CTNNB1 and colorectal neoplasm: In primary colorectal tumors, a relatively small percent (7 of 58 examined) contained somatic interstitial deletions that included all or part of exon 3 of the beta-catenin gene, and RT-PCR analysis from 3 of the 7 tumors detected transcripts that lacked exon 3 and the presence of the normal transcript[39].