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Updated: Nov 20, 2025
Systems Biology of Metabolic Regulation by Estrogen Receptor Signaling in Breast Cancer
Published on: March 17, 2016
Coexpression of Smac/DIABLO and Estrogen Receptor in breast cancer
Magali Espinosa1, Floria Lizárraga2, Karla Vázquez-Santillán2
1Instituto Nacional de Medicina Genómica, Department of Basic Research, Functional Cancer Genomics Laboratory, Mexico City, Mexico.
Background:
Smac/DIABLO is a proapoptotic protein deregulated in breast cancer, with a controversial role as a tumor marker, possibly due to a lack of correlative mRNA and protein analyses.
Objective:
To investigate the association of Smac/DIABLO gene and protein levels with clinical variables in breast cancer patients.
Methods:
Smac/DIABLO mRNA expression was analyzed by qPCR in 57 frozen tissues, whereas protein levels were assessed by immunohistochemistry in 82 paraffin-embedded tissues. Survivin mRNA levels were also measured. In vitro assays were performed to investigate possible regulators of Smac/DIABLO.
Results:
Higher levels of Smac/DIABLO mRNA and protein were found in estrogen receptor (ER)-positive samples (p= 0.0054 and p= 0.0043, respectively) in comparison to ER-negative tumors. A negligible positive association was found between Smac/DIABLO and survivin expression. In vitro assays showed that Smac/DIABLO is not regulated by ER and, conversely, it does not participate in ER expression modulation.
Conclusions:
mRNA and protein levels of Smac/DIABLO were increased in ER-positive breast tumors in comparison with ER-negative samples, although the mechanism of this regulation is still unknown. Public databases showed a possible clinical relevance for this association.
