MYC amplification is emerging as an important predictor of response to HER2-targeted therapies and its role in BRCA1-associated breast cancer makes it an important target in basal-like/triple-negative breast cancers.
Estrogen rapidly induces expression of the proto-oncogene c-myc. c-Myc is required for estrogen-stimulated proliferation of breast cancer cells, and deregulated c-Myc expression has been implicated in antiestrogen resistance.
IMPLICATIONS: This study discovers a paradoxical role of c-MYC in promoting metastasis to the brain and in rendering brain-metastatic cells more susceptible to TRAIL, which suggests the existence of an Achilles' heel, thus providing a new therapeutic opportunity for breast cancer patients.
The prevalence of the most common breast cancer driver abnormalities including TP53 and PIK3CA mutations and MYC and ERBB2 amplifications showed no difference between the two groups.
We conclude that, compared to amplification of HER2/NEU, MYC, or INT2 oncogene loci, p53 gene mutations and deletions are the most frequently observed genetic change in breast cancer related to a single gene.
We have investigated the effects of chemotherapeutic agents such as adriamycin (ADR), camptothecin (CPT), mitomycin-C (MYC-C) and methotrexate (MTX) on the regulation of expression of the tumor susceptibility genes (BRCA1 and BRCA2), and the association of cell cycle progression in human breast cancer and normal breast epithelial cells.
Also, a significant correlation was seen between nuclear β-catenin expression and overexpression of its target genes like EGFR, MYC and CCND1 in the BC samples (P<0.0001).
Finally, we demonstrate that TRA2β is regulated by the MYC oncogene, plays a role in metastasis maintenance in vivo, and its levels correlate with breast cancer patient survival.
We show that these subtypes have differential sensitivity to clinical HER2/EGFR-targeted therapeutics, but small-molecule activators of PP2A, the phosphatase that regulates MYC Ser62 phosphorylation, circumvents these subtype-specific differences and ubiquitously suppresses tumor growth, demonstrating the therapeutic utility of this approach in targeting deregulated MYCbreast cancers.
Multivariate analyses revealed that distance was a risk factor for the coamplification of C-MYC and HER2 in breast cancer in survivors (odds ratio per 1-km increment, 0.17; 95% CI, 0.01-0.63).
The effect of MYC gene status on breast cancer patient outcome seems to depend on the underlying chromosomal instability and appears unfavorable for tumors with MYC amplification without polysomy.
We therefore suggest a novel link between epidermal growth factor and the miR-23a/24-2/27a cluster via the regulation of c-MYC, providing the potential for the miR-23a/24-2/27a cluster to be used as biomarker in the diagnosis and/or treatment of breast cancer.