Meaning of the DR-70(TM) Immunoassay for Patients with the Malignant Tumor

ABSTRACT

BACKGROUND: The DR-70(TM) immunoassay is a newly developed cancer diagnostic test which quantifies the serum fibrin degradation products (FDP), produced during fibrinolysis, by antibody reaction. The purpose of this study was to evaluate the potential of DR-70(TM) immunoassay in screening malignant tumor. METHODS: Sample subjects were 4,169 adults, both male and female, who visited the health promotion center of a general hospital from March 2004 to April 2005 and underwent the DR-70(TM) immunoassay test and other tests for cancer diagnosis. The patient group was defined as 42 adults out of the sample subjects who were newly diagnosed with cancer during the same time period when the DR-70(TM) immunoassay test was performed. Final confirmation of a malignant tumor was made by pathological analysis. RESULTS: The mean DR-70(TM) level was 0.83+/-0.65 microgram/ml (range 0.00 (0.0001)~7.42 microgram/ml) in the control group (n=4,127) as opposed to 2.70+/-2.33 microgram/ml (range 0.12 ~ 9.30 microgram/ml) in the cancer group (n=42), and statistical significance was established (p<0.0001, Student t-test). When categorized by the type of malignant tumor, all cancer patients with the exception of the subgroups of colon and rectal cancer showed significantly higher mean DR-70(TM) levels compared with the control group (p<0.0001, Kruscal-Wallis test). The receiver operating characteristic (ROC) curve analysis revealed < or = 1.091 microgram/ml as the best cut-off value. Using this cut-off value, the DR-70(TM) immunoassay produced a sensitivity of 71.4%, a specificity of 70.1%, a positive predictability of 69.4%, and a negative predictability of 69.2% (1). CONCLUSION: A significant increase in the mean DR-70(TM) value was observed in the cancer group (thyroidal, gastric, breast, hepatic and ovarian) compared with the control group. In particular, the specificity and sensitivity of the DR-70(TM) immunoassay was relatively high in the subgroups of breast, gastric, and thyroidal cancer patients. There is need for further studies on a large number of malignant tumor patients to see how the DR-70(TM) level might be changed according to the differentiation grade and postoperative prognosis of the malignant tumor.