Increased apolipoprotein E gene expression and protein concentration in lung cancer tissue do not contribute to the clinical assessment of non-small cell lung cancer patients.

Background: We tested the hypothesis that apolipoprotein E (apo E) gene expression and protein concentration are increased in resectable non-small cell lung cancer tissue and that these apo E tissue estimations may be beneficially used in clinical assessment of non-small cell lung cancer patients.

Methods: Paired samples of lung cancer and adjacent, apparently healthy, non-cancer lung tissue were collected from 42 patients with resectable non-small cell lung cancer. Apo E gene expression in tissue was measured by quantitative PCR. Apo E protein in tissue and serum was quantified by a nephelometric method. Patients were followed for 3 years.

Results: Apo E gene expression and protein concentration were 1.6 and 4.1-fold higher in the cancer tissue than in the adjacent non-cancer tissue (p<0.0001 in both cases). Increase of apo E protein concentration in the cancer tissue (relative to the non-cancer tissue) correlated with the decrease of apo E protein concentration in the serum (p=0.021). However, none of these apo E estimations related to stage of cancer or histological type of tumor and do not predict patient survival.

Conclusions: Our preliminary study shows that despite the distinct increase of apo E gene expression and protein concentration in the cancer tissue and the concurrent decrease of apo E protein concentration in the serum, the measured apo E values have limited usefulness in clinical assessment of patients with resectable non-small cell lung cancer.