Disorders of Cell Growth

Cancer

Oncology

• Study of cancer

• 25% of Americans develop cancer at some point in life

Nature of cancer cells

• Normal cells that have a permanent CHANGE in them

• Cancer cells perpetuate themselves

• Lose normal growth regulation

Characteristics of cancer cells

Cancer Cells

• Lack of contact inhibition. Cancer cells lack this and continue growing even if they have contact with neighboring cells

• Tumor – Growth e.g. adenoma

• Neoplasia – “new” growth

Cancer cells

• Invade and infiltrate normal cells

• Lack of differentiation– Abnormal size & shape– Abnormal nucleus

Normal cells have differentiation

Cancer cells

• Loss of normal functions

• Divert more blood vessels for themselves for more nutrients

Malignancy

• Detachment and spreading

• Metastasis – cancer cells can detach and spread. Typically they spread via the bloodstream or via lymph vessels

Cancer cells

• Benign = “innocent” These tumors do not metastasize

• Malignant = Cancer. These do metastasize

Causes of Cancer

• Predisposing factors increase the likelihood of developing cancer

• Increase in cell number

• Disordered cell proliferation

• Chronic irritation resulting in changed cells

• Stressors suppressing the immune system

• Hereditary predisposition

Initiation

• DNA mutation

• Not repaired

• Changing of a normal cell to an abnormal cell

Promotion

• Providing an environment for uncontrollable growth

• Encourages growth

Carcinogens

• Agents that initiate or promote abnormal cells and their growth

• 85% of all carcinogens are environmental

Progression

• Abnormal cells become malignant

Immune System

• Our immune system is constantly spotting abnormal cells

• Our immune system can recognize more than 10 million different cancer antigens

Treatments

• Surgery

• Radiation

• Chemotherapy

• Immunotherapy

Danger Signals of Cancer

• Bleeding, discharge

• Lumps, thickening

• Non-healing sores

• Bowel or urinary changes

• Hoarseness or cough

• Mole or wart change

• Difficulty swallowing/ indigestion

Breast lump

Avoidance

• 75% cancer deaths are related to lifestyle

• Avoid direct sunlight

• Low fat diet

• Quit smoking

• Increase roughage in diet

• Fresh fruits & vegetables

• Early detection

Types of Cancer

• Carcinoma – Cancer of the epithelial tissue

• Sarcoma – Cancer of connective tissue

• Leukemia – Cancer of blood

• Lymphoma – Cancer of Lymph tissue