The different molecular subtypes of breast cancer, mainly defined by the presence or absence of estrogen receptor and the cell-surface protein HER2, have important implications for the treatment and prognosis of breast cancer. One goal of the current study was to evaluate the frequency of mucin-1 expression among the different subtypes, to provide hints as to which subtypes are most likely to benefit from a therapy that targets mucin-1.
"We could demonstrate that high mucin-1 is more frequently observed in hormone-receptor positive and HER2 negative breast cancer," Dr Sinn said. "The lowest levels were detected in triple negative cases, i.e. tumors without evidence of estrogen-receptor and HER2. However, even in triple negative breast cancers, mucin-1 was high in 44% of cases."
This data indicates an important role for mucin-1 in breast cancer biology that differs among the various breast cancer subtypes, Dr Sinn said. "The results are of particular interest because currently there are tumor vaccines being tested in clinical trials that induce the patient's immune system to attack cells that carry mucin-1. These agents have already shown efficacy in lung cancer and could be also promising agents in the treatment of breast cancer."
When the researchers correlated the expression of the protein and mRNA with the patient's response to chemotherapy, they found that low levels of expression were predictive for pathological complete response -or eradication of the invasive tumor. This correlation held true for the overall population and in the subgroups of hormone receptor positive, HER2-negative and HR+/HER2- tumors.
"MUC1 is frequently expressed in a large cohort of breast cancers, especially in hormone-receptor positive tumors," the researchers observed. "Its evaluatio
|Contact: Vanessa Pavinato|
European Society for Medical Oncology