What is cancer?

Cancer is not a single disease; rather, it is a term that describes a wide range of diseases characterized by the unregulated growth and spread of cells to different parts of the body. Cancer begins when normal cells in the body, which are its basic building blocks, undergo changes and begin to grow and multiply in an abnormal and uncontrolled manner [1].

Normally, the body follows an organized process to produce new cells to replace old or damaged cells that die. However, in the case of cancer, this process is disrupted, and new cells continue to grow even when they are not needed, while the old cells that should have died do not [1].

How does cancer develop?

These extra cells accumulate to form a mass known as a tumor. Tumors can be benign (non-cancerous) or malignant (cancerous). Benign tumors do not spread to neighboring tissues, while malignant tumors can invade nearby tissues and spread to other parts of the body. The spread of cancer from one part of the body to another is known as metastasis [1] [2].

Cancer is a genetic disease by nature, meaning it results from changes in genes that control cell functions, specifically how they grow and divide. These genetic changes can occur as a result of errors during cell division, or due to DNA damage caused by harmful substances in the environment (such as chemicals in tobacco smoke and ultraviolet radiation from the sun), or they can be inherited from parents [2]. The body usually gets rid of cells with damaged DNA before they turn into cancer cells, but this ability decreases with age, which partly explains the increased risk of cancer later in life [2].

Types of cancer

There are more than 100 different types of cancer, and they can start almost anywhere in the body. Most types of cancer are named based on where they started. For example, lung cancer begins in the lungs, and breast cancer begins in the breast [1]. Cancer can also be described by the type of cell it originated from, such as sarcoma if the cancer begins in the bones and soft tissues, or carcinoma, which is the most common type and begins in the epithelial cells that line the inner and outer surfaces of the body [1] [2].

Examples of hereditary cancer predisposition syndromes include BAP1 syndrome, a genetic condition that increases the risk of various types of cancerous and non-cancerous tumors, typically including certain types of skin, eye, kidney, and chest and abdominal lining tumors [3]. In these cases, cancers tend to appear at a younger age and are often more aggressive than cancers that affect the general population [3].

When should you see a doctor?

Symptoms of cancer depend on the type and stage of its development. Potential symptoms of cancer may include a lump in the breast, blood in urine or stool, bleeding or bruising for no known reason, a sore that does not heal, difficulty swallowing, or a new mole or a change in an existing mole [1]. It is important to note that while cancer may cause a variety of symptoms, it often does not cause pain in its early stages. Do not wait until you feel pain before visiting a healthcare provider [1]. If you have symptoms that do not improve within a few weeks, you should see your doctor for evaluation. For more information about the importance of regular screenings and warning signs, you can visit Early Cancer Detection: The Importance of Regular Screenings and Warning Signs (Arabic).

Medical references

• Cancer
• What Is Cancer?
• BAP1 tumor predisposition syndrome: MedlinePlus Genetics