10.2 MJ slides Flashcards
Study of two classes of genes has established a relationship between what?
Cancer, regulation of cell growth and division, and the cell cycle
1) Proto-oncogenes normally do what?
2) What do tumor suppressor genes normally?
1) Proto-oncogenes normally turn on or increase the rate of cell division (dominant mutations in proto-oncogenes cause cancer)
2) Tumor suppressor genes normally turn off or decrease the rate of cell division (recessive mutations in tumor suppressor genes cause cancer)
-“Gatekeepers”
-“Caretakers”
1) Genes that initiate or maintain cell division are called what?
2) Mutant genes that induce or continue uncontrolled cell proliferation are called what?
1) Proto-oncogenes
2) Oncogenes
1) What are tumor suppressor genes?
2) Where do they act?
3) Deletion or inactivation of these products cause what?
4) What mutations in tumor suppressor genes cause cancer, dominant or recessive? Explain
1) Genes encoding proteins that suppress cell division and regulate the cell cycle
2) At control points in the cell cycle, at G1/S or G2/M
3) Cells to divide continuously
4) Recessive; in other words, the “good” allele for this gene will still provide the function, thus both need to be taken out (Two-hit hypothesis)
What is a tumor suppressor gene that monitors cellular stress?
TP53 (usually referred to as just p53)
P53 prevents neoplastic transformation by several mechanisms; list them
1) Activation of temporary cell cycle arrest (quiescence) and induction of DNA repair genes
2) Induction of permanent cell cycle arrest (senescence)
3) Induction of programmed cell death (apoptosis)
P53 is activated by what 3 things?
Anoxia, inappropriate oncogene signaling, or DNA damage
Describe Hereditary (Familial) Cancer
1) What do you inherit?
2) What are all cells?
3) When is cancer initiated?
1) One inactive allele and one normal allele
2) Heterozygous for the germline mutation
3) When a second inactivating mutation occurs in the normal TSG allele in one cell of the body
Describe sporadic cancer:
1) What do you inherit?
2) What are all cells?
3) When is cancer initiated?
1) Two normal alleles
2) All cells are homozygous for the normal allele
3) When both normal alleles are inactivated by two somatic events in the same cell
1) Patients with bilateral retinoblastoma generally present when?
2) Those with unilateral disease present when?
3) Approximately ___% of patients have unilateral retinoblastoma and ____% bilateral retinoblastoma
1) During the first year of life
2) Between 24 and 30 months
3) 70%; 30%
True or false: All patients with bilateral disease have germline RB1 mutations, but not all patients with germline mutations develop bilateral disease
True
Lynch Syndrome (Formerly HNPCC):
1) A form of colon cancer that develops with very ______ polyps, each with a _______ probability of becoming cancerous.
2) An autosomal caretaker mutation caused by mutations in what?
3) What is required for cancer to develop?
1) few; high
2) One of four DNA mismatch repair genes (MLH1, MSH2, MSH6, and PMS2)
3) Subsequent somatic loss-of-function of the second normal copy of the gene
Typically, cells grow when they are told to, die when they are told to, undergo DNA repair, and are limited by what?
telomere degradation
