JAK1 and breast cancer: Importantly, we observed a positive correlation between the expression levels of MAF and those of FGF18, PTHLH, JAG1, TMEM2, TGFA, JAK1 and SHH in ER+ BCa-patient gene expression datasets, including the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) and The Cancer Genome Atlas (TCGA) BCa cohorts13,38,39 (Fig. 3f).