Tumor DNA hypomethylation of LINE‑1 is associated with low tumor grade of breast cancer in Tunisian patients

• Published in: Oncology letters Vol. 20; no. 2; pp. 1999 - 2006
• Main Authors: Zeggar, Hayet Radia, How‑Kit, Alexandre, Daunay, Antoine, Bettaieb, Ilhem, Sahbatou, Mourad, Rahal, Khaled, Adouni, Olfa, Gammoudi, Amor, Douik, Hayet, Deleuze, Jean‑François, Kharrat, Maher
• Format: Journal Article
• Language: English
• Published: Greece Spandidos Publications 01.08.2020; Spandidos Publications UK Ltd; D.A. Spandidos
• Subjects: Analysis; Biochemistry, Molecular Biology; Breast cancer; Cancer genetics; Cancer patients; Correlation analysis; Deoxyribonucleic acid; Development and progression; DNA; DNA methylation; Epigenetics; Genetics; Genomes; Genomics; Life Sciences; Medical prognosis; Methylation; Software; Statistical analysis; Studies; Transcription (Genetics); Tunisia; DNA methylation; breast cancer; pyrosequencing; long interspersed repetitive DNA retrotransposon; alu repeats; hypomethylation
• ISSN: 1792-1074; 1792-1082
• DOI: 10.3892/ol.2020.11745

DNA hypomethylation of long interspersed repetitive DNA retrotransposon (LINE-1) and Alu repeats elements of short interspersed elements family (SINEs) is an early event in carcinogenesis that causes transcriptional activation and leads to chromosomal instability. In the current study, DNA methylation levels of LINE-1 and Alu repeats were analyzed in tumoral tissues of invasive breast cancer in a Tunisian cohort and its association with the clinicopathological features of patients was defined. DNA methylation of LINE-1 and Alu repeats were analyzed using pyrosequencing in 61 invasive breast cancers. Median values observed for DNA methylation of LINE-1 and Alu repeats were considered as the cut-off (59.81 and 18.49%, respectively). The results of the current study demonstrated a positive correlation between DNA methylation levels of LINE-1 and Alu repeats (rho=0.284; P<0.03). DNA hypomethylation of LINE-1 was also indicated to be associated with low grade (P=0.023). To the best of our knowledge, the current study is the first study regarding DNA methylation of LINE-1 and Alu repeats element in breast cancer of the Tunisian population. The results of the current study suggest that, since hypomethylation of LINE-1 is associated with low grade, it could be used as a biomarker for prognosis for patients with breast cancer.