Molecular features of adenomas predicting metachronous colorectal cancer: a nested-case control study

"Background & Aims: Current morphological features defining advanced adenomas (size ≥10 mm, high grade dysplasia or >25% villous component) cannot optimally distinguish individuals at high-risk or low-risk of metachronous colorectal cancer (me-CRC), which may result in suboptimal surveillance. Certain DNA copy number alterations are associated with adenoma-to-carcinoma progression (cancer-associated events; CAEs). We aimed to evaluate whether CAEs can better predict an individual’s risk of me-CRC than the morphological advanced adenoma features. Methods: In this nested case-control study, 529 individuals with a single adenoma at their first colonoscopy were selected from a Norwegian adenoma cohort. DNA copy number profiles were determined, by means of low-coverage whole genome sequencing. We assessed the prevalence of CAEs in advanced and non-advanced adenomas and its association with me-CRC. For the latter, cases (with CRC) were matched to controls (without CRC), with the same follow-up period as cases, as well as age and sex. Subsequently, odds ratios (OR) for the association of the presence of an advanced adenoma or a molecularly-defined high-risk adenoma with me-CRC were calculated. Results: Molecular high-risk features were observed in 85/267 (32%) of advanced adenomas and in 27/262 (10%) of non-advanced adenomas. Me-CRC was more strongly associated with advanced adenomas (OR 3.58; 95% CI 2.27-5.72) than with molecular high-risk adenomas (OR 1.90; 95% CI 1.14–3.16). After adjusting for other variables, only advanced adenoma remained significantly associated with me-CRC (OR 3.39; 95% CI 2.10–5.55). Conclusion: Molecularly-defined high-risk adenomas were associated with me-CRC, but the association of advanced adenoma with me-CRC was stronger. " Project goal: Evaluate the value of DNA copy numbers alterations detected in a baseline adenoma, in the prediction of risk of metachronous CRC

Type: Other
Archiver: EGA European Genome-Phenome Archive

1 Dataset

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Dataset ID	Description	Technology	Samples
EGAD00001010119	Formalin-fixed, paraffin-embedded samples from 643 colorectal adenomas collected in different hospitals in Norway, from which DNA was extracted, were analysed for DNA copy number alterations. Some adenomas had more than one block (n=42), thus 643 individuals, 685 blocks. Low-coverage whole genome sequencing was run in all samples. For 529 individuals all the clinical information was available. A subset was matched for follow-up time, age and sex in a nested case-control approach (n=366; cases - individuals who developed later on CRC; controls - individuals who did not develop CRC within the same follow-up time).	Illumina HiSeq 2500	685