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Questions and Answers
What is the term used to describe the uncontrolled proliferation of cells that leads to cancer?
What is the term used to describe the uncontrolled proliferation of cells that leads to cancer?
Which of the following cancers is statistically the most lethal?
Which of the following cancers is statistically the most lethal?
What does the 'N' in the TNM score represent?
What does the 'N' in the TNM score represent?
Which type of cancer specifically arises from connective tissue?
Which type of cancer specifically arises from connective tissue?
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Which of the following statements about genetic mutations and cancer is correct?
Which of the following statements about genetic mutations and cancer is correct?
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What is the primary goal of targeted cancer therapies?
What is the primary goal of targeted cancer therapies?
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How does the oncolytic virus function in cancer treatment?
How does the oncolytic virus function in cancer treatment?
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Which of the following statements is true regarding immunotherapy?
Which of the following statements is true regarding immunotherapy?
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What is the effect of high calcium intake on prostate cancer risk according to the Calcium Vitamin D Theory?
What is the effect of high calcium intake on prostate cancer risk according to the Calcium Vitamin D Theory?
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Which of the following is a reason for the modest success of targeting cancer-promoting proteins?
Which of the following is a reason for the modest success of targeting cancer-promoting proteins?
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What role does angiogenesis play in tumor development?
What role does angiogenesis play in tumor development?
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Which drug is specifically noted for inhibiting the mutant BRAF oncoprotein in metastatic melanoma?
Which drug is specifically noted for inhibiting the mutant BRAF oncoprotein in metastatic melanoma?
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What characteristic of the oncolytic virus makes it a promising treatment for cancer?
What characteristic of the oncolytic virus makes it a promising treatment for cancer?
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Which antibody is known to be directed against the epidermal growth factor receptor (EGF) in colon cancer?
Which antibody is known to be directed against the epidermal growth factor receptor (EGF) in colon cancer?
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What is the primary function of Avastin in cancer treatment?
What is the primary function of Avastin in cancer treatment?
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What is the initial effect of EGF binding to its receptor in the MAPK/ERK pathway?
What is the initial effect of EGF binding to its receptor in the MAPK/ERK pathway?
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Which component is responsible for activating Ras by converting GDP to GTP?
Which component is responsible for activating Ras by converting GDP to GTP?
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How do oncogenes that code for proteins affecting apoptosis contribute to cancer?
How do oncogenes that code for proteins affecting apoptosis contribute to cancer?
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What is the primary role of pRB in the cell cycle?
What is the primary role of pRB in the cell cycle?
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What happens when there is a mutation in the RB gene?
What happens when there is a mutation in the RB gene?
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What is the consequence of overexpression of the Myc protein?
What is the consequence of overexpression of the Myc protein?
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Which of the following mutations is associated with an increased risk of colorectal cancer?
Which of the following mutations is associated with an increased risk of colorectal cancer?
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Which mechanism is primarily responsible for DNA damage repair in cells?
Which mechanism is primarily responsible for DNA damage repair in cells?
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What role do tumor suppressor genes play in cancer development?
What role do tumor suppressor genes play in cancer development?
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Which of the following strategies is commonly used in cancer treatment?
Which of the following strategies is commonly used in cancer treatment?
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Which process can lead to aberrant gene expression related to tumorigenesis?
Which process can lead to aberrant gene expression related to tumorigenesis?
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What distinguishes familial retinoblastoma from sporadic retinoblastoma?
What distinguishes familial retinoblastoma from sporadic retinoblastoma?
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Which of the following statements about p53 is true?
Which of the following statements about p53 is true?
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What characteristic distinguishes malignant cells from normal cells regarding growth signals?
What characteristic distinguishes malignant cells from normal cells regarding growth signals?
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How do cancer cells differ from normal cells in terms of chromosomal makeup?
How do cancer cells differ from normal cells in terms of chromosomal makeup?
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What is the initial stage of cancer development characterized by uncontrolled proliferation without metastasis?
What is the initial stage of cancer development characterized by uncontrolled proliferation without metastasis?
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How do oncogenes contribute to cancer?
How do oncogenes contribute to cancer?
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What is a common mechanism by which proto-oncogenes become oncogenes?
What is a common mechanism by which proto-oncogenes become oncogenes?
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What is the role of cancer stem cells in tumor development?
What is the role of cancer stem cells in tumor development?
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In terms of histological changes, what initial alteration occurs during tumor progression?
In terms of histological changes, what initial alteration occurs during tumor progression?
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What is a key characteristic of benign tumors?
What is a key characteristic of benign tumors?
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Which agents are known to possibly cause cancer by altering the genome?
Which agents are known to possibly cause cancer by altering the genome?
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What is one common effect of oncogenes on cellular behavior?
What is one common effect of oncogenes on cellular behavior?
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What aspect of cancer cell metabolism is notably different from normal cells?
What aspect of cancer cell metabolism is notably different from normal cells?
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How do pre-cancerous cells typically differ from malignant cells?
How do pre-cancerous cells typically differ from malignant cells?
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Which type of virus is known to carry genes that can interfere with cell growth regulation?
Which type of virus is known to carry genes that can interfere with cell growth regulation?
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Study Notes
Basic Properties of Cancer Cells
- Cancer is characterized by uncontrolled growth, proliferation, and sometimes metastasis.
- Approximately 30% of deaths are attributed to cancer.
- A neoplasm is an abnormal mass of tissue growing and dividing excessively.
- Neoplasms can be benign (non-cancerous) or malignant (cancerous).
- Proliferation, when unregulated, leads to malignant tumors that invade surrounding healthy tissue.
- Metastasis occurs when cancer cells detach from the primary tumor and spread to distant sites, creating secondary tumors often resistant to treatment.
- The TNM score (Tumor, Node, Metastasis) classifies the stage of cancer based on tumor size, lymph node involvement, and metastasis.
- Cancer is genetic, but not always inherited; mutations can be somatic (acquired) or germline (inherited).
- Lung cancer is the most lethal type, followed by prostate and breast cancers.
Cancer Statistics: Distribution & Gender
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Cancer types are evenly distributed (liver, lung, bone, colon, brain, rectal, pancreatic, kidney, bladder, blood) across genders except for the following:
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Male-specific: testicular and prostate cancer.
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Female-specific: cervical, ovarian, and breast cancer (although can occur in males).
Histological Types of Cancer
- Adenocarcinoma: originates in glandular tissue.
- Carcinoma: originates in epithelial cells.
- Sarcoma: originates in connective tissue.
- Lymphoma: originates in lymphatic tissue.
- Leukemia: originates in white blood cells.
- Glioma: originates in nerve tissue.
- Myeloma: originates in plasma cells.
Basic Properties of a Cancer Cell
- Malignant cells ignore stop signals.
- Growth and division capacity are similar for cancer and normal cells.
- Normal cells stop growing when growth factors are absent or cell contact occurs; malignant cells continue growing.
- Normal cells form monolayers; malignant cells form clumps.
- Cancer cells proliferate independently of external growth factors.
- Cancer cells exhibit an abnormal chromosome complement (aneuploidy); extra or missing chromosomes.
Causes of Cancer
- The exact causes are largely unknown, but mutagenic agents (carcinogenic chemicals, radiation, viruses), DNA/RNA tumor viruses, and alterations in the genome are implicated.
- Migratory factors, including geographic relocation to different climate zones or regions, do play a role.
- Common carcinogens include asbestos, nicotine (associated with oral and lung cancers), papovaviruses (HPV), herpes (Epstein-Barr virus).
- Adenovirus, Hepatitis B virus, are also biological carcinogens
Genetics of Cancer
- Tumorigenesis (malignant tumor development) is a multi-step process involving cumulative genetic alterations.
- Starts with benign tumor with uncontrolled proliferation, but no metastasis.
- Cancer arises from the uncontrolled proliferation of a single cell.
- Specific gene products (e.g., cell cycle regulation, cell adhesion, DNA repair) influence the sequence of genetic alterations in tumor development.
- The initiation, promotion, and progression phases characterize the development of cancer.
Cancer Stem Cells
- Tumours stem from tissue stem cells or progenitor cells.
- Cancer stem cells (CSCs) self-replicate and generate all tumor cell types.
- CSCs are often resistant to chemotherapy and radiation therapy.
Cancer Progression
- Histological changes accompany genetic changes in tumor progression.
- Initially, pre-cancerous cells/ abnormal cells appear.
- They possess some cancer properties but lack the ability to invade tissues or metastasize.
- Cervical cancer's progression takes years, showing increasingly abnormal cells with larger nuclei.
- Pre-cancerous cervical lesions (e.g., cervical intraepithelial neoplasia, cervical dysplasia) represent uncontrolled growth.
Benign vs. Malignant Tumors
- Benign tumors grow locally and do not spread.
- Malignant tumors invade surrounding tissue and metastasize.
Oncogenes
- Proto-oncogenes are normal genes that regulate cell growth and signaling; mutations convert them into oncogenes.
- Oncogenes are activated by gain-of-function mutations (e.g., gene duplication, amplification, rearrangement).
- Uncontrolled proliferation and transformation ensue from oncogene activation.
- Oncogenes can encode growth factors, receptors, cytoplasmic protein kinases, nuclear transcription factors, proteins modifying chromatin, and metabolic enzymes.
- Examples:
- Simian sarcoma virus (sis oncogene, PDGF)
- Altered EGF receptor (erbB oncogene)
- Raf protein kinase (MAPK cascade)
- Src tyrosine kinase, impacting cell signaling, cytoskeleton, and adhesion
- Oncogenes function dominantly; only one copy needs to be mutated.
Tumor Suppressor Genes
- Tumor suppressor genes encode proteins that restrain cell growth; they are like the brakes.
- Examples include APC, BRCA1/2, MSH/MLH1, INK4a, and Rb.
- Most tumor suppressor gene products are negative regulators of cell proliferation.
- The retinoblastoma (RB) gene is a widely studied tumor suppressor gene.
- Mutated RB genes contribute to retinoblastoma (eye cancer).
- pRB regulates the G1 to S phase transition of the cell cycle, preventing uncontrolled cell division.
- Loss of both alleles is necessary for cancer development.
p53
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P53 is a crucial tumor suppressor known as the "guardian of the genome."
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It maintains genomic stability and suppresses tumor formation.
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P53 function is sensitive to mutations in its DNA-binding domain, impacting DNA binding and conformation.
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Upon DNA damage, p53 concentration increases, halting cell division and initiating DNA repair.
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Cells with irreparable damage are then programmed for apoptosis.
New Cancer Combating Strategies
- Current treatments (surgery, chemotherapy, radiation) lack specificity, causing harmful side effects to healthy cells.
- Targeted therapies, immunotherapy, and techniques to block angiogenesis or use Oncolytic viruses, are emerging strategies.
- Immunotherapy: Passive immunotherapy utilizes patient antibodies against tumor cells (e.g., Herceptin, Rituxan).
- Targeting Cancer Proteins: Blocking cancer-promoting proteins (e.g., using Zelboraf to target mutant BRAF).
- Blocking Angiogenesis: Compounds like Avastin disrupt blood vessel formation to deprive tumors of nutrients (Targeting VEGF-R).
- Oncolytic viruses: Engineered viruses selectively infect and destroy cancer cells.
Specific factors in some cancers
- Prostate cancer: Calcium /vitamin D, IGF-I theories implicated in heightened risk.
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Description
Explore the fundamental characteristics of cancer cells, including their uncontrolled growth, types of neoplasms, and the process of metastasis. Understand key statistics related to cancer prevalence and the significance of the TNM score in staging cancer. This quiz delves into both genetic factors and the most common forms of cancer.
