Molecular changes associated with colorectal cancer are detected by stool deoxyribonucleic acid testing but could persist following tumor resection.
Dr John Kisiel and colleagues determined whether methylated gene markers in stool normalize after colorectal cancer resection.
The team studied stools from 22 colorectal cancer cases before and after subtotal resection and from 80 colonoscopy-normal controls.
In blinded fashion, target genes were captured from stool supernatant, bisulfite-treated, and assayed by quantitative allele-specific real-time target and signal amplification.
Results were dichotomized at 95% specificity cutoffs.
The team found that among colorectal cancer cases, median methylated NDRG4 and BMP3 levels decreased dramatically following resection, respectively.
The research team found that among the 14 cases with elevated preoperative levels, 93% fell into the normal range after surgery.
A case whose stool methylated NDRG4 level increased sharply after surgery was found to have recurrent colorectal cancer.
Dr Kisiel's team concludes, "Methylated gene marker levels clear from stool following colorectal cancer resection unless disease is present."
"Postoperative stool marker levels are informative and may be of value in surveillance."