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.
