ATP8A2 is a differentially expressed gene in brain metastatic human breast cancer.
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 ATPase phospholipid transporting 8A2, encoded by ATP8A2, was among the genes whose expression was most different in the brain metastases of patients with metastatic breast cancer as compared to primary tumors of the breast. ATP8A2 mRNA was present at increased quantities in brain metastatic tissues as compared to primary tumors of the breast. Importantly, expression of ATP8A2 in primary tumors was significantly correlated with patient recurrence-free survival. Modulation of ATP8A2 expression may be relevant to the biology by which tumor cells metastasize from the breast to the brain in humans with metastatic breast cancer.