Lower mRNA Expression and Higher Levels of in HER2-Positive Breast Cancer.

Fibroblast growth factor receptor 2 (FGFR2) has been associated with breast cancer. We performed in silico analyses to investigate the mRNA expression and splice variants associated with breast cancer subtypes. Online databases, including cBioPortal and TCGA SpliceSeq, were used to examine the association between the expression and splice variants with breast cancer subtypes. A higher mRNA was significantly associated with luminal, oestrogen receptor (ER)-positive breast cancers, and invasive lobular carcinomas, whereas a lower was associated with human epidermal growth factor receptor 2 (HER2)-positive breast cancer and invasive ductal carcinomas. The epithelial alternatively spliced isoform was significantly enriched in ER+ breast cancer, while the mesenchymal isoform was significantly prevalent in HER2+ cancer. Increased levels of and splice isoforms are associated with less aggressive breast cancer phenotypes, while decreased levels of and increased splice isoform are associated with more aggressive phenotypes.