Genetic changes that cause cancer can be inherited or can arise during a person’s lifetime as a result of errors that occur as cells divide or because of damage to DNA caused by certain environmental exposures: https://www.cancer.gov/about-cancer/understanding/what-is-cancer#how-cancer-arises
Childhood acute lymphoblastic leukemia (ALL) is a type of cancer in which the bone marrow makes too many immature lymphocytes (a type of white blood cell): https://www.cancer.gov/types/leukemia/patient/child-all-treatment-pdq#_1
