How are Tumor cells different from Normal cells? Tumor Biology

Biology of Cancer

How deadly is the Cancer diseases is? What are the exact causes of Cancer diseases? Why do peoples who don’t smoke get cancer? Why is the cure for cancer so elusive? Is there a treatment available for most cancer? Are most of the Cancer diseases are genetically inherited? What is the survival rate of Cancer Patients? Does all Tumor formation lead to Cancer? How many types of Cancers diseases do Humans get affected? If you have a question like above related to Cancer then you should continue reading this post.

pink ribbon cancer awareness

As per the survey, it has been found that peoples around the world have known about only two or three types of cancer and most of them think that cancer is a death message and there is no treatment for the Cancer. But the truth is Medical science is advanced and there are hundreds of medicines designed to cure various cancer diseases.



Cancer is one of the most common diseases found in humans with most of the disease don’t have any known treatments. As per the World health organization survive below are the statistics of Cancer occurrence and its facts.

  • Cancer is the second leading cause of death globally and was responsible for 8.8 million deaths in 2015. Globally, nearly 1 in 6 deaths is due to cancer.
  • Cancer is one of the leading causes of morbidity and mortality worldwide, with approximately 14 million new cases in 2012.
  • More than 60% of the world’s new cancer cases occur in Africa, Asia, and Central and South America; 70% of the world’s cancer deaths also occur in these regions.
  • In 2015, only 35% of low-income countries reported having pathology services generally available in the public sector. More than 90% of high-income countries reported treatment services are available compared to less than 30% of low-income countries.
  • The number of new cases is expected to rise by about 70% over the next 2 decades.


Cancer has accounted for 8.8 million deaths in 2015. The most common causes of cancer death are cancers of:

  • Lung (1.69 million deaths).
  • Liver (788 000 deaths).
  • Colorectal (774 000 deaths).
  • Stomach (754 000 deaths).
  • Breast (571 000 deaths). 

What is Cancer?

A Cancer is a disease caused by an uncontrolled growth and division of abnormal cells in any part of the body. In all types of cancer, some of the body’s cells begin to grow abnormally forming solid tumors with a mass of tissue invading and blocking the normal cells and tissues from its function.

Normally, human cells grow and divide to form new cells as the body needs them. When cells grow old or become damaged, they die, and new cells take their place.

When cancer develops, however, this orderly process breaks down. As cells become more and more abnormal, old or damaged cells survive when they should die, and new cells form when they are not needed. These extra cells can divide without stopping and may form growths called tumors.

All Tumors are not Cancers:

A Tumor is an abnormal mass of tissue which may be solid or fluid. All Tumor growth may or may not be harmful to the health. Based on the proliferation of cells Tumors are differentiated into different types:

Benign Tumor:

Benign Tumor is a type of tissue containing cells with altered genetic material which divide and replicate to form a mass of cells. Benign Tumor is characterized by the lack of the ability to invade neighboring tissue or metastasize.

Benign Tumor is not cancerous and poses a health risk but sometimes when present in some vital places of the body produce pressure on normal cells and tissues which may lead to some health related problem.

Benign tumors can sometimes be quite large, and when removed, they usually don’t grow back.

Do I Have Cancer? 50 Things About 50 Cancers to know mor Click Here!

Premalignant Tumors:

Precancerous or Premalignant cells are abnormal cells that may develop into cancer if they aren’t treated. Some cells develop mild changes that may disappear without any treatment. Other cells pass on genetic changes and new cells gradually become more and more abnormal until they turn into cancer. It can take a long time for this to happen.

Examples of premalignant growths are Actinic keratosis, Hyperplasia, Dysplasia of the cervix, Atypia, Leukoplakia, and metaplasia.

Malignant Tumor:

Types of CancerMalignant Tumor is the type of tissue containing abnormal cells which can spread and invade nearby tissues. These cancer cells can break off and travel to distant places in the body through the blood or the lymph system and form new tumors far from the original tumor. Generally, Malignant Tumor poses the greater health risk to the human body.

The cells in the malignant Tumor are characterized by acceleration of the cell cycle, genomic alterations, invasive growth, increased cell mobility, chemotaxis, changes in the cellular surface, secretion of lytic factors etc.

A morphologically malignant cancerous cell is characterized by a large nucleus, having an irregular size and shape, the nucleoli are prominent, and the cytoplasm is scarce and intensely colored or, on the contrary, is pale.

Biology of Cancer origin

Cancer is a genetic disease that is caused by changes in genes that control the way our cells function, especially how they grow and divide. They can also arise during a person’s lifetime as a result of errors that occur as cells divide or because of damage to DNA caused by certain environmental exposures.

The genetic changes that contribute to cancer tend to affect three main types of genes via proto-oncogenes, tumor suppressor genes, and DNA repair genes.


Proto-oncogenes are involved in normal cell growth and division. However, when these genes are altered in certain ways or are more active than normal, they may become cancer-causing genes allowing cells to grow and survive when they should not.

Tumor suppressor genes:

Tumor suppressor genes are also involved in controlling cell growth and division. Cells with certain alterations in tumor suppressor genes may divide in an uncontrolled manner. 

DNA repair genes:

DNA repair genes are involved in fixing damaged DNA. Cells with mutations in these genes tend to develop additional mutations in other genes. Together, these mutations may cause the cells to become cancerous.

Causes of Cancer:

Smoking Tobacco main cause of Lung cancer

There are various factors which led to the proliferation of cancer cells leading to tumors. Some of the factors are due to the lifestyle and various habits like smoking and chewing tobacco etc and some are genetically inherited by Parents or other Family members.

The list below includes the most-studied known or suspected risk factors for cancer.


Advancing age is the most important risk factor for cancer overall, and for many individual cancer types. According to the most recent statistical data from NCI’s Surveillance, Epidemiology, and End Results program, the median age of a cancer diagnosis is 66 years. This means that half of cancer cases occur in people below this age and half in people above this age. One-quarter of new cancer cases are diagnosed in people aged 65 to 74.


Drinking alcohol can increase the risk of cancer of the mouth, throat, esophagus, larynx (voice box), liver, and breast. The research evidence indicates that the more alcohol a person drinks—particularly the more alcohol a person drinks regularly over time—the higher his or her risk of developing alcohol-associated cancer.


Tobacco use is the most important risk factor for cancer and is responsible for approximately 22% of cancer deaths. People who use tobacco products or who are regularly around environmental tobacco smoke have an increased risk of cancer because tobacco products and secondhand smoke have many chemicals that damage DNA.

Imbalance in Hormone production:

Estrogens, a group of female sex hormones, are known human carcinogens. Studies have shown that a woman’s risk of breast cancer is related to the estrogen and progesterone made by her ovaries.


High-energy radiation, such as x-rays, gamma rays, alpha particles, beta particles, and neutrons, can damage DNA and cause cancer. People who are exposed to high levels of radon have an increased risk of lung cancer.

Cancer-Causing Substances in the Environment: Cancer is caused by changes in certain genes that alter the way our cells function. Some of these genetic changes occur naturally when DNA is replicated during the process of cell division. But others are the result of environmental exposures that damage DNA.

Chronic Inflammation:

Chronic inflammation may be caused by infections that don’t go away, abnormal immune reactions to normal tissues, or conditions such as obesity. Over time, chronic inflammation can cause DNA damage and lead to cancer.

Bad Dieting and Lifestyle:

As per the WHO report, around one-third of deaths from cancer are due to the 5 leading behavioral and dietary risks: high body mass index, low fruit and vegetable intake, lack of physical activity, tobacco use, and alcohol use.

Studies of cancer cells in the laboratory and of animal models have sometimes provided evidence that isolated compounds may be carcinogenic. Following healthy diets are shown to be effective to prevent cancer occurrence.

  • The daily diet with a lot of fresh, vegetables and fruits are shown to be very preventing cancer occurrence.
  • Limiting alcohol intake to 1 alcoholic drink a day or less for women and 2 or less for men.
  • Limited intake of red meats like beef, pork, and lamb.
  • Choosing balanced diet containing whole grains rather than refined grains and sugars.
  • Balanced diets with foods in amounts that help them get to and stay at a healthy weight.


Research has shown that transplant recipients are at increased risk of a large number of different cancers. Some of these cancers can be caused by infectious agents, whereas others are not.


People who are obese may have an increased risk of several types of cancer, including cancers of the breast (in women who have been through menopause), colon, rectum, endometrium (lining of the uterus), esophagus, kidney, pancreas, and gallbladder.

Excess exposure to Sunlight:

The sun, sunlamps, and tanning booths all give off ultraviolet (UV) radiation. Exposure to UV radiation causes early aging of the skin and skin damage that can lead to skin cancer.

Symptoms of Cancer:

The mains symptoms related to cancers are:

  • Change in Skin like A new mole or a change in an existing mole and a sore that does not heal.
  • Change in size or shape of the breast or nipple and Change in the texture of breast skin.
  • A thickening or lump on or under the skin.
  • Hoarseness or a cough that does not go away.
  • Changes in bowel habits.
  • Difficult or painful urination.
  • Weight gain or loss with no known reason.
  • Abdominal pain.
  • Unexplained night sweats.
  • Unusual bleeding or discharge, including Blood in the urine, Vaginal bleeding, and Blood in the stool.
  • Feeling weak or very tired.
  • Problems with eating, such as Discomfort after eating, A hard time swallowing, Changes in appetite.

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