PTPRH 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 the protein tyrosine phosphatase receptor type H , encoded by PTPRH, 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 breast4, as well as in primary tumors of the breast when compared to normal breast tissue5. PTPRH mRNA was present at decreased quantities in brain metastatic tissues as compared to primary tumors of the breast. Importantly, expression of PTPRH in primary tumors was significantly correlated with patient recurrence-free survival. Modulation of PTPRH expression may be relevant to the biology by which tumor cells metastasize from the breast to the brain in humans with metastatic breast cancer.