Cancer is a disease of genetic origin caused by a defect of the genes that encode the molecules responsible for the communication processes of the cells. If a gene defect can cause cancer in an organ, the same defect, regardless of the histological and anatomical unit, may cause cancer in other organs, as well. Cancerous cells, ignoring the regulating processes in the body, start to grow uncontrollably.
The so-called oncogenes play an essential role in the formation of tumors. Oncogenes are genes the defective version of which is responsible for the production of an abnormal protein that can transform a normal cell into a cancerous one. There are also genes that prevent the formation of tumors. These are the tumor inhibitor or tumor suppressor genes. A fair description would be that oncogenes are the gas pedal and the tumor suppressor genes are the break.
The complete human genome map has been known since 2003. Tumor genetic studies identified so far approximately 600 tumor genes (oncogenes and tumor suppressor genes) out of which 138 are responsible for the growth of the most common tumors of epithelial origin, such as lung cancer, colon cancer and breast cancer. The same oncogene may contribute to the tumors forming in several points of the body.
The incidence of certain cancer genes and their defects is higher, while others are much less frequent, with an incidence of merely 1-2%. However, this value should not be ignored, since there sure will be patients in whom the tumor is caused by a rare, “one in a hundred” gene defect. It is recommended to test as many gene defects as possible at the same time.
A cell is like a soap bubble with a wall made of lipid layer. In order for cells to communicate “messaging molecules” are required, which are detected by cells using their “antennas” located on the cell surface. When these antennas get a messaging molecule, the information is transmitted by so-called signaling processes toward the information and command center of the cells, the nucleus. These chains used to transmit information are the signaling pathways.
The life of the cells is in order until a communication problem occurs in these pathways. The tumor formation process is like when the brake pedal is jammed during driving a car. In this case, a signal is transmitted continuously and without interruption from the antennas on the cell surface or other molecules within the cell that are part of the communication chain toward the nucleus. However, this is an abnormal signal because it instructs the cells to constantly divide, to grow abnormally or to form metastases. Unfortunately, cells that were healthy up to that point are unable to recognize that the abnormal signal is coming from a “switch left on”. For this reason, they start to execute the instructions to divide uncontrollably. From this point on, cells start to proliferate and tumor tissue slowly forms.
Any molecule of the cellular signaling pathways can fail, so the signal instructing the cell to divide may start from anywhere. The question is always the same: which defective molecule is responsible for sending false information to the nucleus in the case of a specific tumor? This molecule should be “instructed” to “stop sending the false signal!” This message can be sent to the defective molecule or molecules using modern targeted anticancer drugs.