Our results support the hypothesis that <i>APC</i>-mutant colorectal tumors are transcriptionally distinct from <i>APC</i>-wild-type colorectal tumors with canonical WNT signaling activated by other mechanisms, with possible implications for stratification and prognosis.<b>Significance:</b> These findings suggest that colon adenomas driven by APC mutations are distinct from those driven by WNT gain-of-function mutations, with implications for identifying at-risk patients with advanced disease based on gene expression patterns.<i></i>.
These results support (i) that vitamin D, alone or in combination with calcium, may modify APC, β-catenin, and E-cadherin expression in humans in directions hypothesized to reduce risk for colorectal neoplasms; (ii) vitamin D as a potential chemopreventive agent against colorectal neoplasms; and (iii) the potential of APC, β-catenin, and E-cadherin expression as treatable, pre-neoplastic risk biomarkers for colorectal neoplasms.
Both O<sup>6</sup>-MeG and HCA-induced DNA adducts are linked to the occurrence of KRAS and APC mutations in colorectal tumors of rodents and humans, thereby driving CRC initiation and progression.
APC and KRAS were mutated at significantly lower rates in tumors from patients with IBD than in sporadic colorectal tumors (13% and 20% of cases, respectively).
Finally, sequencing and fluorescence in situ hybridization analysis of the gene APC underlined that a somatic UPD event might represent the second hit to achieve biallelic inactivation of this TSG in colorectal tumors.
Analysis of colorectal tumors identified somatic APC mutations in the cluster region in all polyps, but no loss of heterozygosity was detected in any polyp.
We further show that loss of heterozygosity of the APC gene in tumors from carriers of the APC*E1317Q mutation may involve the mutated allele, not just the wild-type allele, suggesting the APC*E1317Q missense mutation may not be pathologically significant in the development of colorectal tumors.