Abstract
Cyanobacterial blooms caused by Cyanobacteria adversely affect the health of the people living in their vicinity. We elucidated the effect of Cyanobacteria in patients with breast cancer. The serum microbiome of the patients with breast cancer was analyzed using NGS. Serologic tests were performed to analyze the association between the factors affecting the liver function of patients with breast cancer and the amount of Cyanobacteria. In addition, the recurrent-free survival of patients with breast cancer according to the abundance of Cyanobacteria was analyzed. The abundance of Cyanobacteria tended to be correlated with the serological results related to liver function. A high abundance of Cyanobacteria seemed to be more related to late-stage breast cancer. A high recurrent-free survival was related to a low abundance of Cyanobacteria. Even though no toxicity study was conducted, this study demonstrates the impact of phylum Cyanobacteria on the prognosis of patients with breast cancer. Thus, the abundance of Cyanobacteria in the microbiome can help predict the prognosis of patients with breast cancer.