Arylesterase activity of paraoxonase 1 in patients with premalignant lesion of the cervics

Paraoxonase 1 (PON1) is an enzyme which is associated with high density lipoprotein (HDL) in serum. PON1 posseses paraoxonase, arylesterase and lactonase activity and hydrolyze different kinds of substrates. Also, PON1 has antioxidant/antiatherogenic activity, and it removes carcinogenic radicals of lipid peroxidation in human body. It was established earlier that patients with premalignant lesions of cervix have increased lipid peroxidation and changes in antioxidative system, which points importance of oxidative stress in early phase of carcinogenesis. We carried out this study in order to determine PON1 arylesterase activity in patients with premalignant lesions of the cervix. Study included 65 women [38 (32-46) years] with a biopsy confirmed diagnosis of cervical intraepitelial neoplasia (CIN), 18 patients had CIN1, 23 had CIN2 and 24 had CIN3. 109 healthy volunteers [37 (29-42) years] without any cervical or other disease were enrolled in the study as a control group. Concentration of HDL cholesterol and apolipoprotein AI (apoAI) were determined by commercially available reagents. PON1 arylesterase activity was assayed spectrophotometrically with phenylacetate as a substrate. We standardized PON1 arylesterase activity according to the concentration of HDL- cholesterol and apoAI. PON1 arylesterase activity was significantly reduced in group of patients with premalignant lesions of the cervix (53 ± 20 kU/L vs 75 ± 18 kU/L ; P<0, 001). PON1 arylesterase activity standardized on the concentration of HDL (36 ± 28 kU/mmol vs 41 ± 35 kU/mmol ; P=0, 004) and on the concentration of apoAI [28 (23 – 35) kU/g vs 42 (35 – 51) kU/g ; P<0, 001] were lower in the group of patients with premalignant lesion of cervix compared to the healthy volunteers. Diagnostic accuracy of PON1 arylesterase activity in discriminating between healthy subjects and patients with premalignant lesion of the cervix was good [AUC (95% CI): 0, 784 (0, 715 – 0, 842)]. Sensitivity and specificity with corresponding 95% CI was 65 (52 – 76) and 85 (77 – 91), respectively. Cut off value was <=56 kU/L. Our results suggest that PON1 arylesterase activity is reduced in patients with premalignant lesions of the cervix. Furthermore results of diagnostic accuracy in discriminating between healthy subjects and individuals with premalignant lesions of the cervix indicated that PON1 arylesterase activity could be considered as a potentially valuable biomarker for premalignant lesions of the cervix.