Module 3: Cancer Flashcards
What is cancer?
A complex group of >100 diseases affecting a wide range of tissues
Caused by mutations in genes controlling cell growth after exposure to carcinogens
What percentage of mutations in cancer are inherited?
1%
Extra somatic mutations are also required for cancer development
What characterizes cancer?
Loss of growth control leading to an unregulated increase in cell number, metastasis, and invasion of other tissues
How does cancer incidence affect the population?
Affects 1 in 3 people worldwide, leading cause of death in NZ and second worldwide
What was the incidence of cancer in NZ in 2015?
23,215 cases/year
Mortality was 9,615 deaths/year
What is a benign tumor?
Tumor where neoplastic cells are clustered in a single mass, well differentiated, and do not metastasize
What is a malignant tumor?
Tumor with less differentiated cells that invade surrounding tissues and metastasize
How are benign tumors classified?
Tissue name + ‘-oma’
What are carcinomas?
Malignant tumors derived from epithelial cells
What are examples of carcinomas?
Adenocarcinoma, squamous cell carcinoma
Includes cancers of lung, colon, breast, and prostate
What is the difference between normal cells and tumor cells regarding growth factors?
Normal cells depend on growth factors; tumor cells can divide without them
What is the G1/S checkpoint?
Regulates progression into DNA synthesis phase, ensuring growth factors, nutrients, and DNA integrity are present
What is the ‘multi-hit hypothesis’ in cancer?
Each cancer arises from an accumulation of several mutations over a lifetime
What role do proto-oncogenes play in cancer?
They positively regulate cell division; mutations can turn them into oncogenes
What is the function of tumor suppressor genes?
Negatively regulate cell division, preventing abnormal proliferation
What is the main function of p53?
Acts as a sensor for DNA damage and can cause cell-cycle arrest or apoptosis
What is the Ras-MAPK pathway?
A growth factor signaling pathway that, when activated, allows progression through the G1/S checkpoint
What is the significance of telomerase activity in cancer?
Increased telomerase activity allows cells to proliferate indefinitely, leading to cancer
What is the role of DNA repair genes in cancer?
Mutations in these genes can cause genome instability, making further mutations more likely
What types of mutations are involved in cancer development?
Point mutations, insertions, deletions, translocations
These mutations can lead to a gain of function in oncogenes
What is Knudson’s two-hit hypothesis?
Both alleles of a tumor suppressor gene must be inactivated for tumorigenesis to occur
What does ‘contact inhibition of growth’ mean?
Normal cells stop dividing when they come into contact with other cells; tumor cells do not exhibit this
What is the role of growth factors in the G1/S checkpoint?
They activate Cdk4/6, allowing progression through the checkpoint
What is the typical progression of cancer development?
Initiation, promotion, progression
Involves exposure to carcinogens and genetic changes
What are the four phases of the cell cycle?
G1, S, G2, M
What happens if a cell fails to pass a checkpoint?
Cell-cycle arrest or apoptosis may occur
What are the consequences of mutations in tumor suppressor genes?
Loss of function leading to uncontrolled cell division
True or False: All cancers are caused by inherited mutations.
False
Most mutations are somatic and acquired through environmental interactions
What is a common effect of mutations in genes involved in DNA repair?
Genome instability, making further mutations likely
This instability is a key factor in oncogenesis.
What are the three main stages of cancer development?
Initiation, Promotion, Progression
Each stage involves specific biological changes leading to cancer.
What occurs during the initiation stage of cancer development?
Exposure to a carcinogen, damage to DNA, and proto-oncogene activation or tumor suppressor inactivation
This stage can lead to irreversible changes in cells.
What happens during the promotion stage of cancer development?
Altered cells are stimulated to divide by a tumor promoter
These cells may remain dormant or be removed by the immune system.
Define metastasis.
The ability of cancer cells to escape into circulation and develop into secondary tumors
Metastasis is a critical aspect of cancer progression and severity.
List some host risk factors for cancer.
- Hereditary predisposition
- Reproductive hormones
- Obesity
These factors can influence cancer risk and progression.
What role do chemical carcinogens play in cancer development?
They are DNA modifying chemicals that cause mutations
Lifestyle factors like smoking and diet are also considered carcinogenic.
What is the significance of a diet rich in fruits and vegetables concerning cancer?
It may protect against many cancers due to phytochemicals
These compounds can block carcinogens or suppress tumor growth.
What are some clinical manifestations of cancer?
- Neurological problems
- Blood vessel blockage or bleeding
- Effusions
These manifestations can arise from local effects of tumors.
What is cancer anorexia-cachexia syndrome?
A syndrome characterized by protein/energy malnutrition due to cancer’s increased energy demands
It can lead to significant weight loss and nutritional deficiencies.
True or False: Paraneoplastic syndromes are symptoms unrelated to the initial tumor site.
True
These syndromes can result from ectopic hormone production by tumors.
What are the seven warning signs of cancer?
- Change in bowel or bladder habits
- A sore that does not heal
- Unusual bleeding or discharge
- Thickening or lump
- Indigestion or swallowing difficulty
- Change in a wart or mole
- Nagging cough or hoarseness
Recognizing these signs can lead to earlier diagnosis.
What is involved in cancer diagnosis?
Indirect tests, cytology, imaging, tumor markers, and microarray technology
Multiple approaches are necessary for accurate diagnosis and monitoring.
Describe tumor grading.
Microscopic examination of cell appearance and differentiation, graded I to IV
Grade I is well differentiated while Grade IV is undifferentiated.
What is TNM staging?
A system that classifies tumor size (T), lymph node involvement (N), and metastasis (M)
It provides a standardized way to describe cancer spread.
What are some methods for cancer prevention?
- Avoidance of environmental exposures
- Diet and exercise
- Routine screenings
- Vaccination
Prevention strategies are critical in reducing cancer incidence.
What are common treatments for cancer?
- Surgery
- Radiation therapy
- Chemotherapy
- Immunotherapy
- Targeted therapies
Treatment plans are often multidisciplinary, tailored to individual cases.
What is the most prevalent cancer in New Zealand?
Lung cancer
It is the biggest cause of cancer-related deaths in the country.
What are the signs and symptoms of lung cancer?
- Persistent cough
- Coughing up blood
- Chest pain
- Recurring chest infections
Early detection can significantly improve outcomes.
What is the incidence of bowel cancer in New Zealand?
3030 cases diagnosed in 2011
It is one of the highest rates in the world.
What are the risk factors for breast cancer?
- Being female
- Age (50+)
- Family history
- Genetic mutations (BRCA1, BRCA2)
- Nulliparity
- High fat diet
These factors can significantly influence breast cancer risk.
What is the primary treatment for skin cancer?
Surgery, radiation, and chemotherapy
Prevention strategies include sun protection and avoiding tanning beds.
What is the highest cancer incidence rate in the world?
NZ has the highest rate in the world
New Zealand has particularly high rates of skin cancer.
How many melanoma cases are reported per year in NZ?
~ 2,000 per year
This includes around 350 deaths annually.
What are the annual cases of non-melanoma skin cancer in NZ?
~ 67,000 per year
This includes around 130 deaths annually.
What are some risk factors for skin cancer?
- Family history
- Skin that burns easily
- Cumulative sun exposure or severe sunburn episodes
- Sunbeds
- X-ray exposure
- Scars from burns or disease
- Exposure to some chemicals
These factors increase the likelihood of developing skin cancer.
What are common signs and symptoms of skin cancer?
Red, scaly, rough skin lesions on sun-exposed areas
Common areas include hands, head, neck, lips, and ears.
What are the methods for diagnosing skin cancer?
- Skin checks
- Mole maps
- Biopsy
These methods help in the early detection of skin cancer.
What are some prevention strategies for skin cancer?
- Cover skin
- Use sunscreen
- Wear hats and sunglasses
- Check skin regularly
Regular checks should include areas not normally exposed to the sun.
What are the primary treatments for skin cancer?
- Surgery
- Cryotherapy
- 5-fluorouracil cream
- B-Raf inhibitors
- Immunomodifiers
- Photodynamic therapy
- Radiation
Treatment options vary based on the type and stage of cancer.
What is the incidence of prostate cancer in men?
Second most frequently diagnosed cancer (15% of all male cancers)
More than 80% of men will develop prostate cancer by age 80.
What are some risk factors for prostate cancer?
- Male > 50 years
- Poor diet and obesity
- Family history
- Elevated testosterone
The link between red meat consumption and prostate cancer is still being studied.
What are initial symptoms of prostate cancer?
Initially asymptomatic; may include frequent urination and pain
Symptoms can progress to blood in urine.
What are the methods for diagnosing prostate cancer?
- Digital rectal examination (DRE)
- Ultrasound
- MRI
- Biopsy
- PSA screening
The usefulness of PSA screening is still debated.
What are some treatment options for prostate cancer?
- Drugs to decrease testosterone (Finasteride)
- Surgery
- Radiation or brachytherapy
- Chemotherapy
Most prostate cancers are slow-growing and can be managed effectively.
What is the incidence of cervical cancer in NZ?
4th most common cancer in women worldwide; 160 new cases and ~50 deaths annually in NZ
Cervical cancer remains a significant health issue.
What is the greatest risk factor for cervical cancer?
HPV, particularly subtypes 16 & 18
HPV vaccination can significantly reduce the risk.
What are common signs and symptoms of cervical cancer?
- Abnormal vaginal bleeding or discharge
- Tiredness
- Pain in pelvic area, legs, or lower back
Early detection is crucial for effective treatment.
What are the methods for diagnosing cervical cancer?
- Pap test
- Visual inspection (colposcopy)
- Biopsy
- Imaging (ultrasound, CT, MRI, PET, bone scan)
These diagnostics help in the identification and staging of cervical cancer.
What are some treatment options for cervical cancer?
- Surgery
- Radiation or brachytherapy
- Chemotherapy
Treatment plans vary based on the stage of cancer.
What is the leading cause of deaths in New Zealand?
Cancer
Major types include lung, colon, breast, melanoma, prostate, and cervical cancers.
What causes cancer at the genetic level?
Mutations in genes controlling cell growth
This can lead to uncontrolled cell division and tumor formation.
What are the risk factors for developing cancer?
- Exposure to environmental carcinogens
- Smoking
- Diet/obesity
- Alcohol
- Lack of exercise
- Genetics (inheritance of oncogenes & mutated TSGs)
Around 1% of cancers are hereditary.
In terms of leading cause of death in NZ cancer ranks?
1st
The difference between a benign tumour and a metastatic tumour is:
1. Benign are smaller than metastatic
2. Benign are larger than metastatic
3. Only metastatic include cells that have undergone metastasis
4. Only metastatic tumours contain cells that are actively proliferating
5. Only benign contain cells that do not dia via apoptosis
- Only metastatic include cells that have undergone metastasis
The biggest danger to the host caused by benign tumours is…?
1. They secrete novel mutated proteins and enzymes
2. They invade other organs and kill the cells there
3. They compres and damage the surrounding tissue
4. They use up the blood supply and all its nutrients, causing the surroudnign normal tissue to starve
- They compres and damage the surrounding tissue
Tumour cells are able to secrete factors to stimulate formation of new blood vessels to feed the tumour. This formation of new blood vessels is known as:
1. Self-sufficiency
2. Metastasis
3. Replicative mitosis
4. Angiogenesis
- Angiogenesis
Cancers are caused by mutations specifically in genes that control
1. Metastasis and angiogenesis
2. angiogenesis and carcinogenesis
3. Telomeres and growth factors
4. Mitosis and apoptosis
- Mitosis and apoptosis
A gene that commonly contains an activating mutation causing cancer is:
1. The Ras oncogene
2. The p53 oncogene
3. The Grb2 integrin tumour supressor gene
4. The G1/S/G2/M mitotic gene
The Rad oncogene
Suspected cancers are often biopsied and examined under the microscope, then graded based on their appearance. Compared to a Grade I tumour, a Grade III tumour will demonstrate:
- Smaller cells with ‘crab’ legs
- Larger cells with a darker stained nucleus
- Cells that appear abnormal and not well differentiated
- Cells that are well differentiated and look more like ‘normal’ cells for that tissue
- Cells that appear abnormal and not well differentiated
Once a cancer is diagnosed, it is then graded by stage. Compared to a Stage I tumour, a Stage IV tumour would:
1. Be smaller and more likely to be located in a single site, with the tumour contained within a capsule
2. Be more responsive to chemotherapy and have a better prognosis
3. Be larger and have a greater degree of angiogenesis
4. Have metastasized to distant sites around the body
- Have metastasized to distant sites around the body
The single biggest cause of cancer deaths in New Zealand is:
1. prostate cancer
2. lung cancer
3. cervical cancer
4. melanoma
- lung cancer
