RESUMO
Different treatment outcomes and prognoses in patients with breast cancer can be observed with similar clinical predictors; this is because the biology of breast cancer is complex and heterogenous, involving multiple unknown contributing factors. We looked for plasma human mammaglobin (hMAM) mRNA by RT-PCR in 82 Korean patients with breast cancer to determine if there is an association between the presence of plasma hMAM mRNA in these patients and known prognostic factors. The prognostic usefulness of detection of plasma hMAM mRNA expression in these patients was also evaluated by determining overall survival and event-free survival. A significant difference was observed in the rate of positivity of plasma hMAM mRNA between the early stages of cancer (stages I-II, 23.4%) and advanced stages (stages III-IV, 82.9%). The expression rates of estrogen receptor, progesterone receptor, and HER-2/neu in the breast tissue of these patients, by immunohistochemistry, were 69.5, 75.6, and 20.7%, respectively. In the univariate analysis, plasma hMAM expression was significantly correlated with high histological and nuclear grades, nodal metastasis, and negative estrogen receptor and progesterone receptor status. Patients negative for plasma hMAM mRNA had significantly higher rates of event-free survival compared to the patients positive for plasma hMAM mRNA. However, no significant association with overall survival was observed for expression of plasma hMAM mRNA (P = 0.16). Qualitative detection of plasma hMAM mRNA appears to be associated with unfavorable prognostic factors and lower rates of event-free survival in patients with breast cancer.