Leukemia

Acute lymphocytic leukemia (ALL). This starts with white blood cells called lymphocytes in bone marrow. People with ALL make too many lymphocytes that crowd out healthy white blood cells. ALL can advance quickly if it's not treated. It’s the most common type of childhood cancer. Children ages 3 to 5 are most likely to get it, but adults over age 75 can get ALL, too.

You're more likely to get it if you:

• • Have a brother or sister with ALL
• • Were treated with chemotherapy or radiation for another type of cancer in the past
• • Have been near a lot of radiation
• • Have Down syndrome or another genetic disorder

Acute myeloid leukemia (AML). This starts in myeloid cells, which normally grow into white blood cells, red blood cells, and platelets. AML lowers the number of healthy blood cells in all three types. This form of leukemia grows quickly. AML mainly affects people over age 65. It's more common in men than women.

You're chances of getting it are higher if you:

• • Have been treated with chemotherapy or radiation for cancer
• • Have been around toxic chemicals like benzene
• • Smoke
• • Have a blood disorder like myelodysplasia or polycythemia vera, or a genetic disorder like Down syndrome

Chronic lymphocytic leukemia (CLL). This is the most common type of leukemia in adults. Like ALL, it starts from lymphocytes in bone marrow, but it grows more slowly. Many people with CLL don't show any symptoms until years after the cancer starts. CLL mainly affects people in their 70s or older. A family history of blood cancer can raise your odds of it, as can spending a lot of time around chemicals like weedkillers or insecticides.

Chronic myeloid leukemia (CML). This blood cancer starts in myeloid cells, like AML. But the abnormal cells grow slowly. CML is slightly more common in men than in women. It usually affects adults, but kids can sometimes get it, too. You’re more likely to get it if you’ve been around high amounts of radiation.