Circulating HDL and Non-HDL Associated Apolipoproteins and Breast Cancer Severity

Plasma lipids are carried within lipoproteins with various apolipoprotein content. This study evaluates the interest of measuring the apolipoproteins of circulating lipoproteins in breast cancer. Patients with early-stage breast cancer (n = 140) were included. Tumors differed by the expression of estrogen and progesterone receptor (HR- and HR+ for negative and positive expression) and the proliferation marker Ki-67 (≤20% or ≥30%). Apolipoprotein concentrations were determined in plasma, HDL and non-HDL fractions, and results are given in mg/dL, median (25th-75th). Patients did not differ in their plasma and lipoprotein lipid concentrations. HDL apoC-I and non-HDL apoC-II were reduced (1.34 (1.02-1.80) vs. 1.61 (1.32-2.04), p = 0.04; 0.31 (0.18-0.65) vs. 0.63 (0.39-1.02), p = 0.01; respectively), in RH-/high Ki-67 patients in comparison to RH-/low Ki-67 patients, while plasma apoD and HDL apoD were higher (3.24 (2.99-4.16) vs. 3.07 (2.39-3.51), p = 0.04; 2.74 (2.36-3.35) vs. 2.45 (2.01-2.99), p = 0.04; respectively). When RH+/high Ki-67 patients were compared with RH+/low Ki-67 patients, HDL apoC-I and HDL apoC-III were higher (1.56 (1.20-1.95) vs. 1.35 (1.10-1.62), p = 0.02; 2.80 (2.42-3.64) vs. 2.38 (1.69-2.96), p = 0.02; respectively). The distribution of exchangeable apolipoproteins, such as apoC-I, apoC-II, apoC-III, apoD, between lipoproteins is linked to the severity of breast cancer.

Tamoxifen therapy in breast cancer: do apolipoprotein E genotype and menopausal state affect plasma lipid changes induced by the drug?

OBJECTIVE

This study examines the lipid profile change produced in response to tamoxifen (TAM) treatment, and its possible relationship with both apolipoprotein E genotype and menopausal state in patients with breast cancer.

METHODS

Blood samples were collected from 86 Spanish women with breast cancer before initiating TAM treatment and in the following 6, 12 and 18 months of treatment. Plasma lipid levels (total cholesterol, triglycerides, HDL-cholesterol and LDL-cholesterol) were determined using an automatic analyzer. Genotypes for apolipoprotein E (ApoE) were identified by PCR-RFLP using the HhaI enzyme.

RESULTS

In all patients, significant reductions in total cholesterol and LDL-cholesterol concentrations and a significant increase in triglyceride concentrations were observed after 6, 12, and 18 months of TAM treatment compared to baseline (p<0.01 for each time point). In the subset of APOE4-negative patients, triglyceride concentrations also significantly increased after 6, 12, and 18 months of treatment (p=0.019, p=0.045, p=0.001, respectively), while APOE4-positive patients showed no significant lipid changes at 12 and 18 months. However, after 18 months of TAM treatment the overall triglyceride concentrations had risen by 24.75% in APOE4-negative patients vs 29.9% in APOE4-positive patients. In postmenopausal women, significant reductions in total cholesterol, LDL-cholesterol and LDL/HDL ratios were observed at each time point (p<0.020 for each).

CONCLUSIONS

TAM treatment induced similar plasma triglyceride increases in patients with positive or negative APOE genotype. Compared to premenopausal patients, postmenopausal breast cancer patients showed a more beneficial lipid profile change in response to treatment.