Complex sentence: The mother of a child with a highly curable and common form of childhood cancer, acute lymphocytic leukemia (ALL), who moved to Colorado to seek treatment with the marijuana extract, was investigated when she refused chemotherapy for her three-year-old child.
Split into simpler sentences: The mother of a child with acute lymphocytic leukemia (ALL), a common form of childhood cancer, moved to Colorado to seek treatment with the marijuana extract. This form of cancer is highly curable with chemotherapy, and she was investigated when she refused chemotherapy for her three-year-old child.