Identification of microRNA expression in sentinel lymph nodes from patients with breast cancer via RNA sequencing for diagnostic accuracy

Abstract Background Sentinel lymph node (SLN) property assessment (with or without metastasis) is important when deciding the surgery for breast cancer; however, the current diagnosis of SLN metastasis remains to be studied. microRNAs (miRNAs) have been confirmed previously as a molecular marker for the diagnosis, development and prognosis of tumors. However, the detailed role of miRNAs in the diagnosis of SLN metastasis has not been reported. Methods The present study aimed to explore the potential use of miRNAs in the diagnosis of SLN using RNA sequencing (RNA‐seq) and a quantitative real‐time polymerase chain reaction (qRT‐PCR) to compare the expression profiles of miRNAs in patients with breast cancer with or without SLN metastasis. Results The RNA‐seq results revealed that 1993 miRNAs were differentially expressed in patients with breast cancer with SLN metastasis. Among these miRNAs, 1960 were up‐regulated and 33 were down‐regulated. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses revealed that these differentially expressed miRNAs were associated with tumor growth and metastasis and were also predicted to regulate a series of tumorigenesis and metastasis genes. In particular, the most differentially expressed miRNAs were validated by qRT‐PCR, such that miR‐200a‐3p and miR‐96‐5p were up‐regulated and miR‐1‐3p and miR‐486‐3p were down‐regulated in patients with breast cancer with SLN metastasis. Conclusions The findings of the present study suggest that there is an association of miRNAs with SLN metastasis and also that miRNAs function as biomarkers with respect to the choice of therapy and disease prognosis.