Human
paraoxonase 1 (PON1) has been shown to decrease the level of systemic oxidative stress, which is thought to contribute to
cancer development. The aim of this study was to examine the interrelationships between PON1 status and some clinical characteristics in patients with
pancreatic cancer (PC). A group of 73 consecutive patients with PC (stage II-IV) and 73 control subjects were examined. Laboratory studies included five polymorphisms of the PON1 gene (L55M, Q192R, -108C/T, -126C/T, and -162A/G), PON1
arylesterase (PON1-A) and lactonase (PON1-L) activities, as well as some markers of
protein metabolism,
insulin resistance, and oxidative stress. In comparison with the control group, no difference in the distribution of the PON1 polymorphisms was found in
cancer patients, both
arylesterase and lactonase activities being significantly lower (-33, -47 %, respectively, both P < 0.001). There was neither statistically significant association of PON1 polymorphisms with tumour stages nor with
diabetes mellitus connected with PC. The genotype distribution of L55M and ‑108C/T differed only in a subgroup of patients presenting clinically relevant
malnutrition (χ² = 6.50, 6.25, respectively, both P < 0.05). In the PC group, PON1-A and PON1-L activities correlated with Nutritional Risk Index (r = 0.351, 0.409, respectively, both P < 0.01), PON1-L with mid-arm muscle circumference (r = 0.328, P < 0.05), and PON1-A and PON1-L with
serum albumin (r = 0.352, 0.391 respectively, both < 0.01). Our results suggest that PON1 plays an important role in PC, especially in
cancer-associated
malnutrition.