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Questions and Answers
What is the primary characteristic that differentiates malignant neoplasms from benign neoplasms?
What is the primary characteristic that differentiates malignant neoplasms from benign neoplasms?
- Malignant neoplasms are slower growing than benign neoplasms.
- Benign neoplasms can metastasize, while malignant neoplasms cannot.
- Benign neoplasms are invasive and aggressive.
- Malignant neoplasms have a faster growth rate and can metastasize. (correct)
Which type of mutation is responsible for the majority of cancers?
Which type of mutation is responsible for the majority of cancers?
- Transgenic mutations
- Spontaneous chromosomal mutations
- Acquired somatic mutations (correct)
- Inherited germline mutations
How many genetic changes are typically required for a normal cell to transform into invasive cancer?
How many genetic changes are typically required for a normal cell to transform into invasive cancer?
- Four to seven genetic changes (correct)
- More than ten genetic changes
- Two to three genetic changes
- One genetic change
Which of the following is NOT an example of an environmental factor that can induce mutations leading to cancer?
Which of the following is NOT an example of an environmental factor that can induce mutations leading to cancer?
What is the primary focus of oncology?
What is the primary focus of oncology?
What process allows cancer cells to continue dividing uncontrollably once they reach other cells?
What process allows cancer cells to continue dividing uncontrollably once they reach other cells?
How do cancer cells achieve resistance to cell death?
How do cancer cells achieve resistance to cell death?
What role does tumor angiogenesis play in cancer progression?
What role does tumor angiogenesis play in cancer progression?
What is the fundamental reason cancer cells can undergo unlimited replication?
What is the fundamental reason cancer cells can undergo unlimited replication?
Which of the following statements about tumor suppressor genes is correct?
Which of the following statements about tumor suppressor genes is correct?
Flashcards
What is Neoplasia?
What is Neoplasia?
The uncontrolled growth of abnormal cells, which leads to the formation of a tumor. This abnormal growth is considered a disease.
What is a Neoplasm?
What is a Neoplasm?
A mass of tissue that results from abnormal cell growth, also known as tumors. Generally categorized as either benign or malignant.
What are Benign Neoplasms?
What are Benign Neoplasms?
Benign tumors are slow-growing, confined to a localized area, and don't spread to other parts of the body. They are usually non-cancerous.
What are Malignant Neoplasms?
What are Malignant Neoplasms?
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What is Cancer?
What is Cancer?
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What is the origin of a tumor?
What is the origin of a tumor?
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What does it mean when cancer cells are 'independent' in terms of growth signals?
What does it mean when cancer cells are 'independent' in terms of growth signals?
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What is 'loss of contact inhibition' in cancer cells?
What is 'loss of contact inhibition' in cancer cells?
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Explain the concept of 'unlimited replication' in cancer cells.
Explain the concept of 'unlimited replication' in cancer cells.
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Why are cancer cells said to be resistant to cell death?
Why are cancer cells said to be resistant to cell death?
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Study Notes
Neoplasms
- Neoplasia means "abnormal new growth"
- A tissue mass formed by this abnormal growth is called a neoplasm or tumor
- Neoplasms result from uncontrolled cell proliferation
- Oncology is the study of tumors or neoplasms
- Neoplasms are classified into benign and malignant (cancer)
Benign vs. Malignant Neoplasms
- Benign neoplasms grow slowly, are non-invasive, and do not metastasize
- Malignant neoplasms grow quickly, are invasive, and can metastasize
Biological Mechanisms of Cancer
- Cancers arise from non-lethal genetic damage or gene mutations
- Multiple genetic changes (at least 4-7) are needed for a normal cell to become an invasive cancer
- First, second, third, and fourth mutations occur (shown pictorially)
Causes of Genetic Changes
- Inherited: Germline mutations (rare familial cancers, account for ~10% of cancers)
- Acquired: Somatic mutations (sporadic), induced by environmental factors
- Physical agents: UV rays (sun exposure), X-rays
- Chemicals: tobacco products, dietary chemicals, toxins
- Infectious agents: bacteria, viruses
Examples of Cancers from Environmental Exposures
- UV rays: skin cancers (skin melanin protects)
- HPV (human papilloma virus): cervical cancer
- Hepatitis B virus: hepatic carcinoma
- Helicobacter pylori: gastric carcinoma
- Tobacco products: lung cancer, urinary bladder cancer
Cancer Arising from Single Cells
- Tumors form from the expansion of a single cell with genetic damage (clonal)
- Daughter cells have the same abnormal DNA, and continue accumulating damage
- Cancer hallmarks are produced by a series of mutations during progression
Hallmarks of Cancer (Biological Criteria)
- Independence (Self-sufficiency in growth signals): Cancer cells don't need growth factors to divide; they grow autonomously
- Resistance to Anti-growth Signals (mutated tumor suppressor genes): Tumor suppressor genes (e.g., retinoblastoma gene, p53 gene) are impaired, enabling continuous cell division.
- Loss of Contact Inhibition: Cancer cells continue to grow even after contacting other cells, forming a mass (tumor)
- Unlimited Replication (telomeres): Normal cells divide a limited number of times due to telomere shortening. Cancer cells have activated telomerase, an enzyme that elongates telomeres, allowing unlimited divisions (immortality).
- Resistance to Cell Death (Evasion of Apoptosis): Cancer cells resist programmed cell death (apoptosis) even with DNA damage or abnormalities, allowing them to proliferate
- Sustained Angiogenesis: Cancer cells induce the formation of new blood vessels (angiogenesis) to provide nutrients and oxygen for growth and metastasis
- Invasion and Metastasis: Cancer cells invade surrounding tissue and spread (metastasize) to other parts of the body. Steps include loss of intercellular adhesion, extracellular matrix degradation, and cell movement (pseudopodia). Metastatic sub-clones carry more mutations
- Altered cellular metabolism
- Evasion of host immune response
- Drug resistance
Reference
- Robbins & Cotran Pathologic Basis of Disease (9th edition, 2014) (ISBN details provided)
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Description
Explore the key concepts of neoplasms and their biological mechanisms, including the differences between benign and malignant tumors. This quiz covers the causes of genetic changes leading to cancer and the role of inherited versus acquired mutations. Test your knowledge of oncology and neoplastic growth.
