RESUMO
BACKGROUND: The investigation of autoantibodies which may play a role in the processes of angiogenesis and tumorogenesis is important in the early diagnostis of cancer. OBJECTIVE: This study aimed to investigate the levels of autoantibodies to Glu-plasminogen (Pg) in plasma of patients with tumors. METHODS: Plasma samples from healthy volunteers were compared with samples from patients with prostate cancer using 2D electrophoresis and MALDI-TOF mass spectrometry. Plasma samples from 25 patients with prostate cancer, 15 patients with benign prostatic hyperplasia (BPH), 29 patients with breast cancer, and 43 healthy volunteers were tested using ELISA to anti-Pg IgG autoantibodies. Affinity chromatography on Pg-sepharoses was used to assess the quantity of anti-Pg IgG in control plasma and plasma of prostate cancer patients. ATTESTAT program was used for nonparametric analysis. RESULTS: Using 2D electrophoresis, marker spots below 50 kD were detected in prostate cancer samples. These spots were identified as fragments of Pg and IgG. Using affinity chromatography on Pg-sepharose, the quantity of IgG bound to Pg versus total IgG was determined to be 9% in control and 27% in prostate cancer samples. The frequency of occurence of elevated levels of anti-Pg IgG was 84% in prostate cancer samples, 69% in breast cancer samples, 40% in BPH samples, and 11% in healthy plasma. CONCLUSIONS: Autoantibodies to Pg may be involved in tumorogenesis and elevated levels of anti-Pg IgG antibodies may be a risk factor for tumor development.
