OSAKA (Kyodo) -- A Japanese research team has discovered new evidence on how genes function in the large intestine, a move that could shed light on why colorectal cancer often develops on the left side.

Colorectal cancer is the most common cancer in Japan, with 78 percent of patients developing it on the left side of their large intestine, according to the team, including researchers from Osaka University.

The researchers have found that genes on the left-sided colorectum and right-sided colon function differently, the team said in a report published in the U.S. scientific journal Molecular Cancer.

"I hope this can lead to research that can enlighten us to the reasons behind why colorectal cancers are frequently found on the left side," said Shinichi Yachida, a professor at Osaka University.

The group collected the intestinal tissues of both healthy individuals and colorectal cancer patients, who were in the early or advanced stage, and studied their genes.

The researchers found that the expression of genes related to xenobiotic stimulus and antimicrobial peptide was "high" in the right colon, suggesting that foreign substances "not digested and absorbed in the small intestine may undergo metabolism" in the right side of the large intestine, according to the report.

The large intestine is known to absorb water and excrete undigested food.

Genes that have water retention characteristics were among those found on the left-sided colorectum, according to the study.

The study also suggested that controlling the terminal ileum, which is part of the small intestine and vital in immune response, could help prevent colorectal cancer.