Cancer 9/29 Flashcards
What is the term used to describe variation in cell size and shape?
Pleomorphism
What is anaplasia?
Lack of differentiation in tumor cells (bad)
What is a reversible conversion of one differentiated cell type to another?
Metaplasia
Ex: columnar epithelium replaced by squamous epithelium in respiratory tract of smokers
What is the term for a disordered growth and maturation of cells and a disturbance of growth regulation?
Dysplasia
3 factors used to grade a tumor:
Size (T)
Lymph node involvement (N)
Metastasis (M)
What is a bio marker expressed in 75% of breast cancers? How is it treated when positive?
ER+
Endocrine therapy- TAMOXIFEN
What is the target therapy when the HER-2 receptor is expressed in Brest cancer?
Trastuzumab (herceptin)
How is familial breast cancer inherited?
Germ line mutations
Autosomal dominant mutations of BRCA1 or BRCA2
Molecular classification of breast cancer: high expression of cytokeratins 5/6 and 17 and proliferation markers
- Triple negative or basal-like
Molecular classification of breast cancer: keratins (-)
- HER2 (+)
Molecular classification of breast cancer:
ER + high expression
E cadherin +
- Luminal-A
Molecular classification of breast cancer:
ER + lower expression
E cadherin -
- Luminal-B
Molecular classification of breast cancer:
ER+
- Normal breast like
What are the 4 gene mutations that serve as the basis for colon cancer?
- Loss of APC tumor suppressor gene
- Activation of K-ras oncogene
- Loss of DCC tumor suppressor
- Loss of p53 tumor suppressor
What are normal cellular genes that encode proteins involved in cell growth and proliferation?
Proto-oncogenes
what are cancer producing genes derived from Proto-oncogenes?
Oncogenes
7 types of proteins participating in cell growth:
- Growth factors
- GFRs
- Intercellular cell growth signal transducers
- Transcription factors
- Pro or anti-apoptosis proteins
- Cell-cycle control proteins
- DNA repair proteins
What are 2 proto oncogenes that encode cell surface receptors (receptors for gf)?
- Her2
- EGF
Both receptor tyrosine kinases
What is the HER2 mutation that causes cancer?
Val -> Gla
Her2 receptor gene is mutated to NEU gene.
Treat w herceptin
What is the EGF mutation that causes cancer?
Deletion.
Involved in lung cancers.
Are RTK mutations oncogenes or tumor suppressor genes?
Oncogenes.
TKIs target RTK mutated receptors.
What is one of the most frequently mutated proto oncogenes in cancer and an example of a growth signal transducer?
Ras mutations.
Mutation occurs as aa position 12 or 61 -> constitutively active.
What are two important transcription factors that cause cancer when mutated?
- C-Fos
- C-myc
Constitutively active
4 ways the proto-oncogene can be mutated to become an oncogene?
- Promotor mutation
- Coding sequence mutation
- Chromosomal translocation
- Gene amplification
What is the product of a chromosome translocation called? Translocation of what chromosomes causes this?
Philadelphia chromosome
Translocation of Ch 9 & 22
Fusion of bcr and abl
What kind of gene is the Rb gene?
Tumor supressor
What is the two-hit origin of cancer hypothesis?
Some forms of hereditary cancer might be initiated when a person heterozygous for a germ line mutation undergoes a SECOND, SOMATIC MUTATION in the OTHER ALLELE OF THE SAME GENE, rendering the cell homozygous for loss of function.
Only in TS GENES
What is p53?
Tumor supressor, transcription factor.
Involved in DNA damage repair, cell cycle control, apoptosis.
What checkpoint in the cell cycle do Rb and p53 regulate?
G1/S checkpoint
Telomeres are a region of repetitive DNA at the end of a chromosome. What do they do?
Protect end of chromosomes. Shortened during cell divisions, replenished by Telomerase.
As they grow shorter, cells reach end of replicative ability and progress into senescence.
Compared to normal cells, cancer cells’ telomerase activity is (higher/lower) and telomeres are (longer/shorter)
Higher activity
Longer telomeres
True or false: both RNA and DNA viruses can carry oncogenes.
True.
Do RNA or DNA viruses carry oncogenes that function in the cell replication cycle?
DNA viruses do participate in replication cycle. RNA viruses do not.
Retroviruses that cause cancer can be fast or slow tumor forming. Which contains an oncogene?
Fast retroviruses contain oncogene.
How do slow acting retroviruses cause cancer?
Retroviral promoter and enhancer insertions activates c-Myc proto oncogene
How does hpv cause cancer?
Over expression of proteins E6 and E7
E6 inhibits p53
E7 inhibits Rb
