What is Cancer
Cancer is a class of diseases in which a group of cells growing and multiplying disordered and uncontrollable way in our body, have become progressively worse and damaged other healthy tissues, sometimes spreads to other organs in the body via lymph or blood and results may be in death.
The growth of normal cells
Under normal circumstance, cell growth is a natural process without even notice, everyday millions of cell grow to replace millions of dead cells and to keep our body in balance and healthy.
Sometimes, acceleration of cells growth is necessary to prevent further damage to the body organ, such as cut, injure, etc., but after fulfilling their purposes, the growth of cells are back to normal rate again due to our body growth inhibitors. Unfortunately, skin cells sometimes overgrow while healing, leading to scar to the skin.
The primary tumor; size and growth
A primary tumor or original tumor is a tumor that is at the original site where it first arose where tumor progression began and proceeded to yield a cancerous mass. Some types of cancer can begin in several place, such as lymphomas and leukemias. Most cancers can not be detected until they formed a lump as little as a grape. A cancer cells need 42 doubling before itcan produce enough cancer cells to cause death.
How cancer cell invade neighbor cells
If the cancer cells grow to its tumor size, they may also invade and kill their neighbor cells by producing abnormal or excessive signaling chemicals (hormones or cytokines) which upset the normal chemical balance of the body and alter the metabolic pathways, leading to disordered and violent cellular behavior.
There are many ways cancer causes of distant formation of secondary cancers1. Local spreading, lymph vessel, blood vessel1.1. Local spreading as soon as the cancer cells grow to its tumor size, it will invade the nearby area. The reason of its action still unknown, but researchers suspect
a. As the tumor grows, it needs more space by pressing on the nearby normal body tissue nearby naturally for its own survival.
Tumors contain large amount of enzymes produced by the cancerous cells to ensure their survival by breaking down the nearby tissues, making a pathway for itself to invade the healthy tissue. Scientists have discovered a substance made by cancer cells which plays a big part in the local spread of cancers.
If some cancer cells detached from the primary tumor and travel can grow into a secondary cancer but most of time they are trapped in the nearby lymph nodes closest to the original tumor.
1.3. Spread through blood circulation
Similar to spread through lymph vessel, cancer cells detached from origanl tumor can enter the blood stream by slipping pass the blood vessel wall and start grow into the secondary tumor as they are trapped into some small capillaries.
It may sound horrible, but only one out of thousands survive this journal to form a secondary cancer or metastasis.
2. Travel of clumps of cancer along the channels
Out of the above, sometimes, cancer cells detached from the primary tumor can travel through other channels, but they do not spread randomly, because some parts of the body are more vulnerable to becoming metastatic sites than others.
3. Arrival of cancer cells at a distance site
The development of the survival of cancer cells get trapped and grow into second tumor is obvious, but researchers do not know how it can get out of the trapping area to invade other organs of the body.
Angiogenesis is defined as a process involving the growth of new blood vessels from pre-existing vessels. As they arrived in area distancing from the primary tumor. The secondary tumor can persuade the adjacent tissue to build blood vessels by providing it with vital nutrients and oxygen, because they are not also recognized by immune system as some foreign substances.
Causes of cancers
Cancers are primarily an environmental disease with 90-95% of cases attributed to environmental factors and 5-10% due to genetics.
Causes of cancer can be divided into 2 groups
A. Environmental cause
Most common environmental factors cause of cancers include tobacco, diet and obesity, infections, radiation, lack of physical activity, and environmental pollutants. Sometimes, The environmental factors can enhance abnormalities in the genetic material of cells as s result of weakened immune system.
Chemicals such as chlorinated hydrocarbons, asbestos, and hexavalent chromium, have been shown to be carcinogenic can enhance DNA mutations, leading to the growth of cancer. There are some chemicals which can promote cancers by stimulating the rate of cell division, leading to less time for repair enzymes to repair damaged DNA during DNA replication, increasing the risk of cancer.
In the United States obesity is associated with the development of many types of cancer and is a factor in 14–20% of all cancer death. Even through there are no direct link of obesity to cancer risk but it may have a negative effects on immune system and endocrine system.
Worldwide approximately 18% of cancers are related to infectious diseases. There is an indication of which viruses are usual infectious agents that cause cancer but bacteria and parasites may also have an effect.
Radiation can cause cancer in most parts of the body, in all animals, and at any age, although radiation-induced solid tumors usually take 10–15 years, and up to 40 years, to become clinically manifest, and radiation-induced leukemias typically require 2–10 years to appear, due to radiation exposure, including both ionizing radiation and non-ionizing radiation.
B. Hereditary genetic cause.
Due to abnormalities of certain class of gene in cells division and replication such as oncogenes and tumor suppressor genes.
Some hormones factor can enhance the development and spread of sex-related cancer, such as cancer of the breast, endometrium, prostate, ovary, and testis, and also of thyroid cancer and bone cancer.
Although there is no evidence of inflammation caused caner, repeated injuries to the same tissues might promote excessive cell division and replication, thus increasing the risk of a cancerous mutation.
Cancers are classified by the types of cell that have become malignant.
Carcinoma is a malignant tumor found in anywhere of epithelial tissues lining the cavities, surfaces of structures and glands. Although the forming of the malignant tumor in epithelium are still unknown, but it possesses and associates the characteristics of epithelial cells, including those of the breast, prostate, lung and colon.
Sarcoma is a type of cancer that arises from malignantly connective tissue cells originated from embryonic germ cells or bone, cartilage, and fat tissues and cells.
3. Lymphoma and leukemia:
Hematopoietic cells are multipotent stem cells that give rise to all types of the blood cell, including red blood cells, white blood cells, and platelets become cancerous.
4. Germ cell tumor
Cancer derived from pluripotent cells. In adults these are most often found in the testicle and ovary, but are more common in babies and young children.
Cancer derived from immature "precursor" or embryonic tissue. These are also commonest in children.
Types of factor that cause cancers
1. Aging: Due to weakened immune system as a result of wear and tear over years. Some researchers suspected that free radicals may be one of contributors.
2. Tobacco :Due to chemical causes of cells alternation
3. Sunlight :Damage to skin as result of ultra violet.
4. ionizing radiation: Any types of hazard chemicals cause of gene mutation
6. Hormones: Abnormal production of certain hormones can increase the risk of sex-related cancers
7. Family history : Check above