Determination of free DNA level in plasma of patients with ovarian cancer

Objective To determine the plasma DNA level of patients with ovarian cancer and evaluate its potential clinical value.Methods Blood samples were collected from 30 ovarian cancer patients before and after surgery,and from 20 patients with ovarian benign tumor and 20 healthy women.The plasma DNA was extracted by commercial kit and detected by fluorescntmeter.Results The mean plasma DNA level in the cancer patients(25.33 μg·L-1±17.69 μg·L-1) was significantly higher than those in the benign tumor patients(10.28 μg·L-1±4.80 μg·L-1) and normal control(7.60 μg·L-1±3.87 μg·L-1)(P0.001).There was no significant difference between the benign and normal groups.The plasma DNA level of the patients in stage Ⅰ-Ⅱ(15.83 μg·L-1±5.30 μg·L-1) was significantly higher than that in the normal control(P0.01) and was significantly lower than that in stage Ⅲ-Ⅳ(30.83 μg·L-1±20.04 μg·L-1) (p=0.005).The plasma DNA level of patients with metastasis(35.43 μg·L-1±21.08 μg·L-1) was significantly higher than that of patients with no metastasis(16.49 μg·L-1±6.44 μg·L-1)(P=0.006).The DNA level in the cancer patients one month after surgery(10.30±2.45 μg·L-1) was much lower than before surgery(P0.001),near that in the normal control.The overall survival of the patients with high plasma DNA level was much shorter than that of the patients with low DNA level(P=0.027).When the cut-off for diagnosis of ovarian cancer was 15.70 μg·L-1,the sensitivity and specificity were 63.30% and 90.00%,respectively.Conclusion The plasma DNA level may have a potential use in early diagnosis and serve as a predict marker for metastasis potential and prognosis of ovarian cancer.