Essential Cell Biology (4th Edition) Chapter 20 Part I Cell Communities: Cancer
What are the seven key behaviors of cancer cells?
1) Reduced dependence on signals from other cells for growth, survival, and division 2) Less likely to undergo apoptosis 3) can proliferate indefinitely 4) genetically unstable-increased mutation rate due to defects in DNA repair (can come from p53 mutation) 5) Abnormally invasive (lack cell adhesion molecules-cadherins) 6) Cancer cells survive and proliferate in foreign tissues 7) Ability to grow their own blood supply (Angiogenesis)
3 most common cancer treatments
1) Surgery (cut out the tumor) 2)Radiotherapy (damage DNA) 3)Chemotherapy (block cell growth)
what are the two heritable properties of cancer?
1)Proliferate and do not follow normal constraints of the cell cycle 2)Invade and colonize areas normally reserved for other cells
What leads to genes being under different transcriptional controls?
Chromosome breaks and rearrangements
Why is cancer cells less likely to undergo apoptosis?
Due to increased survival factor signaling or due to p53 mutation. (over 50% of human cancers have a p53 mutation)
What is the term for the study of the environment on cancer?
Epigenetics
What is colorectal cancer?
Hundreds or thousands of polyps in the lining of the colon and rectum.
In Dominant mutations, only _____ copy needs to be inherited for the effect to be seen.
ONE
What does gene therapy do for cancer treatment?
Program immune cells to attack cancer
T/F Cancer cells often have highly abnormal chromosomes, reflecting genetic instability
T
Cancer cells stop producing telomerase, which causes?
ends of the chromosome to become too short
What are the three effects of cancer?
1) Alterations in cell proliferation 2) Alterations in DNA damage response 3) Alterations in cell growth
_____% of colorectal cancer patients who are not born with a mutated APC have somatic mutations in both copies of the APC gene.
60
What is a tumor?
A cell that grows and dos not follow normal constraints of the cell cycle. (not all tumors are cancerous, but all cancers are tumors)
What is cancer?
A collection of cells that invade and colonize areas normally reserved for other cells
What are oncogenes?
A gene that when mutated makes the product hyperactive, any abnormal activated gene that can make a cell cancerous
What is lymphoblastic leukemia?
B cells of the immune system become malignant
In Recessive mutations, _______ copies need to be inherited for the effect to be seen.
BOTH
0-4 stages of cancer
First invade epithelium, then surrounding tissues, then the blood or lymph system Stage 0 Carcinoma in situ (confined to its site of origin) Stage I Localized Stage II Early Locally advanced Stage III Late Locally advanced Stage IV Metastasized
What are the normal functions of p53?
Genomic stability, apoptosis, G1 arrest, G2 arrest, differentiation, and angiogenesis
Give examples of benign (non-cancerous) tumors
Lipoma (fatty growth), moles, warts
What is Genetic instability?
Mutations that interfere with the accurate replication and maintenance of the genome. (defect in checkpoints during mitosis or increased mutations due to defect in proteins needed to repair mutated DNA)
Different types of mutations can lead to activation of an __________.
Oncogene
What leads to excessive proliferation of gut stem cells?
Reactivation of WNT pathways in the gut
What does gene therapy do to treat lymphoblastic leukemia?
Removes T cells and inserts gene directing T cells to attack CD19.
T/F One mistake occurs every 10^9 to 10^10 nucleotides copied. Every single gene is likely to have undergone mutation on more than 10^9 separate occasions in any individual
T
T/F Human cells can divide only a limited time in culture=senescence (permanently stop)
T: Senescence- condition or process of deterioration with age. loss of a cell's power of division and growth
What is metastasis?
When cells break loose from primary tumor and enter bloodstream or lymphatic vessels and form secondary tumors ("make a new home")
What is APC?
a tumor suppressor gene
Why does mutations in p53 lead to cancer?
because it causes the cell to no longer activate cell cycle checkpoints
What does anti-angiogenesis do for cancer treatment?
blocks formation of new blood vessels that normally invade the growing tumor
How does gas fumes, smoking, asbestos, and sun light promote cancer?
damages DNA
What is colorectal cancer traced to?
deletion or inactivation of a gene called Adenomatous Polyposis Coli (APC)
What do mutations do?
destroys the gene function
What is teratoma?
hair and teeth tumor that develops from uncontrolled growth of germ cells
APC protein keeps Wnt signaling pathway active/inactive?
inactive
How does obesity promote cancer?
increased metabolism and inflammation, increases free radicals
What is the term for cancerous tumors?
malignant (invade surrounding tissue, proliferate excessively)
How does viruses promote cancer?
messes with transcriptional and cell cycle control of the cell
Somatic mutation in _______ copy leads to cancer.
normal
For Colorectal cancer, one _______ and one _______ gene is inherited.
normal, mutant
What is the mutant form of a normal gene involved in the control of cell growth or division?
proto-oncogene
Mutations underlying cancers are mainly __________ mutaitons
somatic (not germ-line mutations)
What does vaccinations do for cancer treatment?
stimulate patients own immune system to fight the tumor. (Gardasil)
What does Kinase inhibitors do for cancer treatment?
target specific oncogenes (Gleevec)
Cancer cells reactivate ___________ to maintain telomere length
telomerase
What could result in a different promoter being "in charge"?
translocations
