The role of dietary polyphenols in osteosarcoma: A possible clue about the molecular mechanisms involved in a process that is just in its infancy.

Osteosarcoma (OS) is a primary malignant bone tumor mainly affecting children, teenagers and young adults, being associated with early metastasis and poor prognosis. The beneficial effects of polyphenols have been investigated in different areas, including their potential to fight OS. Polyphenols are believed to reduce morbidity and/or slow down the development of cancer. This review aimed to assess the effect of polyphenols in OS and investigate their molecular mechanisms. It was observed that the broad spectrum of health-promoting properties of plant polyphenols in OS occurs mainly due to modulation of reactive oxygen species, anti-inflammatory activity, anti-angiogenesis, apoptosis inducer, inhibition of invasion and metastasis. However, it is worth mentioning that although the promising effects of polyphenols in the fight against OS, most of the studies have been performed using in vitro and in vivo animal models. Therefore, studies in humans are needed to validate the effectiveness of polyphenols in OS treatment. PRACTICAL APPLICATIONS: Polyphenols are widely used for various diseases, however, until now, their real role in the treatment of osteosarcoma remains unknown. This review provides a broad spectrum of research conducted with polyphenols and their potential as adjuvant therapy in the treatment of osteosarcoma. However, prior to their clinical application for osteosarcoma treatment, there is a need to isolate and identify specific polyphenolic compounds with high antitumor activity, increase their oral bioavailability, and to investigate their interactions with chemotherapeutic drugs being used in clinical practice.