For more than a century, cancers have been classified by the organ or tissue where they begin. The breast, lungs, bone marrow, digestive system, and so on – and therapies have been geared to those specific areas. Fortunately, by understanding cancer cell biology, a new perspective has emerged.
Targeted therapy is a treatment that uses drugs or other substances to identify and attack specific cancer cells without harming normal cells. Because targeted therapies are designed to hit specific targets on cancer cells, they are often called “targeted therapies”.
Unlike traditional chemotherapy drugs, which kill any rapidly dividing cells (including cancer cells), targeted therapies are designed to interfere only with the specific molecular pathways that drive cancer growth. Cancer cells have abnormal proteins on their surface or within their cells that allow them to grow and divide uncontrollably. By interfering with these proteins, targeted therapies can stop cancer cells from growing and dividing.
Since targeted therapies interfere with the specific proteins that drive cancer growth, they often have fewer side effects than traditional chemotherapy drugs. In addition, because they are specifically tailored to each person’s cancer, they are more likely to be effective.
Personalize the dosing and the drug to the disease and to the patient. Researchers use what are called biomarkers. In the case of cancer, biomarkers refer to substances, produced by cancer cells or the body in response to cancer, that identify or “mark” the specific type of cancer a patient has. They can be measured by blood, urine, and tissue tests.
From the biomarkers, you can compute a risk score. This score reflects how likely it is that a person’s cancer will progress within a certain period of time. The risk score can help guide the doctor in deciding which treatments to offer and also how aggressively to treat a patient’s cancer.
Aided by powerful new technologies, such as massively parallel sequencing and whole-genome analysis, it is now possible to sequence the genomes of cancers in detail. This information can be used to identify the specific genetic mutations that have arisen in a particular tumor and to select therapies that exploit these vulnerabilities.
Our best way of understanding cancer is by understanding cancer cell biology and how it interacts as a whole. This requires a holistic study of interactions in biological systems, looking at cancer in its entirety and at how the different cell processes influence each other. The field of cancer research is ever-evolving, and with new technologies and treatments being developed all the time, we are getting closer to curing this disease. By understanding cancer cell biology, we can target therapies specifically to each person’s cancer, giving them the best chance at a cure.
Anticancer therapies can be designed to destroy cancer cells preferentially by exploiting the properties that distinguish them from normal cells, including the defects they harbor in their DNA repair mechanisms, cell-cycle checkpoints, and apoptosis pathways. Tumors can also be attacked through their dependence on their blood supply.
By understanding the normal control mechanisms and exactly how they are subverted in specific cancers, it becomes possible to devise drugs to target cancers more precisely. As we become better able to determine which genes are amplified, which are deleted, and which are mutated in the cells of any given tumor, we can begin to tailor treatments more accurately to each individual patient.
References: Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Cancer Treatment: Present and Future. Available from: http://www.ncbi.nlm.nih.gov/books/NBK26811/
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