Gremlin 1, DAN family BMP antagonist (GREM1) is differentially expressed in metastatic breast cancer, both in metastases to the brain and to 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 to discover genes associated with brain metastasis in patients with metastatic breast cancer. We found that Gremlin 1, DAN family BMP antagonist, encoded by GREM1, was among the genes whose expression was most different in the metastatic tumor tissues of patients with metastatic breast cancer, both in metastases to brain and to the lymph nodes when compared to primary tumors of the breast or normal breast tissue, respectively. We observed significant down-regulation of GREM1 in metastasis to the brain. Molecular functions and down-regulation of Gremlin 1, DAN family BMP antagonist may be important for metastasis of primary tumor-derived cancer cells to the lymph nodes and to the brain in humans with metastatic breast cancer and suggests some level of common origin for metastases that reside in the lymph nodes and colonize the brain.