Detection of mammaglobin mRNA as marker for circulating tumor-cells in breast cancer patients

Mammaglobin (hMAM) has been shown to be a marker for the detection of circulating tumor cells in the peripheral blood (pB) of breast cancer (BC) patients via a nested RT-PCR assay. 286 samples from BC patients were classified into four defined clinical subgroups: prior to and after surgery (pre, post), no evidence of disease (NED) and metastatic disease (MD). hMAM mRNA expression was detected in 2/46 pre (4 %), 2/24 post (8 %), 4/135 NED (3 %) and 35/81 MD (43 %) patients. 68 BC patients with NED and negative for hMAM mRNA in their pB were repeatedly tested for at least 6 months. Fifteen of these patients relapsed. Eight of them were hMAM-positive, 5 at time of relapse, one patient 13 months before and two patients 10 and 17 months after relapse was diagnosed. 7/15 BC patients relapsed within 24 months, 5 of them were hMAM-positive versus 3 of 8 patients with later relapses. On the basis of these preliminary results we conclude that tumor cells can be detected via hMAM nested RT-PCR in the pB of BC patients and that hMAM could be a marker for early relapse.