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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2005-12-2
pubmed:abstractText
Tamoxifen has been the mainstay of hormonal therapy in both early and advanced breast cancer patients for approximately three decades. The availability of novel compounds such as aromatase inhibitors (AIs) and fulvestrant, with different mechanism of action, is changing the scenario of endocrine treatment of postmenopausal breast cancer patients. In this review article, we have summarized the current knowledge of the mechanisms of resistance to endocrine therapy, in order to derive information that might be useful for therapeutic intervention. We propose that resistance to endocrine therapy is a progressive, step-wise phenomenon induced by the selective pressure of hormonal agents, which leads breast cancer cells from an estrogen-dependent, responsive to endocrine manipulation phenotype to a non-responsive phenotype, and eventually to an estrogen-independent phenotype. In particular, evidence suggests for each 'action' introduced to block estrogen stimulation of breast cancer cells (i.e. treatment with anti-estrogen), there are one or more corresponding 'reactions' that tumor cells can use to escape our attempts to block their growth: estrogen hypersensitivity associated with increased transcriptional activity of estrogen receptor alpha (ERalpha) and/or increased non-genomic activity of ERalpha, estrogen supersensitivity, increased growth factor signaling, suppression of ERalpha expression and finally estrogen independence. Activation of growth factor signaling is involved in each step of this phenomenon, and might ultimately substitute estrogen in sustaining the growth and the survival of breast cancer cells. In this respect, results of pre-clinical and clinical studies with AIs, fulvestrant and signaling inhibitors sustain this hypothesis. More importantly, the knowledge of the mechanisms involved in the resistance of breast cancer cells to endocrine therapy offers potential for novel therapeutic strategies.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1351-0088
pubmed:author
pubmed:issnType
Print
pubmed:volume
12
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
721-47
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Mechanisms of endocrine resistance and novel therapeutic strategies in breast cancer.
pubmed:affiliation
Cell Biology and Preclinical Models, INT-Fondazione Pascale, Naples, Italy. nicnorm@yahoo.com
pubmed:publicationType
Journal Article, Review, Research Support, Non-U.S. Gov't