A unique case of rectal cancer with coexistence of multiple pathways of carcinogenesis

BackgroundColorectal cancer with a global incidence of 10% has multiple pathways implicated in its carcinogenesis. WNT signaling is the principal underlying pathway via APC gene, while defective mismatch repair genes and epigenetic changes also are known to contribute.Case presentationHere, we present an unusual case of rectal adenocarcinoma in a woman, with germline MSH6 and PMS1 mutations, and simultaneous somatic APC and TP53 mutations treated with surgery and adjuvant capecitabine.ConclusionsThe case is unique suggesting a possible interaction between the two pathways and contributing to carcinogenesis in this patient. This also suggests need for a thorough germline and somatic mutation evaluation in select colorectal cancer patients to direct a tailored therapy.

Automated summary

This article presents a unique case of rectal adenocarcinoma in a woman with germline MSH6 and PMS1 mutations, and simultaneous somatic APC and TP53 mutations. The case highlights a possible interaction between the two pathways and emphasizes the importance of evaluating both germline and somatic mutations in colorectal cancer patients for tailored therapy.