A repertoire of biomarkers helps in detection and assessment of therapeutic response in epithelial ovarian cancer

In epithelial ovarian cancer (EOC), the cancer antigen 125 (CA-125) has been conventionally used to help in diagnosis and assessment of response to treatment. Cur- rently, YKL-40 (Tyrosine-Lysine-Leucine-40) and circu- lating cell-free DNA are being evaluated for possession of similar ability. In this study, we aimed to assess the ability of a repertoire of potential biomarkers in detecting and assessing therapeutic response, in advanced EOC. Blood levels of CA-125, YKL-40, total cell-free DNA (CFDNA), cell-free nuclear DNA (CFnDNA), and cell-free mitochon- drial DNA (CFmDNA) levels were measured in 100 untreated patients of advanced EOC from November 2009 to June 2011, and again on treatment completion from the 20 patients who appeared for follow-up analysis. Significantly, higher proportion of untreated patients had serum CA-125 (3 times upper limit of normal (ULN) (90.0 %; P \ 0.0001) and plasma YKL-40(ULN (77.0 %; P \ 0.0001), both of which significantly decreased, Posttherapy. posttherapy, CFDNA (P \ 0.0001), and CFnDNA (P \ 0.0001) levels significantly decreased as compared to pretreatment levels. Positive and significant correlations existed between pre- therapy CFDNA and CFnDNA (Spearman rho (q) = 1.000; P \ 0.0001), and also with CFmDNA (q = 0.301; P = 0.002), separately between CFnDNA and CFmDNA (q = 0.303; P = 0.002), as well as between plasma YKL-40 and patient age (q = 0.353; (P \ 0.0001). On treatment completion, CFDNA and CFnDNA levels showed positive and significant correlation (q = 1.000; P \ 0.0001). Therefore serum CA-125 and plasma YKL-40 aid detection and assessment of therapeutic response, in advanced EOC. CFDNA and CFnDNA help in estimating extent of thera- peutic response in advanced EOC.