Imatinib Mesylate is primarily used in the treatment of certain types of cancer. It is highly effective in managing chronic myeloid leukemia (CML), where it targets the abnormal BCR-ABL protein produced by the Philadelphia chromosome, inhibiting the growth of cancerous cells. Additionally, it is used to treat gastrointestinal stromal tumors (GISTs) by blocking the activity of the KIT protein, which drives tumor growth. Imatinib Mesylate is also prescribed for patients with acute lymphoblastic leukemia (ALL) who have the Philadelphia chromosome mutation. Its ability to selectively inhibit tyrosine kinases makes it a cornerstone in targeted cancer therapy, significantly improving patient outcomes and survival rates.