Finding a treatment that selectively targets cancer cells without affecting normal cells is the goal of all cancer treatment. Unfortunately, this is a difficult task because cancer cells are formed from normal cells. Drugs like antibiotics can exploit differences between 'self' and 'non-self' cells. But with cancer cells there are no such clear distinctions. Instead, scientists have to determine what makes a specific cancer cell different from a normal cell and then design agents that can selectively target those pathways.
As we have seen with the hallmarks of cancer, there are unique qualities to tumor cells that can be targeted. Every hallmark of cancer is being studied as a potential area for intervention with pharmaceutical agents. Once a good candidate drug is available, the patient’s physician will first need to know if their patient has the appropriate biomarker present. Only testing for this specific biomarker will reveal whether the patient is likely to respond to the new therapy. The laboratory will be used to determine the presence or absence of these biomarkers.
We are living in an age in which personalized medicine is now routinely used to treat cancer patients. Unfortunately, there are still many more biomarkers than there are targeted drugs for them. In these cases, where no targeted therapy is available, patients still receive less-specific chemotherapy agents.
