Controlling the Cell Cycle

Cancer notes

I. The Cell CycleA. Cancer cells have mutations in the genes that

control the cell cycle.

1. Proto-oncogenes- tell the cell cycle to proceed -"go" genes

2. Tumor-suppressor genes- tell the cell cycle to stop when the cell is done dividing and no more cells are needed - “stop” genes

*If either of these are mutated, it causes the cell cycle to go too fast. The cancer cells divide too fast and pile up in one area, this is called a tumor.

Cancer Formation

B. Cancer = uncontrolled cell division

1. single cell loses control of mechanisms due to a genetic mutation.

2. cell divides without limit, and eventually kills the host.

C. Normal cells are controlled by several factors.

1. Normal: stay in the G1 until given a signal to enter S phase. Cancer: enter S phase without waiting for signal.

2. Normal: divide about 50 times and lose the ability to divide. Cancer: divide endlessly

3. Normal: chromosome damage = destroy themselves. Cancer: fail to kill themselves.

D. tumor- a clump of cells

1. benign- harmless tumor which stays in one region

2. cancerous/malignant- tumor continues to grow & invades other tissue

= metastasis

Affects on a Cancer Cell

E. Cancer cell characteristics

1. typically round ---> mobile

2. can grow in liquids

3. abnormal proteins on membrane, allow cancer cells to escape the immune response (camouflage)

4. invade tissues

Dividing cancer cell

II. Carcinogens- substances which promote (cause) cancer development

A. A few examples

1. smoking

2. tanning

3. pollution

4. chemicals

5. radiation

6. high fat diet

Carcinogens

III. Oncology- area of medicine dealing with cancer

A. Oncologist- doctor who treats cancer

Dr. House Dr. Wilson diagnostician oncologist

Cancer Treatment Discussion

Two basic treatments

1. Remove tumor,

2. Radiation/chemicals kill actively dividing cells.

It is hard to remove all the tumor cells. Tumors often lack sharp boundaries for easy removal, and metastatic (migrating) tumors can be very small and anywhere in the body.

Radiation and chemotherapy are aimed at killing actively dividing cells, but killing all dividing cells is lethal: you must make new blood cells, skin cells, etc. So treatment must be carefully balanced to avoid killing the patient.

If any of the tumor cells are resistant to the chemical, they will survive and multiply. The cancer seems to have disappeared, but it comes back a few years later in a form that is resistant to chemotherapy. Using multiple drugs can decrease the risk of relapse: it’s hard for a cell to develop resistance to several drugs at the same time.

CANCER TREATMENT SIDE EFFECTS

RADIATION

Nausea.

Hair Loss.

Fatigue / Malaise

Low Blood Count

Skin reactions (dryness, itching, redness, blistering)

Mucous Membranes affected (reddened, crusting, inflammation)

Scarring

Carcinogenicity. Radiation is one of the causes of cancer. Very rarely leukemia may result some five to twenty years after radiation exposure, due to bone marrow cells being damaged during radiation therapy. Similarly cancer can result in the area treated twenty or more years later.

Diarrhea

Swelling

Urinary/bladder problems

Infertility

CHEMOTHERAPY

Nausea and vomiting

Hair loss (alopecia): head, eyebrows, body hair

Bone marrow depression

Fatigue

Mouth sores

Weight gain

Decreased tolerance to cold

Sargramostim- flu-like syndrome including fever, chills, tiredness and headache is common.

Bone & joint pain

retaining fluid in the legs or feet, causing swelling

Visual changes such as increased sensitivity to light or double vision

redness, itching and irritation of the eyes

Ringing or pain in the ears

John Kanzius Machine

Kanzius Salt Water Burning

Telomerase and cancer