Pathology Flashcards
describe the function of tumour suppressor genes and how they work
Tumour Suppressor Genes – the normal function of these genes is inhibition of cell proliferation or repair of damaged DNA – abnormalities (of both alleles) of tumour suppressor genes can drive a normal cell towards a cancerous state eg. BRCA1
they inhibit cell division or stimulate cell death
may also: mutation in the gene such that the resultant protein has reduced or loss of function
Describe the function of oncogenes and how they work
Oncogenes – the normal function of these genes is an increase in cell proliferation – abnormalities of only one allele of an oncogene can drive a normal cell towards a cancerous state eg. HER2
They stimulate cell division or inhibit cell death
they can result in:
- more of the gene product being expressed,
- a mutation in the gene such that the resultant protein has increased function
- expression occurring in the wrong cell type
- at the wrong time
What cancer is associated wit the chemical abstesos
mesothelioma
What cancer is associated with the chemical from aniline dyes
bladder cancer
What cancer is associated with radiation
thyroid cancer
what is a possible cause for cervix cancer
sexual activity - HPV
give an example of a natural gas that can cause cancer
radon gas
What is the cancer associated with HPV
cervical cancer
what is the cancer associated with HepBVirus
liver cancer
what is the cancer associated with Epstein Barr Virus
lymphoma
what is the disease associated with Kaposi’s Sarcoma
Human Herpes Virus 8
what is the cancer associated with hepatitis B and C
hepatocellular carcinoma (HCC)
how does hepatitis B cause HCC
Chronic Hepatits B infection results in a cycle of inflammation necrosis and regeneration of cells. This increased turnover of cells increases the likelihood of genetic mutations developing and hepatocellular carcinoma occuring
what is the cancer associated with Helicobacter pylori
how does it cause cancer
gastric adenocarcinoma and gastric MALT lymphoma
Long-term infection with H. pylori results in chronic inflammation and the subsequent increased cell turnover increases the likelihood of mutations developing
What type of genes are the p53 gene, the APC gene and the Rb gene
tumour suppressor genes
What is the gene associated with Retinoblastoma
Rb
What is the gene associated with FAP
APC
What is the gene associated with HNPCC (Lynch Syndrome)
MSH2/MLH1
What is the gene associated with breast cancer and ovarian cancer
BRCA1/BRCA2
What is the gene associated with Li-Fraumeni syndrome
p53
Compare the sporadic and familial forms of retinoblastoma based off the Knudson Hypothesis
Sporadic form:
- a mutation has to occur in both copies of the retinoblastoma gene, unlikely
- the longer the period of time that elapses the more likely this is, but it is unlikely to occur more than in one cells. Hence tumours occur late and are unilateral.
Familial form:
- the child inherits from one mutant copy of the retinoblastoma gene, so only one additional mutation needed
- the disease occurs earlier and also there is a high probability of it occurring in more than one cell, and thus tumours may be multi-focal and bilateral.
What are the characteristics of Familial adenomatous polyposis (FAP)
- polyposis - the development of multiple benign (noncancerous) adenomatous polyps (>100) in the colon and rectum, which are described as having a “dense carpet-like appearance” on colonoscopy or sigmoidoscopy.
- early age of onset. Polyps begin to develop at an average age of 16 years (range of seven to 36 years).
What are the Clinical features of Li-Fraumeni syndrome
Cancers at a young age:
- Development of adrenocortical carcinoma
- Development of soft-tissue sarcomas
- Acute leukaemias and brain tumours
- Osteosarcomas
- Premenopausal breast cancer is common
What are the genes FGF fibroblast growth factor
PDGF - platelet derived growth factor examples of
growth factors
what are the genes: HER2neu EGFR EGFR C-Kit examples of
Growth factor receptors
what are the genes: V-src K-ras abl examples of
signal transduction pathways
what is the gene c-myc an example of
nuclear protein
what is the gene Bcl2 an example of
resistance to apoptosis
Describe the Philadelphia chromosome (Ph1)
This is a translocation of a portion of the q arm of chromosome 22 to the q arm of chromosome 9, designated t(9:22). The result is that a fusion gene is created by juxtapositioning the Abl1 gene on chromosome 9 to a part of the BCR (“breakpoint cluster region”) gene on chromosome 22
What cancer is characterised by the Philadelphia chromosome (Ph1)
Chronic Myeloid Leukemia
Which drug is prescribed for a patient who is HER2 positive
Trastuzumab
what drugs will a patient not respond to if they have a mutated KRAS gene
cetuximab or panitumumab
An 87 year old woman has invasive breast cancer.
Which laboratory test will be used to inform management?
a) HER2
b) KRAS
c) BCR-ABL
d) FAP
e) APC
a
A 67 year old man has a malignant tumour arising on the surface of the lung and encasing the lung in a solid mass. Which is the most likely cause?
a) Asbestos
b) HHV8
c) Helicobacter pylori
d) Hepatitis C
e) Human papillomavirus
a
A 27 year old man has familial adenomatous polyposis.
Which abnormal gene has he inherited?
a) APC
b) MSH2
c) P53
d) BRCA1
e) RB
a
Givetwo morphological examples ofreversible cell injury
see lecture 2 slide 32 for microscope slides
- Swelling of the cell – Hydropic change:
- (impaired function of energy- dependant ion pumps in plasma membrane ) - Fatty change (Steatosis):
- Deranged lipoprotein transport leads to accumulation of lipid in the cytoplasm of hepatocytes.
- CAUSES:
>Alcohol
>Obesity
define and describe apoptosis
when does it happen
lecture 2 slide 46 for diagram on how it works
- A defined, orderly sequence of intracellular events leading to cell death
- Energy Dependent:activeprocess
- Cells break into fragments-apoptotic bodies & express vitronectin- attracts phagocytes.
- No inflammatory reaction
- single cell at a time pattern to death of cells
Caspases-intracellular proteases which play important role
activated by:
> Extrinsic pathway -signals from outside the cell
> Intrinsic pathway-internal pathways such as DNA damage
Can be physiological:
- Eliminates cells no longer needed maintaining a steady number of various cell populations
- Examples:
>Embryogenesis
- Involution of hormone dependent tissue eg endometrium in menstruation
- Death of host cells after they have served their purpose eg in inflammation
Can be pathological:
- Eliminates cells that are injured beyond repair
- Example:
> DNA damage from toxins or ultraviolet radiation
define necrosis and what causes is
“Catastrophic” cell death following injury
accompanied by the release of potent mediators
of inflammation
Caused by factors such as;
- Decreased oxygen,
- Infection,
- Toxins,
- Trauma
describe coagulative necrosis
Commonest form of necrosis
On microscopy preservation of the basic outline of the cells is seen , until cells removed by phagocytosis
Localised area of necrosis-Infarct - most likely caused by an acute vascular insufficiency eg a blockage of an artery
often see an acute inflammatory reaction
CompareandcontrastApoptosis and Necrosis
see lecture 2 slide 48 for diagram
Apoptosis: - Role = Physiological or Pathological - Cell = > Shrinkage of cell > Single Cells affected - Plasma membrane = Intact - Inflammation = no - Pathways = Specific genes and pathways - Energy dependant = yes
Necrosis: - Role = Pathological - Cell = > Cells enlarge (swelling) > Multiple cells or tissues involved - Plasma membrane = Disrupted - Inflammation = Frequent - Pathways = No specific pathways - Energy dependant = no
describe CASEOUS necrosis
“Caseous”-cheese-like when viewing grossly
Dead tissue shows no structure- cell outlines not evident on microscopy
Characteristic of Tuberculosis
what part of the body is affected with Acute hepatitis
liver
define acute inflammation and list the FIVE clinical features of acute inflammation
The initial protective tissue response to injury or destruction of tissues, which serves to destroy, dilute, or wall off both the injurious agent and the injured tissues.
The three main elements of acute inflammation are changes in small blood vessels, recruitment of neutrophils and increased levels of chemical mediators.
The FIVE “Cardinal” clinical features:
- Redness
- Swelling
- Heat
- Pain
- loss of function
define chronic suppurative inflammation, pus, abscess and empyema.
Chronic Suppurative (pus producing) Inflammation is the PERSISTENT ACCUMULATION of PUS.
PUS = a mixture of living, dead and dying neutrophils (and bacteria), cellular debris and inflammatory exudate
ABSCESS = A collection of pus within a newly formed cavity within TISSUES
EMPYEMA = A collection of pus within a naturally existing ANATOMICAL CAVITY
describe and explain the systemic effects of inflammation
Weight loss:
- Increase in metabolic demands (inflammation uses energy)
Pyrexia:
- Endogenous pyrogens acting on hypothalamus
General, non-specific symptoms:
- The basal ganglia in the brain ganglia are responsible for getting us motivated and moving.
- When inflammation is excessive or persistent, changes in the basal ganglia, probably due to circulating chemicals, can lead to:
>feeling run down
> apathy
> depression
> fatigue
describe some of the benefits and harmful effects of inflammation
Beneficial:
- Dilution of toxins
- Entry of antibodies
- Fibrin formation and isolation of micro-organisms
- Delivery of nutrients and oxygen
- Stimulation of immune system
Harmful:
- Digestion of normal tissue
- Swelling
- Loss of normal function
- Inappropriate or excessive inflammatory response eg. Asthma
what causes acute inflammation
Microbial infections including pyogenic (i.e. pus forming) organisms
Physical agents
e.g. heat, cold, trauma, irradiation
Chemicals
e.g. corrosives, acids, alkalis, toxins
Tissue necrosis of any cause
Foreign bodies
what is the main cell type in acute inflammation
The key cell type is the neutrophil or neutrophil polymorph or polymorphonuclear leucocyte
what are the 7 stages of phagocytosis
- chemotaxis and adherence of microbe to phagocyte
- ingestion of microbe by phagocytes
- formation of a phagosome
- fusion of the phagosome with a lysosome to form a phagolysosome
- digestion of ingested microbe by enzymes
- formation of residual body containing indigestible material
- discharge of waste materials
what is chemotaxis
Chemotaxis is the ability of cells such as neutrophils to move along a concentration gradient towards some chemical substance
what is the role of chemical mediators of inflammation
- Vascular dilatation
- Increased vascular permeability
- Promote leukocyte adhesion
- Promote chemotaxis
A 32 year old man has acute appendicitis and his appendix is removed and examined histologically.
Which inflammatory cells would be present?
a) Eosinophils
b) Lymphocytes
c) Macrophages
d) Neutrophils
e) Plasma cells
d
A 21 year old woman has acute inflammation of her left ovary and left fallopian tube.
Which diagnosis is most likely?
a. Acute salpingo-oophoritis
b. Acute epididymo-orchitis
c. Acute proctitis
d. Acute diverticulitis
e. Acute pancreatitis
a
A 25 year old man with acute pancreatitis feels run down and miserable.
Which region in the brain has been affected by circulating chemicals to cause these symptoms?
a. Basal ganglia
b. Hypothalamus
c. Pituitary gland
d. Cerebellum
e. Fourth ventricle
a
Define what is meant by the term chronic inflammation
- Chronic inflammation refers to a prolonged inflammatory response that involves a progressive change in the type of inflammatory cells present at the site of inflammation.
- It is characterised by the simultaneous destruction and repair of tissues
- It can follow an episode of acute inflammation or develop ab initio as a low grade smouldering form
List the causes of chronic inflammation
Persistent microorganisms that are difficult to eradicate
Immune Mediated Inflammatory Diseases
Prolonged Exposure to potentially toxic agents
list the cell types involved in chronic inflammation
Lymphocytes*
Macrophages*
plasma cells
eosinophils
mast cells
what is the role of macrophages in chronic inflammation
- Phagocytosis
- Production of inflammatory mediators
- Initiation of immune response
what is the role of T-lymphocytes in chronic inflammation
- T-lymphocytes change to effector T-lymphocytes
- these secrete cytokines
these cytokines:
> RECRUITMENT OF OTHER LYMPHOCYTES
> RECRUITMENT OF MACROPHAGES INTO AREA
> PRODUCTION OF INFLAMMATORY MEDIATORS
> DESTRUCTION OF TARGET CELLS
> INTERFERON PRODUCTION
what is granulomatous inflammation
and what is a granuloma
A form of chronic inflammation characterised by the formation of the granuloma (plural granulomata)
A GRANULOMA is a collection of macrophages that have transformed into epithelioid (epithelial –like) macrophages
surrounded by a collar of lymphocytes
with a few plasma cells
what are the causes of granulomatous inflammation
- Micro-organisms:
> Mycobacterium tuberculosis (Tuberculosis)
> Mycobacterium Leprae (Leprosy) - Foreign bodies:
a. Endogenous:
> bone
>uric acid crystals
> adipose tissue
b. Exogenous:
> sutures
> implanted prostheses - Idiopathic:
> Crohn’s Disease
> Sarcoidosis
> Wegener’s granulomatosis
what are the complications associated with chronic inflammation
- Fibrosis, scarring, contracture, stricture
- Loss of function
- Dystrophic calcification (abnormal calcification of tissues)
- Carcinogenesis: DNA damage, NF Kappa Bpathway,effects of immunosuppression
- Amyloid
Explain what is meant by tissue healing and define the terms regeneration and repair
Regeneration = Proliferation of cells and tissues to replace lost structures
Distinguish between tissues that are labile, constantly renewing and quiescent/stable and permanent without the ability to regenerate
Labile Cells:
- Continuously dividing
- Replace dead or sloughed-off cells.
- These tissues contain pools of stem cells, which have enormous proliferative and self-renewing ability
Stable or QuiescentCells: - Conditionally renewing - Divide at a very slow rate normally, but can divide when needed - eg: > Liver > Pancreas > Bone
Permanent Cells: - No effective regeneration - Cells that have left the cell cycle permanently - eg : > Central Nervous System > Cardiac muscle > Skeletal muscle