expression indicated platinum resistance, and platinum-resistant patients expressed more RAD51. Patients with high RAD51 expression had shorter OS (HR = 2.968, P < 0.0001) and poorer PFS (HR = 2.838, P < 0.0001). RAD51 expression level was negatively correlated with patients’ survival length. Conclusions Ovarian cancer had pronounced RAD51 expression and RAD51 conferred ovarian cancer dependency. High RAD51 expression indicated poor survival and decreased drug sensitivity. RAD51 has predictive value in ovarian cancer and can be exploited as a predictive biomarker.

Varicocele is the most common cause of male infertility. Varicoceles are classified into two types: clinical and subclinical varicoceles. Some researchers reported right subclinical varicoceles are often accompanied with left clinical varicoceles. However, the treatment is controversial. Our aim was to compare the clinical outcome of unilateral varicocelectomy (UV) and bilateral varicocelectomy (BV) in infertile males with left clinical and right subclinical varicocele. A total of four randomised controlled trials (RCT) were enrolled in this study, including 637 cases with left clinical and right subclinical varicocele (318 cases in the BV group and 319 cases in the UV group). The fixed effects model combined difference in progressive sperm motility between the two groups was 6.42% (95% CI: 5.09, 7.75). The random effects model combined difference in normal sperm morphology between the two groups was 2.04% (95% CI: 0.60, 3.48). The odds ratio shown by the fixed effects model in spontaneous pregnancy rate was 1.73 (95% CI: 1.24, 2.43). No statistically significant difference between the two groups was found in sperm concentration and sperm motility. Thus, BV may be superior to UV for infertile male patients with left clinical and right subclinical varicocele. However, more properly conducted RCTs are still needed.

Varicocele is one of the common correctable causes of male infertility. Recent studies have demonstrated varicocelectomy in males with abnormal semen parameters was associated with better fertility outcome, but the effect of adjuvant drug therapy after varicocelectomy on fertility outcome in patients with varicocele-associated infertility remains undefined. Hence, the present meta-analysis was performed to assess the efficacy of adjuvant drug therapy after varicocelectomy. The protocol was registered with PROSPERO (No. CRD42018093749). Ten randomised controlled trails containing 533 patients with adjuvant drug therapy after varicocelectomy and 368 patients with no medical treatment after varicocelectomy were included. Our analysis revealed that the improvement in pregnancy rate after adjuvant drug therapy was insignificant. (OR = 1.70, 95%CI = 0.99-2.91), but resulted in significant improvements in sperm concentration (MD = 13.71, 95%CI = 5.80-21.63) and motility (MD = 4.77, 95%CI = 3.98-5.56) at 3 months, sperm DNA integrity (SMD = 3.13, 95%CI = 1.50-4.75) and serum FSH level (MD = -1.02, 95%CI = -1.79 to -0.24). Therefore, compared to no medical treatment, the adjuvant drug therapy, especially the use of antioxidants seems to be associated with better fertility outcome. However, more evidences with high-quality studies are necessary to conform its benefits.