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What is cancer defined as?
What is cancer defined as?
The uncontrolled division of cells in a specific tissue or organ, forming a tumor (mass of altered cells) impeding the good functioning of the system and that can invade nearby tissues and be fatal.
What are the earliest recorded instances of tumors?
What are the earliest recorded instances of tumors?
Cancer incidence is generally higher in males than in females.
Cancer incidence is generally higher in males than in females.
False
Cancer mortality is generally higher in northern and richer countries.
Cancer mortality is generally higher in northern and richer countries.
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Which of the following is NOT a category of cancer causes?
Which of the following is NOT a category of cancer causes?
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Which of these is NOT a lifestyle factor that can contribute to cancer development?
Which of these is NOT a lifestyle factor that can contribute to cancer development?
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The G1/S checkpoint ensures that the cell has enough nutrients to replicate DNA.
The G1/S checkpoint ensures that the cell has enough nutrients to replicate DNA.
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The G1/S checkpoint checks for DNA damage.
The G1/S checkpoint checks for DNA damage.
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What external signals can stimulate cell growth?
What external signals can stimulate cell growth?
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What is the role of Rb protein in the G1 to S phase transition?
What is the role of Rb protein in the G1 to S phase transition?
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The genes associated with DNA replication are not produced until the S-phase of the cell cycle.
The genes associated with DNA replication are not produced until the S-phase of the cell cycle.
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What is the primary purpose of DNA replication during the S phase?
What is the primary purpose of DNA replication during the S phase?
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The initiation of DNA replication in the S phase is solely controlled by DNA polymerase.
The initiation of DNA replication in the S phase is solely controlled by DNA polymerase.
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Which DNA repair mechanism is responsible for correcting mismatches that occur during DNA replication?
Which DNA repair mechanism is responsible for correcting mismatches that occur during DNA replication?
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Describe the role of MutS and MutL proteins in Mismatch Repair (MMR).
Describe the role of MutS and MutL proteins in Mismatch Repair (MMR).
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Homologous Recombination (HR) is an error-prone repair process.
Homologous Recombination (HR) is an error-prone repair process.
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Non-Homologous End Joining (NHEJ) is a high-fidelity repair process.
Non-Homologous End Joining (NHEJ) is a high-fidelity repair process.
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The G2 checkpoint ensures that all DNA has been correctly replicated without damage, including the removal of transcription factors.
The G2 checkpoint ensures that all DNA has been correctly replicated without damage, including the removal of transcription factors.
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What is the role of ATM/ATR in the G2 checkpoint?
What is the role of ATM/ATR in the G2 checkpoint?
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The Cdk1/Cyclin B complex is activated by phosphorylation.
The Cdk1/Cyclin B complex is activated by phosphorylation.
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The activation of Cdk1/Cyclin B complex is referred to as 'Mitosis Promoting Factor' (MPF).
The activation of Cdk1/Cyclin B complex is referred to as 'Mitosis Promoting Factor' (MPF).
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Which of these removes inhibitory phosphates from Cdk1/Cyclin B complex?
Which of these removes inhibitory phosphates from Cdk1/Cyclin B complex?
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The Wee1 kinase adds an inhibitory phosphate to the Cdk1/Cyclin B complex.
The Wee1 kinase adds an inhibitory phosphate to the Cdk1/Cyclin B complex.
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What is the primary outcome of mitosis?
What is the primary outcome of mitosis?
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During which stage of mitosis do the chromosomes line up at the cell's equator?
During which stage of mitosis do the chromosomes line up at the cell's equator?
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The Anaphase-Promoting Complex (APC/C) plays a crucial role in regulating the separation of chromosomes during anaphase.
The Anaphase-Promoting Complex (APC/C) plays a crucial role in regulating the separation of chromosomes during anaphase.
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What is the function of Mad2 in the metaphase to anaphase checkpoint?
What is the function of Mad2 in the metaphase to anaphase checkpoint?
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The separation of sister chromatids occurs during telophase.
The separation of sister chromatids occurs during telophase.
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Proto-oncogenes are normally involved in inhibiting the cell cycle, cell growth, and differentiation.
Proto-oncogenes are normally involved in inhibiting the cell cycle, cell growth, and differentiation.
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Tumor suppressor genes promote the activation and progression of the cell cycle, cell growth, and differentiation.
Tumor suppressor genes promote the activation and progression of the cell cycle, cell growth, and differentiation.
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Mutations in proto-oncogenes are typically hyperactivated in cancer.
Mutations in proto-oncogenes are typically hyperactivated in cancer.
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Which of these is NOT a characteristic of the tumor microenvironment?
Which of these is NOT a characteristic of the tumor microenvironment?
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What is the role of angiogenesis in cancer?
What is the role of angiogenesis in cancer?
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Metastasis refers to the spread of cancer cells through blood and lymphatic systems, but not directly to other organs.
Metastasis refers to the spread of cancer cells through blood and lymphatic systems, but not directly to other organs.
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The 'seed and soil' hypothesis proposes that cancer cells spread to organs with compatible microenvironments.
The 'seed and soil' hypothesis proposes that cancer cells spread to organs with compatible microenvironments.
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Which migration mode is characterized by amoeboid movement?
Which migration mode is characterized by amoeboid movement?
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Cancer cells can spread via hematogenous, lymphatic, and transcoelomic routes, but not through the nervous system.
Cancer cells can spread via hematogenous, lymphatic, and transcoelomic routes, but not through the nervous system.
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Organotropism refers to the tendency of cancer cells to metastasize to organs with distinct microenvironments.
Organotropism refers to the tendency of cancer cells to metastasize to organs with distinct microenvironments.
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Study Notes
Introduction to Oncology
- Cancer is uncontrolled cell division forming a tumor that disrupts normal bodily functions. It can invade nearby tissues and potentially be fatal
- Evidence of tumors dates back 1.7 million years (Edwin Smith Papyrus, 3000BC)
- Cancer incidence is increasing globally, more common in wealthier northern countries
- Median age of cancer diagnosis is 66 years
Causes of Cancer
- Chemical & Physical Carcinogens: Tobacco, benzene, asbestos, ionizing radiation, UV rays, radon
- Biological Carcinogens: Viruses (e.g., Epstein-Barr Virus (EBV)), bacteria, and parasites
- Lifestyle Factors: Western diet, alcohol, lack of exercise, obesity, and chronic inflammation
- Internal Factors: Genetics, hormones, immune dysfunction, aging, and epigenetic changes
Cell Cycle and Cancer
- G1 Phase (Gap 1): Primarily focused on cell growth and protein/organelle synthesis in preparation for DNA replication. This phase can last 22-23 hours.
- G1/S Checkpoint: Checks cell size, nutrient availability, and DNA integrity. External signals (e.g., epidermal growth factor (EGF), fibroblast growth factor (FGF), Sonic hedgehog) stimulate growth through specific pathways.
- Restriction point: If these checks are satisfactory, the cell progresses to DNA replication (S phase).
- S Phase (Synthesis): DNA replication occurs to produce two identical copies of each chromosome, essential for cell division. Various DNA repair mechanisms, such as mismatch repair (MMR) and homologous recombination (HR), are essential during this phase to correct replication errors, preventing mutations.
- G2 Phase (Gap 2): Cell growth and preparation for mitosis, verifies DNA replication integrity. This is controlled by checkpoints (G2/M).
- M Phase (Mitosis): The cell divides into two daughter cells with identical genetic material. This phase includes phases like prophase, metaphase, anaphase, and telophase. The Metaphase and Anaphase checkpoints guarantee proper chromosome alignment and separation before cell division.
Tumor Suppressor Genes and Proto-oncogenes
- Proto-oncogenes: Genes that regulate cell growth, differentiation, and division to maintain bodily function. In cancer they are inactive or under-functioning
- Tumor suppressor genes: Genes that inhibit cell growth and division. In cancer they are over-active
- Example: BRCA1/2 mutations are associated with hereditary breast and ovarian cancers.
Tumor Microenvironment
- Composed of immune cells, fibroblasts, extracellular matrix (ECM), and blood vessels
- Cancer cells exhibit characteristics of self-sufficiency in growth, insensitivity to anti-growth signals, apoptosis resistance, limitless replication, sustained angiogenesis (blood vessel formation), and tissue invasion
Cancer Cell Traits and Survival Mechanisms
- Evading Apoptosis: Cancer cells avoid programmed cell death, potentially immortalizing them
- Angiogenesis: Cancer cells promote the growth of new blood vessels to supply themselves with nutrients
- Metastasis: Cancer cells spread to other parts of the body via blood and lymph systems.
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Description
This quiz covers fundamental concepts in oncology, including the definition of cancer, its historical evidence, and its causes. Understand the various carcinogens and lifestyle factors that contribute to cancer incidence. Test your knowledge about the cell cycle phases and their relation to cancer development.
