Podcast
Questions and Answers
What is the primary characteristic of cancer?
What is the primary characteristic of cancer?
How many kinds of human cancers have been identified?
How many kinds of human cancers have been identified?
What does it mean for most cancers to be of clonal origin?
What does it mean for most cancers to be of clonal origin?
Which statement best describes the multistep process of cancer?
Which statement best describes the multistep process of cancer?
Signup and view all the answers
Which of the following is NOT a way chemicals contribute to cancer development?
Which of the following is NOT a way chemicals contribute to cancer development?
Signup and view all the answers
Which virus is known to cause cervical cancer in humans?
Which virus is known to cause cervical cancer in humans?
Signup and view all the answers
What type of cancer is associated with Rous sarcoma virus (RSV)?
What type of cancer is associated with Rous sarcoma virus (RSV)?
Signup and view all the answers
Which characteristic defines a malignant cancer?
Which characteristic defines a malignant cancer?
Signup and view all the answers
What is the primary type of individual that Burkitt lymphoma occurs in?
What is the primary type of individual that Burkitt lymphoma occurs in?
Signup and view all the answers
What percentage of human cancers are estimated to arise from causes other than viruses?
What percentage of human cancers are estimated to arise from causes other than viruses?
Signup and view all the answers
Which of the following genes is identified as a prototype tumor suppressor gene?
Which of the following genes is identified as a prototype tumor suppressor gene?
Signup and view all the answers
What role do mutations in proto-oncogenes typically play in cancer development?
What role do mutations in proto-oncogenes typically play in cancer development?
Signup and view all the answers
Which protein is required for apoptosis induced by DNA damage?
Which protein is required for apoptosis induced by DNA damage?
Signup and view all the answers
What is a characteristic of tumor suppressor genes compared to oncogenes?
What is a characteristic of tumor suppressor genes compared to oncogenes?
Signup and view all the answers
What is the relationship between oncogenes and proto-oncogenes?
What is the relationship between oncogenes and proto-oncogenes?
Signup and view all the answers
Which oncogene was the first to be identified from a retrovirus?
Which oncogene was the first to be identified from a retrovirus?
Signup and view all the answers
What role does Rb play in the cell cycle?
What role does Rb play in the cell cycle?
Signup and view all the answers
Which protein inhibits Cdk4,6/cyclin D complexes?
Which protein inhibits Cdk4,6/cyclin D complexes?
Signup and view all the answers
What type of mutation results in the activation of an oncogene?
What type of mutation results in the activation of an oncogene?
Signup and view all the answers
Which of the following is NOT classified as a tumor suppressor gene?
Which of the following is NOT classified as a tumor suppressor gene?
Signup and view all the answers
What is the primary function of wild-type p53 in response to DNA damage?
What is the primary function of wild-type p53 in response to DNA damage?
Signup and view all the answers
Which characteristic is typical of proto-oncogenes?
Which characteristic is typical of proto-oncogenes?
Signup and view all the answers
Which of the following mutations is associated with the Ras protein acting as an oncogene?
Which of the following mutations is associated with the Ras protein acting as an oncogene?
Signup and view all the answers
What is the effect of oncogenes on cellular behavior?
What is the effect of oncogenes on cellular behavior?
Signup and view all the answers
In the context of tumor suppressors, what does 'loss-of-function' refer to?
In the context of tumor suppressors, what does 'loss-of-function' refer to?
Signup and view all the answers
Which protein is a transcription factor that can become an oncogene?
Which protein is a transcription factor that can become an oncogene?
Signup and view all the answers
What is the primary function of the NF1 protein in cell division?
What is the primary function of the NF1 protein in cell division?
Signup and view all the answers
How does the APC protein affect cell division?
How does the APC protein affect cell division?
Signup and view all the answers
What function does p53 serve in cellular processes?
What function does p53 serve in cellular processes?
Signup and view all the answers
What is the primary function of BRCA1 and BRCA2 proteins?
What is the primary function of BRCA1 and BRCA2 proteins?
Signup and view all the answers
What characterizes tumor-suppressor genes?
What characterizes tumor-suppressor genes?
Signup and view all the answers
What is the focus of epigenetics in cellular biology?
What is the focus of epigenetics in cellular biology?
Signup and view all the answers
Which of these describes the role of checkpoint proteins?
Which of these describes the role of checkpoint proteins?
Signup and view all the answers
What is the primary role of the p53 protein in relation to DNA damage?
What is the primary role of the p53 protein in relation to DNA damage?
Signup and view all the answers
In the context of retinoblastoma, what does the 'two-hit' model imply?
In the context of retinoblastoma, what does the 'two-hit' model imply?
Signup and view all the answers
What effect does the Rb protein have on the transcription factor E2F?
What effect does the Rb protein have on the transcription factor E2F?
Signup and view all the answers
What type of retinoblastoma typically occurs in the late stages of life?
What type of retinoblastoma typically occurs in the late stages of life?
Signup and view all the answers
Which of the following accurately describes the process of apoptosis?
Which of the following accurately describes the process of apoptosis?
Signup and view all the answers
What typically happens when tumor-suppressor genes like Rb or p53 lose their function?
What typically happens when tumor-suppressor genes like Rb or p53 lose their function?
Signup and view all the answers
Caspases are associated with which cellular process?
Caspases are associated with which cellular process?
Signup and view all the answers
Which gene was the first human tumor-suppressor gene identified?
Which gene was the first human tumor-suppressor gene identified?
Signup and view all the answers
How does the loss of p53 gene function affect cancer progression?
How does the loss of p53 gene function affect cancer progression?
Signup and view all the answers
Which of the following best describes how tumor-suppressor genes function?
Which of the following best describes how tumor-suppressor genes function?
Signup and view all the answers
Which mechanisms can alter gene expression without changing the DNA sequence?
Which mechanisms can alter gene expression without changing the DNA sequence?
Signup and view all the answers
How can epigenetic changes indirectly contribute to disease?
How can epigenetic changes indirectly contribute to disease?
Signup and view all the answers
What type of chromatin modification is commonly abnormal in cancer cells?
What type of chromatin modification is commonly abnormal in cancer cells?
Signup and view all the answers
What can result from mutations in genes encoding chromatin-modifying proteins?
What can result from mutations in genes encoding chromatin-modifying proteins?
Signup and view all the answers
Which cancer is associated with mutations in DNA methyltransferase?
Which cancer is associated with mutations in DNA methyltransferase?
Signup and view all the answers
What is a common environmental agent associated with lung cancer?
What is a common environmental agent associated with lung cancer?
Signup and view all the answers
Which environmental agent is linked to multiple myeloma and lymphoma?
Which environmental agent is linked to multiple myeloma and lymphoma?
Signup and view all the answers
Which modification is made by histone acetyltransferase?
Which modification is made by histone acetyltransferase?
Signup and view all the answers
What is a key feature of epigenetic changes caused by environmental agents?
What is a key feature of epigenetic changes caused by environmental agents?
Signup and view all the answers
Which type of histone modification is linked to breast cancer?
Which type of histone modification is linked to breast cancer?
Signup and view all the answers
Which treatment is being explored to target epigenetic changes in cancer?
Which treatment is being explored to target epigenetic changes in cancer?
Signup and view all the answers
What is a potential outcome of chromatin remodeling in cancer cells?
What is a potential outcome of chromatin remodeling in cancer cells?
Signup and view all the answers
Which cancer type is NOT commonly associated with mutations in histone methyltransferase?
Which cancer type is NOT commonly associated with mutations in histone methyltransferase?
Signup and view all the answers
Study Notes
Genetic Basis of Cancer
- Cancer is a disease of uncontrolled cell division, a genetic disease at the cellular level.
- Human cancers are categorized by the cell type that becomes cancerous; more than 100 types have been identified.
- Most cancers arise from a single cell, a clonal growth.
- Cancer development is a multistep process, starting as a benign, non-invasive growth, then progressing with genetic changes to become cancerous.
- Cancer can be staged based on its invasiveness; malignant is invasive, and metastatic spreads to a different body site.
Characteristics of Cancer
- Most cancers originate from a single cell with clonal growth.
- Cancer cells divide repeatedly forming a growth.
- Cancer begins as a benign growth, not invasive.
- Cancer's multi-step process involves additional genetic changes leading to cancerous growth.
- Cancers are staged based on:
- Malignant, meaning invasive, and spreading to surrounding tissues
- Metastatic, meaning spread to different sites in the body.
Causes of Cancer
- Radiation and many chemical carcinogens cause damage to DNA, leading to mutations.
- Other chemical carcinogens stimulate cell proliferation, contributing to cancer development.
- Viruses can cause cancer in humans and other species.
- Members of several families of tumor viruses directly cause cancer in both experimental animals and humans.
Tumor Viruses
- Specific virus families cause specific types of human cancers:
- DNA viruses: Hepatitis B viruses, SV40 and polyomaviruses, Papillomaviruses, Adenoviruses, Herpesviruses
- RNA viruses: Hepatitis C virus, Retroviruses
Oncogenes
- Specific genes called oncogenes cause cell transformation, providing insights into cancer's molecular basis.
- Studies of viral oncogenes led to the discovery of cellular oncogenes, involved in non-virus-induced cancers.
- The key link between viral and cellular oncogenes was identified through retroviruses.
- The first oncogene identified was the src gene of Rouse sarcoma virus. -Further studies have identified more than two dozen distinct oncogenes in various retroviruses.
- Proto-oncogenes are normal genes that can mutate into oncogenes, causing cancer. -Mutations in proto-oncogenes are typically dominant, where a mutated gene product promotes cancer. -Oncogenes are mutated forms of proto-oncogenes, that are either overexpressed or are mutated in structure, resulting in the promotion of cancer.
Tumor Suppressor Genes
- Tumor suppressor genes are involved in controlling cell growth, acting to inhibit proliferation and tumor development.
- The Rb gene, a prototypical tumor suppressor gene is identified by studies of retinoblastoma inheritance patterns.
- Loss or inactivation of Rb and other tumor suppressors, including p53, lead to numerous human cancers.
- Tumor suppressor proteins act as inhibitors of cell proliferation and cell survival. -Rb, INK4, p53 proteins negatively regulate cell cycle progression. -p53 is essential in apoptosis, induced by DNA damage or other stimuli. Inactivation enhances tumor cell survival.
Rb Protein
- Rb protein controls cell division, regulating the transcription factor E2F. -Phosphorylation of Rb by cyclin-dependent kinases causes detachment from E2F. This allows E2F and therefore activating cell cycle genes. -Binding of Rb to E2F inhibits its function, and prevents the cell from progressing through the cell cycle. -In the absence of a functional Rb protein, cells can progress through the cell cycle continually.
p53
- p53 is a tumor suppressor gene involved in determining cell damage.
- If DNA damage is detected, p53 promotes cellular pathways, activating DNA repair, halting cell division, and inducing apoptosis (programmed cell death).
- About 50% of human cancers are connected with p53 gene defects.
Apoptosis
- Apoptosis is a process of programmed cell death, involving cell shrinkage, chromatin condensation, and DNA degradation.
- Caspases are proteases in apoptosis that act like "executioners".
- In apoptosis, the cell breaks down into vesicles, and the immune system eventually removes them.
Epigenetics
- Epigenetics is the study of heritable changes in gene expression that occur without changes to the underlying DNA sequence.
- Epigenetic mechanisms such as DNA methylation and histone modifications alter gene expression without changing the DNA sequence.
- Epigenetic factors are also linked to cancer.
Epigenetic Changes in Cancer
- Several chromatin modifications, DNA methylation, histone modification, chromatin remodeling are abnormal in cancer cells.
- Mutations in genes encoding chromatin-modifying proteins can cause inhibition, or increased function, influencing gene expression patterns.
- Environmental agents can alter chromatin modifying protein functions.
Environmental Agents that Alter Chromatin Modifying Proteins
- Some environmental agents directly alter chromatin-modifying protein functions.
- Scientists are still investigating whether epigenetic changes from environmental agents cause cancer.
- Various examples of environmental agents associated with cancer and epigenetic changes are listed in a table.
Cancer Treatments Aimed at Epigenetic Changes
- Researchers are researching drugs to affect DNA methylation and covalent histone modifications, to inhibit cancer cells.
- 5-azacytidine and decitabine are DNA methyltransferase inhibitors and are effective in diseases such as leukemia. However, mechanisms aren't entirely understood.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the fundamental genetic concepts underlying cancer development in this quiz. Understand the classification of cancer types, the significance of clonal growth, and the multi-step process of how benign growths can progress to invasive cancer. Test your knowledge on the characteristics and staging of different cancers.
