Molecular Biology of Cancer Article Quiz
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Questions and Answers

What is the main focus of the article published in January 2003?

  • Cancer prevention strategies
  • Statistical analysis of cancer incidences
  • The molecular biology of cancer (correct)
  • Treatment methodologies for cancer

Which of the following authors has the highest number of publications?

  • Kimberly Fultz
  • Jesse Martinez
  • Eugene Gerner (correct)
  • Natalia A Ignatenko

In which publication platform can the article on molecular biology of cancer be found?

  • Google Scholar
  • ResearchGate (correct)
  • ScienceDirect
  • PubMed

What was the total number of citations for Jesse Martinez at the time of the publication?

<p>72 citations (B)</p> Signup and view all the answers

Which author is affiliated with the University of Alaska Fairbanks?

<p>Kimberly Fultz (D)</p> Signup and view all the answers

What primarily drives tumorigenesis according to the content?

<p>Accumulation of genetic mutations (D)</p> Signup and view all the answers

Which of the following is a key feature of the model describing tumor development?

<p>At least five mutations are needed for malignant tumors (B)</p> Signup and view all the answers

What do mutations in genes primarily affect in tumor cells?

<p>Cell growth regulation (C)</p> Signup and view all the answers

What is referred to as 'clonal evolution' in the context of tumor development?

<p>The progressive accumulation of mutations in tumor cells (A)</p> Signup and view all the answers

Which of the following changes are mentioned as important to tumorigenesis?

<p>Genetic mutations and epigenetic changes (C)</p> Signup and view all the answers

What is the relationship between benign tumors and malignant tumors in the model discussed?

<p>Malignant tumors evolve from preexisting benign tumors (D)</p> Signup and view all the answers

What is suggested about the order of mutations during tumor development?

<p>Mutations may accumulate in a preferred but not invariable order (C)</p> Signup and view all the answers

What are oncogenes and tumor suppressor genes associated with in tumorigenesis?

<p>Mutational activation and inactivation respectively (D)</p> Signup and view all the answers

What must occur before most chemical agents become carcinogenic?

<p>Metabolic activation (B)</p> Signup and view all the answers

Which of the following is NOT a type of mutation that can occur in initiated cells?

<p>Tumor promotions (B)</p> Signup and view all the answers

What is the role of DNA repair mechanisms related to initiated cells?

<p>Remove DNA adducts (C)</p> Signup and view all the answers

What consequence can result from repeated exposure to tumor promoters?

<p>Evolution of more malignant cells (A)</p> Signup and view all the answers

What can halt the formation of tumors after the initiation step?

<p>Halting application of tumor promoters (C)</p> Signup and view all the answers

Which step is involved in the initiation process of carcinogenesis?

<p>Carcinogen metabolism (A)</p> Signup and view all the answers

What describes the progression phase in the context of neoplastic development?

<p>Acquiring additional mutations (D)</p> Signup and view all the answers

What is required for tumor development, even if a tumor promoting agent is applied repeatedly?

<p>An initiating agent (C)</p> Signup and view all the answers

What is the significance of identifying genetic defects early in tumorigenesis?

<p>It allows for the development of preventive strategies. (C)</p> Signup and view all the answers

Why could no single oncogene reproduce all the physiological traits of a transformed cell?

<p>Transformation requires the action of multiple oncogenes. (A)</p> Signup and view all the answers

What do the early stages of carcinogenesis primarily involve?

<p>A combination of genetic alterations and environmental factors. (C)</p> Signup and view all the answers

What does the multistep model of tumorigenesis suggest?

<p>Less aggressive intermediates precede lethal neoplasms. (C)</p> Signup and view all the answers

According to the multistep model of tumorigenesis, what is the role of oncogene cooperativity?

<p>It signifies that cells must lose their normal growth regulation. (B)</p> Signup and view all the answers

Which of the following stages is NOT part of the carcinogenesis process?

<p>Transcription (A)</p> Signup and view all the answers

What major insight does the identification of mutated genes provide?

<p>It enables targeted development of therapeutic agents. (C)</p> Signup and view all the answers

What does the term 'carcinogenesis' refer to?

<p>The development of genetic alterations leading to cancer. (C)</p> Signup and view all the answers

What role do cytochrome P450 monooxygenases play in carcinogenesis?

<p>They metabolize carcinogenic compounds. (D)</p> Signup and view all the answers

Which of the following is NOT a phase II metabolizing enzyme mentioned?

<p>Aromatic amine transferase (C)</p> Signup and view all the answers

Which environmental agent is classified as a direct-acting carcinogen?

<p>Nitrogen mustard (C)</p> Signup and view all the answers

What type of DNA damage can result from ionizing radiation?

<p>Double-strand breaks (D)</p> Signup and view all the answers

What occurs if DNA adducts are not repaired?

<p>They enhance the mutation rate. (A)</p> Signup and view all the answers

Which type of mutations are referred to as 'hot spots'?

<p>Regions of genes frequently mutated. (D)</p> Signup and view all the answers

What occurs when DNA repair does not take place after the formation of carcinogen-DNA adducts?

<p>The cell undergoes apoptosis or replication without repair. (D)</p> Signup and view all the answers

Which of the following is a role of phase I enzymes in metabolic activation of carcinogens?

<p>They introduce functional groups on substrates. (C)</p> Signup and view all the answers

Which of the following is a common outcome of chemical agents damaging DNA?

<p>Formation of cross-links (B)</p> Signup and view all the answers

What is the main consequence of mutations in oncogenes?

<p>Unregulated tumor growth (A)</p> Signup and view all the answers

The activation or inactivation of which type of genes is associated with tumor progression?

<p>Tumor suppressor genes (B)</p> Signup and view all the answers

What is the result of metabolic activation of a procarcinogen?

<p>It forms a carcinogen-DNA adduct. (D)</p> Signup and view all the answers

What might an initiated cell develop if DNA replication occurs without repair?

<p>Characteristics of malignant tumor cells. (C)</p> Signup and view all the answers

Which substance is listed as a recognized procarcinogen?

<p>Dimethylnitrosamine (A)</p> Signup and view all the answers

What is a common outcome if a carcinogen binds to DNA and is not repaired?

<p>Development of mutations. (C)</p> Signup and view all the answers

Which enzyme types are involved in the phase I activation of carcinogenic agents?

<p>Monooxygenases and reductases. (B)</p> Signup and view all the answers

Flashcards

Molecular Biology of Cancer

The study of the molecular mechanisms underlying the development and progression of cancer.

Cancer

A disease characterized by uncontrolled cell growth and the ability of these cells to invade and spread to other parts of the body.

Cancer Cell Transformation

The process by which normal cells acquire the ability to grow and divide uncontrollably, eventually becoming cancerous.

Benign Tumors

Tumors that remain localized and do not spread to other parts of the body.

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Malignant Tumors

Tumors that can invade surrounding tissues and spread to distant parts of the body (metastasis), often leading to life-threatening complications.

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Tumorigenesis

The process by which normal cells transform into cancerous cells.

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Proto-oncogenes

Genes whose normal function is to control cell growth. Mutations in proto-oncogenes can lead to uncontrolled cell growth.

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Tumor suppressor genes

Genes that normally suppress tumor development. Mutations in tumor suppressor genes can lead to uncontrolled cell growth.

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Clonal evolution

The accumulation of genetic mutations over time that leads to cancerous cells.

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Gene duplication

A type of gene mutation that occurs when a gene is accidentally copied during cell division.

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Epigenetic changes

Changes in gene expression that are not caused by changes in DNA sequence. These changes can be passed down to daughter cells.

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Programmed cell death (apoptosis)

The process by which cells are programmed to die.

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Adenoma

A benign tumor that can grow slowly and may not spread, but can still potentially become cancerous.

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Oncogenes

Genes that, when mutated, contribute to cancer development by promoting uncontrolled cell growth.

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Oncogene Cooperativity

The cooperative action of multiple oncogenes to produce a fully transformed cancerous cell.

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Carcinogenesis

The process by which normal cells are transformed into cancer cells by exposure to physical or chemical agents.

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Initiation

The first stage in carcinogenesis, where the initial genetic mutation is introduced.

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Promotion

The second stage in carcinogenesis, where the initial mutation is promoted and amplified.

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Progression

The final stage in carcinogenesis, where the tumor grows and spreads aggressively.

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Early Genetic Intervention

The strategy of identifying early genetic changes in tumor formation to prevent the development of advanced cancers.

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Initiation in Cancer

Involves alterations in cellular DNA that make cells susceptible to further neoplastic development, but not necessarily cancerous.

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Promotion in Cancer

The process by which initiated cells are stimulated to grow and divide uncontrollably, leading to tumor formation.

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Tumor Promoter Dependence

Multiple applications of a tumor-promoting agent are required for tumor development. Stopping the promoter can prevent tumor formation.

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12-O-tetradecanoylphorbol-13-acetate (TPA)

A type of tumor promoter that works by fostering the selection and expansion of cells with genetic mutations that allow them to grow faster and more aggressively.

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Clonal Selection in Cancer

Cells with a more malignant phenotype are selected and expand, leading to the advancement of cancer.

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Progression in Cancer

The process by which cancer cells acquire additional mutations that make them even more aggressive, leading to invasion and spread.

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Carcinogen Metabolism

Chemical carcinogens often need to be metabolized into their active form before they can damage DNA.

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DNA Repair in Cancer

Cells have mechanisms to repair damaged DNA, but if these mechanisms fail, mutations can accumulate and contribute to cancer.

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What is a carcinogen?

A chemical that can cause cancer.

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What is a procarcinogen?

A chemical that becomes carcinogenic only after being metabolized by the body's enzymes.

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What are metabolic activation enzymes?

Enzymes that convert procarcinogens into active carcinogens.

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What is detoxification?

The process by which the body breaks down and eliminates harmful substances.

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What is a carcinogen-DNA adduct?

A molecule formed when a carcinogen binds to DNA, potentially leading to mutations.

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What is DNA repair?

The process by which cells repair damage to their DNA.

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What is an initiated cell?

A cell that has undergone genetic changes that make it more likely to become cancerous.

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What is cell transformation?

The process by which normal cells acquire the characteristics of cancer cells.

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Carcinogens

Chemicals that can cause cancer by damaging DNA and altering genetic information.

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Phase I metabolizing enzymes

These enzymes activate carcinogens by converting them into reactive forms that can bind to DNA and cause mutations.

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Phase II metabolizing enzymes

These enzymes neutralize harmful substances by conjugating them with molecules that make them easier to excrete.

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Electrophiles

Chemicals are converted into positively charged molecules that bind to negatively charged groups on DNA, causing damage.

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Mutation hot spots

Regions of genes that are frequently mutated in cancer compared to other regions within the same gene.

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Genetic variability in cancer

The ability of different types of cancers to differ in their severity and progression based on the specific genes mutated.

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Study Notes

Molecular Biology of Cancer

  • Cancer is a leading cause of death worldwide, particularly in the US
  • Cancer is a complex disease with diverse types and defects in genes
  • Gene defects involve either loss or gain of gene functions
  • Cancer development, or carcinogenesis, is a multistep process driven by accumulating mutations in key genes
  • The accumulation of mutations in critical genes drives tumorigenesis
  • Tumor development is analogous to Darwinian evolution at a microscopic scale
  • Each successive mutation provides a growth advantage for tumor cells compared to normal cells
  • This process of successive mutations is called clonal evolution
  • Tumorigenesis includes alterations in cell proliferation, apoptosis, and invasiveness
  • Mechanism-based strategies are available for cancer prevention and treatment
  • Genomes sequenced like the human genome have contributed to understanding cancer mechanisms

Tumorigenesis

  • Normal cells progress through a normal-precancer-cancer sequence
  • Cancer incidence increases with the fifth power of age
  • At least five rate-limiting steps must be overcome in cancer development
  • Cancer development, or carcinogenesis, involves genetic mutations affecting cell growth, apoptosis, and genetic stability
  • Genetic and epigenetic changes are associated with cancer development
  • These changes happen in a particular order but not always
  • Lethal neoplasms are preceded by less aggressive intermediate steps with predictable genetic alternations

Carcinogenesis

  • Carcinogenesis is the process of genetic mutations induced by physical or chemical agents
  • Carcinogenesis can be divided into three stages: initiation, promotion, and progression.
  • Initiation involves irreversible genetic changes, often mutations in growth control genes
  • Promotion involves increased proliferation of initiated cells, while not inducing further DNA damage
  • Progression involves more genetic mutations leading to malignancy and metastasis

Epigenetic Changes

  • Gene function can be altered either through mutations or epigenetic alterations
  • An important epigenetic mechanism is DNA methylation, the addition of a methyl group to DNA's cytosine nucleotides
  • DNA methylation influences gene expression by affecting accessibility for proteins that regulate transcription
  • Cancerous cells have a global DNA hypomethylation at the genome level, but also have localized hypermethylation, and these changes affect transcription of genes

Oncogenes

  • Oncogenes usually derive from normal host genes that are mutated to drive cell proliferation or reduce sensitivity to cell death
  • Examples of oncogenes include Growth factors, Growth factor receptors, Membrane-associated guanine nucleotide-binding proteins, Serine-threonine protein kinases, Cytoplasmic tyrosine kinases, Nuclear proteins
  • Genetic alterations like chromosomal translocation or gene amplification result in oncogene activation
  • Activated oncogenes lead to uncontrolled cell proliferation

Tumor Suppressor Genes

  • Tumor suppressor genes regulate or directly inhibit cell growth
  • Defects or mutations in these genes cause cancer
  • Key tumor suppressor genes include APC, BRCA1, BRCA2, CDK4, hMLH1, hMSH2, hPMS1, hPMS2, MEN1, NF1, p53, Rb, WT1
  • Inactivation of these genes can lead to cancer predisposition

Interventions

  • Prevention strategies target processes like initiation, promotion, or the invasive phenotype
  • Biochemical targets might include reactive oxygen species (ROS), dihydroxy bile acids
  • Cyclooxygenase-2 (COX-2) is involved in some cancers
  • Gene therapy involves introducing genetic material to cells for therapeutic purposes
  • Approaches like immunotherapy, suicidal gene therapy, or targeting tumor suppressor function/oncogene overexpression can be used for treatment

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Molecular Biology of Cancer PDF

Description

Test your knowledge on the key concepts from the January 2003 article on the molecular biology of cancer. This quiz covers authorship, significant findings, tumor development models, and key genetic factors related to tumorigenesis. Perfect for students and professionals interested in oncology and cancer research.

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