Detection of human mammaglobin mRNA in serial peripheral blood samples from patients with non-metastatic breast cancer is not predictive of disease recurrence.

Introduction: Human mammaglobin (hMAM) mRNA is a sensitive and specific marker of breast cancer cells. We evaluated if hMAM mRNA detection in serial peripheral blood samples from non-metastatic breast cancer patients predicts for disease recurrence.

Methods: Patients scheduled for adjuvant or neoadjuvant chemotherapy were eligible. Serial blood samples were collected up to 5 years, the first before (neo)adjuvant chemotherapy. hMAM gene expression was analysed by RT-PCR. Specificity was evaluated in blood samples from healthy volunteers. A total of 321 patients were included.

Results: The incidence of pre-chemotherapy hMAM-positive samples was similar in patients who latter experienced cancer recurrence (22.4%) and those who remained disease-free (17.9%; P = 0.46). Similarly, the mean number of positive follow-up samples was similar in both groups (0.15 +/- 0.22 and 0.13 +/- 013; P = 0.29). Furthermore, there was no difference in disease-free (P = 0.63) or overall survival (P = 0.57) in patients with and without positive baseline samples or between patients whose follow-up samples were always hMAM negative and those with at least one positive sample. Multivariate survival analysis confirmed that hMAM mRNA detection before or after (neo)adjuvant chemotherapy was not predictive of recurrence.

Discussion: There is no evidence that hMAM mRNA detection at diagnosis or during follow-up predicts for breast cancer recurrence.