ABSTRACT
Objective To study the infection rate of fusobacterium nucleatum cancer re appeared in patients with colorectal cancer before and after radiotherapy,and the changes after cancer recarrence.Methods A total of 20 persons receiving physical examination were recruited in the control group and collected the stool specimens,and 40 colorectal cancer patients were selected in the study group.All of the subjects in the study group were collected stool specimens before operation 3 days and after operation 5 day,after radiation therapy 7 days and 30 days.The patients were followed-up 1 year.The bacterial fluid was collected by filtration,and real-time fluorescence quantitative PCR was used to detect the expression of fusobacterium nucleatum gene in feces.Results The positive rate of fecal fusobacterium fusiformis was 30% in the study group and 5% in the control group.The gene relative expression of 12 colorectal cancer patients before operation 3 days and after operation 5 days,after radiation therapy 7 days and 30 days were 5.20±0.34,8.50±0.45,1.20±0.22,0.20±0.15.The fusobacterium nucleatum gene expression of 12 patients with positive fusobacterium after operation 5 days was significantly increased compared with that before operation 3 days(t=10.419,P=0.001),which after radiation therapy 7 days and 30 days was significant lower than that before operation 3 days(t=12.728,P=0.001;t=25.889,P=0.001).Six patients recurred among 1 year,the fusobacterium nucleatum gene expression was 7.2±0.56,which was significant higher than that after radiation therapy 7 days.Conclusion The infection of fusobacterium nucleatum might be a risk factor for colorectal cancer,and the gene relative expression might be an early warning indicator of recurrence.