Indian hedgehog regulates intestinal stem cell fate through epithelial-mesenchymal interactions during development.

Background & Aims: Intestinal stem cells (ISCs) are regulated by the mesenchymal environment via physical interaction and diffusible factors. We examined the role of Indian hedgehog (Ihh) in mesenchymal organization and the mechanisms by which perturbations in epithelial-mesenchymal interactions affect ISC fate.

Methods: We generated mice with intestinal epithelial-specific disruption of Ihh.

Microsatellite instability and novel mismatch repair gene mutations in northern Chinese population with hereditary non-polyposis colorectal cancer.

Objective: Hereditary non-polyposis colorectal cancer (HNPCC) syndrome is the most common cause of hereditary colorectal cancer with an early age of onset. Microsatellite instability (MSI) and germline mutation in one of the DNA mismatch repair (MMR) genes are found in the majority of HNPCC families and provide an opportunity for genetic diagnosis and prophylactic screening. The MMR gene mutation spectrum may vary across different populations and be influenced by founder mutations that prevail in specific ethnic groups.