How Marijuana Can Disrupt Leukemia Cells @alternet: New scientific research shows that marijuana's cannabinoids have the ability to “target and switch off pathways” that allow cancers to grow. Leukemia is the blanket term for the four different types of cancer found in bone marrow and blood cells. There are roughly 200,000 U.S. cases per year and typically found in adults over the age of 55, but also found in children under the age of 15.