What is multiple endocrine neoplasia type 2 (MEN 2)?
Multiple endocrine neoplasia type 2 (MEN 2) is a genetic disorder associated with a high lifetime risk of developing medullary thyroid cancer. MEN 2 is caused by germline (inherited) mutations in the RET proto-oncogene located on chromosome 10. Proto-oncogenes are responsible for promoting cell growth. When altered, or mutated, they become oncogenes that can promote uncontrolled cell growth and ultimately tumor formation. Having a mutation in just one of the two copies of a particular proto-oncogene is enough to cause a change in cell growth. For this reason, oncogenes are said to be “dominant” at the cellular level (although the change in cell growth may or may not be detectable at a clinical level). However, the process of developing a cancer actually requires mutations in multiple growth control genes. Therefore, inheriting a mutation in one copy of the RET gene is just the first step in the process. The remainder of the mutations necessary for tumor development are acquired (not in
