Answer:
Leukemia.
Step-by-step explanation:
Cancer is the excess growth of the cells that might occur due to the mutation in the specific gene that regulates the cell cycle. The different types of cancer are leukemia, sarcoma and carcinoma.
The leukemia is the cancer of the blood cells. The number of the blood cells is extremely high and abnormal in the leukemia. The leukemia is the most common cancer present in the childhood cancers. The chemotherapy is dne to treat the cancer.
Thus, the answer is leukemia.