Podcast
Questions and Answers
Which of the following is NOT a primary characteristic of cancer?
Which of the following is NOT a primary characteristic of cancer?
The risk of developing cancer decreases with age.
The risk of developing cancer decreases with age.
False (B)
What is a major cause of death in developed countries, as mentioned in the text?
What is a major cause of death in developed countries, as mentioned in the text?
Cancer
In Australia, approximately 1 in ______ men will be diagnosed with cancer.
In Australia, approximately 1 in ______ men will be diagnosed with cancer.
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Match the descriptions with the correct terms related to cancer:
Match the descriptions with the correct terms related to cancer:
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What gene mutations are primarily associated with Hereditary Nonpolyposis Colon Cancer (HNPCC)?
What gene mutations are primarily associated with Hereditary Nonpolyposis Colon Cancer (HNPCC)?
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Mutation carriers of HNPCC have a 40-50% lifetime cancer risk.
Mutation carriers of HNPCC have a 40-50% lifetime cancer risk.
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What process is disrupted in Chronic Myelogenous Leukaemia (CML) due to the Philadelphia chromosome?
What process is disrupted in Chronic Myelogenous Leukaemia (CML) due to the Philadelphia chromosome?
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DNA and histone modifications can lead to ______.
DNA and histone modifications can lead to ______.
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What therapy uses anti-cancer drugs to destroy cancer cells?
What therapy uses anti-cancer drugs to destroy cancer cells?
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What is the main goal of targeted cancer therapy?
What is the main goal of targeted cancer therapy?
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Environmental factors have no impact on cancer development.
Environmental factors have no impact on cancer development.
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Match the type of cancer therapy with its description:
Match the type of cancer therapy with its description:
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The BCR-ABL hybrid gene leads to ______ cell division in CML.
The BCR-ABL hybrid gene leads to ______ cell division in CML.
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What percentage of cancers are associated with viruses?
What percentage of cancers are associated with viruses?
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What is the role of HPV E7 protein in cancer development?
What is the role of HPV E7 protein in cancer development?
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Most skin cancers are caused by UV light exposure.
Most skin cancers are caused by UV light exposure.
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What is the average age of diagnosis for mutation carriers of HNPCC?
What is the average age of diagnosis for mutation carriers of HNPCC?
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What is Gleevec used for?
What is Gleevec used for?
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Microsatellites are ___________ in repetitive DNA regions that are highly mutable.
Microsatellites are ___________ in repetitive DNA regions that are highly mutable.
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What is the primary starting point for all cancers?
What is the primary starting point for all cancers?
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Most cancers are familial.
Most cancers are familial.
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What major consequence occurs due to mutations in tumor-suppressor genes?
What major consequence occurs due to mutations in tumor-suppressor genes?
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BRCA1 and BRCA2 are examples of ________ genes that play a role in DNA repair.
BRCA1 and BRCA2 are examples of ________ genes that play a role in DNA repair.
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Match the cancer types with their descriptions:
Match the cancer types with their descriptions:
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Which of the following statements about familial cancers is true?
Which of the following statements about familial cancers is true?
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The G1/S checkpoint is where the cell prepares to divide.
The G1/S checkpoint is where the cell prepares to divide.
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How many mutations are generally required for the development of cancer?
How many mutations are generally required for the development of cancer?
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Familial Adenomatous Polyposis (FAP) is primarily caused by mutations in the ________ gene.
Familial Adenomatous Polyposis (FAP) is primarily caused by mutations in the ________ gene.
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What kind of mutation can lead to the development of oncogenes?
What kind of mutation can lead to the development of oncogenes?
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All cancer cells demonstrate genomic instability.
All cancer cells demonstrate genomic instability.
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Which checkpoint checks that all chromosomes are correctly lined up before cell division?
Which checkpoint checks that all chromosomes are correctly lined up before cell division?
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______ mutations often lead to an increased risk of breast cancer in females.
______ mutations often lead to an increased risk of breast cancer in females.
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What is a consequence of mutations in proto-oncogenes?
What is a consequence of mutations in proto-oncogenes?
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Study Notes
Week 10: Genes and Cancer
- Cancer is a phenotype resulting from both environmental and genetic factors.
- Cancer is a group of diseases affecting multiple cells and tissues.
- Two key characteristics of cancer:
- Uncontrolled cell division
- Ability of cells to spread (metastasis)
- Improvements in medical treatments have increased life expectancy but also increase cancer risk.
- Cancer is a major cause of death in developed countries, with around 30% of deaths attributed to it in Australia.
- Age is the biggest risk factor for developing cancer.
- Risk increases with age, and early diagnosis leads to better treatment and outcomes.
What Causes Cancer?
- Cancer has a variety of causes, including:
- Genetic predisposition
- Mutagenic chemicals
- Some viruses
- Chromosomal changes
- Environmental factors
- Time (accumulation of mutations over time)
- Mutations are the starting point for all cancers.
- Most cancers are sporadic, arising from the accumulation of mutations over time, though environmental factors can accelerate this process.
- More than two mutations are typically required to develop cancer.
Some Cancers are Familial
- Some cancers run in families.
- These familial cases have identified cancer genes.
- These cases often involve inheritance of one mutated gene, with the normal gene mutating later—a process called loss of heterozygosity (LOH).
- Other mutations are also often needed for cancer to develop.
Inheritable Susceptibilities
- Specific genes associated with various cancers and their chromosomal locations are presented in a table. (The exact table is not provided)
Progression of Cancer
- Cancer starts in a single cell.
- Mutations accumulate over time.
- Cancer cells repeatedly divide.
- Cancer cells become more aggressive.
- Cancer cells can spread to new locations.
Types of Cancer
- Carcinoma affects tissues lining internal organs.
- Sarcomas affect connective or supportive tissue.
- Leukemia affects blood and blood-related cells.
- Lymphomas and myelomas affect the immune system.
- Brain and spinal cord cancers affect the central nervous system.
- Cancer types are also classified by location.
Some Mutations Disrupt the Cell Cycle
- Many cancers originate in epithelial cells, which are constantly renewed.
- Mutations can disrupt the regulation of the cell cycle, leading to uncontrolled cell division.
Cell Cycle Checkpoints
- Checkpoints ensure proper cell cycle progression, checking for internal and external conditions, size, nutrients, growth factors, and DNA quality.
- A primary checkpoint occurs early in the cell cycle determining whether to enter or halt in a state of inactivity (GO).
- DNA copy integrity and protein production are further assessed at other checkpoints.
Checkpoint Regulation Genes
- Tumor suppressor genes decrease or stop cell division, working mostly during G1/S or G2/M phases.
- Mutations in tumor suppressor genes can result in uncontrolled cell division.
- Proto-oncogenes start or maintain cell growth/division and are normally activated by signals—in cancer, these are often permanently switched on.
Retinoblastoma
- Retinoblastoma 1 (RB1) is a tumor suppressor gene.
- Mutations can lead to several different cancers, including retinal, bone, lung, and bladder cancers, and is commonly diagnosed in children between 1 and 3 years of age.
Retinoblastoma
- RB1 is on chromosome 13q1.
- Codes for pRB, a protein binding to transcription factor E2F.
- pRB activity regulates the cell cycle.
- Its inactivation allows cells to progress through the cell cycle even with DNA damage.
Ras Proto-oncogenes
- A family of proto-oncogenes that code for signal transducers.
- The RAS protein is important in cell signaling.
- Activating mutations in RAS lead to cancer.
- A single base mutation in the protein can cause cancer.
DNA Repair and Genome Stability
- Cancer often results from genomic instability, such as aneuploidy, loss of chromosomes, duplication, deletions, etc.
- Loss of DNA repair capacity leads to a progressive increase in mutations throughout the life cycle of a cancer.
DNA Repair Problems
- Damaged DNA repair genes can lead to uncontrolled cell growth and development.
- The accumulation of mutations within DNA affects the genetic stability of the cells.
Breast Cancer and DNA Repair Genes
- Mutations in BRCA1 or BRCA2 increase the risk of breast and ovarian cancer in females and prostate cancer in males.
- BRCA1 and BRCA2 are DNA repair genes, crucial for repairing double-strand breaks in DNA.
BRCA1 and BRCA2 DNA Repair Mechanisms
- Detailed descriptions of the mechanisms BRCA1 and BRCA2 use for DNA repair are given. (The description is too complex to fit a single bullet point.)
BRCA Mutations
- BRCA mutations account for a significant portion of hereditary breast cancers (15-20%) and a smaller portion of all breast cancers overall (5-10%).
- Frequency of BRCA mutations varies across different types of cancer (breast, ovarian, prostate). (Exact figures are presented in a table).
The Pathway to Colon Cancer
- Several mutations are required to develop colon cancer.
- Genetic and environmental factors are significant.
- Much of colon cancer is sporadic, though around 5% results from hereditary transmission.
- Key hereditary forms, including Familial Adenomatous Polyposis(FAP) and Hereditary Nonpolyposis Colon Cancer (HNPCC), are discussed.
FAP (Familial Adenomatous Polyposis)
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Accounts for around 1% of all colon cancers.
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Inheriting one mutated APC gene leads to a 100% lifetime risk of colon cancer.
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The APC gene is a critical tumor suppressor gene.
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Multiple polyps commonly appear from adolescence, and their accumulation and growth contribute to the development of colon cancer.
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Detailed description of FAP progression is given
-
Mutations in additional genes beyond APC and KRAS are implicated.
HNPCC (Hereditary Nonpolyposis Colon Cancer)
- Mutation carriers of HNPCC genes have a high lifetime risk of developing colon cancer; diagnosis typically occurs between 40-50 years.
- HNPCC results from mutations in DNA repair genes.
- Yearly colonoscopies, genetic screening of family members, and early detection are key measures for managing individuals with HNPCC.
Chromosomal Rearrangements and Cancer
- Several cancers have linked translocation events involving different chromosomes.
- Translocations involving ABL and BCR, for example, are implicated in Chronic Myelogenous Leukemia (CML).
- Specific chromosome translocations are associated with several cancers. A table linking them is not included.
Chronic Myelogenous Leukemia (CML)
- Translocation between chromosomes 9 and 22 occurs.
- This forms the Philadelphia chromosome.
- The translocation leads to uncontrolled cell division.
Cancer is a Genomic Disease
- DNA sequencing, family studies, and genome-wide association studies (GWAS) identify cancer-driving genetic alterations.
- The goal is to compile a comprehensive cancer mutation catalog.
Better Identification of Cancer Genes
- Cancer gene identification in typical tissues allows for comparison with cancerous tissues.
- Studies have shown an average of 90 differences in gene mutations between normal and cancerous tissues.
Epigenetics and Cancer
- DNA and histone modifications can lead to cancer development.
- Epigenetic factors (e.g., methyl groups) influence gene activity.
- These factors can affect cell cycle control and contribute to uncontrolled and/or damaged cell proliferation.
Historical Cancer Therapy and Modern Approaches
- Historical methods included chemotherapy and radiation therapy, which were nonspecific and could harm normal cells.
- Modern approaches include focused therapies, such as immunotherapy and targeted therapy, as well as personalised medicine.
- Immunotherapy helps the immune system recognize and attack cancer cells.
- Targeted therapies use drugs to directly target specific cancer cells.
- These approaches provide a more personalized and efficacious approach to treatment.
Personalized Cancer Therapy
- Personalised cancer treatment aims to tailor medical interventions to individual patient needs based on genetic and molecular characteristics.
Targeted Therapy for CML
- The drug Gleevec targeted the BCR-ABL fusion protein preventing cell division in CML.
Zero Childhood Cancer
- A national clinical trial focused on childhood cancers in Australia.
- This initiative aims to identify and monitor minute information about tumors.
Environmental Effects on Cancer
- Environmental elements (e.g., viruses, chemicals, radiation, diet, smoking, sun exposure) can damage DNA, which can be harmful.
Viruses and Cancer
- Some viruses cause 15% of cancers.
- HPV viruses are linked to cervical cancer.
Other Environmental Agents (Smoking)
- 75-85% of smokers develop cancer, with tobacco significantly increasing cancer risk.
Other Environmental Agents (Sunlight)
- Exposure to sunlight, including tanning beds, is a major risk for skin cancer, particularly for those with fair skin.
Reducing Cancer Risks
- Lifestyle modifications, such as avoiding tobacco, consuming a balanced diet, managing obesity risk, staying active, and minimizing environmental exposure are important in preventing many types of cancer.
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Description
Explore the relationship between genetics and cancer in this quiz focusing on Week 10 curriculum. Understand the key characteristics of cancer, its causes, and the impact of age and environmental factors on its development. Test your knowledge on how mutations lead to cancer and the improvements in medical treatments.
