Alterations in the transcriptional profile of genes in tumors as a prerequisite for personalization of treatment in breast cancer patients

Comparative mRNA expression analysis confirms that a short preoperative course of aromatase inhibitors induces a more potent and uniform molecular response, characterized by profound suppression of proliferation and complete inhibition of estrogen-dependent signaling. Tamoxifen therapy is also effective but results in less pronounced suppression of key targets and, crucially, may be accompanied by early activation of the <i>MYC</i> oncogene, a potential marker for resistance development.