Cancer Flashcards
Define neoplasia
New growth
What cellular components is cancer associated with?
Abnormal cellular gene expression
Cellular proliferation and differentiation
Is a benign tumor still cancer?
Yes- because it is an abnormality of cell growth
What determines if a cancer is benign or malignant?
Histology
What type cancer normally invades adjacent tissues?
Malignant
What is anaplasia?
A lack of differentiated features
The more anaplastic a cell is the more….
Malignant
Why does tumor necrosis happen in malignant cancers?
Cell divisions happen so fast that the new cells surrond the old cells and block O2 and nutrients
-oma means
benign tumor
what are two names for malignant tumors?
Carcinoma and sarcoma
What type of malignant tumor has an epithelial origin?
Carcinoma
What type malignant tumor has a mesenchymal origin?
Sarcoma
What is an adenoma?
Benign tumor of glandular tissue
90% of cancer are what type of origin?
Epithelial (carcinoma)
Why can tumor cells divide so fast and keep dividing?
Proliferate despite lack of growth signals Ignore death signals Have telomerase Lose anchorage dependence Don't have density dependent inhibition
What is a proto-oncogene?
Component of cell growth activating pathways
Normal functioning gene form
What is the cancer-associated form of an proto-oncogene?
Oncogene
What are the 4 categories of oncogenes?
Growth factors
Receptors
Cytoplasmic signaling molecules
Nuclear transcription factors
What is a small peptide secreted into extracellular space?
Growth factor
What does an oncogene do to growth factors?
Secrete more growth factors
What do growth factor receptors do?
Transmit growth factor into target
What does an oncogene do to a growth factor receptor?
Allow for expression of absent receptors
Allows receptors to respond w/o growth factor
What does an oncogene do to a cytoplasmic signaling pathway?
Manufactures excess or abnormal components of growth cascades
may signal the cascade w/o receptor input
What is Ras?
A G protein involving in cytoplasmic signaling pathways.
Mutations to this cause persistent activity
What is a transcription factor?
Something that triggers the cell to go to S phase
What does an oncogene do to transcription factors?
Overproduces them, or losses the regulation
What are some common proto-oncogenes involved with transcription factors ?
Myc, jun, fos
What are four basic ways a protooncogene turns into an oncogene?
- Retrovirus introduces oncogene
- Proto-oncogene suffers mutation
- DNA sequence that regulates proto-oncogene expression is damaged/ lost
- Error in chromosome replication- extra copies of proto-oncogene
What do tumor suppressor genes do?
Inhibit tumor proliferation; loss of function may lead to tumor development
What does Rb gene do?
Codes for nuclear pRB protein
what does the nuclear pRB protein do?
Blocks cell division by binding Transcription factors to inhibit transcription of genes that initate cell cycles
When will the nuclear pRB protein release Tfs?
When it is highly posphorylated
What does the P53 gene do?
Inhibits cell cycle (at G1) by binding to damaged DNA and preventing replication; can trigger apoptosis
What happens when there is a lack of or abnormal p53 gene?
genetically damaged cells divide–> tumors
A mutation in what gene causes an 85x high risk of cancer?
BRCA1
What are the three steps of carcinogenesis?
Initiation
Promotion
Progression
What does Ras do?
Makes it so cancer cells aren’t anchorage dependent
What does Myc do?
Causes immortality by turning on telomerase
Is one genetic mistake enough to cause carcinogeneiss?
No- multiple are usually needed along with Ras and Myc
WHat happens in initiation?
Mutations activate proto-oncogenes and inactivate tumor suppressor
What is a carcinogen?
Agents that promote initiation
What is promotion?
Where mutant cell proliferates
Transition due to another mutation (hormones can help)
What is progression?
When proliferating cells begin to exhibit malignant behavior
What is metastasis?
When cancer cells escape tissue of origin and initiate new colonies in distant tissues
How do cancer cells metastasize?
Move through basement membrane of blood of lymph vessel and through extracellular space and repeat this pattern in a new tissue
What is angiogenesis?
Growth of blood vessels, allows tumor to grow >2 mm, later stage of metastasis
What is VEGF?
Vascular endothelial growth factor, produced in response to hypoxia by tumor cells
What tells you the histology and degree of anaplasia?
Grading
What tells you the location and pattern of spread of the tumor?
Staging
What is the TNM system?
Tumor, node, metastasis
What is cachexia?
Wasting within the body, effect of cancer
overall weight loss and generalized weakness
What are paraneoplastic syndromes?
Symptom complexes not explained by tumor properties; ex- cushing syndrome and hyponatremia caused by small cell carcinomas
