Ch.8 Cancer

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What is cancer?
Uncontrolled mitosis

Leads to producing excess cells that are abnormal

ACS: "Cancer is a group of diseases characterized by uncontrolled growth and spread of abnormal cells. If the spread is not controlled, it can result in death."
Tumor
A mass of extra cells created by mitosis
Benign vs Malignant
Benign: A tumor that contains cells that are not invasive and do not move in the body

Malignant: A tumor that contains cells that can be invasive and have the potential to move in the body.
What is metastasis?
The movement of cells with lymphatic fluids or blood to new locations in the body.
Why can cancer cause problems?
Malignant cells are invasive and interfere with the function of healthy cells, no longer perform the functions they are supposed to perform in the body, and can put pressure on surrounding tissues and organs.
What are some common early detection tests?
PAP Smear: cervical cancer

Mammogram: breast cancer

Colonoscopy: breast cancer

PSA (Prostate-Specific Antigen Test): prostate cancer
Characteristics of Cancer cells
Lack of contact inhibition: normal cells stop dividing when they pile up on each other. Cancer cells ignore the signal and continue to divide.

Immortality: A normal cell divides about 50 times, apoptosis is triggered, then the cell dies. Cancer cells don't.

Reversion to immature form: Prevents the cells from doing their normal job
Why do cell cycle check points fail?
Mutations occur in a single cell
-These can be inherited or induced
Carcinogens
Factors known to increase the rate of mutations in genes related to cancer
Why does cancer happen?
Too many growth factors are present
-Growth factors are proteins that stimulate the cell cycle
-Required for normal mitosis
-But too many over stimulate the cell cycle

Mutation of porto-oncogenes
-Good genes
-Code for proteins to regulate cell cycle
-When mutated, they become oncogenes (bad)
-No longer regulate cell cycle

Mutations to DNA Repair Genes
-Good genes
-Repair minor damage to DNA
-If mutated, repair function is lost (bad)

Mutation of tumor suppressor gene
-Good gene
-Code for proteins that destroy malignant cells
-If mutated, the defense is lost (bad)
-BRCA1-Breast Cancer
Diagnosis
Must look at cells to tell if they are cancerous
Biopsy
Most common analysis of cells

Done by comparing rate of mitosis to a control value of the same tissue type
Cancer Scans
PET Scan (Positron Emission Tomography)

Involves drinking a glucose solution marked with radioactive tracer
Plasia
Formation
Hyperplasia
Accumulation/increased number of cells
Metaplasia
Normal cells change type
Anaplasia
Cells revert back to immature form; indicate malignancies
Dysplasia
Abnormal growth of tissue or organ; precancerous
Grade I
Cells differ slightly from normal cells
Grade II
Cells are more abnormal
Grade III
Cells are very abnormal; hard to differentiate
Grade IV
Cells are immature, primitive, and undifferentiated; it is difficult to decide the origin of cells.
Stage O
Cancer is located only in the inner lining surface of an organ and is not invading the organ
Stage I
The cancer has not spread past the tissue or organ where it started
Stage II
There is some local and regional spread of cancer, usually to draining lymph nodes.
Stage III
Extensive local and regional spread of cancer, usually to draining lymph nodes
Stage IV
Cancer has spread (metastasized) beyond the regional lymph nodes to distant parts of the body
What does surgery do?
Cuts out the tumor
Not an option for all types of cancer
Goal is clean margins
Often involves follow up with other methods
Radiation
Radiation exposure leads to formation of free radicals
-At high doses, this can kill the cell
-If controlled and localized, this may have a change at destroying cancerous cells

Administered externally or internally

Side effects are due to the death of normal cells which are killed by exposure

Cells that divide the fastest are most damaged
Chemotherapy
Toxins that cause damage to cells that divide fast
-Can prevent chromosomal replication, alter spindle fibers, target specific proteins

Systematic approach

Adminstered orally

Major side effects due to damage to healthy cells
Angiogenesis
Process of blood vessels growing into tumor
Cannabidiol (CBD)
Major alkaloid found in cannabis

Used to treat epilepsy, spasms, anxiety, schizophrenia, nausea

Found to inhibit cancer growth

Found to inhibit cancer cell invasiveness
Immunotherapy
Treatment boost the killing power of immune system by making cancer cells easier to identify

Enhancing the ability of the body to repair/replace normal cells
Examples of immunotherapies
Antibodies: immune cells that recognize and bind to abnormal or foreign cells to mark and destroy or incapacitate them

Cytokines: tell your immune system to attack

Cancer vaccines
Targeted Therapies
Radiation seeds

Angiogenesis inhibitors

Apoptosis-inducing drugs