Tumor Markers and Cancer Biology Quiz

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Questions and Answers

Which of the following is associated with elevated levels of β-HCG?

Testicular tumors (correct)

Liver cancer

Lung cancer

Breast cancer

What is the normal range for PSA levels in adults?

< 10 ng/mL

Normal varies by age

< 20 ng/mL

< 4 ng/mL (correct)

Which condition is NOT indicated by increased PSA levels?

Kidney stones (correct)

Prostate cancer

Benign prostatic hypertrophy

Chronic prostatitis

What is a primary use of tumor markers like β-HCG and PSA?

To identify cancer in asymptomatic individuals Signup and view all the answers

Which statement about clinically relevant tumor markers is true?

Elevated levels indicate a significant tumor mass. Signup and view all the answers

What is characteristic of a malignant tumor?

Invade surrounding tissue and grow rapidly Signup and view all the answers

What defines a metastatic tumor?

Develops from a malignant primary tumor Signup and view all the answers

Which of the following is NOT a characteristic of cancer cells?

Transient nature of cell growth Signup and view all the answers

What is the role of tumor-associated antigens?

To be recognized as foreign by the immune system Signup and view all the answers

What defines virus-induced tumors?

Express viral antigens on their surfaces Signup and view all the answers

What is the function of oncogenes?

Lead to abnormal cell growth if downregulated Signup and view all the answers

Which of the following is true about proto-oncogenes?

Alterations can lead to abnormal cell growth Signup and view all the answers

What is a feature of tumor-specific peptides?

Induced by chemical means for expression Signup and view all the answers

What is the primary use of tumor markers?

To monitor therapeutic response and determine tumor burden Signup and view all the answers

Carcinoembryonic antigen (CEA) is mainly associated with which type of cancer?

Colon cancer Signup and view all the answers

What is the normal level range of CEA in healthy individuals?

Up to 2.5 ng/ml Signup and view all the answers

Which condition can cause elevated levels of α-fetoprotein (AFP)?

Hepatocellular carcinoma Signup and view all the answers

How is a significant rise in AFP levels used in clinical monitoring?

For monitoring hepatomas and testicular cancers Signup and view all the answers

What are the subunits of Human Chorionic Gonadotropin (HCG)?

α and β Signup and view all the answers

Which of the following can lead to elevated CEA levels, aside from cancer?

Inflammatory bowel disease Signup and view all the answers

Which condition is notably associated with elevated HCG levels?

Pregnancy Signup and view all the answers

What is α-fetoprotein (AFP) classified as?

An oncofetal antigen Signup and view all the answers

Which mechanism is NOT involved in natural immunity to tumors?

T cell activation by IL-1 Signup and view all the answers

What protein is often associated with colorectal cancer?

Carcinoembryonic antigen (CEA) Signup and view all the answers

Which statement accurately describes T cell-mediated immunity?

Cytokines such as TNFα can destroy tumor cells. Signup and view all the answers

What role do antibodies play in humoral-mediated immunity against tumors?

They can block CTL binding sites. Signup and view all the answers

What is a common way that tumors evade the immune system?

By downregulating Class I MHC expression Signup and view all the answers

Which immune cells are primarily responsible for macrophage-mediated cytotoxicity?

Macrophages Signup and view all the answers

Which component is NOT a part of humoral-mediated immunity?

Cytotoxic T lymphocytes (CTLs) Signup and view all the answers

Which tumor marker is primarily associated with liver cancer?

AFP Signup and view all the answers

What type of therapy uses the immune system to destroy tumor cells?

Active immunotherapy Signup and view all the answers

Which of the following is NOT a use of CA 19-9 tumor marker?

Screening Signup and view all the answers

What method detects genetic mutations associated with cancer?

PCR Signup and view all the answers

Which tumor marker is commonly used in diagnosing ovarian cancer?

CA 125 Signup and view all the answers

What do monoclonal antibodies in passive immunotherapy target?

Tumor antigens Signup and view all the answers

What type of cancer is associated with the use of PSA tumor markers?

Prostate Signup and view all the answers

Which is an example of therapeutic cancer vaccines?

TSA-specific Signup and view all the answers

What characterizes a malignant tumor?

It can spread to other parts of the body Signup and view all the answers

What distinguishes benign tumors from malignant tumors?

Benign tumors do not spread to other areas Signup and view all the answers

What type of genes are considered proto-oncogenes?

Genes that promote cell division Signup and view all the answers

What happens when there are mutations in tumor-suppressor genes?

Cell division becomes uncontrolled Signup and view all the answers

Which of the following best describes a neoplasm?

An abnormal mass caused by uncontrolled cell growth Signup and view all the answers

What is a characteristic of cancer cells compared to normal cells?

They can divide indefinitely Signup and view all the answers

Which of the following is a common characteristic of major body defenses against cancer?

They help identify and destroy abnormal cells Signup and view all the answers

What is a potential outcome of immunoediting in tumor biology?

Survival of tumor variants resistant to immune responses Signup and view all the answers

Study Notes

Immunology & Serology I - 0202308

Course offered by Al-Quds University, Faculty of Health Professions, Department of Medical Laboratory Sciences
Instructor: Dr. Rasmi Abu-Helu (Ph.D., Immunology)
Course code: 0202308

Tumor Immunology

Course covers tumor biology, tumor antigens, clinically relevant tumor markers, laboratory tests for tumors, immune defenses against tumors, immunoediting and tumor escape, and immunotherapy.

Chapter Overview

Topics covered are tumor biology, tumor antigens, clinically relevant tumor markers, laboratory tests for tumors, immune defenses against tumors, immunoediting and tumor escape, and immunotherapy.

Learning Objectives

Students will be able to compare benign and malignant tumors.
Students will be able to define and give examples of proto-oncogenes.
Students will be able to describe the role of oncogenes.
Students will be able to describe the characteristics of the major body defenses against cancer.
Students will be able to identify and discuss the characteristics of tumor markers.
Students will be able to discuss new developments in cancer diagnostic testing.

Introduction to Tumor Biology

Tumor (neoplasm) is an abnormal cell mass.
Cancer is malignant tumors that can spread.
Cancer is caused by mutations in proto-oncogenes and tumor suppressor genes.
Causes include uncontrolled cell division and other characteristics

Definitions

Neoplasm: An abnormal mass of tissue resulting from uncontrolled growth of normal cells, even after the growth stimulus is removed.
Benign tumor: A mild and non-progressive tumor that pushes aside normal tissue but does not invade it as it expands.
Malignant tumor: Consisting of poorly differentiated cells that grow rapidly, invade surrounding tissue, and rob normal tissue of nutrients.
Metastatic tumor: A secondary tumor derived from a malignant primary tumor.

Characteristics of Cancer Cells

Sustained proliferation
Resist death
Induce angiogenesis
Immortality
Invasion and metastasis
Avoid suppressors of cell growth
Altered metabolism
Evasion of immune defenses
Genomic instability
Accelerated growth in the presence of inflammation.

Tumor-Associated Antigens

For immune system to react against tumor, it must have antigens recognized as foreign.
Examples include enzymes, receptors, and membrane antigens, etc.
Most relevant are surface membrane molecules, which can be either antigenic or suppress membrane proteins essential for immune recognition and activation.

Tumor-Specific Peptides

Intracellular proteins expressed on tumor cells with MHC class I and II.
This expression can be chemically induced.

Virus-Induced Tumors

Tumors caused by viruses.
Tumor cells express viral antigens on their surfaces.
Tumor cells recognized as non-self by the immune system.

Genome-Encoded Tumor Antigens

Oncogenes: if downregulated, the protein product can lead to tumor.
Proto-oncogenes: found in all nucleated cells (yeast to human), involved in cell growth; alterations in gene expression or protein structure may lead to abnormal cell growth.

Oncofetal Antigens

Found on normal fetal cells.
Produced in minute amounts after birth.
Become expressed later after malignant transformation.
Examples: a-fetoprotein (AFP) and carcinoembryonic antigen (CEA).
~90% of colorectal cancers have CEA.

Immunity to Tumors

Natural immunity:
- Macrophage-mediated cytotoxicity: Macrophages killing tumor cells on contact.
- NK cells: 50% of tumors have mutations decreasing MHC class I on their surfaces, facilitating killing by NK cells.
Humoral-mediated immunity:
- Antibodies: Antibodies produced targeting tumor cell surface antigens.
- Lysis of tumor cells (via complement activation and antibody-dependent cellular cytotoxicity (ADCC) reactions involving NK cells, PMNs, and macrophages).
T cell-mediated immunity:
- Cytokines: IL-1 activates T, B, and NK cells, TNFα destroys tumor cells, IFNg produced by activated T, B, and NK cells.
- CTLs (cytotoxic T lymphocytes): directly lyse tumor cells.

Immune Defenses Against Tumor Cells

Immune system comprises various components (e.g., NK cells, macrophages, CTLs, antibodies, cytokines) acting in concert to eliminate or control tumor cells.
Elimination, equilibrium, and escape phases are associated with immune response to tumors.
These processes involve apoptosis and other mechanisms to eliminate altered cells and maintain immune surveillance to control tumor growth.

Body Defenses Against Cancer

Various factors contribute to immune evasion by tumors including antigen loss variants of tumor cells, defective MHC I expression or dysfunction and immunosuppressive cytokines that prevent effective anti-tumor immune response.

Immunoediting and Tumor Escape

Elimination phase: robust innate and adaptive immune responses kill tumor cells
Equilibrium phase: immune system controls limited number of altered cells
Escape phase: immune system is suppressed, and inflammation promotes uncontrolled tumor growth.
Tumor cells highly altered & more resistant to immune responses; apoptosis is impaired.

Tumor Evasion of Immune System

Anti-tumor antibodies might block sites for CTL binding.
Tumor cells might express less class I MHC which prevents CTL-mediated death.
Tumor cells might provide poor costimulatory signals.

Tumor Markers

Glycoproteins found in small amounts in normal serum, but elevated in certain cancer types.
Used to screen for cancer, monitor therapeutic response, and determine tumor burden.

Carcinoembryonic Antigen (CEA)

Used in management of GIT tumors (e.g., colon cancer, adenocarcinoma of the colon, pancreas, liver, lung)
Found in inflammatory bowel disease (IBD), ulcerative colitis, polyps, tumors of the GIT, Crohn disease, and cigarette smokers.
Highest levels of CEA are found in metastatic disease.
Normal CEA levels in normal people are up to 2.5 ng/ml.
Levels 4-5 times normal have been used to predict colorectal tumor recurrence.

α-Fetoprotein (AFP)

High levels in patients with hepatocellular carcinoma & hepatoblastoma, testicular & ovarian cancer, viral hepatitis & cirrhosis, and ulcerative colitis.
Very important marker in monitoring cancer therapy.
Normal range of AFP concentrations in humans is 0-20 ng/ml.
A 5-fold or higher rise is used for monitoring hepatomas and testicular cancers.
AFP levels may also be raised in some non-malignant liver conditions like cirrhosis, hepatitis.

Human Chorionic Gonadotropin (hCG)

Composed of 2 subunits (α & β, β-hCG).
Found in serum and urine during pregnancy.
Produced by neoplastic cells of testicular cancer and other tumors.
Levels useful for evaluating patients with gestational trophoblastic disease, testicular tumors, and ovarian germ cell tumors.
Normal range in adults is <15 ng/mL.

Prostate-Specific Antigen (PSA)

Glycoprotein that dissolves seminal gel after ejaculation.
Found in very low amounts in blood of normal individuals.
Increased in prostate cancer, benign prostatic hypertrophy (BPH), acute & chronic prostatitis.
Levels correlate with prostate size, stage of cancer, response to treatment.
Used in screening for prostate cancer—used in conjunction with digital rectal examination.
PSA level below 4 ng/mL.

Clinically Relevant Tumor Markers

Biological substances found in increased amounts in blood, body fluids, or tissues of patients with specific types of cancers.
Concentration depends on tumor cell proliferation and size; elevated levels indicate a significant tumor mass.
Ideal marker is highly sensitive and specific.

Clinical Uses of Tumor Markers

Population screening: used to identify cancer in asymptomatic people.
Diagnosis: used to identify cancer in a particular patient.

Common Serum Tumor Markers

Various tumor markers (e.g., AFP, CA 125, CA 19-9, CEA, hCG, PSA) are associated with specific cancers or conditions, and are used clinically for diagnosis, prognosis, and monitoring.

Laboratory Tests for Tumors

Immunohistochemistry: uses labeled antibodies to detect tumor antigens in tissue biopsies.
Immunoassays: measures levels of circulating tumor markers.
Molecular methods: detects genetic mutations associated with cancer (e.g., PCR, karyotyping, FISH, microarray, DNA sequencing).

Immunotherapy

Also known as biological response modifier therapy.
Uses the ability of the immune system to destroy tumor cells.
Active immunotherapy: stimulates patient's immune system to respond to tumor antigens (cancer vaccines).
Passive immunotherapy: administration of soluble components of the immune system (e.g., cytokines) and monoclonal antibodies that target specific tumor antigens (e.g., surface antigens, receptors, angiogenesis factors, and immune checkpoint molecules).
Adoptive immunotherapy: transfer of cells of the immune system (e.g., TILs, CAR-T cells) to patients.

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Description

Test your knowledge on tumor markers such as β-HCG, PSA, and CEA. This quiz covers their roles, normal levels, and associated conditions in cancer biology. Assess your understanding of key concepts related to malignancy and cancer cell characteristics.