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What is the result of tumor cells failing to express co-stimulatory molecules for T-cells?
What is the effect of tumor growth factor- β (TGF-β) on the immune system?
What is the result of antigen masking by tumor cells?
What is a common effect of local tumor progression?
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What is a potential effect of a benign pancreatic β-cell adenoma?
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What is a common complication of tumor growth?
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What is an acute presentation of a tumor?
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What is a potential effect of a pituitary adenoma?
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Which of the following conditions is NOT an example of a non-neoplastic precancerous condition?
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What is the term for the immune system's ability to detect and eliminate emerging malignant cells?
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What is the estimated percentage of individuals with congenital immunodeficiencies who develop cancers?
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Which of the following is a mechanism by which tumor cells can escape the immune system?
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What is the term for the increased frequency of cancers in immuno-deficient hosts?
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What is an example of an acquired immunodeficiency?
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What is the purpose of HLA class I molecules in immune response to tumors?
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Which of the following is NOT a reason why most cancers occur in individuals without immune deficiency?
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What is the primary purpose of grading and staging of cancers?
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What is the main difference in weight loss between cancer cachexia and starvation?
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What is the significance of the number of mitoses in cancer grading?
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What is the classification of a well-differentiated cancer?
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What is the reason for increased basal metabolic rate in cancer cachexia despite reduced food intake?
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What is the basis of the TNM staging system?
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What percentage of patients with cancer exhibit paraneoplastic syndromes?
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What does the 'T' in the TNM staging system refer to?
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What is the term for the production of hormones not indigenous to the tissue of origin of the tumor?
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What is the significance of 'N0' in the TNM staging system?
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What is the term for the clinical syndromes that occur in patients with cancer that cannot be explained by local or distant spread of the tumor?
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What is the frequency of hypertrophic osteoarthropathy and clubbing of the fingers in patients with bronchial carcinomas?
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What is the classification of an undifferentiated cancer?
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What is the significance of 'M1' in the TNM staging system?
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What is the term for the production of soluble factors by the tumor and the host in response to the tumor?
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What is the term for the weakness, anorexia, and anemia that occur frequently in patients with cancer?
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What is the primary advantage of using monoclonal antibodies in identifying cell products or cell surface markers?
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Which of the following tumors is NOT associated with an elevated carcinoembryonic antigen (CEA) level?
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What is the primary use of flow cytometry in the diagnosis of cancer?
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Which of the following tumor markers is NOT associated with germ cell tumors of the testis or ovary?
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What is the primary difference between biochemical assays and monoclonal antibodies in the diagnosis of cancer?
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Which of the following molecular techniques is used to analyze the expression of multiple genes in a single reaction?
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What is the primary advantage of using prostate-specific antigen (PSA) in the diagnosis of prostate cancer?
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Which of the following is a limitation of using biochemical assays in the diagnosis of cancer?
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Study Notes
Precancerous Conditions
- Certain conditions are known to have an increased risk of association with cancer, divided into two groups:
- Non-neoplastic conditions (e.g., chronic ulcerative colitis, chronic atrophic gastritis, chronic viral B & C hepatitis, cutaneous actinic keratosis, leukoplakia of oral cavity, vulva, and penis)
- Benign neoplasms (e.g., villous adenoma of the colon, familial adenomatous polyposis of the colon)
Host Defenses against Cancer—Tumor Immunity
- A normal function of the immune system is to inspect the body for emerging malignant cells and destroy them (immune surveillance)
- The strongest evidence for the existence of immune surveillance is the increased frequency of cancers in immuno-deficient hosts (congenital or acquired)
- Mechanisms developed by tumor cells to escape the immune system:
- Selective outgrowth of antigen-negative tumor cells
- Loss or reduced expression of MHC molecules
- Lack of co-stimulation
- Immunosuppression (e.g., tumor growth factor-β, secreted by many tumors)
- Antigen masking: cell-surface antigens of tumors may be hidden or masked from the immune system
- Killing of cytotoxic T cells
Effects of Tumors on the Host
- Local progression:
- Critical locations (e.g., pituitary adenoma)
- Obstructions (e.g., neoplasms in the GIT)
- Functional hormonal activity:
- Neoplasms arising in endocrine glands may produce manifestations by synthesizing hormones
- More common with benign tumors than with cancers
- Bleeding and secondary infections:
- Destructive growth of cancers or expansile pressure of a benign tumor
- Ulcerations, leading to bleeding and infections
- Acute presentation:
- Perforation of the stomach, small or large intestine
- Spontaneous rupture or infarction of the tumor itself
- Cancer cachexia:
- Syndrome of progressive loss of weight, accompanied by weakness, anorexia, and anemia
- Due to anorexia, tumor parasitism, and the action of soluble factors (e.g., tumor necrosis factor)
- Paradoxically increased basal metabolic rate despite reduced food intake
- Equal loss of fat and muscle, unlike in starvation
- Paraneoplastic syndromes:
- Symptom complexes that occur in patients with cancer, can't be explained by local or distant spread of the tumor or by the elaboration of hormones not indigenous to the tissue of origin
- Frequent (10% of patients with cancer)
- May be the earliest manifestations of an undiscovered malignancy
- May be serious and sometimes fatal
- May simulate clinically metastatic disease and confuse management
- Examples: endocrinopathies, neuromyopathies, dermatopathies, hypertrophic osteoarthropathy, vascular and hematologic changes, fever, nephrotic syndrome, and amyloidosis
Grading and Staging of Cancers
- Grading:
- Microscopic features that influence the expected behavior of cancers
- Classified into four grades (1 to 4) with increasing anaplasia (G1: well-differentiated, G2: moderately differentiated, G3: poorly-differentiated, G4: undifferentiated)
- Less clinical value than staging
- Staging:
- Based on the size of the primary cancer, extent of local extension, and presence or absence of blood-borne metastases
- Two major staging systems: International Union Against Cancer (UICC) and American Joint Committee (AJC)
- TNM system: T (primary tumor size), N (node involvement), M (metastases)
- Staging varies for each specific form of cancer, but general principles apply
Tools for Diagnosing and Monitoring Cancers
- Availability of specific monoclonal antibodies has greatly facilitated the identification of cell products or cell surface markers
- Biochemical assays (serum tumor markers):
- Tumor markers: substances released by cancer cells or created by the body in response to cancer cells
- Examples: carcinoembryonic antigen (CEA), prostate-specific antigen (PSA), α-fetoprotein (AFP)
- Flow cytometry:
- Technique used to measure individual cell characteristics (e.g., membrane antigens, DNA content)
- Used for classification of leukemias and lymphomas
- Molecular techniques:
- PCR (polymerase chain reaction)
- Real-time PCR
- DNA microarray analysis
- Tissue microarrays analysis
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Description
This quiz covers precancerous conditions, including non-neoplastic and benign neoplasms, that increase the risk of cancer development. Examples of such conditions are discussed.
