MicroRNA Expression Tied to Triple-Negative Breast Cancer in Latin America

A grouping of 17 microRNA genes and their level of expression, can be used to distinguish between different cases of triple-negative breast cancer (TNBC), according to the findings of a study published in Oncotarget. The results could also further explain the patterns of tumor development among certain ethnicities.

The study looked into the genomics of patients with cancer from Brazil. Fifty-four samples of non-treated primary breast tumors collected from the pathology tumor bank at the Hospital Nossa Senhora das Graças, in Paraná. Those samples were split between patients with TNBC and those with other tumor forms. 

“The panel of miRNAs identified demonstrated the impact of CNAs in miRNA expression levels and identified miRNA target genes potentially affected by both CNAs and miRNA deregulation,” the authors wrote. “These targets, involved in critical signaling pathways and biological functions associated specifically with the TNBC transcriptome of Latina patients, can provide biological insights into the observed differences in the TNBC clinical outcome among racial/ ethnic groups, taking into consideration their genetic ancestry.”

The DNA and RNA were isolated, purified, and quantified. Ancestral analysis was performed on single nucleotide polymorphisms (SNPs) using the SNP chip, Illumina Infinium QC Array. 

Genome-wide copy number profiling was made possible by array-CGH using the SurePrint G3 Human CGH Microarray made by Agilent. The Global miRNA expression profiling was then performed using the NanoString nCounter technology Human v2 miRNA Expression Assay. The 2 data sets were integrated, especially through the identification of copy number alterations (CNAs), according to the study results. 

The final tally produced a 17-microRNA panel which showed elevated expression in the patients with TNBC. What’s more, the majority of the target RNA molecules were significantly correlated with the aggressiveness of the tumor, including its advanced grade and stage. 

“The panel of miRNAs we identified indicate potential, critical cancer-related pathways and gene networks that could be targeted for the treatment of TNBC in Latinas, once our findings are validated by larger studies,” said Luciane Cavalli, the lead author, of Georgetown Lombardi, in a statement released Tuesday. 

The findings could eventually prove actionable for screening, and in the clinic added Cavalli.

“Targeting these genetic alterations, that represent the unique biology of their tumors, may lead to more efficient treatments, which could increase the longevity of Latina women who do not have many therapeutic options to fight this very aggressive disease,” she said.