The first target of targeted cancer therapies with the cellular receptor for estrogen, a female sex hormone that many breast cancers need to grow. Drugs that interfere with the ability to estrogen to stimulate cancer cells have proven to be any effective breast cancer treatment, and today there are a number of targeted therapies focused on various breast cancers.
Since then, other targeted therapies approved by the Food and Drug Administration have been developed as treatments for different types of cancers, including: gastrointestinal stromal tumor (a rare cancer of the GI tract), dermatofibrosarcoma protuberans, myelodysplastic/myeloproliferative disorders, systemic mastocytosis, acute lymphoblastic leukemia, chronic myelogenous leukemia, acute promyelocytic leukemia, gastroesophageal junction adenocarcinoma, non-small cell lung cancer (if it has metastasized or cannot be surgically removed), squamous cell carcinoma of the head or neck, colorectal cancer, metastatic colon cancer, advanced renal cell carcinoma, advanced kidney cancer, subependymal giant cell astrocytoma, some pancreatic neuroendocrine tumors, metastatic medullary thyroid cancer, metastatic melanoma, cutaneous T-cell lymphoma, peripheral T-cell lymphoma, chronic lymphocytic leukemia, certain types of B-cell non-Hodgkin lymphoma, Hodgkin lymphoma, anaplastic large cell lymphoma AIDS-related Kaposi sarcoma, multiple myeloma, mantle cell lymphoma, glioblastoma, hepatocellular carcinoma and soft tissue sarcoma.
While targeted therapies have significant potential as cancer-fighters, they do have some limitations. For starters, they only work for cancers for whose scientists have identified antigens. Also, there is the potential for cells to develop resistance to these therapies, so in many cases targeted therapies are used in conjunction with other treatments.