When breast cancer spreads, the disease typically invades the long bones of the body, such as the femur and tibia. Inside these long bones, giant marrow cells known as megakaryocytes (or MKs) go into overdrive in the presence of cancer and may contribute to destructive bone loss and embolisms. "The breast cancer survival rate is about 90 percent when it's detected early but drops considerably lower once the cancer has spread to the bones," says graduate student Walter Jackson. There hasn't been enough research on how these specialized bone marrow cells affect the spread of cancer cells, in spite of the fact that many cancer patients die of thromboembolism, or blood clots, he notes. "It's important that we learn more about bone metastasis and how to slow it down."