Effect of polyphenols on HER2-positive breast cancer and related miRNAs: Epigenomic regulation

HER2-positive breast cancer is one of the most aggressive subtypes accounting for nearly 30% of diagnosed cases. It is associated with reduced disease-free survival, tumor invasiveness, and a poor overall prognosis. Unfortunately, numerous patients develop resistance to conventional therapies; therefore, many ongoing clinical trials are testing new possible treatments. Polyphenols are the main bioactive components of the Mediterranean diet with multiple beneficial properties playing a key role in cancer prevention through epigenetic regulation. Aberrant variations in microRNAs levels regulating oncogenes or tumor suppressor genes expression may lead to tumor development. Evidence has shown that dietary polyphenols modulate HER2-positive breast cancer-associated microRNAs, resulting in a reduction of tumor growth and metastatic potential, and chemosensitivity restoration without displaying toxicity-derived adverse effects. These beneficial properties make polyphenols a potential therapeutic approach for HER2-positive breast cancer patients in the clinical setting, alone or in combination with conventional therapies.