Cancer(a)

Cancer

Malignant Tumor  Masses of altered cells that divide abnormally  Potentially lethal

Neoplasms  Abnormal masses of cells that ignore controls

over growth and division  Benign neoplasms stay put, don’t spread; examples are moles and other tumors Malignant neoplasms are cancers (carcinomas). Their cells break away and invade other tissues giving rise to more abnormal masses.

Cancer and the Cell Cycle

http://www.geocities.com/CollegePark/Lab/1580/cycle.html

Check Point Genes  The cell cycle has built in check points

controlled by specific genes.  These check point genes are the basis for the mechanisms that advance, delay or block the cell cycle

p53  p53 is an example of a checkpoint gene.  Its product puts the brake on cell division

when chromosomes are damaged.  Controls the G1 to S transition  Cell cycle will not continue until DNA damage it repaired.  Most common gene associated with cancer http://www.geocities.com/CollegePark/Lab/1580/p53.html

p53 Damage  When both genes for p53 are damaged, the

cell can grow abnormally.  This damaged cell’s daughter cells will grow abnormally and so on…  p53 normally will keep the cell from passing on damaged DNA to daughter cells  In many cases DNA damage is so great that p53 programs “cell suicide” (apoptosis)  p53 is a type of tumor suppressor gene

Oncogenes  Many cancers are known to arise through

mutations (changes in genes) in one or more checkpoint genes.  Oncogenes are mutated genes that have the potential to induce cancer. These are growth factor genes that are over expressed.

Mutagens  Mutagens are chemical or physical factors

which can cause changes in genes (mutations)  Ultraviolet radiation, x-rays, asbestos, substances in tobacco smoke to name a few….

Mutation Accumulation  Most neoplasms that become malignant are

cell lines that have accumulated several mutations (9-12).  Usually it takes the passage of time to accumulate that many mutations.  Cancer is associated with aging.

Characteristics of Cancers  The cancer cell membranes and cytoplasm

profoundly change. Cell structures are altered and abnormal proteins accumulate.  Cancer cells grow and divide abnormally.  Cancer cells lack normal adhesive properties. Cancer cells separate from each other and establish colonies elsewhere in the body… new masses form.

Metastasis  This is the process of abnormal cell migration

and tissue invasion of cancer cells.  Abnormally growing and dividing cells have negative effects on surrounding tissue.

Fatalities  In developing countries, 15-20% of the deaths

result from cancer.

Some Good News  While cancer is a multi-step process involving

more than one gene, researchers are busy identifying those genes.  Pharmaceutical firms are rapidly developing drugs to target specific abnormally functioning genes.  Cancer is likely curable, but not necessarily always preventable.

Skin Cancers  Many people have benign skin neoplasms…

moles and tumors  Sometimes these become malignant  Beware of changes in a mole’s physical appearance  In 2001 there were 7,700 deaths from malignant melanomas in the U.S.

Characteristics of Malignant Melanomas  Malignant cells form dark, encrusted lumps  They may itch like an insect bite or bleed

easily  Spreads fastest of the skin cancers

Melanoma Risk Factors  Habitually irritation of moles (e.g. shaving or

wearing abrasive clothes).  Skin chronically chapped, cracked or sore  Ultraviolet radiation exposure  History of cancer in the family  Endured radiation therapy  Sun burn easily

A,B,C,D’s of Moles and Melonoma  Most people have a number of brownish

spots on their skin - freckles, birthmarks, moles. Almost all such spots are normal, but some may be skin cancers. Key warning signs of melanoma are shown below. Be alert to irregularities in shape, edges, color, and size. The ABCD's of melanoma are as follows: Asymmetry, Border irregularity, Color variability, and Diameter larger than a pencil eraser. http://www.skincancer.org/index.php

Asymmetry  Asymmetry  Most early melanomas

are asymmetrical: a line through the middle would not create matching halves. Common moles are round and symmetrical.

http://www.skincancer.org/index.php

Border  Border  The borders of early

melanomas are often uneven and may have scalloped or notched edges. Common moles have smoother, more even borders.

http://www.skincancer.org/index.php

Color  Color  Common moles usually

are a single shade of brown. Varied shades of brown, tan, or black are often the first sign of melanoma. As melanomas progress, the colors red, white and blue may appear. http://www.skincancer.org/index.php

Diameter  Early melanomas tend

to grow larger than common moles generally to at least the size of a pencil eraser (about 6mm, or 1/4 inch, in diameter).

http://www.skincancer.org/index.php

Detect Warning Signs?  If you detect any of these warning signs,

see a physician promptly.

The Skin Cancer Foundation  For a free brochure including a body map and

the warning signs of all major skin cancers, send a stamped, self-addressed, businesssize envelope to:  The Skin Cancer Foundation PO Box 561 Dept. SEW New York, NY 10156

http://www.skincancer.org/index.php

Other Skin Cancers  Basal Cell Carcinoma

(most common type)  Slow growing  Raised lump that ay be uncolored, reddish – brown or black

http://www.aad.org/pamphlets/bcc.html

Other Skin Cancers (cont.)  Squamous Cell

Carcinoma (2nd most common)  Pink in color  Firm to the touch  Spreads under surface of skin often in areas exposed to light

Are there precautions that will reduce my risk?  Minimize your exposure to the sun at midday and between the hours of     

10:00AM and 3:00PM. Apply sunscreen with at least a SPF-15 or higher, to all areas of the body which are exposed to the sun. Reapply sunscreen every two hours, even on cloudy days. Reapply after swimming or perspiring. Wear clothing that covers your body and shades your face. (Hats should provide shade for both the face and back of the neck.) Avoid exposure to UV radiation from sunlamps or tanning parlors. Protect your children. Keep them from excessive sun exposure when the sun is strongest (10:00AM and 3:00PM), and apply sunscreen liberally and frequently to children 6 months of age and older. Do not use sunscreen on children under 6 months of age. Parents with children under 6 months of age should severely limit their children's sun exposure.

American Academy of Dermatology

Can you “catch cancer”? In other words, are some forms infectious?  “Bites spread fatal 'devil' cancer  Facial tumours that have killed thousands

of Tasmanian devils could be spread by the animals biting each other during squabbles over carcasses.  Abnormalities in the chromosomes of the cancer cells were the same in every tumor (suggesting a single common origin).”

From Nature magazine

http://news.bbc.co.uk/1/hi/sci/tech/4674446.stm

Tasmanian Devils Researchers hypothesis that affected Devils transmit this abnormal cell line to other Devils via bites. So in the case of these facial tumors, the answer seems to be yes.

Cervical Cancer and Human Papilloma Virus  “Q: I was surprised recently to learn that cancer of

the cervix may be caused by a virus. I had never heard this before and would like more information.

 A: Cancer of the cervix should probably be

reclassified as a sexually transmitted disease. More than 95% of all cases can be attributed to three types of human papilloma virus (HPV). This is the virus that causes genital warts. “  (From: http://healthlink.mcw.edu/article/951329620.html)

Cervical Cancer and HPV

Yes, cervical cancer is infectious.

“Vaccine could cut cervical cancer deaths “  Sun Sep 3, 11:33 PM ET  “LONDON (Reuters) - GlaxoSmithKline's (GSK.L)

experimental vaccine against a virus that causes cervical cancer could cut the number of cases and deaths from the illness by up to 76 percent, the drug company said on Monday. “ Reuters Photo: Cervical cancer cells in an undated microscopic image. GlaxoSmithKline's experimental vaccine against a virus that...