Cancer 1 redo Flashcards
What is Cancer?
- Cancer is a term used for a group of diseases in which cells divide in an abnormal manor.- Subsequently these cells are able to invade other tissues
There are more than […] types of cancer.
- There are more than 100 different types of cancer.
Most cancers are named for the…
…organ or type of cell in which they start
Further cancers can be grouped depending on the …
…type of tissue they originate from
Define carcinoma
cancer that begins in the skin or in tissues that line or cover internal organs.
Define sarcoma
cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.
Define leukemia
cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of abnormal blood cells to be produced and enter the blood.
Define Lymphoma and myeloma
cancers that begin in the cells of the immune system.
Define Central nervous system cancers
cancers that begin in the tissues of the brain and spinal cord.
What are the different Hypotheses of the Origin of Neoplasia?
- Viral Oncogene Hypothesis 2. Oncogenes and Tumor Suppressor Genes 3. Epigenetic Hypothesis 4. Failure of Immune Surveillance
Define malignant
if tumor invades surrounding tissue (cancerous)
Define Metastatic?
If individual cells break away and start a new tumor elsewhere. (cancerous)
Define benign
if tumor has no effect on surrounding tissue (non cancerous)
Proto-oncogenes have…
…regulatory functions in the development & growth of the cell
Changes in expression or function of proto-oncogenes lead to…
… a cell becoming cancerous
Proto-oncogenes are examples of…
…growth signaling components
When a proto-oncogene changes its expression or function it is termed…
…an oncogene
What happens when a proto-oncogene turns into a oncogene?
The cell becomes cancerous
Viral oncogenes are…
…homologues of cellular control genes that disrupt cell cycle control
There are three main mechanisms that …
…may lead to a cell losing it’s ability to regulate its cell cycle
What are the three main mechanisms that may lead to a cell losing it’s ability to regulate its cell cycle?
- ‘Hijacking’ of the cell cycle * e.g. by viral pathogens 2. Altered protein function * e.g. Mutation of the DNA coding region 3. Inappropriate activation/repression of genes * e.g. Mutation of the DNA control regions of a gene * e.g. Loss of epigenetic control mechanisms
The first oncogene product with an explicit function was the…
…v-SIS protein
Whats the v-SIS protein?
a modified form of platelet-derived growth factor (PDGF)
Infection of cells with simian sarcoma virus, which harbours v-SIS, results in…
…production of functional PDGF- This autocrine stimulation generates a chronic growth stimulus for PDGF-responsive cells
Organism infections assoicated wit human cancer?
- Hepatitis B & C Virus * Human Papilloma Virus * Epstein-Barr Virus * Human T-Cell Lymphotropic Virus * HIV & Human Herpesvirus 8 * Heliobacter pylori * Schistosomes * Liver fluke
Cancerous infections associated with human cancer?
- Liver Cancer * Cervical Cancer * Burkitt’s Lymphoma * Adult T-cell Leukemia * Kaposi’s Sarcoma * Gastric cancer * Bladder cancer * Cholangiosarcomas
Receptor oncogenes are activated in human cancers by…
…gene amplification (which leads to over-expression), rearrangements, and point mutations
Both N- and C-terminal deletions can…
…partly activate the transforming potential of receptor tyrosine kinases- As found in a subset of non-small-cell lung cancer (NSCLC)
What is NSCLC?
non-small-cell lung cancer
Activating mutations in the TK domain of EGFR are limited to…
…the first four exons, and show a remarkable structural diversity, including point mutations, deletions, and insertions.
Whats EGFR?
Epidermal growth factor
Different forms of mutations are found at differing rates in…
…NSCLC
L858R is a…
…point mutation in exon 21
The EGFR mutations result in…
…tyrosine kinase activity even when no growth factor is bound- (the cell is continually being told to grow and reproduce)
What happens in the Transduction pathway?
- Signal passes through cell* Response - Activation/deactivation of a process