Cancer intro Flashcards
epistatic
only one lesion per pathway required to acquire cancer
4 ways to dysregulate cellular process in cancer
inappropriate proliferation, resist differentiation and apoptosis, genomic instability, grow where it shouldnt
viral oncogene
viral genes capable of altering cells
cellular oncogene
genes involved in development or maintenance of malignant phenotype
protooncogene
conserved eurkaryotic genes, can become oncogenes with changes in expression or mutation
what are 4 oncogenic mechanisms
growth factors, signal transduction, cell cycle control, regulation of gene xpression
2 common growth factors related to cancer
TGF-alpha w/ ras mutation and PDGF, PDGF-R w/ sis viral oncogene
2 important tumor suppressor genes
p53 and p16(INK4a)
Li-fraumeni syndrome
hereditary predisposition to cancer from p53 mutation, affected pts born w/ one abnormal copy- tumors will have mutations at both alleles
Cdk4 (cyclin D) effect on cell proliferation
blocks retinoblastoma, which inhibits cell cycle-high in lymphomas and breast cancer
p53 mutation effect on cell proliferation
p53 stimulates retinoblastoma which in turn inhibits cell cycle- losing p53 loses inhibition
pRB mutation effect on cell cycle
pRB is inhibitor, loss causes loss of inhibition and greater cell proliferation
p16 mutation effect on cell cycle
p16 blocks cyclin D which in turn blocks pRB which inhibits cell cycle- long chain but w/o p16= more cyclin d= less pRB=more cell division
p53 role in apoptosis
promotes this process, when mutated cells become resistant to apoptosis
what are some things a tumor must to do metastasize and cause harm
- locally invade
- grow into lymphatics/ blood vessels
- spread to other sites
- attach to endothelium
- grow and destroy normal stroma in new home
- induce new blood vessels
what are some mutations involved in colon cancer progression?
FAP- familial adenomatous polyposis, RAS- protooncogene, DCC- tumor suppressor deleted in colon cancer
mutations involved in pancreatic cancer
K-ras, p16, p53
hyperplasia
increase in cell number can be physiologic (hormonal) or pathologic
hypertrophy
increase in cell size with production of more subcellular components, physiologic (skeletal muscle) or pathologic (cardiomyocytes)
metaplasia
change from one differentiated cell type to another, commonly see in lung epithelium in smoking
dysplasia
atypical proliferation of cells: weird size/nuclei, disorderly arrangement and maturation
neoplasia
abnormal growth of tissue, can be well or poorly differentiated, autonomous
benign neoplasms
growth without invasion or spread, resembles normal cells and well differentiated with low mitotic rate
causes of morbitiy with benign neoplasms
size, location, production of cell products
