title: Low levels of serum miR-99a is a predictor of poor prognosis in breast cancer.
abstract: MicroRNA (miRNA) deregulation has been previously linked to the initiation and development of breast cancer. Although miR-99a is aberrantly expressed in many types of cancers, including breast cancer, the serum miR-99a expression level in breast cancer and its clinical significance remains unknown. Blood samples were obtained from 72 patients with breast cancer and 40 healthy volunteers, and subjected to real-time polymerase chain reaction to evaluate the level of expression of serum miR-99a in the study participants. Furthermore, we investigated the association between serum miR-99a and the clinical outcome of breast cancer. Serum miR-99a expression was significantly downregulated in patients with breast cancer, compared to that in healthy controls (P < 0.01). Moreover, the serum miR-99a was correlated with various clinical parameters of breast cancer, including lymph node metastasis (P = 0.0194), distant metastasis (P = 0.0037), Ki67 intensity (P = 0.0164), TNM stage (P = 0.0096), and histological grade (P = 0.0051) of cancer. Additionally, breast cancer patients displaying lower miR-99a levels showed poorer overall survival rates (P = 0.0411). The serum miR-99a level was also found to be an independent risk factor for breast cancer (hazard ratio = 3.176, 95% confidence interval = 1.543-7.360, P = 0.023). Our data indicated that serum miR-99a expression was downregulated in breast cancer patients; moreover, this downregulation was associated with poor prognosis, suggesting that serum miR-99a could function as a tumor suppressor in breast cancer.
authors.affiliation: Tumor Research Department, Shaanxi Provincial Tumor Hospital, Xi'an, China lijunsxch@163.com.
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.affiliation: Breast Surgery Center, Shaanxi Provincial Tumor Hospital, Xi'an, China.
authors.forename: Z J
authors.initials: ZJ
authors.lastname: Song
authors.affiliation: Tumor Research Department, Shaanxi Provincial Tumor Hospital, Xi'an, China.
authors.forename: Y Y
authors.initials: YY
authors.lastname: Wang
authors.affiliation: Tumor Research Department, Shaanxi Provincial Tumor Hospital, Xi'an, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Yin
authors.affiliation: Tumor Research Department, Shaanxi Provincial Tumor Hospital, Xi'an, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Tumor Research Department, Shaanxi Provincial Tumor Hospital, Xi'an, China.
authors.forename: X
authors.initials: X
authors.lastname: Nan
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000235:genetics* / Q000401:mortality; D016022:Case-Control Studies; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D019394:Ki-67 Antigen / Q000097:blood / Q000235:genetics; D008207:Lymphatic Metastasis; D035683:MicroRNAs / Q000097:blood / Q000235:genetics*; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D011960:Receptors, Estrogen / Q000235:genetics / Q000378:metabolism; D011980:Receptors, Progesterone / Q000235:genetics / Q000378:metabolism; D012307:Risk Factors; D016019:Survival Analysis
chemical_list: D019394:Ki-67 Antigen; D035683:MicroRNAs; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C561679:MIRN99 microRNA, human; C508053:ERBB2 protein, human