We evaluated <i>ESR1</i> methylation in CTCs and paired plasma ctDNA as a potential biomarker for response to everolimus/exemestane treatment.<b>Experimental Design:</b> A highly sensitive and specific real-time MSP assay for <i>ESR1</i> methylation was developed and validated in (i) 65 primary breast tumors formalin-fixed paraffin-embedded (FFPE), (ii) EpCAM<sup>+</sup> CTC fractions (122 patients and 30 healthy donors; HD), (iii) plasma ctDNA (108 patients and 30HD), and (iv) in CTCs (CellSearch) and in paired plasma ctDNA for 58 patients with breast cancer.
To explore the clinical relevance of our model, we examined expression levels of three genes involved in activation of the MSP signaling pathway (MSP, MT-SP1, and MST1R) in human breast tumors.
By modifying an existing mouse model of breast cancer, we discovered that macrophage-stimulating protein promoted breast tumor growth and metastasis to several organs.
The shortest region of homozygosity in primary human breast tumor is located between the DNF15S2 and RAF1 loci in the 3p21-p25 region on the short arm of chromosome 3.