Probiotics-based Anticancer Immunity in Breast Cancer

 A growing number of evidence is available in support of the advantageous role of a balanced intestinal microbiota in the progression and manifestation of malignant tumors, not only in the gastrointestinal tract but in other distant tissues as well, with the most potential role in breast carcinoma. Breast cancer involves a complex interplay of several factors, such as familial history, use of hormonal replacement therapy, dietary habits, lifestyle, environment, clinical features, genetics and epigenetics. Recently, a positive correlation between a patient’s breast microbiome and cancer has beocme a novel potential risk factor. In the present chapter, we tried to discuss the role of microbiome as a potential breast cancer risk factor and tried to investigate the literature focussing on the proposed mechanisms behind the interaction of microbiome, human genetic makeup involved in the onset of breast carcinogenesis and determining the effect of transformed breast, milk and gut microbiome on the physiological status of both normal and malignant breast. We also tried to shed light on the resistance to chemotherapeutic treatment among individuals with altered microbiomes with an emphasis on the role of the microbiome in developing and maintaining inflammation, epigenetic alterations and estrogen metabolism. Interestingly, bacterial species are indispensable modulatory agents of widely used chemotherapeutic/ immunotherapeutic regiments. But the exact role of commensal bacteria in immunity, formation of neoplasia and response to treatment needs much more research because most of the available knowledge is based on animal model studies and needs its translation to humans which requires great precision and has various hurdles too. Therefore, we tried to give a comprehensive overview of current knowledge in terms of breast cancer therapeutics and suggest integrating probiotic bacteria and/or modulation of the intestinal microbiota to be used as immune adjuvants, targeting to enhance the effectiveness of conventional anti-tumor treatments and cancer immunotherapies as well.

Keywords: Breast microbiome, Breast cancer, Cancer therapeutics, Immunotherapies, Probiotic bacteria.