The document discusses cancer at a high level. It defines cancer as uncontrolled cell growth and describes how some cancers cause rapid growth while others are slower. Cancerous cells can spread through the body via the lymph nodes and tumors can be malignant, meaning they invade nearby tissues and metastasize. There are many causes of cancer including smoking, alcohol, viruses, chemicals and radiation. Cancers are named for where they begin and the type of cell. The direct cause of cancer is changes to DNA from environmental and genetic factors.
2. Cancer describes the disease that results when cellular changes
cause the uncontrolled growth and division of cells.
Some types of cancer cause rapid cell growth, while others cause
cells to grow and divide at a slower rate.
Certain forms of cancer result in visible growths called tumors,
while others, such as leukemia do not.
Cancerous cells may appear in one area, then spread via the lymph
nodes. These are clusters of immune cells located throughout the
body.
Cancerous tumors are malignant, which means they can spread
into, or invade, nearby tissues.
The process of cancer cells leaving an area and growing in another
body area is termed metastatic spread or metastasis.
3. There are many causes of cancer.
Smoking
Heavy alcohol consumption
Chemical mutagen
Physical mutagen
Viruses
4. Cancers are named for the area in which they begin and the type of cell
they are made of, even if they spread to other parts of the body.
For example, a cancer that begins in the lungs and spreads to the liver is
still called lung cancer.
Carcinoma is a cancer that starts in the skin or the tissues that line other
organs.
Sarcoma is a cancer of connective tissues such as bones, muscles, cartilage,
and blood vessels.
Osteosarcoma: related to bone
Chondrosarcoma: related to cartilage
Liposarcoma: related to fat
Myosarcoma: related to muscles
Leukemia is a cancer of bone marrow, which creates blood cells.
Lymphoma and myeloma are cancers of the immune system.
5. The direct cause of cancer is changes (or mutations) to the DNA in your
cells. Genetic mutations can be inherited. They can also occur after birth as
a result of environmental forces. Some of these forces include:
exposure to cancer-causing chemicals, called carcinogens
exposure to radiation
unprotected exposure to the sun
certain viruses, such as human papilloma virus (HPV)
smoking
lifestyle choices, such as type of diet and level of physical activity
6. Benign tumor: Cell remain cluster together in a single mass and cannot
spread to other site.
Malignant tumor: Cancer cells invade in surrounding tissue and circulate
in whole body through lymphatic system. This process is known as
metastasis.
Benign and malignant tumors are classified according to origin of cells.
Carcinoma: originate from the endodermal tissue.
Sarcoma: originate from the mesodermal connective tissue.
Leukemia/Lymphomas: originate from the blood tissue and immune
system.
Transition from normal cell to tumor cell is called transformation.
7. Oncogene, tumor supressor genes and carcinogen are the cancer causing
agent.
Oncogenes: oncogenes cause cancer. It can express in high level and
mutated cell.
When normal cells change or altered, it convert into cancer cell.
Oncogenes generate from proto-oncogenes. Proto-oncogenes are normal
gene, which involve in cell growth, proliferation and inhibition of
apoptosis.
Normally multiple oncogene, mutated apoptotic gene and tumor supressor
gene cause cancer.
Proto-oncogene: It is normal gene, which convert in to oncogene due to
mutation.
It encode proteins, which help in cell growth and differentiation. It increase
the inhibition of apoptosis.
It involve in signal transduction pathway.
Example of proto-oncogenes: RAS, WNT, MYC, TRK, ERK.
8. Tumor-supressor genes: It is antioncogenes. It protect the cell from
cancer path.
When any normal cell loss their function or activity, it will be progress into
cancer cells.
Tumor supressor gene can be divided in many categories.
Caretaker gene, Gate keeper gene and landscaper genes.
These all gene encode the protein, which regulate cell cycle and promote
apoptosis.
Example of tumor supressor genes: Retinoblastoma protein
p53 (tumor supressor gene)
When cellular damage occur then p53 prevent the cell cycle. If damage does
not repair, it cause apoptosis.
However, mutated p53 does not prevent the cell cycle and damaged cells
continue divide and caused cancer.
9. Normal p53 Mutated p53
Cell cycle arrest Apoptosis
DNA repair
Cell cycle restart
Cell Cycle continue
Cells can become
cancerous