RESUMO
In this study, we examined several molecular markers in prostate and breast cancer patients and in normal individuals. The markers tested were: variations in the quantity of plasma DNA, glutathione-S-transferase P1 gene (GSTP1), Ras association domain family 1A (RASSF1A), and ataxia telangiectasia mutated (ATM) methylation status in plasma, carcinoembryonic antigen (CEA) and prostate-specific membrane antigen (PSMA) mRNA in peripheral blood mononuclear cells (PBMC) and plasma samples from prostate cancer patients. DNA quantification in plasma was performed using real-time PCR (RT-PCR). We assessed the methylation status of GSTP1 in plasma DNA using methylation-specific PCR (MSP) assay, while the methylation status of RASSF1A and ATM genes was examined by the MethyLight technology. RT-PCR analysis was used for the detection of mRNA, PSMA, and CEA. In 58.3% of newly diagnosed prostate cancer patients and 26.7% of prostate cancer patients under therapy, plasma DNA levels were increased. Additionally, 48.5% of breast cancer patients showed plasma DNA levels above the cutoff limit. GSTP1 Promotor hypermethylation was detectable in 75% of plasma samples obtained from patients with newly diagnosed prostate cancer and in 36.8% of patients under therapy, whereas 26% and 14% of the breast cancer patients tested were positive for RASSF1A and ATM methylation, respectively. The combination of DNA load and promotor methylation status identified 88% of prostate cancer patients and 54% of breast cancer patients. This study shows that free-circulating DNA can be detected in cancer patients compared with disease-free individuals, and suggests a new, noninvasive approach for early detection of cancer.
Assuntos
Biomarcadores Tumorais , Neoplasias da Mama , DNA/sangue , Plasma/química , Neoplasias da Próstata , RNA/sangue , Antígenos de Superfície/sangue , Antígenos de Superfície/genética , Proteínas Mutadas de Ataxia Telangiectasia , Neoplasias da Mama/sangue , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/genética , Antígeno Carcinoembrionário/sangue , Antígeno Carcinoembrionário/genética , Proteínas de Ciclo Celular/sangue , Proteínas de Ciclo Celular/genética , Metilação de DNA , Proteínas de Ligação a DNA/sangue , Proteínas de Ligação a DNA/genética , Feminino , Marcadores Genéticos , Glutamato Carboxipeptidase II/sangue , Glutamato Carboxipeptidase II/genética , Glutationa S-Transferase pi/sangue , Glutationa S-Transferase pi/genética , Humanos , Masculino , Regiões Promotoras Genéticas , Neoplasias da Próstata/sangue , Neoplasias da Próstata/diagnóstico , Neoplasias da Próstata/genética , Proteínas Serina-Treonina Quinases/sangue , Proteínas Serina-Treonina Quinases/genética , Proteínas Supressoras de Tumor/sangue , Proteínas Supressoras de Tumor/genéticaRESUMO
Extracellular nucleic acids could serve as molecular markers in the early detection of cancer and in the prediction of disease outcome. In this study we examined six molecular markers, such as: variations in the quantity of DNA in plasma, glutathione-S-transferase P1 (GSTP1) gene methylation status in plasma, carcinoembryonic antigen (CEA) and prostate-specific membrane antigen (PSMA) mRNA in peripheral blood mononuclear cells (PBMC), and plasma samples from prostate cancer patients in different stages. The combination of DNA load and GSTP1 promoter methylation status identified 83% (10/12) of the prostate cancer patients before therapy. This study shows that free circulating DNA can be detected in patients with prostate cancer compared with disease-free individuals, and suggests a new, noninvasive approach for early detection of prostate cancer.
