Reduced plasma lipoprotein lipase activity in patients with malignancy-associated weight loss

Post-heparin in plasma lipoprotein lipase activity was measured in 28 cancer patients with varying degrees of weight loss, and in 16 normal volunteers. Total lipoprotein lipase activity was decreased by 35.4% (P<0.001) in the cancer group. The component lipase activities, hepatic (H(LPL)), and peripheral (P(LPL)), were decreased by 40% (P<0.001) and 38% (P<0.005) respectively. In addition, the level of total peripheral lipoprotein lipase correlated well with the percent body weight lost by these patients (r=0.6, P<0.01). Regardless of extent of disease, patients with lung cancer showed the lowest enzyme activity (mean 191 mU/ml ± 30 SEM, P<0.001) and the greatest percent of weight loss (mean 16%), while patients with breast cancer had nearly normal lipase activity (mean 315 mU/ml ± 50 SEM, normal 340 mU/ml ± 22 SEM, P<0.10) and minimal weight loss (mean 8.4%). Fasting serum triglycerides were significantly elevated in the patient group (mean 120 mg/dl ± 9.7 SEM) as compared to normal (mean 71 mg/dl ± 7 SEM), P<0.001). The mean fasting insulin level was elevated in the patient group (13 mU/ml ± 3.0 SEM), although in the majority of the patients it was found within the normal range (4-24 mU/ml). We conclude that the significant decrease in the total LPL activity may be responsible in part for the characteristic hypertriglyceridemia present in cancer patients.