title: Correlation of miRNA expression profiling in surgical pathology materials, with Ki-67, HER2, ER and PR in breast cancer patients.
abstract: BACKGROUND
  New molecular markers related to prognosis and/or clinical outcome have been extensively studied in breast cancer. In particular, microRNA (miRNA) has attracted the interest of both basic and clinical investigators as one of the promising molecular markers of breast cancer patients. MiRNAs are a class of short noncoding RNAs that regulate mRNAs at posttranscriptional level and are deregulated in various human malignancies. Previous studies have reported that miRNAs were stably conserved in 10% formalin-fixed paraffin-embedded tissues without significant degradation, in contrast to more fragile RNA.
  
  
  METHODS
  Therefore, in this study, we examined 21 surgical breast cancer specimens using the Human Cancer microRNA PCR Array system (QIAGEN) to explore potential molecular targets of miRNAs.
  
  
  RESULTS
  Profiling of miRNA expression in archival materials demonstrated that a group of deregulated miRNAs was associated with clinicopathological parameters of the patients, such as Ki-67, HER2, ER and PR. For instance, an abundant expression of multiple let-7 miRNA family, also known as tumor suppressor, was detected in low Ki-67 and HER2 groups. Elevated expression of 8 miRNAs overlapped between Ki-67+/HER2+/ER+/PR+ groups, including several known oncogenic miRNAs such as miR-148b, miR-15b, miR-200c, miR-150, miR-191, miR-96, miR-25 and miR-21.
  
  
  CONCLUSIONS
  These results all indicated that when analyzing miRNAs in surgical pathology specimens of breast cancer as a biomarker, they should be examined as a cluster through miRNA profiling, rather than relying on the analysis of a single miRNA.
authors.affiliation: 1 Department of Pathology, Tohoku University Graduate School of Medicine, Sendai, Miyagi - Japan.
authors.forename: Minako
authors.initials: M
authors.lastname: Sakurai
authors.forename: Mariko
authors.initials: M
authors.lastname: Masuda
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Miki
authors.forename: Hisashi
authors.initials: H
authors.lastname: Hirakawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Suzuki
authors.forename: Hironobu
authors.initials: H
authors.lastname: Sasano
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D005260:Female; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D008875:Middle Aged; D010340:Pathology, Surgical / Q000295:instrumentation* / Q000379:methods*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics*; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*
chemical_list: D035683:MicroRNAs; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone