Highly sensitive detection of the MGB1 transcript (mammaglobin) in the peripheral blood of breast cancer patients

We describe a new one‐step RT‐PCR assay for the detection of the mammaglobin ( MGB1 ) gene transcript in the peripheral blood of breast cancer patients. With this approach, the MGB1 transcript could be detected in the peripheral blood of 22 of 54 (41%) breast cancer patients prior to any therapy. This method, using specific primers for cDNA synthesis, proved to be more sensitive (10 −6 to 10 −11 , usually 10 −7 ) than previously reported methodologies. This increased sensitivity was achieved without compromising specificity, as the MGB1 transcript was not detected in 38 blood samples of healthy donors and in only 1 of 18 blood samples of patients presenting with hematologic malignancies. A positive correlation was seen between MGB1 positivity and breast cancer stage: 0/3 (0%) in stage 0, 3/13 (23%) in stage I, 6/17 (35%) in stage II, 5/10 (50%) in stage III, 8/11 (73%) in stage IV ( p = 0.003). The prognostic and therapeutic implications of MGB1 positivity by one‐step RT‐PCR in the peripheral blood of breast cancer patients, especially in clinically localized disease (stages I and II), should be evaluated after long‐term clinical follow‐up of these patients. © 2003 Wiley‐Liss, Inc.