Cancer cells are cells that have undergone a malignant transformation. This means that they have acquired the ability to grow uncontrollably and invade other tissues in the body. Cancer cells can spread (metastasize) to other parts of the body through the bloodstream or lymphatic system.
Cancer cells are characterized by uncontrolled growth, the ability to invade other tissues, and the potential to metastasize to other parts of the body. Cancerous cells are cells gone wrong, in other words. They no longer respond to many of the signals that control cellular growth and death, as described in the Krebs Cycle. Cancer cells originate within tissues and, as they grow and divide, they change even further from normal. Over time, these cells become increasingly resistant to the controls that maintain normal tissue and as a result, they divide more rapidly than their progenitors and become less dependent on signals from other cells.
Metastasis is the process by which cancer cells spread from the site of origin to other parts of the body. This occurs through a combination of local invasion and the ability to enter the bloodstream or lymphatic system and travel to distant sites. Cancerous cells that have metastasized are often more aggressive and difficult to treat than those that remain at the site of origin.
There are many types of cancer, each with its own set of characteristics. However, all cancer cells share certain properties that allow them to grow uncontrollably and spread throughout the body. Cancer is a complex disease that requires a multimodal approach for treatment. Surgery, radiation, and chemotherapy are the most common treatments for cancer.
Once cancer cells have metastasized, they can grow into new tumors at distant sites. This process is responsible for the majority of cancer-related deaths.
Abstract metastases, rather than primary tumors, are responsible for most cancer deaths. In this stage, cancerous cells enter the bloodstream or the lymphatic system and travel to a new location(s) in the body, where they begin to feed and divide, laying the foundation for secondary tumors. Not all cancerous cells can metastasize. In order to spread in this way, the cells must have the ability to penetrate the normal barriers of the body so that they can both enter and exit the blood or lymph vessels, this is typically referred to as cancer stem cells.
Cancer stem cells (CSCs) are a type of cell that has the ability to give rise to new tumors. Theory suggests that only a small subset of cells within a tumor are able to metastasize. CSCs are thought to be more resistant to therapy and more likely to give rise to new tumors.
This theory is supported by the fact that, in some cases, all the cancerous cells in a tumor may be destroyed by therapy, but the tumor continues to grow because of the presence of CSCs.
CSCs are thought to be more resistant to therapy and more likely to give rise to new tumors. The existence of CSCs was first proposed in the 1950s, but the concept gained traction in the 1990s when researchers began to study the properties of these cells.
Although the existence of CSCs is still debated in some circles, the bulk of evidence suggests that they play a role in tumor growth, metastasis, and recurrence. The exact number of CSCs in a given tumor is not known, but it is thought to be very small. In some cases, only a single cell may be responsible for the growth of a tumor.