Ever hear someone say that every human has cancer at a given moment in time? Although clinically undetected cancers are common, the natural defenses of your body often eliminate abnormal cells before a cancerous disease state occurs.
A number of genetic failures are necessary before unbridled replication begins. We will address the genetic fail-safes forestalling cancer, the path of these replicating cells as they make their way through the body, and the immune response to these untethered cells.
The top image shows a single necrotic tumor cell in the center of a squamous carcinoma.
Cancer is not a new disease. A text within the Edwin Smith Papyrus describes the removal of several growths from Egyptian patients in 1600 BCE. The text mentions the use of a “fire drill” a to remove growths that lack a treatment, with these growths matching descriptions of modern tumors.
In the 16th Century CE, physicians believed cancer to be contagious, leading to the isolation of breast cancer patients from the rest of society. Prior to adoption of our current cellular understand of cancer, physicians theorized that cancer developed from prior physical trauma. Physicians, however, lacked the ability to link physical trauma inflicted on animals in experiments to cancerous growths later in their life.
90 trillion cells
An adult human is comprised of anywhere from sixty to ninety trillion cells. Odds are, out of the 90,000,000,000,000 cells in your body, you going to have a few rogue ones, ones that will be replicating uncontrollably at any one time.
Cells are meant to die and be replaced by new ones – skin cells are sloughed off and replaced by soft, shiny new members of your body. Cellular replication is a natural process, as long as it leads to a proper cell lifespan and replication rate. Proper replication stems from a delicate cascade of cell signaling steps taking into account the availability of nutrients and growth factors. A chain reaction of errors, however, in genetic quality and cell signalling lead to the unwarranted replication of cells and eventual tumor growth.
Tumor suppressor genes yield proteins that cause cellular suicide at the appropriate time or prevent replication of cells with damaged DNA, while a buildup of mutations in tumor suppressor genes can lead to cells growing to an inappropriate age. Mutations also play a role in cellular replication, as mutation and activation of oncogenes in the body can lead to the uncontrolled replication of cells and possibly tumor growth.