Modification of microflora imbalance: future directions for prevention and treatment of colorectal cancer?

Increasing incidence and mortality of colorectal cancer brings the necessity to uncover new possibilities in the prevention, diagnosis and treatment. The microbiome as the collective genetic material of the microflora, overexceed the number of genes in the human genome and is unique for each individual. Due to the benefits providing for the host and mainly for immediate interaction with the host immune system, a gastrointestinal microflora can be considered "cardinal microbiome". Host-microbial relations includes symbiotic, pathogenic and competitive interactions. Causal role of gastrointestinal microflora in colorectal carcinogenesis is still not well determined. This minireview is focused on current evidence in understanding the role of bacteria in colorectal carcinogenesis, the impact of bacterial dysbiosis on tumor formation, and ability of probiotics and bacterial vectors to modulate the gastrointestinal microflora as prevention and therapy tool in colorectal cancer.