HPS 420 Exam With Complete Solutions
benign - ANSWER Grows slowly, don't invade surround tissue, don't metastasize, not life
threatening, define border
Malignant - ANSWER Grows rapidly, invade other tissue, can metastize, own blood
supply, usually life threatening, harder to define border
6 hallmarks of cancer - ANSWER 1. self-sufficiency in growth signals (oncogenes)
2. insensitivity to antigrowth signals
3. evasion of apoptosis
4. limitless replicative potential
5. sustained angiogenesis
6. tissue invasion and metastasis
3 types of genes typically mutated in cancer - ANSWER 1. Proto-oncogenes, growth
regulators respond to mitogens, cytokines, cell-to-cell contact, a gain of function
mutation in only ONE COPY is needed to activate.
2. Tumor suppressor gens, negative growth factors, need inactivation of both copies of
tumor suppressor genes.
3. DNA stability genes- genes that monitor and maintain integrity of DNA. Loss of these
genes lead to defective sensing of DNA lesions and improper repair of damage.
4 mechanisms leading to oncogene activation - ANSWER 1. retroviral integration
through recombination- retroviral genome integrates close to proto-oncogene where
then under control of the retrovirus promoter.
2. DNA mutation of regulatory sites- assumption that specific genes are responsible for
causing cancer (H-ras)
3. Gene amplification- Increase the number of DNA copies. can result in
intra-chromosomal amplified regions called double minutes or regions amplified called
homogenously staining regions (HRS)
4. chromosome (rearrangement) translocation- Example: Chronic Myelogenous
Leukemia (CML) typically has translocation (9;22)
2 Subcategories of tumor suppressor genes. - ANSWER 1. Gatekeepers- directly
regulate the growth of tumors. By inhibiting cell division and prompting cell death.
Li-Fraumeni families caries a mutant p53 (p53 is a gatekeepers)
, 2. Caretakers: genes that control maintaince of the genetic information. leads to
genomic instability and indirectly promotes growth by causing an increase in mutation
rate. Genes involved in DNA reapair and stability genes are caretaker genes. EX. DNA
repair protein.
Somatic Homozygosity - ANSWER explain recessive tumor suppressor genes lost.
Law of Bergonic and Tribondeau - ANSWER Tissues are radiosensitive if their cells are
less differentiated have a greater proligerative capacity, and divide more rapidly.
Early (Acute) effect - ANSWER Results from the death of a large number of cells and
occur within a FEW DAYS OR WEEKS of irradiation in tissue with a rapid rate of turn
over. DEATH OF A LARGE NUMBER OF CELL.
Late Effects - ANSWER Late effects are much more sensitive to changes in fractionation
than early effect APPEAR AFTER A DELAY ON MONTHS OR YEARS and occur
predominantly in slowly proliferating tissue.
Growth factors induced by radiation - ANSWER 1. Interleukin-1: Acts a hematopoietic
radiorotectant.
2. Basic fibroblast growth factor: Induces endothelial cell growth, inhibits
radiation-induced apoptosis protects against micro vascular damage.
3. Platelet-derived growth factor B: increase damage to vascular tissue.
4. Transforming growth factor B: induces a strong inflammatory response, stimulates
growth of connective tissue and inhibits epithelial cell growth.
5. TNF: mediates inflammatory response, protects hematopoietic cells.
Functional subunits (FSUs), two arrangement of FSU and example of a tissue having this
type of arrangement. - ANSWER Functional subunit- is a compartment of an organ that
performs part of the organ funciton. Survival of the FSU depend on the survival of one or
more clonogenic cells within the FSUs.
EX: of tissues that are clearly structured defined: liver, kidney, and lung.
Tissues not clearly structulry defined: Skin, mucosa, and spinal cord.
2 kinds of FSU - ANSWER Parallel: FSUs are arranged independently of each organ, thus
disabling one FSU does not affect other FSU.
EX: Kidney, liver.
Series: FSUs are arranged in a chain-like sequence, disabling one FSU stops function in
all subsequent FSUs causing total organ failure.
EX: spinal cord or gastrointestinal track.
benign - ANSWER Grows slowly, don't invade surround tissue, don't metastasize, not life
threatening, define border
Malignant - ANSWER Grows rapidly, invade other tissue, can metastize, own blood
supply, usually life threatening, harder to define border
6 hallmarks of cancer - ANSWER 1. self-sufficiency in growth signals (oncogenes)
2. insensitivity to antigrowth signals
3. evasion of apoptosis
4. limitless replicative potential
5. sustained angiogenesis
6. tissue invasion and metastasis
3 types of genes typically mutated in cancer - ANSWER 1. Proto-oncogenes, growth
regulators respond to mitogens, cytokines, cell-to-cell contact, a gain of function
mutation in only ONE COPY is needed to activate.
2. Tumor suppressor gens, negative growth factors, need inactivation of both copies of
tumor suppressor genes.
3. DNA stability genes- genes that monitor and maintain integrity of DNA. Loss of these
genes lead to defective sensing of DNA lesions and improper repair of damage.
4 mechanisms leading to oncogene activation - ANSWER 1. retroviral integration
through recombination- retroviral genome integrates close to proto-oncogene where
then under control of the retrovirus promoter.
2. DNA mutation of regulatory sites- assumption that specific genes are responsible for
causing cancer (H-ras)
3. Gene amplification- Increase the number of DNA copies. can result in
intra-chromosomal amplified regions called double minutes or regions amplified called
homogenously staining regions (HRS)
4. chromosome (rearrangement) translocation- Example: Chronic Myelogenous
Leukemia (CML) typically has translocation (9;22)
2 Subcategories of tumor suppressor genes. - ANSWER 1. Gatekeepers- directly
regulate the growth of tumors. By inhibiting cell division and prompting cell death.
Li-Fraumeni families caries a mutant p53 (p53 is a gatekeepers)
, 2. Caretakers: genes that control maintaince of the genetic information. leads to
genomic instability and indirectly promotes growth by causing an increase in mutation
rate. Genes involved in DNA reapair and stability genes are caretaker genes. EX. DNA
repair protein.
Somatic Homozygosity - ANSWER explain recessive tumor suppressor genes lost.
Law of Bergonic and Tribondeau - ANSWER Tissues are radiosensitive if their cells are
less differentiated have a greater proligerative capacity, and divide more rapidly.
Early (Acute) effect - ANSWER Results from the death of a large number of cells and
occur within a FEW DAYS OR WEEKS of irradiation in tissue with a rapid rate of turn
over. DEATH OF A LARGE NUMBER OF CELL.
Late Effects - ANSWER Late effects are much more sensitive to changes in fractionation
than early effect APPEAR AFTER A DELAY ON MONTHS OR YEARS and occur
predominantly in slowly proliferating tissue.
Growth factors induced by radiation - ANSWER 1. Interleukin-1: Acts a hematopoietic
radiorotectant.
2. Basic fibroblast growth factor: Induces endothelial cell growth, inhibits
radiation-induced apoptosis protects against micro vascular damage.
3. Platelet-derived growth factor B: increase damage to vascular tissue.
4. Transforming growth factor B: induces a strong inflammatory response, stimulates
growth of connective tissue and inhibits epithelial cell growth.
5. TNF: mediates inflammatory response, protects hematopoietic cells.
Functional subunits (FSUs), two arrangement of FSU and example of a tissue having this
type of arrangement. - ANSWER Functional subunit- is a compartment of an organ that
performs part of the organ funciton. Survival of the FSU depend on the survival of one or
more clonogenic cells within the FSUs.
EX: of tissues that are clearly structured defined: liver, kidney, and lung.
Tissues not clearly structulry defined: Skin, mucosa, and spinal cord.
2 kinds of FSU - ANSWER Parallel: FSUs are arranged independently of each organ, thus
disabling one FSU does not affect other FSU.
EX: Kidney, liver.
Series: FSUs are arranged in a chain-like sequence, disabling one FSU stops function in
all subsequent FSUs causing total organ failure.
EX: spinal cord or gastrointestinal track.
