Biology of Cancer
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Questions and Answers

What is the main reason why pancreatic and ovarian cancers have a higher percentage of fatalities compared to breast and prostate cancers?

  • They have a higher incidence rate
  • The cancers are more aggressive and spread faster
  • Fewer treatment options are available for these cancers
  • They are often diagnosed at a later stage (correct)

    • What is the primary mechanism by which viruses contribute to the development of cancer?

  • By inducing genomic instability
  • By inducing apoptosis in infected cells
  • By inserting viral DNA into the host genome (correct)
  • By activating growth suppressors

    • What is the term for the process by which cancer cells develop a blood supply?

  • Metastasis
  • Invasion
  • Apoptosis
  • Angiogenesis (correct)

    • Which of the following is NOT a hallmark of cancer?

    <p>Inducing immune destruction</p> Signup and view all the answers

    What is the term for the genetic changes that occur in cancer cells that affect gene expression or function?

    <p>Mutations</p> Signup and view all the answers

    What is the primary mechanism by which radiation contributes to the development of cancer?

    <p>Increasing cell turnover and injury</p> Signup and view all the answers

    What is the term for the process by which cancer cells resist programmed cell death?

    <p>Resisting cell death</p> Signup and view all the answers

    What is the term for the process by which cancer cells develop the ability to multiply indefinitely?

    <p>Enabling replicative immortality</p> Signup and view all the answers

    What is the primary function of the p53 gene?

    <p>To act as a 'guardian of the genome', detecting genomic damage</p> Signup and view all the answers

    What is a characteristic of cancer cells?

    <p>They do not exhibit contact inhibition and can grow uncontrollably</p> Signup and view all the answers

    What is the result of inactivating tumor suppressor genes in cancer cells?

    <p>Increased HIF-1α and increased angiogenesis</p> Signup and view all the answers

    What is the role of VEGF in cancer?

    <p>It is a vascular endothelial growth factor that promotes angiogenesis</p> Signup and view all the answers

    What is the result of increased HIF-1α in cancer cells?

    <p>Increased resistance to chemotherapy</p> Signup and view all the answers

    What is the function of angiogenesis inhibitors in normal tissue?

    <p>To bind to cellular surface receptors and decrease vessel growth</p> Signup and view all the answers

    What is the role of p53 in the intrinsic apoptosis pathway?

    <p>It is an activator of apoptosis</p> Signup and view all the answers

    What is the result of p53 suppression in cancer cells?

    <p>Decreased apoptosis and increased angiogenesis</p> Signup and view all the answers

    What is the hallmark of inducing angiogenesis in cancer?

    <p>Establishing new blood vessels and promoting vascularization</p> Signup and view all the answers

    What is the role of Li-Fraumeni syndrome in cancer?

    <p>It is a familial cancer syndrome caused by a mutation in the p53 gene</p> Signup and view all the answers

    What is the primary function of the G1 checkpoint in the cell cycle?

    <p>To verify that DNA is undamaged and resources are available</p> Signup and view all the answers

    What is the result of the t(9;22) translocation in chronic myeloid leukemia (CML)?

    <p>A BCR-ABL fusion protein that promotes growth of myeloid cells</p> Signup and view all the answers

    What is the role of proto-oncogenes in normal cell proliferation?

    <p>To encode components of pathways that regulate normal cell proliferation</p> Signup and view all the answers

    What is the function of the M checkpoint in the cell cycle?

    <p>To ensure that sister chromatids are attached to mitotic spindles</p> Signup and view all the answers

    What is the effect of the HER2/neu gene overexpression in breast cancer?

    <p>Hyper-responsiveness to growth factors</p> Signup and view all the answers

    What is the role of the Rb tumor suppressor gene in normal cell proliferation?

    <p>To monitor anti-growth cellular signals and block activation of the growth/division phase</p> Signup and view all the answers

    What is the result of the t(8;14) translocation in Burkitt Lymphoma?

    <p>An excess production of a proliferative factor</p> Signup and view all the answers

    What is the effect of the BCR-ABL fusion protein in chronic myeloid leukemia (CML)?

    <p>Promotion of growth of myeloid cells</p> Signup and view all the answers

    What is the primary function of oncogenes in cancer cells?

    <p>To promote cell growth and division independent of normal regulatory mechanisms</p> Signup and view all the answers

    What is the effect of the Rb gene mutation in retinoblastoma?

    <p>Less regulation of cell growth</p> Signup and view all the answers

    What is the primary mechanism by which immune cells like cytotoxic T cells and NK cells contribute to cancer treatment?

    <p>By activating the intrinsic pathway for apoptosis</p> Signup and view all the answers

    What is the primary limitation of using tumor markers for cancer diagnosis?

    <p>They are not useful for screening healthy individuals</p> Signup and view all the answers

    What is the primary advantage of using surgery as a cancer treatment?

    <p>It allows for the relief of symptoms caused by tumor obstruction</p> Signup and view all the answers

    What is the primary goal of cancer treatment using a combination of drugs?

    <p>To target the hallmarks of cancer</p> Signup and view all the answers

    What is the primary mechanism of action of radiation therapy in cancer treatment?

    <p>It targets rapidly dividing cells, including cancer cells and normal cells</p> Signup and view all the answers

    What is the key characteristic that distinguishes a malignant tumor from a benign tumor?

    <p>Invasion of normal tissue</p> Signup and view all the answers

    What is the primary advantage of using chemotherapy in combination with other drugs?

    <p>It allows for the targeting of multiple weaknesses in cancer cells</p> Signup and view all the answers

    What is the term for the formation or presence of a new, abnormal growth of tissue?

    <p>Neoplasm</p> Signup and view all the answers

    What is the primary goal of immunotherapy in cancer treatment?

    <p>To change the immune response to cancer cells from protective to destructive</p> Signup and view all the answers

    What is the term for a benign tumor that arises from fat cells?

    <p>Lipoma</p> Signup and view all the answers

    What is the primary advantage of targeted cancer therapy?

    <p>It targets specific growth characteristics of a class of tumor</p> Signup and view all the answers

    What is the term for a premalignant condition characterized by abnormal growth and cellular atypia?

    <p>Dysplasia</p> Signup and view all the answers

    What is the primary role of molecular and genetic analyses in cancer treatment?

    <p>To classify the spectrum of mutations underlying a specific cancer phenotype</p> Signup and view all the answers

    What is the primary limitation of using chemotherapy as a cancer treatment?

    <p>It is not effective for cancer cells that are resistant to chemotherapy</p> Signup and view all the answers

    What is the term for the study of the functions and interactions of all the genes in the genome?

    <p>Genomics</p> Signup and view all the answers

    What is the primary mechanism of action of monoclonal antibodies in cancer treatment?

    <p>They target unique antigens on cancer cells and induce apoptosis</p> Signup and view all the answers

    What is the term for a malignant tumor that arises from epithelial tissues?

    <p>Carcinoma</p> Signup and view all the answers

    What is the term for a preinvasive epithelial tumor that is localized to the epithelium and has not penetrated the local basement membrane?

    <p>Carcinoma in situ</p> Signup and view all the answers

    What is the term for the process by which cancer cells develop increased vascularity?

    <p>Angiogenesis</p> Signup and view all the answers

    What is the term for a benign tumor that arises from uterine smooth muscle?

    <p>Leiomyoma</p> Signup and view all the answers

    What is the primary difference between genetics and genomics?

    <p>Genomics includes both germ cell and somatic cell mutations, as well as genetic interactions.</p> Signup and view all the answers

    What is the main characteristic of sporadic cancers?

    <p>They involve genetic changes in somatic cells.</p> Signup and view all the answers

    What is the purpose of a family pedigree in identifying hereditary cancer?

    <p>To identify which gene to test for and whom to consider testing.</p> Signup and view all the answers

    What is the significance of BRCA1 and BRCA2 genes in hereditary breast cancer?

    <p>They are tumor suppressor genes that regulate DNA repair.</p> Signup and view all the answers

    What is the typical lifetime risk of developing breast cancer for women with BRCA1 or BRCA2 mutations?

    <p>50-80%</p> Signup and view all the answers

    What is the role of PTEN gene in breast cancer?

    <p>It is a gene that increases the risk of breast cancer.</p> Signup and view all the answers

    What is the main difference between hereditary and familial cancers?

    <p>Hereditary cancers are caused by genetic mutations, while familial cancers are caused by environmental factors.</p> Signup and view all the answers

    What is the approximate increase in the risk of colorectal cancer for individuals with one affected first-degree relative?

    <p>2-3 times higher</p> Signup and view all the answers

    What is the main characteristic of autosomal dominant mutations?

    <p>One parent must have the disorder.</p> Signup and view all the answers

    What is the purpose of genetic counseling and testing in hereditary cancer?

    <p>To identify individuals at high risk of cancer and provide preventive measures.</p> Signup and view all the answers

    What is the primary function of the APC gene related to cancer?

    <p>Tumor suppressor</p> Signup and view all the answers

    What is the result of inactivating the BRCA tumor suppressor gene?

    <p>The repair of damaged DNA is impaired.</p> Signup and view all the answers

    What is the approximate lifetime risk of colorectal cancer for individuals with Hereditary Nonpolyposis Colorectal Cancer (HNPCC)?

    <p>80%</p> Signup and view all the answers

    What is the purpose of predictive genetic testing in the context of cancer?

    <p>To identify inherited gene mutations that increase cancer risk</p> Signup and view all the answers

    What is the mode of inheritance of Hereditary Nonpolyposis Colorectal Cancer (HNPCC)?

    <p>Autosomal Dominant</p> Signup and view all the answers

    What is the percentage of colorectal tumors that have an APC mutation?

    <p>85%</p> Signup and view all the answers

    What is the primary role of a genetic counselor in the context of cancer risk?

    <p>To evaluate family history and counsel on risk and management</p> Signup and view all the answers

    What is the name of the criteria used to identify patients with Hereditary Nonpolyposis Colorectal Cancer (HNPCC)?

    <p>Both A and B</p> Signup and view all the answers

    Study Notes

    Cancer Incidence in the US

    • Pancreas and ovary have a lower incidence of cancer, but a higher percentage of those who develop these cancers die
    • Breast and prostate cancers are more survivable than lung and bronchus cancers

    What is Cancer?

    • A disease caused by an uncontrolled division of abnormal cells in a part of the body

    Inheritance of Cancer

    • Heritable cancer syndromes exist, but the majority of cancers are not familial
    • Cancer is a genetic disease, but most mutations that lead to cancer are somatic (occur in body cells, not germ cells)

    Hallmarks of Cancer

    • 8 Hallmarks and 2 traits that enable cancer progression:
      • Avoiding immune destruction
      • Sustaining proliferative signaling
      • Deregulating cellular energetics
      • Resisting cell death
      • Inducing angiogenesis
      • Genomic instability (mutator phenotype)
      • Activating invasion and metastasis
      • Tumor-promoting inflammation
      • Enabling replicative immortality
      • Evading growth suppressors

    Genetic Changes in Cancer

    • Mutations: DNA alterations that affect expression or function of a gene
    • Epigenetic effects: DNA methylation, histone acetylation, altered expression of non-coding RNA
    • Causes of genetic mutations:
      • Viruses (e.g. HPV increases risk of cervical cancer)
      • Bacteria (e.g. chronic H. pylori increases risk of gastric adenocarcinoma)
      • Chemicals (e.g. smoking increases risk of lung cancer)
      • Radiation (e.g. UV and ionizing radiation increase risk of skin cancer)

    Multiple Hits Lead to Cancer

    • Exposure, infection, or mutation can render a "hit" that increases the risk of cancer
    • One or two "hits" can leave a cell more prone to mutation and cancer development

    Hallmark: Sustained Proliferative Signaling

    • Cancer cells do not obey or require normal signals for cell division
    • Proto-oncogenes: genes that encode components of pathways that regulate normal cell proliferation
    • Mutated proto-oncogenes (oncogenes) can lead to checkpoint dysfunction

    Cell Division

    • Checkpoints: G1, S, and M (in Metaphase)
    • G1 checkpoint: cell checks for DNA damage and resource availability
    • S checkpoint: cell checks for DNA errors
    • M checkpoint: cell checks for sister chromatid attachment

    Hallmark: Evading Growth Suppressors

    • Tumor-suppressor genes: genes that monitor antigrowth cellular signals and block cell growth
    • Examples: Rb, p53
    • Mutations in tumor-suppressor genes can lead to persistent cell growth

    Hallmark: Inducing Angiogenesis

    • Angiogenesis: the process of establishing new blood vessels
    • Angiogenic factors and inhibitors normally control vessel development
    • In cancer, angiogenesis is up-regulated, leading to increased blood supply

    Hallmark: Resisting Cell Death

    • Apoptosis: programmed cell death
    • In cancer, apoptosis is disrupted, leading to uncontrolled cell growth
    • Two pathways to apoptosis: intrinsic and extrinsic

    Tumor Markers

    • Substances produced by both benign and malignant cells
    • Examples: hormones, enzymes, genes, antigens, and antibodies
    • Useful for:
      • Screening and identifying individuals at high risk for cancer
      • Diagnosing specific types of tumors
      • Following the clinical course of a tumor

    Cancer Treatment

    • Surgery: allows for diagnosis and staging of disease, and can be used for prevention in high-risk groups
    • Radiation therapy: used to kill cancer cells while minimizing damage to normal structures
    • Chemotherapy: attacks rapidly dividing cells, often used in combination with other treatments
    • Immunotherapy: targets unique antigens on cancer cells or changes the immune response to a tumor
    • Targeted disruption of cancer: uses a combination of drugs to target specific hallmarks of cancer

    Tissue Pathology of Cancer

    • Definitions:
      • Neoplasm/Tumor: a new, abnormal growth of tissue
      • Malignant: a tumor that tends to invade normal tissue or recur after removal
      • Benign: a slow-growing tumor that is non-invasive and does not metastasize
    • Cancer: a malignant tumor

    Cancer Classification

    • Based on:
      • Tissue and organ of origin
      • Extent of distribution (stages)
      • Microscopic appearance of the malignant tumor
      • Critical genetic changes in the cancer cells

    Progression to Malignancy

    • Cancers develop incrementally as they accumulate genetic mutations
    • Careful surveillance can detect atypical cells or abnormal growth before it has progressed to malignancy

    Genetics and Cancer

    • Genomics: the study of functions and interactions of all genes in the genome

    • Genomics vs Genetics:

      • Genetics: applies to mutations that can be inherited
      • Genomics: applies to germ cell mutations and somatic cell mutations, and interactions between genes and environment

    • All cancers involve genes:

      • Critical cancer genes: oncogenes and tumor suppressor genes
      • These genes regulate cell growth, division, differentiation, and death### Breast Cancer

    • Most common cancer in women

    • 5-10% of breast cancer cases in the US are inherited

    • 90% of breast cancer cases are not inherited

    • BRCA1 and BRCA2 are the genes associated with inherited breast cancer

    • Women with BRCA1 mutations have a 50-80% lifetime risk of developing breast cancer

    • Women with BRCA2 mutations have a 50-80% lifetime risk of developing breast cancer

    • BRCA1 also associated with 20-50% lifetime risk of ovarian cancer and moderate risk of colon and prostate cancer

    • BRCA2 also associated with 10-20% lifetime risk of ovarian cancer

    • Both BRCA1 and BRCA2 are tumor suppressor genes that code for proteins important in DNA damage repair

    • Mutations in BRCA1 and BRCA2 impair DNA repair, increasing cancer risk

    Colorectal Cancer

    • Family history increases the risk of colorectal cancer
    • Risk of colorectal cancer in people with one affected first-degree relative is 2-3 times higher than the general population
    • Hereditary syndromes that increase the risk of colorectal cancer include Familial Adenomatous Polyposis (FAP) and Hereditary Nonpolyposis Colorectal Cancer (HNPCC)

    Familial Adenomatous Polyposis (FAP)

    • Caused by a mutation in the APC gene, which encodes a tumor suppressor
    • Can occur sporadically in somatic cells, but inherited mutations lead to FAP
    • 85% of colorectal tumors have an APC mutation

    Hereditary Nonpolyposis Colorectal Cancer (HNPCC)

    • Also known as Lynch Syndrome
    • Caused by mutations in any of 6 genes involved in DNA repair
    • Affected individuals have an 80% lifetime risk of colorectal cancer
    • Autosomal dominant inheritance pattern
    • Increases risk of colon (80%), endometrial (60%), ovarian, stomach, small intestine, biliary tract, renal, and skin cancers

    Genetic Testing for Cancer Risk

    • Predictive genetic testing looks for inherited gene mutations that increase cancer risk
    • May be suggested for individuals with a strong family history of certain cancers, a personal history of cancer, or family members of someone with an inherited gene mutation
    • Genetic counseling involves evaluating family history, creating a family pedigree, and counseling on risk and management of inherited cancer

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    Description

    This quiz covers cancer incidence in the US, types of cancer, inheritance of cancer, and what cancer is as a genetic disease.

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