Cancer is a large group of diseases (over 200) characterized by uncontrolled growth and spread of
abnormal cells.*
•We use the term “cancer” to refer to a group of almost 200 different diseases. Our bodies are made
up of about 30 trillion cells. The cells group together to form tissues and organs. Cancer can arise in
any of those cells.
•For example, stomach cancer is a different disease than breast cancer. It has different treatments, etc.
There are even different types of breast cancer and skin cancer, etc.
Etiology of Cancer
All cancers are multifactorial in origin. They include genetic, hormonal, metabolic, physical, chemical
and environmental factors. Most human cancers are spontaneous.
Normal Cells Vs. Cancer Cells
Cancer cells:
Lose control over growth and multiplication
Do not self-destruct when they become worn out or damaged
Crowd out healthy cells
Cancer cells reproduce every 2-6 weeks.
Signs and Symptoms of Cancer
• Change in bowel habits or bladder functions
• Sores that do not heal
• Unusual bleeding or discharge
• Lumps or thickening of breast or other parts of the body
• Indigestion or difficulty swallowing
• Recent change in wart or mole
• Persistent coughing or hoarseness.
•Thickening or lump in breast or other parts of the body. Many cancers can be felt through the
skin, particularly in the breast, testicle, lymph nodes (glands), and the soft tissues of the body. A
lump or thickening may be an early or late sign of cancer. Any lump or thickening should be
reported to your doctor. You may be feeling a lump that is an early cancer that could be treated
successfully.
•Indigestion or d
ifficulty swallowing. These symptoms may indicate cancer of the esophagus,
stomach, or pharynx (throat).
•Recent change in a wart or mole. A change in color, loss of definite borders, or an increase in size
should be reported to your doctor without delay. The skin lesion may be a melanoma which, if
diagnosed early, can be treated successfully.
•A nagging cough or hoarseness. A persistent cough that does not go away is a sign of lung cancer.
Hoarseness can be a sign of cancer of the larynx (voice box) or thyroid. These are often late signs of
cancer.
•Additional general symptoms
•Unexplained weight loss, Fever, Fatigue, Pain.
Characteristics of cancer cells
•1. Lack differentiation and do not contribute to body functioning
•2. Have abnormal nuclei that are enlarged and may have an abnormal number of chromosomes
•Unlimited ability to divide
–one way is through turning on the telomerase gene that allows telomeres on chromosomes to
continually be built thus allowing a cell to divide over and over again
•Form tumors
–Benign tumors are usually encapsulated and do not invade adjacent tissue while a cancerous
tumor usually is not encapsulated and eventually invades surrounding tissue
•Can divide without growth factors
•Become abnormal gradually through a multistage process
•Undergo angiogenesis and metastasis.
The 3 phases in the development of
cancer cells
1. Initiation – a single cell undergoes a
mutation that causes it to divide
repeatedly
2. Promotion – a tumor develops and
cells within the tumor mutate
3. Progression – a cell mutates in such
awaythatallowsittoinvade
surrounding tissue.