title: Frequent epigenetic inactivation of RSK4 by promoter methylation in cancerous and non-cancerous tissues of breast cancer.
abstract: Breast cancer is one of the most common cancers and is the second leading cause of cancer-related death in women worldwide. Ribosomal s6 kinase4 (RSK4) is a potential tumor suppressor in multiple cancers, while its role in breast cancer is largely unknown. Our study here aimed to explore the relationship between RSK4 expression with the clinicopathologic characteristics and the promoter methylation status of RSK4. Real-time PCR and bisulfite sequencing PCR were, respectively, used to detect the expression difference of RSK4 mRNA and RSK4 methylation in the 49 breast cancer and paired non-cancerous samples. The associations of RSK4 expression and methylation status with the clinicopathologic characteristics were analyzed. In the 49 breast cancer patients' specimens, RSK4 mRNA expression was found to be significantly decreased in most of breast cancer tissues compared with paired non-cancerous tissues (p = 0.002), which was largely due to the promoter hypermethylation (p = 0.005). Frequency of RSK4 promoter methylation in breast cancers was significantly higher than paired non-cancerous tissues (p = 0.009); RSK4 methylation was not associated with all clinicopathological features. The silencing of RSK4 due to promoter hypermethylation is a frequent event in breast cancer. The majority of cancers have a higher level of methylation status when compared with non-cancerous tissues. RSK4 may be a valuable biomarker for the study of breast cancer carcinogenesis and progression.
authors: Department of Breast Surgery, The Affiliated Tumor Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China.
authors: Qiuyun
authors: Q
authors: Li
authors: Yi
authors: Y
authors: Jiang
authors: Wei
authors: W
authors: Wei
authors: Yinan
authors: Y
authors: Ji
authors: Hui
authors: H
authors: Gao
authors: Jianlun
authors: J
authors: Liu
mesh_terms: D001483:Base Sequence; D014408:Biomarkers, Tumor; D001940:Breast / Q000378:metabolism*; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism; D018899:CpG Islands; D019175:DNA Methylation; D018450:Disease Progression; D044127:Epigenesis, Genetic; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006801:Humans; D008875:Middle Aged; D008969:Molecular Sequence Data; D011379:Prognosis; D011401:Promoter Regions, Genetic; D038744:Ribosomal Protein S6 Kinases, 90-kDa / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D014408:Biomarkers, Tumor; C501305:RPS6KA6 protein, human; D038744:Ribosomal Protein S6 Kinases, 90-kDa