Tea phytochemicals for breast cancer prevention and intervention: From bench to bedside and beyond

The National Cancer Institute of the United States had projected breast cancer as one of the topmost prevalent malignancies of 2016. It was estimated that in 2016, 246,660 new cases of invasive breast cancer were expected to be diagnosed in women in the US, along with 61,000 new cases of non-invasive (in situ) breast cancer. The heterogeneity of breast cancer accounts for its differential molecular subtyping. Recent incorporation of high throughput approaches helps early prognosis of breast cancer, but recurrence of the disease stands to be one of the most daunting fact behind non-availability of third line treatment. At this point of crisis, application of chemopreventive measures could possibly resolve the enigma of breast cancer. The world class beverage tea has proven its efficacy in ameliorating various genetic and epigenetic anomalies in breast cancer. Tea phytoconstituents are known to modulate myriad molecular events which include prominent regulators of intracellular signaling, such as phosphatidylinositide 3-kinase/protein kinase B/nuclear factor-κB, epidermal growth factor receptor, vascular endothelial growth factor, B-cell lymphoma 2 (Bcl-2) and Bcl-2 associated X protein in the development and progression of breast carcinoma. This review aims to encompass the detailed modulatory roles of tea phytochemicals, their analogs and nanoformulations against mammary carcinoma and the probability of using tea in therapeutic management of breast cancer. Finally, current limitations, challenges and future directions of tea and breast cancer research are also critically discussed.