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24 Cards in this Set

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Reproduction System- Genetics of Cancer by Thatcher/Pratt
Reproduction System- Genetics of Cancer by Thatcher/Pratt
Multihit hypothesis...most important checkpoints
retinoblastoma (Rb) and p53. most to all cancers have mutations in one, the either or both. These normally are the tumor suppressors
List five steps of oncogenesis.
1. uncontrolled cell cycle progression
2. immortalization (unlimited replication and division)
3. evasion of apoptosis
4. growth factor insensitivity (independence from induction and resistance to inhibition)
5. angiogenesis
6. metastasis (invadopodia)
List the six types of genes that contribute to carcinogenesis.
1.Oncogene
2. Tumor Suppressor
3. Telomerase DNA Repair- limited corrects mutations; GOF; somatic
4. Apoptotic Genes- programmed cell death; gain/loss OF; dom/recessive
5. Cadherins- cell adhesion; LOF; somatic inheritance
Distinguish between oncogenes and tumor suppressors, and list the examples presented for each.
Oncogenes- promotes cell cycle; mutations are a gain of function; inheritance pattern is dominant

tumor suppressor- inhibits cell cycle; mutations are loss of function; inheritance pattern is recessive
Explain the two hit model for Retinoblastoma.
Both Rb alleles MUST be mutated.
Two types of retinoblastoma:

Inherited: the worst. bilateral, multiple foci, early age of onset, autosomal dominant, reduced penetrance

Sporadic: asymmetric; isolated tumor' later onset; no inheritance pattern

Familial: because every retinoblast begins wiht a mutated Rb allele, every mutation of the other allele results in a tumor

Sporadic: Because there are billions of retinoblasts, the chance of mutating both Rb allele in the same cell is slim.
Describe the two carcinogenic translocations that are explained in the notes.
CML: T(9,22) Philadelphia chromosome; bcr (22)-abl (9)--> produces a fusion protein between the abl oncogene and the 'breakpoint cluster region'

Burkitt's Lymphoma: T(8,14); translocation links immunoglobulin enhancer on chrom 14 with c-myc oncogene on 8
Describe the two types of carcinogenic gene amplification.
Double Minutes: piece of the chromosome that got out of the chromosome that forms rings linked together. there are large abundance of this one gene that is over-expressed that can cause cancer. ex., neuroblastoma

Gomogeneous Staining Regions (HSR)- within a chromosome, there is one region that is replicated over and over.
Define chromosome instability syndromes.
DNA repair problems. no questions on this.
-xeroderma pigmentosa
-bloom syndrome
-ataxia telengiectasia
-fanconi anemia

brca genes are also dna repair enzymes and tumor suppressors.
Most common oncogene activated in tumor cells is...
RAS
it's just that cell that sets of a tumor to start proliferating, right?
nope, it's all the surrounding cells and connective tissues.
___ ____ are critical regulators of biological events. Signals transmitted via proteins located around these ____ can cause the cell to reconfigure its attachments.
Cell adhesions. this is in regards to cell-cell contact and the extracellular matrix.
What are the 2 components to all tumors (benign or malignant)?
1. parenchyma – composed of the transformed or neoplastic cells (biological behavior)

2. supporting, non-neoplastic stroma (outside connective tissue) composed of connective tissue
-Crucial to the growth of the neoplasm as a source for nutrients and a means of communication that influences the growth of the tumor
p53 is lost/mutated in almost 100% of cancers...what is the major major 'push' towards cancer progression?
E(epithelial)-cadherin. keeps cells to the neighbors, so when we see these cells unzipper and is gone, we can see that in cancer. one of the many changes in the timeline of cancer progression that will move that cell forward. pulls away when there are too many mutations on a cell.
Invasion of the ECM is an active process (4 steps):
1. Detachment of cell-cell adhesions (E-cadherin!)
2. Degradation of basement membrane
3. Attachment to novel ECM components (many of which can be produced by tumor cells themselves)
4. Migration (break through into the the ECM)
What is a crucial "signaling molecule" for the normal functioning of cells?
ECM. The ECM is one of the environmental factors (like hormones) that can communicate with a cell, modifying nuclear structures &leading to selective gene expression.

E-cadherin molecules keep cells together and can transmit “anti-growth” signals via β-catenin
Basement membrane is responsible for what type of neoplasms?

What defines the carcinoma?

What do pathologists use to determine if epithelial neoplastic cells are invasive or in situ?
Epithelial neoplasms 

Neoplastic cells breaching the basement membrane define the carcinoma as invasive rather than just in situ (a key distinction with prognostic and possibly therapeutic implications)

Pathologists sometimes use antibodies directed against collagen type 4 or laminin to try to determine if a epithelial neoplastic cells are invasive or in situ
Benign Breast Disease. 2 types.

what is the most common benign tumor of the breast?
1) Fibroadenoma- overgrowth of the stroma
-Most common benign tumor of the breast; typically occurs in the 20s-30s

2) Cysts- fluid filled epithelium
-may make breasts feel lumpy
Definition of hyperplasia and atypical hyperplasia
Hyperplasia: Any increase in cell number without cytological changes in cellular morphology

Atypical Hyperplasia: Any increase in cell number WITH cytological changes in cellular morphology, especially nuclear morphology
DCIS (ductal carcinoma in situ): the “precursor” to breast cancer
It is in situ or “in place” because the cells are *still bound by the basement membrane and extracellular matrix*

morph changes, dna is diff, behaving differently to the cell cycle, but the basement membrane is still holding strong.
Breast Carcinomas
The tumor is invading the breast,
it has *broken through the basement membrane and matrix*

well differentiated- still looks like normal tissue should look like even though there's lots of it.

poorly differentiated- mass of cells no resemblance to acini
angiogenesis is a true marriage of the ___ and the ____
parenchyma and the stroma. working together to the point that tumors are experiencing hypoxia, they will stimulate cytokines (VEGF) produced by tumor cells that are stored in the stroma. they do this so they can live in a region that they're not supposed to. tumors bringing their own blood supply.

Many proteases, elaborated directly by the stromal cells surrounding the tumor, can release the angiogenic basic FGF stored in the ECM – altering the balance between angiogenic and anti-angiogenic factors.
The “dark side” of stroma
associated *fibroblasts and *myofibroblasts in neighboring CT can exhibit altered expression of genes that encode ECM molecules, proteases, protease inhibitors and various growth factors like VEGF

This is a prominent feature of certain invasive cancers, including lobular carcinoma of the breast. 
parenchyma talking to stroma, then stroma (which was manipulated by a tumor) changing over and becoming a part of the tumor itself.
features of invasive cancers, including the most invasive of the breast, then lobular carcinoma.

cancer:
1. accumulation of genetic changes.
2. connective tissue surrounding it...important for staging, grading, control and treatment of tumors.