Intestinal microbiota at the stage of tumor induction in experimental breast cancer

Abstract

Despite decades of clinical research, breast cancer (BC) remains a serious problem worldwide with a high mortality rate. In recent years, the role of microbiota in the pathogenesis of malignant neoplasms of various localization including breast cancer has been shown. The intestinal microbiota is currently considered as an important factor in the pathogenesis of oncological diseases. The research goal was to conduct a culture-based study of the microbiota of the large intestine in female Wistar rats during the induction of breast cancer with N-methyl-N-nitrosourea (MNU). The studies were conducted on sexually mature female Wistar rats. At the beginning of the experiment, the age of the Wistar females was 3 months, and the weight of the animals was 200-210 grams. Two groups of animals were formed for the study. Fecal samples from the studied groups of rats were collected for subsequent cultural testing. The study showed that all trial animals were dominated by the representatives characteristic of the normobiota of the intestine of warm-blooded animals, namely: Bifidobacterium spp; Lactobacillus spp; Escherichia coli with pronounced enzymatic properties; Enterococcus spp.; Clostridium spp. In addition, Staphylococcus spp; yeast-like fungi of the genus Candida and molds were identified. Escherichia coli with reduced enzymatic activity was also detected. However, on the 35th day of tumor induction, the appearance of representatives of pathogenic intestinal microflora was detected in rats with experimental cancer. The chemically induced development of breast cancer affects the composition of the intestinal microbiota in rats and causes an imbalance of the intestinal microbiota which may subsequently lead to further development and progression of the tumor.