What is Cancer?

Last Update on September 13, 2022

Medically reviewed by Dr. Priya Tiwari

| Signs and Symptoms | How Does Cancer Develop? | Fundamentals | Genes that Cause Cancer | Transmission | Types |

Cancer is a condition when a few of the cells of the body grow out of control and spread to other regions of the human body.

The human body, which contains trillions of cells, can develop cancer practically everywhere. Human cells often divide to create new cells as the body requires. This process is known as cell growth and multiplication. A new cell replaces an old one when it dies or is damaged.

Sometimes, this systematic process fails, causing damaged or abnormal cells to divide when they shouldn’t. These cells have the ability to develop into tumors, which are tissue lumps. Malignant tumors may or may not exist (benign).

Entering nearby tissues, spreading to distant regions of the body, or both is possible for cancerous tumors (a process called metastasis). Cancer tumors are also called malignant tumors. Malignancies of the blood, including leukemia, seldom develop solid tumors although many other cancers do.

Noncancerous cells do not enter or spread to neighboring tissues in the body. Benign tumors typically don’t restore after removal. However, benign tumors can sometimes grow to be quite enormous. Some, like benign brain tumors, can have grave side effects or even be deadly.

1. Signs and Symptoms of Cancer:

Depending on what region of the body is affected, cancer can create a variety of signs and symptoms.

Some common signs and symptoms of cancer are:

  • Fatigue
  • Blow the skin, a lump or thickening might be felt
  • Suddenly loss or increased weight
  • Skin color changes such as skin color change to yellow, darkening, or red, sores that won’t heal, or modifications to existing moles
  • Alterations in bowel or bladder patterns
  • Persistent cough or breathing issues
  • Having trouble swallowing
  • Hoarseness
  • Persistent heartburn or discomfort following a meal
  • Persistent, irrational joint or muscle pain
  • Persistent, irrational fevers or sweats at night
  • Bruising or bleeding that is not normal

2. How does Cancer Develop?

Cancer is a genetic disease because the genes that control how our cells behave, specifically how they expand and divide, are modified. Cancer-causing genetic changes can occur because:

  • Due to errors that happen when cells divide.
  • DNA deterioration is caused by harmful environmental factors, such as the poisons in cigarette smoke and the sun’s UV radiation.
  • Cancer cells were transferred to us by our parents.

Cells with damaged DNA are typically removed by the body before they develop into cancer, but with the passing of time, the body becomes less capable to remove cells. This leads to a higher chance of developing cancer later in life.

The genetic changes in every person’s cancer are different from one another. More changing will take place when the cancer cells spread throughout the body. Different cells in the same tumor cells may have different genetic changing.

3. Fundamentals of Cancer:

  • Cancer develops when cells divide uncontrolled and spread throughout the tissues.
  • Most DNA changes that lead to cancer take place in regions of DNA known as genes. Genetic changes are another name for these modifications.
  • Genes involved in regular cell growth can become oncogenes as a result of a DNA change. Encogenes, which cannot be switched off like regular genes, result in uncontrollable cell growth.
  • Tumor suppressor genes prevent cancer in healthy cells by promoting or inhibiting cell growth. Uncontested cell growth and cancer can result from DNA changes that deactivated tumor suppressor genes can result in uncontrolled cell growth and cancer in the human body.
  • Cancer cells are enclosed by a variety of immune cells, fibroblasts, molecules, and blood cells within a tumor. These ate the tumor microenvironment.
  • Immune system cells can identify and destroy cancer cells, however, some cancer cells are able to resist detection or block an attack. Some cancer treatments can support the immune system in targeting and destroying cancer cells.
  • The genetic changes in each person’s cancer are different from one another. Unique genetic changes may cause a person’s cancer to be more or less likely to react to a certain treatment.
  • Cancer-causing gene changes can be transmitted or result from certain environmental factors. Additionally, errors that occur during cell division might result in genetic changes.
  • Most frequently, as a person ages, cancer-causing gene changes progressively accumulate, increasing their likelihood of developing the disease in later life.
  • Cancer cells have the ability to leave the primary tumor and move through the lymphatic or cardiovascular system to distant parts of the body, where they exit the blood vessels to create new tumors. This process is called Metastasis.

4. Different types of Genes that Cause Cancer:

Proto-oncogenes, tumor suppressor genes, and DNA repair genes are the three primary gene groups that are typically affected by the genetic alterations that cause cancer. These changes are basically referred to as cancer drivers.

Proto-oncogenes play a role in regular cell division and development. However, these genes may develop into cancer-causing genes (or oncogenes), allowing cells to grow and maintain when they shouldn’t by being changed in specific ways or being more active than usual.

Genes that prevent tumors are also involved in regulating cell division and proliferation. Particular tumor suppressor gene changes can cause cells to divide uncontrollably.

DNA repair genes restore the DNA damaged cells. It is common for cells with changes in these genes to also have changes in other genes and chromosomal abnormalities including duplications and deletions of chromosomal segments. These alterations might work together to turn the cells cancerous.

Researchers have discovered that specific changes frequently occur in a variety of cancer forms as they learn more about the molecular alterations that cause cancer. There are numerous cancer medicines on the market right now that focus on cancer-related gene mutations. No matter where cancer first developed, several of these treatments are available to anyone with a tumor that carries the targeted mutation.

5. Transmission of Cancer cells:

Metastatic cancer is a type of cancer that has progressed from the site of its initial development to another location in the body. Metastasis is the process through which cancer cells expand to other areas of the body.

The initial or basic cancer’s name and cancer cell type also apply to metastatic cancer. As distinct from lung cancer, breast cancer that has spread to the lung and formed a tumor is known as metastatic breast cancer.

Metastatic cancer cells basically responsible for the original tumor’s cells when viewed under a microscope. Additionally, there are some biological similarities between metastatic cancer cells and the initial cancer cells, such as the existence of specific chromosome changes.

People with metastatic cancer may sometimes live longer with the aid of treatment. In other situations, the major goals of treating metastatic cancer are to stop cancer from spreading or to minimize the symptoms. Most cancer patients die from metastatic disease, which can result in a lack of how the body works.

6. Tissue changes that do not cause cancer:

Cancer is not always a result of tissue changes in the body. However, if some tissue alterations are not treated, they may progress to cancer. Here are a few instances of tissue changes that are not cancer but are occasionally under observation in case they develop into cancer:

  • Hyperplasia: When cells within a tissue expand more quickly than is typical, an accumulation of extra cells is called hyperplasia. Under a microscope, the tissue’s cells and organizational structure nonetheless appear normal. Chronic irritation is one of several causes or diseases that can lead to hyperplasia.
  • Dysplasia: In comparison to hyperplasia, dysplasia is a more advanced disorder. There is also an accumulation of extra cells in dysplasia. However, the tissue’s organization has changed, and the cells appear aberrant. Generally speaking, the likelihood of developing cancer increases with how aberrant the cells and tissue appear. Some forms of dysplasia could require monitoring or treatment, while others don’t. An aberrant mole that develops on the skin and is referred to as a dysplastic nevus is an illustration of dysplasia. While most dysplastic nodules do not progress to melanoma, some do.
  • Carcinoma: The condition that is considerably further advanced is carcinoma in situ. The aberrant cells do not infect the surrounding tissue the way cancer cells do, even though it is commonly referred to as stage 0 cancer. However, certain in situ carcinomas may progress to cancer, thus they are typically treated.

 7. Types of Cancer:

List of cancer types: