Mucinous carcinomas are a rare entity accounting for up to 2% of all breast cancers, which have been shown to display a gene expression profile distinct from that of invasive ductal carcinomas of no special type (IDC-NSTs).
These include BRCA1 mutation-associated breast cancers, which are typically high grade invasive ductal carcinomas of no special type (IDC-NSTs) with pushing margins that do not express estrogen receptor (ER), progesterone receptor (PR) or the HER2 receptor tyrosine kinase ('triple negative').
We sought to determine whether at the genomic level, histological special types of breast cancer are distinct from grade- and estrogen receptor (ER)-matched invasive carcinomas of no special type (IC-NSTs), and to define genes whose expression correlates with gene copy number in histological special types of breast cancer.