Podcast
Questions and Answers
What role do tumor suppressor genes typically play in cell regulation?
What role do tumor suppressor genes typically play in cell regulation?
According to Knudson's 'Two Hit Hypothesis', how many mutant alleles must a cell contain to initiate tumor formation?
According to Knudson's 'Two Hit Hypothesis', how many mutant alleles must a cell contain to initiate tumor formation?
What must occur in addition to inheriting a mutant allele for tumorigenesis to initiate?
What must occur in addition to inheriting a mutant allele for tumorigenesis to initiate?
Why do individuals who inherit one mutant allele tend to develop cancer at a younger age?
Why do individuals who inherit one mutant allele tend to develop cancer at a younger age?
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Which cancer is specifically associated with the retinoblastoma gene?
Which cancer is specifically associated with the retinoblastoma gene?
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What is the primary function of the retinoblastoma gene in relation to cell cycle progression?
What is the primary function of the retinoblastoma gene in relation to cell cycle progression?
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Which of the following is a result of the alteration of cell function in the context of cancer?
Which of the following is a result of the alteration of cell function in the context of cancer?
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Tumor suppressor genes are altered in which of the following scenarios?
Tumor suppressor genes are altered in which of the following scenarios?
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What can mutations in the promoter region influence?
What can mutations in the promoter region influence?
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What is a potential result of mutations that make proteins more active?
What is a potential result of mutations that make proteins more active?
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What is an effect of constitutive activation of oncogenes?
What is an effect of constitutive activation of oncogenes?
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How do activated oncogenes affect normal tissue homeostasis?
How do activated oncogenes affect normal tissue homeostasis?
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What common change occurs in oncogenes due to genetic alterations?
What common change occurs in oncogenes due to genetic alterations?
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What can occur if mutations 'hit the gas' on oncogenes?
What can occur if mutations 'hit the gas' on oncogenes?
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What type of activation can many oncogenes exhibit?
What type of activation can many oncogenes exhibit?
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How do mutations affecting transcriptional activity impact cellular function?
How do mutations affecting transcriptional activity impact cellular function?
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What does the term 'malignancy' refer to in terms of cellular behavior?
What does the term 'malignancy' refer to in terms of cellular behavior?
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Which of the following statements explains the progression of tumors?
Which of the following statements explains the progression of tumors?
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How do mutations contribute to cancer proliferation?
How do mutations contribute to cancer proliferation?
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What is the relationship between differentiation and tumor aggressiveness?
What is the relationship between differentiation and tumor aggressiveness?
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What does a Grade G1 tumor indicate about its differentiation?
What does a Grade G1 tumor indicate about its differentiation?
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What characterizes the proliferation of different clones in cancerous cells?
What characterizes the proliferation of different clones in cancerous cells?
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Which grade represents poorly differentiated cancer cells?
Which grade represents poorly differentiated cancer cells?
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What is one of the key features that allows tumor cells to grow independently?
What is one of the key features that allows tumor cells to grow independently?
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What does a 'pre-malignant' state indicate?
What does a 'pre-malignant' state indicate?
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What factor is primarily assessed to determine the grade of a tumor?
What factor is primarily assessed to determine the grade of a tumor?
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Which of the following refers to the ability of tumor cells to spread to other parts of the body?
Which of the following refers to the ability of tumor cells to spread to other parts of the body?
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Which factor is crucial in determining the time scale of cancer progression?
Which factor is crucial in determining the time scale of cancer progression?
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What does the term 'pleomorphism' refer to in cancer grading?
What does the term 'pleomorphism' refer to in cancer grading?
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What does 'growth advantage' in the context of cancer mutations often lead to?
What does 'growth advantage' in the context of cancer mutations often lead to?
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What is a consequence of the gain of function in oncogenes in malignant tumors?
What is a consequence of the gain of function in oncogenes in malignant tumors?
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Which grade signifies undifferentiated cancer cells that undergo rapid division?
Which grade signifies undifferentiated cancer cells that undergo rapid division?
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Which factor does NOT apply to the characteristics of tumor cells as outlined in the hallmarks of cancer?
Which factor does NOT apply to the characteristics of tumor cells as outlined in the hallmarks of cancer?
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How do tumor cells typically achieve limitless potential for replication?
How do tumor cells typically achieve limitless potential for replication?
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In the context of tumor grading, what does a Grade G2 indicate?
In the context of tumor grading, what does a Grade G2 indicate?
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What is the key characteristic of neoplastic cells in terms of differentiation?
What is the key characteristic of neoplastic cells in terms of differentiation?
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What affects the behavior of tumor cells under selective pressure?
What affects the behavior of tumor cells under selective pressure?
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Which of the following best describes the cellular characteristics of a Grade G3 tumor?
Which of the following best describes the cellular characteristics of a Grade G3 tumor?
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What commonly occurs in tumor cells due to the loss of function in tumor suppressor genes (TSGs)?
What commonly occurs in tumor cells due to the loss of function in tumor suppressor genes (TSGs)?
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What is the term used for the process that increases the formation of new blood vessels in tumors?
What is the term used for the process that increases the formation of new blood vessels in tumors?
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What is the role of genetic mutations in colorectal cancer (CRC)?
What is the role of genetic mutations in colorectal cancer (CRC)?
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What are adenomas in the context of colorectal cancer?
What are adenomas in the context of colorectal cancer?
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Which of the following is NOT a phase in the multi-step model of CRC?
Which of the following is NOT a phase in the multi-step model of CRC?
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How is colorectal cancer typically diagnosed?
How is colorectal cancer typically diagnosed?
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What happens to benign colorectal adenomas as more genetic changes occur?
What happens to benign colorectal adenomas as more genetic changes occur?
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Which of the following indicates a potential diagnosis of colorectal cancer?
Which of the following indicates a potential diagnosis of colorectal cancer?
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What is a common characteristic of benign colorectal polyps?
What is a common characteristic of benign colorectal polyps?
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Which statement best summarizes the progression of CRC?
Which statement best summarizes the progression of CRC?
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Study Notes
Cancer Epidemiology & Carcinogenesis
- Epidemiology studies disease distribution and patterns within populations.
- Informs public health research and policy decisions.
- Forms the basis of evidence-based medicine, identifying risk factors for preventive medicine.
- Data collection is systematic and unbiased.
- Focuses on disease frequency and patterns.
- Uses large databases and complex statistical methods.
- Much cancer data is publicly available.
Most Common Cancers (Worldwide)
- Lung
- Breast
- Colorectal
- Prostate
- Stomach
Top 5 Cancers in the UK
- Breast
- Prostate
- Lung
- Bone
- Melanoma skin cancer
Top 5 Causes of Death
- Lung
- Liver
- Colorectal
- Breast
- Stomach
Incidence & Deaths
- Incidence and deaths are related but provide different information.
- Incidence data shows disease prevalence.
- Incidence also depends on detection methods (e.g., screening).
- Screening can affect incidence statistics.
- Treatment can affect both incidence and death rates.
Relative Survival Chances
- Measured as 1, 5, and 10-year survival rates.
- Percentage of patients still alive following diagnosis.
- Survival rates vary by cancer type and stage.
- Clinical and research efforts aim to improve survival rates.
Age as a Risk Factor for Cancer
- Childhood tumours often are embryonal (blastomas) or leukaemias—small numbers.
- Young adults see fewer tumours, mainly germ cell.
- Middle to old age, epithelial neoplasms become more common.
- Accumulated genetic changes are a key factor.
Colorectal Cancer: Causes & Risk Factors
- Many factors influence colorectal cancer risk, interacting in complex ways.
- Age is a significant factor, with risk increasing with age.
- Diet (high fat, low fiber) is an important factor, as is a history of inflammatory bowel disease.
- Hereditary predisposition and polyp presence also increase risk.
- Studies indicate a strong role for diet in cancer risk, but this is difficult to isolate with many lifestyle factors involved.
- The EPIC study is large-scale research into cancer and diet.
Lung Cancer
- Similar incidence in women and men, despite varying smoking rates.
- Increased rates in older age groups because of earlier exposure to carcinogens, not higher current smoking.
- The impact of historical smoking rates is notable.
Cervical Cancer
- Australia aims to eliminate cervical cancer by 2035.
- Early detection of pre-cancerous changes (in situ disease) is key to successful prevention and treatment.
- Cervical cancer is largely preventable using screening and prevention efforts.
Carcinogenesis (Initiation, Propagation, Progression)
- Substances capable of causing cancer (carcinogens) have diverse mechanisms.
- Carcinogens act through initiation, propagation, and progression in three steps.
- There are different types and classes dependent on likelihood, classified into groups.
- Groups based on evidence in humans and animals.
Chemical Carcinogens
- Polycyclic hydrocarbons like tars, cigarette smoke, and cooked foods are associated with skin and lung cancers.
- Aromatic amines, like those from rubber, dyes, and cooked meat, are linked to bladder and other cancers.
- Nitrosamines from tobacco, diet (smoked meats), are carcinogenic and linked to stomach and colorectal cancers, among others.
- Vinyl chloride is linked to angiosarcoma of the liver.
- Alkylating agents such as mustard gas are also carcinogens.
Biological Carcinogens
- Various viruses can cause different types of cancer.
- Human papilloma virus (HPV) is strongly associated with cervical cancers.
- Other viral associations include cancers like liver (Hepatitis B & C) and lymphomas (Epstein-Barr Virus).
Viral Carcinogens
- Various viral infections lead to cancer development in various tissues.
Dietary Factors & Cancer Risks
- High-fat diets are linked to breast and colon cancers.
- High-fiber diets are associated with lowered cancer risk.
- Nitrates and processed meats are linked to stomach and colon cancer.
- Fruit and vegetables, and avoidance of alcohol, are linked to lower cancer risk.
- WHO/IARC classifies red meat as a class 1 carcinogen.
Biological Carcinogens
- Several viruses are known to cause cancer.
- HPV is associated with cervical cancer.
- Other viruses have links to liver, and lymphomas.
Oncogenes
- Mutated proto-oncogenes that promote cell growth and prevent cell death.
- Diverse mechanisms, including altered protein function, amplification and overexpression, are associated with the activation of oncogenes.
- Oncogene activation is a key step in tumor development.
Tumor Suppressor Genes (TSGs)
- Normal genes negatively regulating cell growth and promoting cell death or differentiation.
- Loss of TSG function contributes to unregulated cell growth, a hallmark of cancer.
- Knudson's "two-hit hypothesis" describes how TSG inactivation relates to cancer development.
- Examples of TSGs include p53 and APC.
Hallmarks of Cancer
- Key characteristics found in most cancers, including self-sufficiency in growth signals, insensitivity to anti-growth signals, tissue invasion and metastasis, limitless potential for replication, sustained angiogenesis, and evading apoptosis.
Multistep Nature of Cancer
- Cancer arises from a gradual accumulation of genetic changes, not a single event.
- Accumulation of mutations leads to gradual transformations.
- Benign tumours may be predecessors to malignant cancers, which are characterized as increasingly aggressive and less differentiated.
Histological Differences
- Benign tumors have expansive, non-invasive growth patterns; malignant tumors have expansive, invasive growth.
- Benign tumors tend to resemble the original tissue type structurally versus malignant. Histological characteristics distinguish between them and allow for classification.
Staging
- Stage describes the extent of the disease, both locally and to distant sites.
- Grading and staging are critical in prognosis and determining treatment options.
- TNM system categorizes tumors (T), lymph nodes (N), and distant metastasis (M) to create graded stage descriptors.
Dysplasia
- Abnormal cell growth/differentiation in tissues which sometimes precedes cancer.
- Dysplasia is assessed through tissue examination and serves as a measure of risk.
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