The aim of the present study was to investigate the association between cell-free DNA (cf-DNA) levels and clinicopathological characteristics of patients with ovarian cancer using a branched DNA (bDNA) technique, and to determine the value of quantitative cf-DNA detection in assisting with the diagnosis of ovarian cancer. Serum specimens were collected from 36 patients with ovarian cancer on days 1, 3 and 7 following surgery, and additional serum samples were also collected from 22 benign ovarian tumor cases, and 19 healthy, non-cancerous ovaries. bDNA techniques were used to detect serum cf-DNA concentrations. All data were analyzed using SPSS version 18.0. The cf-DNA levels were significantly increased in the ovarian cancer group compared with those of the benign ovarian tumor group and healthy ovarian group (P<0.01). Furthermore, cf-DNA levels were significantly increased in stage III and IV ovarian cancer compared with those of stages I and II (P<0.01). In addition, cf-DNA levels were significantly increased on the first day post-surgery (P<0.01), and subsequently demonstrated a gradual decrease. In the ovarian cancer group, the area under the receiver operating characteristic curve of cf-DNA and the sensitivity were 0.917 and 88.9%, respectively, which was higher than those of cancer antigen 125 (0.724, 75%) and human epididymis protein 4 (0.743, 80.6%). There was a correlation between the levels of serum cf-DNA and the occurrence and development of ovarian cancer in the patients evaluated. bDNA techniques possessed higher sensitivity and specificity than other methods for the detection of serum cf-DNA in patients exhibiting ovarian cancer, and bDNA techniques are more useful for detecting cf-DNA than other factors. Thus, the present study demonstrated the potential value for the use of bDNA as an adjuvant diagnostic method for ovarian cancer.

The BRCA2 N372H is the only common polymorphism that leads to the amino acid change based on the reports up to date. Previous studies explored the relationship between the single nucleotide polymorphism and ovarian cancer risk, but the results were inconsistent or inconclusive.To investigate the association between N372H in BRCA2 gene and ovarian cancer susceptibility, a systematic literature search was performed for related publications in the databases of PubMed, Gene, and Google Scholar.Total 2344 cases and 9672 controls in eligible studies were included in this meta-analysis. χ2 -based Q test and an I2 index were used to identify the heterogeneous records. Potential publication biases were assessed by Begg and Egger tests.In the overall analysis, the results showed a significant association between BRCA2 codon 372 polymorphism and increased risk of ovarian cancer (HH versus NN: odds ratio (OR) = 1.22, 95% confidence interval (CI) 1.01–1.48, P = 0.037). In the Australia subgroup analysis, significant association was also detected (HH versus NN: OR = 1.40, 95% CI 1.04–1.87, P = 0.026). The subgroup analysis for serous cancer subgroup showed that the significant association could be detected under recessive model (OR = 1.38, 95% CI, 1.01–1.89, P = 0.04) and under homozygote comparison (OR = 1.46, 95% CI, 1.06–2.01, P = 0.022).Our meta-analysis suggests that the N372H polymorphism is associated with susceptibility of ovarian cancer. The allele H might increase the risk of ovarian cancer, especially, for ovarian cancers of the serous subtype.