Neoplasia Flashcards
What is Sporadic Cancer?
a mutation in a single cell that divides and a tumour develops
What is Hereditary Cancer?
a cancer gene mutation that is present in every cell
What is Familial Cancer?
Increased risk of cancer in families compared to the general population
- shared genetic and environmental factors
What causes most cancers?
genetic abnormalities
What are mutations in genetic material caused by? (4)
- radiation
- exposure to carcinogens
- infections
- failure of cellular proof-reading mechanisms
What does genetic mutations result in?
- loss of regulation over cell growth and proliferation
- abnormal signaling by an oncogene and tumor suppressor gene
What do Tumour Suppressor genes do? (6)
- inhibit proliferation
- control cell growth
- down regulate cell cycle
- repair DNA
- Act as a checkpoint for DNA damage
- Mutations result in loss of function
What do Proto-oncogenes do? (8)
- Code normal proteins that promote:
- cell growth
- cell survival
- cause cellular proliferation
- inhibit cell death
- gain of function
- becomes an oncogene when the proto-oncogene is mutated or deregulated
- result is cancer
Explain the 2 Hit Hypothesis:
First hit: is when on the parent chromosomes has a mutation
Second hit: is when the combined chromosomes both have a mutation
In order for cancer to develop, both chromosomes need to have a mutation
What does the 2 Hit Hypothesis say about people who have a hereditary disposition to cancer?
They already have a chromosome with a mutation, so they only require a single hit on the other chromosome to develop cancer
Describe the Progression of Cancer:
Initiation: Healthy -> mutation -> Premalignant cell
Promotion: Proliferation of premalignant cells
Transformation: second alteration produces malignant cell from a premalignant cell
Progression: Malignant cells divide forming clinical cancer
What are the Hallmarks of Cancer? (6)
- evading apoptosis
- Self-sufficiency in growth signals
- Insensitivity to anti-growth signals
- Tissue invasion and metastasis
- limitless replicative potential
- Sustained angiogenesis
What are non-modifiable risk factors?
factors which patients cannot change
What are modifiable risk factors?
factors we can change within patients
What are the non-modifiable risk factors of cancer? (7)
- age
- sex
- ethnicity
- geography
- genetic susceptibility
- precursor lesions or preneoplastic conditions
- reproductive history
What are the modifiable risk factors of cancer? (8)
- smoking
- obesity
- physical activity
- diet
- Alcohol consumption
- injection drug use
- sexual history
- uv radiation exposure
What are Carcinogens?
Diverse, natural, and synthetic products that can either be direct acting or indirectly acting, that affect the RNA, DNA and proteins within ourselves, resulting in cancer
What are the different types Carcinogens?
Chemical
- components of cigarette smoke
- asbestos
Radiation
- UV
- ionizing radiation
Viral and microbial
What is a Neoplasm?
Tumour = abnormal mass of tissue
What does a Neoplasm result from?
- excessive cell division
- evasion of apoptosis
What is Cancer a result of?
Cancer = Malignant
- deregulated growth
- ability to invade tissues
How are Tumours named?
- Cell type (tissue origin)
- Nature of tumour
- benign
- malignant
Describe a Benign tumour:
- usually suffix “oma”
- named based on architectural pattern
- based on tissue type
What cancer types are exceptions to the “oma” rule?
- melanoma
- lymphoma
Describe a Malignant tumour:
- classified based on tissue type
- Sarcoma -> arises from connective tissue
- Carcinoma -> arises from epithelial tissue
What are the characteristics of Tumours? (4)
- differentiation and anaplasia
- rate of growth
- local invasion
- metastasis
What is Differentiation?
extent to which cells resemble normal tissue counterpart
- well differentiated
- moderately differentiated
- poorly differentiated
What is Anaplasia?
lack of differentiation
- do not resemble any tissue
- high degree of atypia and pleomorphism
What is the rate of growth for Benign tumours?
slow growth
What is the rate of growth for Malignant tumours?
rapid growth
How does growth rate correlate blood supply?
Tumour cells promote angiogenesis by secreting growth factors
What is Angiogenesis?
Formation of blood factors
How does growth correlate with differentiation?
Poorly differentiated tumours grow faster
What are the characteristics of Benign tumours when it comes to invasion?
- well circumscribed
- do not invade
- expansile growth
What are the characteristics of Malignant tumours when it comes to invasion?
- irregular/ill-defined margins
- invade and destroy tissue
- infiltrative growth
How do Carcinomas begin?
- as localized growths originating from a single cell
- start off confined to the epithelium
What occurs if the basement membrane is intact on carcinomas?
Carcinoma in situ or High grade dysplasia
What is Metastasis?
Tumour that is discontinuous from the primary lesion and involves other tissue
- unequivocal sign of malignancy
What are the different pathways of Metastasis?
- Seeding via body cavities -> peritoneal, pleural, pericardial cavities
- Lymphatic spread
- Hematogenous spread
Describe Lymphatic spread:
- most common, typically carcinomas
- spread to lymph nodes through lymphatic drainage
Describe Hematogenous spread:
- Carcinomas and preferred route of spread for sarcomas
- liver and lungs frequent sites
What are Paraneoplastic Syndromes?
a group of rare disorders that are triggered by an abnormal immune system response to a cancerous tumour or neoplasm
What can occur with Local Effects of a Tumour?
- depends on tumour location
- symptoms can occur with both benign and malignancy tumours
What can occur with Hormonal Effects of a Tumour?
- Hormone producing tumours
ex. B cell adenoma in pancreas -> insulin production -> hypoglycemia
Adrenal cortex adenoma -> steroid production -> secondary effects
What is Cancer Cachexia?
- progressive loss of fats & lean body mass with weakness, anorexia & anemia
- not due to nutritional demand by tumour
several factors may be responsible: - reduced food intake
- reduced synthesis & storage of fat or increased mobilization of fatty acids
Why is Paraneoplastic Syndrome important?
May be earliest manifestation of an occult neoplasm, mimic metastatic disease, and cause significant, even lethal, clinical problem
What symptoms can Paraneoplastic Syndrome cause?
- endocrine (lung carcinoma may cause Cushing’s disease)
- neurological (seizures, changes in speech and muscle tone)
- blood cell abnormalities (increased clotting)
What is the process of Grading Cancer?
Estimates aggressiveness of the neoplasm and is based on the degree of differentiation
- assess pathologically
What are some of the criteria used to grade cancer? (3)
- differentiation
- mitoses
- necrosis
What is the graded scale?
- well differentiated
- moderately differentiated
- poorly differentiated
What is the process of Staging Cancer?
determined using a combination of clinical and pathological parameters
What is Clinical Staging of Cancer?
Based on information obtained prior to definitive treatment
What is Pathological Staging of Cancer?
Information obtained at surgery and from examination of the tissues by a pathologist
What is Pathological Staging of Cancer based on? (3)
- tumour size
- extent of spread to regional lymph nodes
- presence or absence of metastasis to other organs
What are the 5 reasons to stage Cancer?
- use of common language across health care providers and patients
- helps guide treatment
- estimation of prognosis
- comparison of results over time
- clinical trials standardization
What is Screening?
the process of identifying asymptomatic individuals with an elevated risk of cancer
What does earlier identification allow?
- earlier diagnosis
- early treatment
- opportunity to decrease morbidity and mortality from the disease
What are the most routinely screened cancers?
- cervical cancer -> pap test/smear
- Breast cancer -> mammography
- Colon cancer -> fecal immunohistochemical test (FIT), Colonoscopy
What are the most routinely screened cancers?
- cervical cancer -> pap test/smear
- Breast cancer -> mammography
- Colon cancer -> fecal immunohistochemical test (FIT), Colonoscopy
By screening, what are you able to detect?
Precursor lesion
How is cancer diagnosed?
- tissue sample
- examination under the microscope by a pathologist
What are the limitations to regular cancer screenings?
- Sometimes test results suggest you have cancer even though you don’t (called a false positive).
- The test may not detect cancer even though it is present (called a false negative).
- Some cancers would not necessarily lead to death or decreased quality of life (overdiagnosis).
- Having screening tests may lead to more tests and procedures that may be harmful.
