title: Identification and pathway analysis of microRNAs with no previous involvement in breast cancer.
abstract: microRNA expression signatures can differentiate normal and breast cancer tissues and can define specific clinico-pathological phenotypes in breast tumors. In order to further evaluate the microRNA expression profile in breast cancer, we analyzed the expression of 667 microRNAs in 29 tumors and 21 adjacent normal tissues using TaqMan Low-density arrays. 130 miRNAs showed significant differential expression (adjusted P value = 0.05, Fold Change = 2) in breast tumors compared to the normal adjacent tissue. Importantly, the role of 43 of these microRNAs has not been previously reported in breast cancer, including several evolutionary conserved microRNA*, showing similar expression rates to that of their corresponding leading strand. The expression of 14 microRNAs was replicated in an independent set of 55 tumors. Bioinformatic analysis of mRNA targets of the altered miRNAs, identified oncogenes like ERBB2, YY1, several MAP kinases, and known tumor-suppressors like FOXA1 and SMAD4. Pathway analysis identified that some biological process which are important in breast carcinogenesis are affected by the altered microRNA expression, including signaling through MAP kinases and TP53 pathways, as well as biological processes like cell death and communication, focal adhesion and ERBB2-ERBB3 signaling. Our data identified the altered expression of several microRNAs whose aberrant expression might have an important impact on cancer-related cellular pathways and whose role in breast cancer has not been previously described.
authors.affiliation: Laboratorio de Genómica del Cáncer, Instituto Nacional de Medicina Genómica. Mexico City, Mexico.
authors.forename: Sandra
authors.initials: S
authors.lastname: Romero-Cordoba
authors.forename: Sergio
authors.initials: S
authors.lastname: Rodriguez-Cuevas
authors.forename: Rosa
authors.initials: R
authors.lastname: Rebollar-Vega
authors.forename: Valeria
authors.initials: V
authors.lastname: Quintanar-Jurado
authors.forename: Antonio
authors.initials: A
authors.lastname: Maffuz-Aziz
authors.forename: Gerardo
authors.initials: G
authors.lastname: Jimenez-Sanchez
authors.forename: Veronica
authors.initials: V
authors.lastname: Bautista-Piña
authors.forename: Rocio
authors.initials: R
authors.lastname: Arellano-Llamas
authors.forename: Alfredo
authors.initials: A
authors.lastname: Hidalgo-Miranda
mesh_terms: D000328:Adult; D000368:Aged; D001940:Breast / Q000378:metabolism; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism; D019295:Computational Biology; D017124:Conserved Sequence; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics; D005260:Female; D020869:Gene Expression Profiling; D016147:Genes, Tumor Suppressor; D006801:Humans; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D009857:Oncogenes; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics* / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism
chemical_list: D035683:MicroRNAs; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D048049:Extracellular Signal-Regulated MAP Kinases