MPP6 is differentially expressed in human metastatic breast cancer, in the brain and in the lymph nodes.
Metastasis to the brain is a clinical problem in patients with breast cancer (1-3). We mined published microarray data (4, 5) to compare primary and metastatic tumor transcriptomes for the discovery of genes associated with brain metastasis in humans with metastatic breast cancer. We found that membrane protein, palmitoylated 6 (MAGUK p55 subfamily member 6), encoded by MPP6, was among the genes whose expression was most quantitatively different in the brain metastases of patients with metastatic breast cancer. MPP6 mRNA was present at decreased quantities in brain metastatic tissues as compared to primary tumors of the breast. Importantly, expression of MPP6 in primary tumors was correlated with patient overall survival in patients with breast cancer. Modulation of MPP6 expression may be relevant to the biology by which tumor cells metastasize from the breast to the brain.