Distribution and gene mutation of enteric flora carrying β-glucuronidase among patients with colorectal cancer.

OBJECTIVE: To explore the difference of distribution in intestinal flora among colorectal cancer patients and healthy controls and investigate characteristics and changes of sequences in beta-glucuronidase (β-glucuronidase, β-G).

METHODS: Bacterial genomic DNA and E. coli DNA in feces were extracted from colorectal cancer patients and healthy controls respectively. Specific primers for β-G gene were designed and amplified by PCR as templates of fecal bacteria genomic DNA and E. coli DNA respectively.

RESULTS: Compared with normal control, the amount of E. coli in cancer group increased significantly, Lactobacillus and Bifidobacterium probiotics reduced significantly, and proportional quantity of anaerobic bacteria and aerobic bacteria reversed. The intestinal flora carry β-G in both groups, and homologies with uidA gene sequences encoding the β-G were 99% and 98% respectively. In colorectal cancer group the 1141th and 1148th A base were deleted. The 1149th A base mutated into T base, and the 1158th bit A base mutated into G base; however, in healthy control group the 1141th and 1148th position A base was deleted, and the 1149th A base mutated into T base.

CONCLUSION: There are differences of intestinal flora distribution between cancer group and healthy control group. The gene mutation and deletion of intestinal flora of β-G gene appear at the same time at 1141th, 1148th and 1149th in both cancer group and healthy control group, and 1158th genetic mutation appears only in colon cancer group.