| Abstract: | The majority of colorectal cancers (CRCs) arise from adenomatous polyps. In this study, we sought to present the underrecognized CRC with the residual polyp of origin (CRC RPO +) as an entity to be utilized as a model to study colorectal carcinogenesis. We identified all subjects with biopsy-proven CRC RPO + that were evaluated over 10 years at Mayo Clinic, Rochester, MN, and compared their clinical and pathologic characteristics to CRC without remnant polyps (CRC RPO −). Overall survival and disease-free survival overlap with an equivalent hazard ratio between CRC RPO + and RPO − cases when age, stage, and grade are adjusted. The somatic genomic profile obtained by whole genome sequencing and the gene expression profiles by RNA-seq for CRC RPO + tumors were compared with that of age -and gender-matched CRC RPO − evaluated by The Cancer Genome Atlas. CRC RPO + cases were more commonly found with lower-grade, earlier-stage disease than CRC RPO −. However, within the same disease stage and grade, their clinical course is very similar to that of CRC RPO −. The mutation frequencies of commonly mutated genes in CRC are similar between CRC RPO + and RPO − cases. Likewise, gene expression patterns are indistinguishable between the RPO + and RPO − cases. We have confirmed that CRC RPO + is clinically and biologically similar to CRC RPO − and may be utilized as a model of the adenoma to carcinoma transition. |
