MCB Lecture 64 Neoplasia I Flashcards
Describe pathological and physiologic causes of hyperplasia
Pathological: too many growth factors, hormones
Physiological: growth of the uterus during pregnancy
Describe pathological and physiologic causes of hypertrophy
Pathological: hypertension, leading to increased heart cell size and stenosis
Physiological: athletes heart, lifting weights: increased muscle size
Describe two causes of metaplasia
Smoking: ciliated columnar epithelium replaced with stratified squamous
Barrett oesophagus: simple squamous replaced with columnar in response to gastric acid reflux
What is dysplasia?
Pre malignant condition of proliferation
What are the features of cells that have undergone dysplasia?
Loss of cell polarity
Loss of tissue architecture
Atypical mitoses
Proliferation
What is the outcome of dysplasia?
Expected progression on to cancer
What is neoplasia?
New growth of cells
What is the name for the study of cancer?
Oncology
What suffix is used to denote benign neoplasms?
-oma
What are the features of benign neoplasms?
Well differentiated
Discrete location
Can not invade and replace healthy tissues
Can’t metastasise
What is cystic teratoma?
This is an example of a benign neoplasm
It arises from stem cells, so many different tissue types are see that produce hair, teeth and secrete stuff
What are the features of malignant neoplasms?
They can metastasise and invade and replace healthy tissues
They are no longer well differentiated
They are not localised to a discrete area
Much dysplasia
Less differentiated
What are the most common cancers?
The gender specific cancers such as breast and prostate are the most common
Which cancers contribute to the most deaths?
Lung, colorectal, breast and prostate
What is an individual’s lifetime risk of cancer?
1/3
What are the two broad categories of aetiology of cancer?
Environmental and hereditary
What are some environmental causes of cancer?
What are the common features of the mode of action of these things?
Smoking, industrial, dietary
They all contain highly reactive oxygen species that make the genome unstable
All cancer, hereditary or otherwise, is due to …
Genomic instability
Why are double stranded breaks dangerous?
When the cell tries to repair this, mistakes are often made, leading to mutations
What does non-ionising radiation do?
Makes thiamine dimers
What does ionising radiation do?
Causes double and single stranded breaks
Describe how oncogenic viruses cause cancer
eg?
They insert genes into the host genome. This may disrupt tumour suppressor genes
HPV, EDV
Describe how immunodeficiency leads to cancer
Eg. ?
When an individual is immunosupressed, they can not kill neoplastic cells and many tumours result
E. HIV
How can chronic inflammation lead to cancer?
The cytokines and other inflammatory substances are highly reactive
How can genetics play a role in cancer?
Gene mutation of an oncogene or tumour suppressor gene
Eg. BRCA-1, Rb gene, APC
What are the 5 methods of detection of cancer?
Physical examination Histology / cytology Tumour markers Imaging Molecular diagnosis
Describe how physical examination is used to detect cancer
This is no longer sufficient
Describe how cytology and histology is used to detect cancer
Looking at biopsies under the microscope: cell numbers and tissue structure etc.
Describe how tumour markers are used to detect cancer
What are the two main ways this is done?
Immunohistochemistry: using MHC that is specific for antigens involved with cancer
Eg. EGF receptor is the antigen. MHC binds, and is seen because it is marked
Biochemical assay: same thing, done in the blood
Describe how imaging is used to detect cancer
Inject isotopically marked glucose and then use PET scanning to see where is highly metabolically active
How can cancers be diagnosed molecularly:
- What are we looking for?
- How can we find it?
PCR: eg. Of BCR-abl to detect residual leukaemia cells in CML
Genome wide profiling: microarrays, RNA-seq
Describe the difference in survival rate when breast cancer is detected early
Early detection: 98% survival over next 5 years
What are the two modes of staging of cancer?
Which is the most useful?
Grading
Staging
Staging is more useful
Describe how grading of cancer is done
Look at the cells and grade them based on:
Level of differentiation
Mitoses
Architecture
Give it a grade from low to high
Describe how staging of cancer is done
Stage it based on: size of primary lesion T
Presence of metastasis M
Extent of spread to region lymph nodes N
Describe the TNM system of cancer staging
T: size of primary tumour
M: presence of metastasis
N: extent of spread to the regional lymph nodes
Eg T1-T4
