Differential expression of fatty acid binding protein 4 in cancers of the breast.

Breast cancer affects women at relatively high frequency (1). We mined published microarray datasets (2, 3) to determine in an unbiased fashion and at the systems level genes most differentially expressed in the primary tumors of patients with breast cancer. We report here significant differential expression of the gene encoding fatty acid binding protein 4, FABP4, when comparing primary tumors of the breast to the tissue of origin, the normal breast. FABP4 mRNA was present at significantly lower quantities in tumors of the breast as compared to normal breast tissue. Analysis of human survival data revealed that expression of FABP4 in primary tumors of the breast was correlated with recurrence-free survival in patients with HER2+ cancers, demonstrating a relationship between primary tumor expression of a differentially expressed gene and patient survival outcomes influenced by molecular subtype. FABP4 may be of relevance to initiation, maintenance or progression of cancers of the female breast.