Chapter 25: Genetic Basis of Cancer

Question 1

cancer characteristics

Answer 1

clonal: originate in a single cell
multistep process
begins with precancerous genetic change: a benign growth
become malignant and invasive
can be metastatic: migrate to other parts of body

Question 1

cancer

Answer 1

disease characterized by uncontrollable cell division
genetic disease at cellular level, not inheritable
more than 100 kinds of human cancer
result of multiple somatic mutations that accumulate in a single cell

Question 2

inheritance of cancer

Answer 2

5-10% cancers have inherited component
most are not inherited

Question 3

causes of cancer

Answer 3

some are result of spontaneous mutations and viruses (HPV)
most are related to exposure to mutagens

Question 4

carcinogens

Answer 4

specific compounds known to cause cancer
ex. UV light, smoking

Question 5

oncogenes

Answer 5

mutated forms of normal genes (proto-oncogenes)
mutations that lead to hyperactivation
allows for uncontrollable cell growth

Question 6

proto-oncogenes

Answer 6

often mutated in cancer
normal function is to regulate cell growth
ex. epidermal growth factor (EGF)

Question 7

tumor-suppressor genes

Answer 7

prevent proliferation of cancer cells
if inactivated by a mutation –> more likely cancer will occur

Question 8

p53 gene

Answer 8

master tumor-suppressor gene
about 50% all human cancers associated with defects in. p53
primary role is to determine if a cell has occurred DNA damage –> three types of cellular pathways to prevent division

Question 9

genetic testing

Answer 9

available for certain types of cancer:
familial adenomatous polyposis
familial breast cancer
often involve a defect in tumor suppressor genes