From Military.com:

"Army Seeks WWII DNA Samples

Week of March 31, 2008
The Army is trying to locate more than 6,300 families to collect DNA samples for the purpose of identifying missing Soldiers from World War II and the wars in Korea and Vietnam. The military maintains a database of mitochondrial DNA samples from family members of missing-in-action Soldiers in the Armed Forces DNA Identification Lab. The DNA samples help the Army identify missing Soldiers' remains when they are uncovered so they can be returned to the families. Families with unaccounted-for Soldiers, or anyone who knows of a family with an unaccounted-for Soldier, should contact the Past Conflict Repatriation Branch by calling 1-800-892-2490 or sending an e-mail to tapscper@conus.army.mil."

If you know anyone who has a relative who is MIA, please forward this info along.