Week 3- Cancer Flashcards
Type of neoplasm that has lost growth regulation but is well differentiated?
Benign tumor
Type of neoplasm that has lost growth regulation but are not well differentiated?
Malignant tumor
Well differentiated cells that have lost their growth control measures, are localized and demarcated, which facilitates surgical removal.
Benign neoplasm
Less differentiated, tend to grow rapidly, invade neighboring tissues, and spread to other sites (metastasis).
Malignant neoplasm
Ability of a cell to divide and make copies of itself. Requires growth signals including growth factors and other environmental signals that stimulate the cell to divide.
Proliferation
The degree of specialization of a given cell.
Differentiation
Are more differentiated that reticulocytes, can no longer divide, are considered terminally differentiated.
Erythrocytes
Often less well differentiated or less mature than their normal counterparts.
Cancer cells
Can divide indefinitely and proliferate continually, overcome the association between telomere loss and cell death, activate the enzyme telomerase to add new telomeres to chromosomal ends, circumvent the cell death process.
“Immortalized” cancer cells
Signal to enter G1 that commits cell to complete the cell cycle. It govern whether the cell will pass the R point.
pRB (retinoblastoma protein)
When disrupted leads to increase I proliferation of the cell. Normally acts as a brake.
pRB
A cell protein that normally has anti cancer functions centered around DNA repair including: activates DNA repair proteins when DNA has sustained damage, arrests cell cycle to allow DNA repair proteins time to fix mutations, and initiates apoptosis if DNA damage cannot be reversed.
p53
Means mutation is involved. Mostly acquired.
Genetic type of cancer
Means that the mutation is passed on from a parent.
Inherited type of cancer
Normally function to inhibit cell geothermal and division.
Tumor suppressor gene
May be formed by mutations in normal cell genes that promote cell growth. May also be acquired through infection. Mutations in these genes may lead to unregulated growth or cancer.
Oncogenes
These genes correct mistakes that happen to the DNA sequence either during DNA replication or from environmental exposure. Failure to fix these mutations increase the risk of cancer.
DNA repair genes
Type of cancer with a limited number of genes.
Simple cancer
Type of cancer with different acquired mutations.
Complex cancer
Most inherited forms of cancer involve changes in this gene?
TS gene
A rare childhood cancer of the eye that involves changes in the Tumor suppressor called pRB. Mutation of both alleles of the pRB gene is required. Loss of pRB gene leads to unregulated growth or cancer
Retinoblastoma
Form of colon cancer involving mutations in the DNA repair genes. Requires several stepwise mutations in both oncogenes and TS genes to give rise to the damaged DNA repair genes.
Hereditary nonpolyposis Colon Cancer
In this form of cancer one may observe: deletion of the adenomatous polyposis Colón TS gene, deletion of the 2nd apc allele, mutation of the ras oncogene, loss of both alleles of deleted in Colón cancer (dcc) TS gene, loss of p53 TS gene
Fap
These cells exhibit altered cell growth and differentiation with uncontrolled proliferation and poor differentiation.
Cancer cells
Changes that occur when a normal cell becomes cancerous:
- Chromosomal changes
- Altered biochemical properties
- Aberrant adherence properties.
Factors that go with altered biochemical properties:
- Promote growth by secretory growth factors/hormones
2. Promote spread by creating proteases
Chromosomal changes associated with cancer cells:
- Aneuploid- loss of diploid state
- Translocations and other rearrangements
- Chromosomal instability
Factors of abherrant adherence properties of cancer cells
- Loss of contact inhibition
- Anchorage independence
- Promotion of invasion and metastasis
3 stages of tumor development:
- Initiation
- Promotion
- Progression
Stage of tumor development that causes DNA mutation, is irreversible, and occurs first.
Initiation
Stage of tumor development that causes stimulation of cell proliferation, reversible in early stages, and follows initiation.
Promotion
Stage of tumor development that the tumor obtains a malignant phenotype, is invasive and metastatic, and has genome instability.
Progression
This is an active process involving transfer of cancer cells across tissue barriers.
Invasion
Invasion includes 3 processes:
- Adhesion- adherence of cancer cells to basement membrane or extracellular matrix
- Proteolysis- breakdown of extracellular barriers
- Motility- movement of cancer cells from original to neighboring sites
This promotes tumor cell invasion and metastasis by formation of new blood vessels.
Angiogenesis
Involves entry of tumor cell to blood/lymph and distribution to other body sites. Requires both invasion and angiogenesis.
Metastasis
Clinical manifestations of cancer
- Pain (more so in progressive disease)
- Cachexia- a severe form of malnutrition
- Declining hematopoiesis- anemia is often observed and to which tumors in bone or bone marrow suppression can contribute.
The loss of cell differentiation in cancerous tissue.
Anaplasia
Activation of this oncogene can increase cell proliferation:
RAS
Best known tumor suppressor genes are:
P53 and pRB genes.
