The mission of the National Marrow Donor Program is to help people who need a life-saving marrow or blood cell transport by matching patients to potential donors using the NMDP registry - which, at 6 million people and growing, is the largest listing of volunteer donors in the world.

Since it began operations in 1987, the NMDP has facilitated more than 30,000 marrow transplants for patients who do not have matching donors in their families with more than 300 transplants each month.

Today and tomorrow, Vanderbilt students have the chance to join the registry and the possibility to contribute their own bone marrow to save a life.

Registration requires a short cheek swab and a questionnaire. Cheek swabs will then be tissue typed, and students will be placed on the registry, where they will remain until they turn 60. Those students who have already signed up for the NMDP do not need to get typed again; however, they can donate blood to Marrowthon.

Signing up for the registry is only the first step toward bone marrow donation. Tissue typing for potential is determined by analyzing 36 individual factors in their tissue sample. The odds of being a perfect match for any unrelated individual is one in 20,000 people. Below are two stories - one donor and one recipient - of individuals who found themselves in the middle of a bone marrow transport.

Editor's note: Changes have been made to the article to reflect the correction: Students who register during Marrowthon are not required to pay the $52.