The most common type of childhood cancer is acute lymphocytic leukemia (ALL), a blood and bone marrow cancer that creates immature white blood cells that can't perform their typical functions. Because of this, the disease worsens quickly.

Most likely to occur in early childhood, ALL is more common in boys than girls, according to the American Cancer Society. Children younger than 5 are at highest risk for developing the disease.

Asmaa Ferdjallah, M.D., a Mayo Clinic pediatric hematologist and oncologist, treats children of all ages with ALL. Here's what she wants families to know about this disease:

The American Cancer Society estimated that 6,540 new cases of ALL would be diagnosed in both children and adults in 2023. This represents less than 0.5 percent of all cancers in the United States.