Prognostic Role of mRNA Expression in Breast Cancer.

PURPOSE

We investigated the prognostic role of mRNA expression in breast cancer using The Cancer Genome Atlas (TCGA) and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) databases.

METHODS

Clinical and biological data of 1,093 breast cancers from TCGA database and 1,904 breast cancers from METABRIC database were analyzed. Overall survival (OS) and breast cancer-specific survival (BCSS) were determined.

RESULTS

The group with high mRNA expression showed worse survival than the group with low mRNA expression regarding both OS ( = 0.012 in TCGA, < 0.001 in METABRIC) and BCSS ( = 0.001 in METABRIC). According to multivariate analysis, the level of mRNA expression was an independent prognostic factor in both TCGA (hazard ratio [HR], 1.570; 95% confidence interval [CI], 1.026-2.403; = 0.038) and METABRIC (HR, 1.254; 95% CI, 1.087-1.446; = 0.002) databases. The prognostic impact of mRNA expression was effective only for luminal A subtype ( < 0.001 in METABRIC). Positive correlation was observed between mRNA expression and copy number alteration (CNA) ( = 0.577, < 0.001 in TCGA; ρ = 0.343, < 0.001 in METABRIC). Methylation showed negative correlations with both mRNA expression and CNA ( = -0.272, < 0.001 in TCGA). The expression of mRNA had little association with the mutation status in breast cancers, having a mutation frequency of approximately 0.6%.

CONCLUSION

mRNA expression was significantly associated with breast cancer prognosis. It was found to be an independent prognostic factor for breast cancer. Prognostic role of mRNA expression was effective only in luminal A subtype. Further studies are needed to validate the prognostic role of mRNA expression in breast cancer, thus paving a way for clinical application of in practice.