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Questions and Answers
Which characteristic is NOT true for benign tumors?
Which characteristic is NOT true for benign tumors?
Which term refers to abnormal cells that can spread distantly?
Which term refers to abnormal cells that can spread distantly?
What suffix is commonly used to name benign tumors?
What suffix is commonly used to name benign tumors?
What type of tumor is classified as carcinoma?
What type of tumor is classified as carcinoma?
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Which type of tumor is NOT recognized as malignant?
Which type of tumor is NOT recognized as malignant?
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How does immunosuppression affect cancer progression?
How does immunosuppression affect cancer progression?
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Which viruses are associated with an increased risk of cancer?
Which viruses are associated with an increased risk of cancer?
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What mechanism is described by the term 'metastasis'?
What mechanism is described by the term 'metastasis'?
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What is a key characteristic of cells undergoing Epithelial–Mesenchymal Transition (EMT)?
What is a key characteristic of cells undergoing Epithelial–Mesenchymal Transition (EMT)?
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What happens during the invasion phase of cancer progression?
What happens during the invasion phase of cancer progression?
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What is a characteristic of cancer cells that allows them to grow independently of external signals?
What is a characteristic of cancer cells that allows them to grow independently of external signals?
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What role do proto-oncogenes play in normal cellular function?
What role do proto-oncogenes play in normal cellular function?
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Which event is a common mechanism of oncogene activation?
Which event is a common mechanism of oncogene activation?
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What effect does the mutation of tumor-suppressor genes have on cellular growth?
What effect does the mutation of tumor-suppressor genes have on cellular growth?
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What is the result of genomic instability in cancer cells?
What is the result of genomic instability in cancer cells?
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Which process leads to the decreased need for growth factors in cancer cells?
Which process leads to the decreased need for growth factors in cancer cells?
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What are caretaker genes responsible for?
What are caretaker genes responsible for?
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What is a potential consequence of chromosome instability in cancerous cells?
What is a potential consequence of chromosome instability in cancerous cells?
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What is the role of telomeres in cell division?
What is the role of telomeres in cell division?
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Which of the following is an angiogenic factor secreted by advanced cancers?
Which of the following is an angiogenic factor secreted by advanced cancers?
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What is the Warburg effect associated with?
What is the Warburg effect associated with?
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What is a defining characteristic of tumor-associated macrophages (TAM)?
What is a defining characteristic of tumor-associated macrophages (TAM)?
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How do cancer cells evade apoptosis?
How do cancer cells evade apoptosis?
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What is a consequence of telomere shortening in body cells?
What is a consequence of telomere shortening in body cells?
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What condition is associated with chronic inflammation and stomach cancer?
What condition is associated with chronic inflammation and stomach cancer?
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What is one effect of the reverse Warburg effect?
What is one effect of the reverse Warburg effect?
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What is the most frequently reported symptom of cancer?
What is the most frequently reported symptom of cancer?
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Which of the following mechanisms contributes to pain in cancer?
Which of the following mechanisms contributes to pain in cancer?
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What is the syndrome of cachexia characterized by?
What is the syndrome of cachexia characterized by?
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Which of the following cancers is known to metastasize to the bones?
Which of the following cancers is known to metastasize to the bones?
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Which symptom of cancer may be triggered by biological substances released by a tumor?
Which symptom of cancer may be triggered by biological substances released by a tumor?
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What can cause leukopenia in cancer patients?
What can cause leukopenia in cancer patients?
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What is NOT a suggested cause of fatigue in cancer patients?
What is NOT a suggested cause of fatigue in cancer patients?
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What mechanism leads to anemia in cancer patients?
What mechanism leads to anemia in cancer patients?
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What is the risk associated with chemotherapy medications due to their toxicity to bone marrow?
What is the risk associated with chemotherapy medications due to their toxicity to bone marrow?
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What are the gastrointestinal manifestations caused by chemotherapy?
What are the gastrointestinal manifestations caused by chemotherapy?
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In the staging of cancer, what does Stage IV represent?
In the staging of cancer, what does Stage IV represent?
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Which of the following best describes the TNM system?
Which of the following best describes the TNM system?
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What is one key problem associated with tumor markers?
What is one key problem associated with tumor markers?
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What role do tumor markers play in cancer management?
What role do tumor markers play in cancer management?
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What is the main goal of radiation therapy in cancer treatment?
What is the main goal of radiation therapy in cancer treatment?
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What does immunohistochemical analysis of tumors help classify?
What does immunohistochemical analysis of tumors help classify?
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Study Notes
Cancer
- Cancer is a disease where abnormal cells grow without control and invade other tissues.
- The term comes from the Greek word for crab, karkinoma.
- Also known as a neoplasm, meaning new growth.
Benign vs. Malignant Tumors
| Feature | Benign | Malignant |
|---|---|---|
| Growth rate | Slow | Rapid |
| Capsule | Well-defined | Not encapsulated |
| Invasion | Not invasive | Invasive |
| Differentiation | Well-differentiated | Poorly differentiated |
| Mitotic index | Low | High |
| Metastasis | Do not metastasize | Can spread distantly (metastasis) |
Tumor Classification and Nomenclature
-
Benign Tumors: Named with the suffix "-oma" and are related to the tissue of origin
- Examples: Lipoma, Leiomyoma, Meningioma
- These benign tumors can sometimes progress to cancer
-
Malignant Tumors: Named for the tissue of origin, using "-carcinoma" for epithelial tissues and "-sarcoma" for mesenchymal tissues.
-
Carcinoma: Originates from epithelial tissue.
- Adenocarcinoma: From ductal or glandular tissue.
- Sarcoma: Originates from mesenchymal tissue (connective tissue, muscle, bone).
- Lymphoma: Originates from lymphatic tissue.
- Leukemia: Originates from blood-forming cells.
-
Carcinoma: Originates from epithelial tissue.
Carcinoma in situ (CIS)
- Pre-invasive epithelial malignant tumors.
- These tumors haven't broken through the basement membrane or invaded the surrounding stroma.
Biology of Cancer Cells
- Cancer is largely a disease of aging.
- Multiple mutations are essential for cancer development.
- Clonal Proliferation/Expansion: A cell with a mutation acquires traits favoring its survival over nearby cells. This includes increased growth and/or decreased apoptosis.
- Transformation of Normal Cells: Normal cells lose their need for growth factors, ability to recognize contact inhibition, develop anchorage independence (ability to grow outside their original site), and become immortal.
Sustained Proliferative Signaling
- Proto-oncogenes: Normal genes responsible for cell growth.
- Oncogenes: Mutant proto-oncogenes that cause uncontrolled cell growth.
- Oncogene activation mechanisms: Point mutations in RAS genes which converts the gene functionality from regulated to unregulated.
- Tumour-suppressor genes (anti-oncogenes): Genes that encode proteins that normally restrict cell division.
Evading Growth Suppressors
- Mutation/inactivation of tumour suppressor genes allows uncontrolled cell growth. Examples are:
- Retinoblastoma (RB) gene and Tumor protein p53 (TP53).
Genomic Instability
- Increased genomic mutations during cell life cycles increases cancer risk.
- Caretaker Genes: Repair damaged DNA. Damage to caretaker genes increases genomic instability.
Telomeres and Immortality
- Normal body cells have a limited number of divisions.
- Telomeres are protective caps on chromosomes.
- Telomerase, an enzyme, maintains telomere length.
- Cancer cells often reactivate telomerase, allowing for unlimited divisions.
Angiogenesis
- Growth of new blood vessels is critical for tumor growth.
- Advanced cancers secrete angiogenic factors (VEGF, PDGF, bFGF) to stimulate blood vessel formation.
Reprogramming Energy Metabolism
- Warburg effect: Cancer cells use glycolysis, even in the presence of oxygen.
- Cancer cells often increase their speed and effectiveness of glycolysis (aerobic glycolysis) to supply their accelerated growth.
- Reverse Warburg effect: Some cancer cells show a reduced glycolysis rate under certain conditions.
Resisting Apoptotic Cell Death
- Apoptosis is programmed cell death.
- Defects in intrinsic and extrinsic pathways (processes that regulate apoptosis) cause resistance.
Inflammation and Cancer
- Chronic inflammation is a significant factor in cancer development.
- Helicobacter pylori infection associated with peptic ulcer disease, stomach cancer and other cancers.
- Tumour-associated macrophages (TAMs) often promote tumor survival and correlate with worse prognosis.
Immune System and Cancer
- The immune system normally protects against cancer.
- Immunosuppression can enhance cancer growth, including Non-Hodgkin's lymphoma and Kaposi sarcoma.
- Release of immunosuppressive factors from the microenvironment of a tumor enhances resistance and reduces responsiveness of a tumor to chemo/radiotherapy.
Viruses and Cancer
- Viruses, such as hepatitis B and C, Epstein Barr virus (EBV), Kaposi sarcoma herpesvirus (KSHV), human papillomavirus (HPV), Human T-cell lymphotropic virus type 1 (HTLV-1), cause various forms of cancer.
Metastasis
- Spread of cancer from the primary site.
- Direct invasion of surrounding tissues (local spread)
- Spread via the lymphatic and blood systems to distant organs.
- Epithelial-mesenchymal transition (EMT) is a process where cancer cells lose their epithelial characteristics and gain the ability to migrate and invade.
Local Spread
- Cellular multiplication
- Mitotic rate vs. cellular death rate.
- Release of lytic enzymes.
- Decreased cell-to-cell adhesion.
- Increased motility.
Distant Metastasis
- Spread via vascular and lymphatic pathways.
- Selectivity of different cancers to different sites (e.g., breast cancer to bones, lymphomas to spleen).
- Dormancy.
Clinical Manifestations of Cancer
- Paraneoplastic Syndromes: Symptoms caused by substances released by tumors, not by the direct effect of tumor growth. Can be the first sign of an undiagnosed cancer.
- Pain: Little or no pain is commonly associated with early stages of malignancies. Influenced by various psychological and systemic factors. Mechanisms: Pressure, Obstruction, Invasion of sensitive structures, Stretching of visceral surfaces, Tissue destruction, Inflammation/Infection.
- Fatigue: Common symptom. Subjective clinical manifestation. Possible causes: sleep disturbance, biochemical changes secondary to disease/treatment, level of activity, nutrition, and psychosocial/environmental factors
- Cachexia: Severe form of malnutrition. Symptoms include anorexia, weight loss, anemia, asthenia, and alterations in protein, lipid, and carbohydrate metabolism
- Anemia: Decrease of hemoglobin in the blood. Mechanisms: chronic bleeding, severe malnutrition, therapies, bone marrow disorders or malignancy in blood-forming organs.
- Leukopenia and thrombocytopenia: Direct invasion of bone marrow by tumors or side effects of chemo.
- Gastrointestinal manifestations: Ulcers, malabsorption, diarrhea, nausea.
- Hair and skin manifestations: Alopecia (hair loss), skin breakdown, dryness
Diagnosis
- Manifestations from site and tumor size
- Diagnostic tests
Staging
- Microscopic analysis for the presence of metastasis is used in staging. Stages include: I - no metastasis, II - local invaision, III - spread to regional structures IV - distant metastasis.
- TNM system is a standard system for describing primary tumor characteristics, lymph node involvement, and extent of metastasis.
Tumor Markers
- Substances released by cancer cells found in blood, CSF, or urine.
- Used to screen, diagnose, and monitor disease.
Histology
- Tumor classification based on immunohistochemical analysis of protein expression for treatment improvement.
- Supplementary genetic analysis which divides cancers into prognostically and therapeutically relevant groups for more effective treatment.
Cancer Treatment
- Surgery: Preventative surgery, diagnosis, and staging biopsies, lymph node sampling. Palliative surgery offers comfort and quality of life.
- Radiation: Designed to eliminate/reduce tumors with minimum damage to normal tissue. Lonizing radiation damages the cancer cells' DNA.
- Chemotherapy: Takes advantage of specific vulnerabilities in cancer cells. Usually given in combination therapy.
- Induction Chemotherapy: Shrinks or eliminates tumors.
- Adjuvant Chemotherapy: Given after surgery to eliminate micrometastases.
- Neoadjuvant Chemotherapy: Given before localized treatment to shrink a tumor.
Immunotherapy
- Vaccines against oncogenic viruses provide protection.
- Therapeutic vaccines have shown limited effectiveness.
- Allogeneic cancer vaccines continue to be tested.
Targeted Disruption
- Used in combination with chemotherapy.
- Highly specific for cancer cells.
- Aims to inactivate cancer cells, block angiogenesis, alter cell metabolism, and induce apoptosis, and neutralize cytokines/chemokines.
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Description
Test your knowledge on the characteristics and behaviors of tumors and cancer progression. This quiz covers benign and malignant tumors, the effects of immunosuppression, and key terms related to cancer biology. Perfect for students studying oncology or related fields.
