Further, we used the IBC World Consortium data set, which contains mRNA expression data on both inflammatory breast cancer and non-inflammatory breast cancer from 3 institutions20 (IBC, n = 137; non-IBC, n = 252), together with Affymetrix gene chips, normalized with MAS5 algorithm, to analyze ERK2 (212271_at) mRNA gene expression stratified by estrogen receptor, progesterone receptor, and HER2 status. Here, PGR is linked to breast cancer.