Elevated MLXIP expression distinguishes basal-like human breast cancer.

Patients diagnosed with basal-like breast cancer face a more aggressive disease course and more dismal prognosis than patients diagnosed with luminal A and luminal B breast cancer molecular subtypes (1-4). We mined published microarray data (5, 6) to understand in an unbiased fashion the most distinguishing transcriptional features of tumors from patients with basal or basal-like subtype breast cancer. We observed transcriptome-wide differential expression of MLX-interacting protein, MLXIP, when comparing tumors of patients with basal-like breast cancer with that of other PAM50 molecular subtypes. MLXIP mRNA was present at significantly higher quantities in the tumors of patients with basal-like breast cancer. Analysis of patient survival data revealed that MLXIP primary tumor expression was correlated with distant metastasis-free survival in HER2+ subtype breast cancer. Elevated MLXIP expression appears to distinguish basal-like human breast cancer from the other molecular subtypes.