Cancer is a biologically complex disease. During the malignant transformation process, significant genetic changes occur in the cells, that allow cancer to evade the body’s defense mechanisms. Many of the cell’s genes are linked to these defense mechanisms, a great number of mutations are needed for cancer to develop.
The pathological process undergone by the cells during malignant transformation holds not only scientific importance, but also great medical impact. In recent years, researchers have developed innovative drugs, known as biologic drugs, or biopharmaceuticals. These drugs target specific parts of the cell, and their activity depends on the pathways of cancer progression. Different biological drugs are suitable for different types of cancer progression pathways and should be personalized for each patient.
These recent changes in cancer therapy have turned cancer genetics into a leading research topic in the field of medicine worldwide. Tracking genetic changes and characterizing them are now an important part of diagnosis and treatment for many cancer patients.
Genetic analysis of colon cancer
Research published in the scientific journal “Nature” attempted to create a comprehensive analysis of the genetic alterations in colorectal cancer samples. Researchers set to accurately characterize a full genome of malignant cancer cells from the colon and rectum. 276 samples were taken, 97 of them underwent whole genome sequencing.
Researchers searched for different gene mutations, related to protein encoding. These alterations can be specific mutations in important genes, copies of DNA segments in cancer cells, DNA methylation (a chemical process leading to the “silencing” of genes), and messenger RNA expression, leading to changes in protein production in the cell.
During the analysis, researchers found that around 16% of carcinomas were hyper-mutated. Excluding the hyper-mutated cancer cells (that showed high microsatellite instability), colon and rectum carcinomas were found to have very similar genetic characteristics.
Twenty-four genes were found to be significantly mutated. Among them are genes known to be linked to colorectal cancer: K-RAS, APC, TP53, and more.
In addition to these known genes, several other mutations were found to be of importance in cancer therapy. Mutations to the ERBB2 gene were common, and so were amplifications of the growth factor gene – IGF2. Researchers also identified that many carcinomas are related to alterations in the transcriptional targets involving the protein MYC.
These discoveries are not just purely scientific. Certain drugs available today are specifically activated according to mutations discovered in this research. ERBB2 gene amplifications are known in breast cancer patients, patients baring these amplifications can now be treated with a drug known as Herceptin (trastuzumab). This genetic study therefore translates into rapid clinical benefit for patients.
Personalized therapy for colon cancer
Personalized medicine is not just a futuristic or experimental form of therapy. This treatment is becoming increasingly common today, including in treating colorectal cancer. Different researchers showed that cancer aggressiveness scale and the risk of cancer spreading, are linked to a series of genetic changes.
Molecular tests for genetic changes can help answer important questions, such as – should colorectal cancer patients that were diagnosed during the first stages of the disease and underwent surgery be given adjuvant chemotherapy?
Molecular tests for cancer are available for breast cancer and colorectal cancer patients. These tests help make important decisions during therapy and prevent unwanted side effects caused by chemotherapy. Oncology, it seems, gladly welcomes personalized medicine and its benefits.