Tumor Markers in Oncology

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Questions and Answers

Which tumor markers are indicated for evaluating patients with gesta7onal trophoblastic disease?

CA-125

β-HCG (correct)

AFP

PSA

What condition is associated with elevated levels of Prostate-Specific Antigen (PSA)?

Benign prostatic hypertrophy (correct)

Liver cirrhosis

Ovarian cancer

Testicular tumors

What is the normal PSA level in ng/mL for adults?

< 25

< 10

< 20

< 15 (correct)

How should tumor markers ideally perform in clinical settings?

Highly sensitive and specific Signup and view all the answers

Which of the following describes a clinical use of tumor markers?

Population screening for asymptomatic individuals Signup and view all the answers

What characterizes malignant tumors?

Poorly differentiated cells that grow rapidly Signup and view all the answers

What is a metastatic tumor?

A secondary tumor derived from a malignant primary tumor Signup and view all the answers

Which characteristic is NOT associated with cancer cells?

Reduced growth in the presence of inflammation Signup and view all the answers

What types of molecules are primarily tumor-associated antigens?

Surface membrane molecules Signup and view all the answers

What role do oncogenes play in tumor development?

They can lead to tumor formation if downregulated Signup and view all the answers

How do tumor cells become recognized by the immune system?

Through the expression of viral proteins on their surfaces Signup and view all the answers

What is one of the metabolic alterations in cancer cells?

Altered metabolism favoring rapid growth Signup and view all the answers

What can induce the expression of tumor-specific peptides?

Chemical stimulation Signup and view all the answers

Which of the following is a characteristic of oncofetal antigens?

Become expressed after malignant transformation Signup and view all the answers

What is an example of a natural immunity mechanism against tumors?

Macrophage-mediated cytotoxicity Signup and view all the answers

What role does TNF-alpha play in tumor immunity?

Destroys tumor cells Signup and view all the answers

Which of the following statements about tumor evasion is true?

Tumor cells may provide poor costimulatory signals Signup and view all the answers

Which substance activates T, B, and NK cells as part of cytokine involvement in immunity?

Interleukin-1 Signup and view all the answers

Which type of immunity involves the production of antibodies against antigens found on tumor cell surfaces?

Humoral-mediated immunity Signup and view all the answers

What percentage of colorectal cancers express carcinoembryonic antigen (CEA)?

90% Signup and view all the answers

Which immune cells are primarily involved in lysis of tumor cells via antibody-dependent cellular cytotoxicity (ADCC)?

Natural killer (NK) cells Signup and view all the answers

What is the primary use of tumor markers?

To screen for cancer Signup and view all the answers

Which cancers are specifically associated with Carcinoembryonic Antigen (CEA)?

Colon cancer and adenocarcinoma of the colon Signup and view all the answers

What do elevated levels of CEA typically indicate?

Metastatic disease Signup and view all the answers

What is the normal concentration range of α-Fetoprotein (AFP) in humans?

0-20 ng/ml Signup and view all the answers

In which conditions might AFP levels be elevated?

Cirrhosis and viral hepatitis Signup and view all the answers

What is a significant use of monitoring AFP levels?

Monitoring cancer therapy Signup and view all the answers

Which component of the Human Chorionic Gonadotropin (HCG) is found during pregnancy?

Both α and β subunits Signup and view all the answers

HCG is produced by which type of cells when associated with cancer?

Neoplastic cells Signup and view all the answers

Which tumor marker is primarily associated with ovarian cancer?

CA 125 Signup and view all the answers

What is the primary use of PSA in oncology?

Screening, diagnosis, prognosis, and monitoring Signup and view all the answers

Which method is used to detect genetic mutations associated with cancer?

Molecular methods Signup and view all the answers

What is active immunotherapy designed to do?

Stimulate the immune system Signup and view all the answers

Which of the following is a characteristic of passive immunotherapy?

Administration of soluble immune components Signup and view all the answers

Which of the following tumor markers is associated with pancreatic cancer?

CA 19-9 Signup and view all the answers

What type of immunotherapy includes the use of monoclonal antibodies?

Passive immunotherapy Signup and view all the answers

Which of the following is NOT a use for tumor markers?

Surgical removal Signup and view all the answers

What is the definition of a neoplasm?

An abnormal mass of tissue due to uncontrolled growth. Signup and view all the answers

Which of the following best describes a benign tumor?

It pushes aside normal tissue without invasion. Signup and view all the answers

What primarily causes cancerous tumors?

Mutations in proto-oncogenes and tumor-suppressor genes. Signup and view all the answers

Which type of tumor is considered malignant?

A tumor that is capable of spreading. Signup and view all the answers

What is the primary difference between benign and malignant tumors?

Benign tumors do not spread, while malignant tumors can. Signup and view all the answers

What are proto-oncogenes responsible for?

They regulate cell division and prevent cancer. Signup and view all the answers

Which of the following statements is true regarding tumor markers?

They are used to identify and monitor tumors. Signup and view all the answers

What will happen if the growth stimulus for a neoplasm is removed?

The neoplasm may continue to grow uncontrollably. Signup and view all the answers

Study Notes

Immunology & Serology I - 0202308

Course offered by the Faculty of Health Professions, Department of Medical Laboratory Sciences at Al-Quds University
Course instructor: Dr. Rasmi Abu-Helu (Ph.D., Immunology)
Course details provided might be part of larger course material.
Current presentation topic is Tumor Immunology.

Tumor Immunology - Chapter Overview

Key topics within Tumor Immunology include:
- Tumor Biology
- Tumor Antigens
- Clinically Relevant Tumor Markers
- Laboratory Tests for Tumors
- Immune Defenses Against Tumors
- Immunoediting and Tumor Escape
- Immunotherapy

Learning Objectives

Students will be able to compare benign and malignant tumors
Students will be able to define and provide examples of proto-oncogenes
Students will be able to describe oncogene roles
Students will be able to describe characteristics of major bodily defenses against cancer
Students will be able to discuss characteristics of tumor markers
Students will be able to discuss developments in cancer diagnostic testing

Introduction to Tumor Biology

Tumor (neoplasm) is an abnormal cell mass
Cancer is a malignant tumor that can spread
Mutations in proto-oncogenes and tumor suppressor genes cause cancer
Uncontrolled cell division and other characteristics are present in cancer

Definitions

Neoplasm: An abnormal mass of tissue resulting from uncontrolled growth of normal cells, even after removing the growth stimulus.
Benign tumor: Mild, non-progressive tumor that pushes normal tissue aside as it expands without invading it
Malignant tumor: Composed of poorly differentiated cells that rapidly grow and invade surrounding tissue, depriving 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 the immune system to react to a tumor, the tumor must have antigens recognized as foreign.
Relevant antigens include enzymes, receptors, and membrane antigens.
Surface membrane molecules may be antigenic.
Suppressing membrane proteins essential for immune recognition and activation is also relevant.

Tumor-Specific Peptides

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

Virus-Induced Tumors

Viruses can cause tumors.
Tumor cells express viral antigens on their surfaces
Tumor cells are recognized as non-self by the immune system

Genome-Encoded Tumor Antigens

Oncogenes: If downregulated, their protein product can lead to tumor development.
Proto-oncogenes: Found in all nucleated cells; involved in cell growth; alteration in gene expression or protein structure may result in abnormal cell growth.

Oncofetal Antigens

Found on normal fetal cells, but produced in minute amounts after birth.
Become expressed later after malignant transformation.
Examples include alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA).
CEA is found in ~90% of colorectal cancers.

Immunity to Tumors (Natural Immunity)

Macrophage-mediated cytotoxicity: Macrophages kill tumor cells upon contact
NK cells: 50% of tumors have mutations that reduce MHC class I on their surfaces, making them susceptible to NK cell killing.

Immunity to Tumors (Humoral Immunity)

Antibodies can be produced against tumor cell surface antigens.
Tumor cell lysis occurs via complement activation and antibody-dependent cellular cytotoxicity (ADCC) that involves NK, PMNs (polymorphonuclear leukocytes), and macrophages.

Immunity to Tumors (T-cell Mediated Immunity)

Cytokines play a role in tumor immunity: IL-1 activates T, B, and NK cells; TNFα destroys tumor cells; interferon-γ (IFNγ) is produced by activated T, B, and NK cells.
CTLs (cytotoxic T lymphocytes) can directly lyse tumor cells.

Immune Defenses Against Tumor Cells

A complex interplay of immune cells and components is involved in tumor defense.

Body Defenses Against Cancer

Immune evasion by tumors—Mutations in MHC genes, antigen-loss variant of tumor cells, and loss of T-cell recognition contribute to this evasion.
- Production of immunosuppressive proteins & Inhibition of T-cell activation can also occur.

Immunoediting and Tumor Escape

The immune system's role in eliminating, controlling, or escaping tumor cells is a dynamic process.

Tumor Evasion of Immune System

Anti-tumor antibodies might block CTL binding sites.
Tumor cells might express less Class I MHC, preventing CTL-mediated death.
Tumor cells may provide poor costimulatory signals

Tumor Markers

Glycoproteins found in small amounts in normal serum, but elevated in certain cancers.
Used for cancer screening, monitoring therapeutic response, and determining tumor burden.

Carcinoembryonic Antigen (CEA)

Used in management of gastrointestinal (GIT) tumors, including colon cancer, adenocarcinoma of the colon, pancreas, liver, and lung
Found in inflammatory bowel disease (IBD), ulcerative colitis, polyps, tumors of GIT, Crohn disease, and cigarette smokers.
Highest levels are found in metastatic disease.
Normal CEA levels are up to 2.5 ng/mL in normal people.
4–5 times normal levels may indicate colo-rectal tumor recurrence.

α-Fetoprotein (AFP)

High levels found in patients with hepatocellular carcinoma, hepatoblastoma, testicular and ovarian cancers, viral hepatitis, and cirrhosis, and ulcerative colitis.
Very important marker in cancer therapy monitoring.
Normal range is 0-20 ng/mL.
Monitoring hepatomas and testicular cancers is via a 5-fold or higher rise in this protein.
Raised levels can be non-malignant, such as due to cirrhosis, hepatitis, and other liver damage.

Human Chorionic Gonadotropin (HCG)

Composed of α and β subunits (β-HCG)
Found in serum and urine during pregnancy, produced by neoplastic cells in testicular cancer and other tumors
Levels of β-HCG aid in evaluating patients with gestational trophoblastic disease, testicular tumors, and ovarian germ cell tumors
Normal range is < 15 ng/mL in adult men.

Prostate-Specific Antigen (PSA)

Glycoprotein that dislodges seminal gel after ejaculation.
Found in very low amounts in the blood of normal individuals
Increased in prostate cancer, benign prostatic hypertrophy, and acute/chronic prostatitis
Levels correlate with prostate size, cancer stage, and treatment response.
Used for prostate cancer screening, often in conjunction with digital rectal examinations.
Normal PSA levels are below 4 ng/mL.

Clinically Relevant Tumor Markers

Biological substances found in increased amounts in blood, body fluids, or tissues of cancer patients.
Serum concentration depends on tumor cell proliferation and size; high levels indicate significant tumor mass.
Ideally, tumor markers should be highly sensitive and specific.

Clinical Uses of Tumor Markers

Population screening to identify cancer in asymptomatic individuals (e.g., PSA).
- Note: Early detection is possible but false positives and negatives can occur.
Diagnosis to identify cancer in a particular patient (e.g., PSA).

Common Serum Tumor Markers

Table lists examples of common serum tumor markers and their associated cancers; their uses in screening (S), diagnosis (D), prognosis (P), and monitoring (M) are also listed.

Laboratory Tests for Tumors

Immunohistochemistry uses labeled antibodies to detect tumor antigens in tissue biopsies.
Immunoassays measure circulating tumor marker levels.
Molecular methods detect genetic mutations associated with cancers. (e.g., PCR, karyotyping, FISH, microarray, DNA sequencing)

Immunotherapy

Also known as biological response modifier therapy.
Uses the immune system's ability to destroy tumor cells.
- Active immunotherapy stimulates patient immune response to tumor antigens—includes preventative vaccines (e.g., HPV, HBV) and therapeutic vaccines (e.g., TSA-specific, Provenge).
- Passive immunotherapy involves administering soluble components of immune system (e.g., cytokines) to boost immune response and increase white blood cell production; monoclonal antibodies targeting specific tumor antigens also fall under this category.
- Adoptive immunotherapy involves transferring immune cells to cancer patients (e.g., TILs to melanoma patients or genetically-engineered T cells (CAR-T)).

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Description

This quiz covers essential concepts related to tumor markers, their clinical uses, and associations with various cancers, including gestational trophoblastic disease and prostate cancer. Test your knowledge on tumor characteristics, immunological aspects, and molecular alterations in tumor cells.