posted on 2017-10-27, 14:14authored byAjay M. Verma
Introduction: Bowel cancer screening programme (BCSP) subjects aged 55
are screened by bowel scope sigmoidoscopy, aged 60-75 by faecal occult
blood testing (FOBt - positive subjects undergo colonoscopy). Whilst effective,
FOBt lacks high sensitivity, specificity and accuracy, >90% sigmoidoscopies
and 50% colonoscopies are normal or non-adenoma diagnosis.
Endoscopy screening is invasive, resource intensive and can cause harm.
Uptake of FOBt and bowel scope is <60%. A blood based screening test is an
appealing alternative.
Methods: We investigated microRNAs (miRs) – short non-coding RNA
molecules as potential biomarkers. 181 FOBt+ subjects and 29 others
undergoing endoscopy were recruited – 128 males, 82 females. 117 with polyps
(99 adenomas), 12 colorectal cancer, 81 controls.
RNA was extracted from plasma and processed. Pooled groups were analysed
using microarray assay cards. Ten candidate miRs 19a, 98, 146b, 186, 331–5p,
452, 625, 222#, 664 and 1247 were identified. Cases were analysed for
candidate microRNA expression by quantitative polymerase chain reaction.
Results: Candidate miRs showed significant levels of expression in subjects
with adenomas on T-testing. miRs 98 & 19a; p=<0.05, miRs 146b, 625;
p=<0.01, miR-186 p=<0.001. The results were more significant for male
subjects.
Receiver operated characteristic curves for miR-panels showed: Polyps in
male subjects, miRs 98, 186, 452; sensitivity 0.600, specificity 0.872.
Adenomas in male subjects, miRs 98, 186, 452. Sensitivity 0.606/0.591,
specificity 0.875/0.900. Polyps with diverticulosis/haemorrhoids; miRs 186,
452, 331–5p; sensitivity 0.600/0.633, specificity 0.889/0.867. Adenomas with
diverticulosis/haemorrhoids; miRs 625, 452, 331–5p; sensitivity 0.714,
specificity 0.864.
Conclusion: This study suggest plasma microRNAs are potential screening
biomarkers for male subjects with colorectal polyps, adenomas and subjects
with adenomas and diverticulosis/haemorrhoids. Further study is needed to
validate these exciting findings.