Cancer

Bio 130 Human Biology

Cancer

Normal cells have regulation that keeps their rates of cell division in check.

Normal cells generally remain in one location

Cancer is unregulated growth of a cell population


Characteristics of Benign Tumors and Cancers

Table 18.1


Terms

Hyperplasia – increased formation Tumor – new growth Benign tumors- have defined

characteristics Dysplasia- cells change form Cancer- at least some cells loose

organization.


Tumors

Benign: Remain in one location Single, well-defined mass May be surrounded by connective tissue

Cancerous: Abnormal cell structure, may appear undifferentiated May spread Edge of tumor not clearly defined


Malignant Tumor Development

Figure 18.2


How cancers develop

Is genetic in character Proto-oncogenes Oncogenes Tumor suppressor genes p53


How Cancer Develops

Mutated or damaged genes Proto-oncogenes: normal regulatory genes Oncogenes: mutated or damaged proto-oncogenes Tumor suppressor genes: regulatory genes repress cell

growth, division, differentiation, adhesion May be turned off, damaged, or mutated in cancers

Mutator genes: genes of DNA repair, when they are damages the cell is more likely to make a mistake.


Indicated cause of cancer

Carcinogens Inherited susceptibility Viruses and bacteria

Starts with a single cell that is no longer under normal control


Cancer Characteristics loss of contact inhibition

Cancer cells do not self-destruct when their DNA is damaged

Cancer cells divide indefinitely Cancer cells attract a blood supply Cancer cells do not adhere to neighboring

cells


The immune system plays an important role

If your immune system recognizes a cell as being cancerous then it will be destroyed


Progredssion of cancer requires multiple genetic changes in regulatory genes.


Testing for Cancer

Tumor Imagine X rays Positron emis

temography Magnetic resonance

imaging Genetic testing

Enzyme markers

PET and MRI focus on metabolic differences

Ethaical problems withgenetic testing?

Large scale testing.


Cancer Treatments

Conventional treatments: surgery, radiation, and chemotherapy

Delivery mechanisms: coated metal beads, light-sensitive drugs

Immunotherapy: promotes the immune response Starving cancers: inhibits angiogenesis Molecular treatments: target oncogenes


Treatment of cancer

Surgery Radiation Chemotherapy Immunotherapy Inhibiting angiogenesis


Surgery, Radiation, and Chemotherapy Are Conventional Ways to Treat Cancer

Surgery is used to remove tumors Radiation therapy is used to kill localized cancer cells Chemotherapy is used to kill cancer cells throughout the

body Immunotherapy boosts the immune responses against

cancer cells Inhibition of blood vessel formation may slow the spread

of cancer cells Gene therapy may someday help fight cancer in several

ways


Some common cancers

Skin Breast Prostate Lung Colon rectum


Ten Most Common Cancers

Table 18.3


Prevention

Best way to beat cancer is to not get it.


Most Cancers Are Preventable

Know family history Get regular medical screenings Learn self-examination techniques Avoid direct sunlight 10 a.m. to 4 p.m., avoid

sunlamps and tanning salons Watch diet and weight Don’t smoke Drink in moderation, if at all Be informed

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Cancer