When Caethe Goetz was diagnosed with multiple myeloma, a rare form of bone marrow cancer, at age 49 in 2003, both she and her doctor were perplexed.

The disease affects only 20,000 Americans a year, typically African-American males in their late 60s. Goetz's family has no history of cancer.

However, when her doctor learned she was a former U.S. Marine, he thought he might have found the answer to the mystery. Since multiple myeloma is one of the 14 diseases that the U.S. government recognizes as related to contact with the toxic defoliant Agent Orange, he speculated that the roots of her illness came from her military service.