Introduction: Breast cancer (BC) is the most common cancer amongst Egyptian women and worldwide. MicroRNA-21 (miR-21), on chromosome 17q21.3, is one of the most up-regulated microRNAs in cancer that silences multiple target genes involved in cancer-signaling pathways. The aim of this study was to assess the correlation between numerical aberrations of chromosome 17 and the miR-21 expression profile in BC tissues in female Egyptian patients.
Methods: The study included 37 female patients with sporadic primary breast carcinoma, their age ranged from 31 to 65 years. Fresh breast tissue specimens were evaluated for miR-21 expression levels using reverse transcription-polymerase chain reaction technology and cytogenetic fluorescent in situ hybridization analysis for chromosome 17 aneusomy.
Results: miR-21 was up-regulated 12.9-fold in BC tissues compared with normal adjacent tissue. Over-expression was significantly associated with several clinico-pathologic characteristics; as higher tumor grade, more tumor size, advanced stage, and poor prognostic index. In addition, chromosome 17 monosomy and trisomy were observed in 21.6 and 5.4 % of BC patients, respectively. However, the large majority (73 %) of patients had heterogeneous cell populations. Chromosome 17 copy number heterogeneity in cell populations were significantly associated with advanced clinical stage and higher miR-21 expression profile in BC tissues.
Conclusion: Chromosome 17 aneusomy and miR-21 expression are positively correlated and can potentially serve as prognostic markers in BC.