Targeted molecular therapy is a type of personalized medical therapy designed to treat cancer by interrupting unique molecular abnormalities that drive cancer growth. The drugs used in targeted therapy are designed to interfere with a specific biochemical pathway central to the development, growth, and spread of that particular cancer. The therapy is personalized to meet each person’s individual needs because cancer develops differently in everyone. In some cancers the molecular targets are known, but in others the targets are still being identified. In some cases, the same types of cancer have different molecular targets. Identifying the molecular targets in any given patient's cancer requires working closely with pathologists to carefully identify the correct cancer pathology. Targeted therapy provides medical oncologists a better way to customize cancer treatment. Advantages of targeted therapy include: Potentially less harm to normal cells, potentially fewer side effects. Improved effectiveness and improved quality of life .