Fulvestrant – ready to start its journey in the breast cancer adjuvant endocrine world?

Protein expression profiling of primary mammary epithelial cells derived from MMTV-neu mice revealed that HER2/NEU-driven changes in protein expression are functionally clustered

MMTV-neu transgenic mice overexpressing NEU in their mammary glands develop tumor after 6 months of age. To find a novel protein biomarker using this mouse model, we identified and characterized the proteins that were differently expressed between primary mammary epithelial cells from 2 months old MMTV-neu heterozygote mice and wild type (WT) littermates using two-dimensional digest (ChemDigest/Trypsin)-LC-MS/MS. The differentially expressed proteins were selected and analyzed using DAVID Bioinformatics resource. The proteins involved in anti-apoptosis, purine metabolism, ribosome and proteasome functions were upregulated, whereas cell adhesion-related proteins were downregulated in PMECs from MMTV-neu mice when compared with WT PMECs. The results indicate that several functional units are coregulated by HER2/NEU. We hypothesize that these changes in the cellular proteome may be responsible for early onset of HER2/NEU-driven tumorigenesis.

Fulvestrant ('Faslodex'): current and future role in breast cancer management

Fulvestrant ('Faslodex') is a new type of estrogen receptor antagonist with no agonist effects, that reduces cellular levels of both estrogen and progesterone receptors. Results from two Phase III trials showed that fulvestrant is at least as effective as the third-generation selective aromatase inhibitor anastrozole in postmenopausal women with advanced breast cancer following progression on antiestrogen therapy, indicating the potential for second-line fulvestrant in this setting. In clinical practice, fulvestrant is well tolerated, with good rates of clinical benefit observed as first-line therapy and following progression on prior endocrine agents. Other endocrine agents have been shown to have good clinical activity when resistance to fulvestrant has developed, showing that fulvestrant lacks cross-resistance with other treatments. Ongoing trials are investigating the efficacy of fulvestrant after failure on aromatase inhibitors and evaluating its use in combination with therapies that target growth factor receptor signaling pathways.