Biomarkers in Clinical Research

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Questions and Answers

What is an example of an endobiotic biomarker?

Cancer cell

Lead

Ultrasound

Cholesterol (correct)

What is a xenobiotic biomarker?

A biomarker that is normally present in the human body

A biomarker used in infectious disease diagnosis

A biomarker used in cancer diagnosis

A biomarker that is foreign to the human body (correct)

What is a surrogate endpoint in clinical research?

A laboratory measure used as a substitute for a clinically relevant outcome (correct)

A diagnostic biomarker used in cancer research

A prognostic biomarker used in infectious disease research

A direct measure of how patients feel, function, and survive

What is an example of a diagnostic biomarker?

Cancer cell Signup and view all the answers

What is the purpose of a biomarker in clinical trials?

All of the above Signup and view all the answers

What is an example of a prognostic biomarker?

CECP Signup and view all the answers

What is the purpose of a surrogate endpoint in clinical trials?

To replace clinically meaningful endpoints Signup and view all the answers

What is a characteristic of a surrogate endpoint?

It is a laboratory measure used as a substitute for a clinically relevant outcome Signup and view all the answers

What type of biomarker is tumor size?

Biomarker of a pathogenic process Signup and view all the answers

What does a biomarker reflect in the context of a health hazard?

An interaction between a biological system and a health hazard Signup and view all the answers

What is an example of a biomarker that reflects a pathophysiological effect of a pathogen?

CD4 count in PLWHIV Signup and view all the answers

What is measurement error in the context of biomarkers?

The difference between the measured biomarker and the true exposure Signup and view all the answers

What is true exposure in the context of biomarkers?

The underlying biological factor that the biomarker is meant to measure Signup and view all the answers

What is an example of a biomarker that reflects a biological effect that results from contact with an agent?

Skin rash density Signup and view all the answers

What is an example of a biomarker that reflects a concentration of a product of biotransformation?

25(OH)vit D Signup and view all the answers

What is a common source of error in biomarker measurement?

Variability and/or error introduced during specimen collection, processing, and storage Signup and view all the answers

What are the three categories of environmental agents?

Contaminants of the general environment, agents used in the personal environment, and toxic agents in specific environments Signup and view all the answers

What is a limitation of using questionnaires to document exposure to environmental agents?

Exposure is often unknown or un-sensed by individuals Signup and view all the answers

What is an advantage of using individual measurement over population level measurement of present exposures?

It takes into account personal behavior, especially avoidance of exposure Signup and view all the answers

What is the difference between potential dose and applied dose?

Potential dose is the amount ingested, inhaled, or applied to the skin, while applied dose is the amount absorbed or deposited in the body Signup and view all the answers

What is the biologically effective dose?

The amount of the chemical that has interacted with a target site and alters a physiologic function Signup and view all the answers

What is a benefit of using biomarkers in people's daily life?

They provide more accurate and personalized information Signup and view all the answers

Study Notes

Biomarkers for Clinical Research

Biomarkers can be classified into two categories: endobiotic (normally present in the human body and needed for healthy bodily function, e.g., cholesterol) and xenobiotic (foreign to the human body, e.g., lead).
Biomarkers can be used for diagnostic, prognostic, susceptibility, exposure, or outcome purposes.

Clinical Use of a Biomarker

Biomarkers have a spectrum of use and specifications in clinical trials, including infectious and non-communicable diseases.
Examples of biomarkers include circulating endothelial cells (CEC), circulating endothelial cell progenitors (CECP), and others.

Biomarkers in Cancer

Biomarkers can be used in cancer research to identify surrogate endpoints.
Surrogate endpoints are laboratory measures that substitute for clinically meaningful endpoints.
Examples of surrogate endpoints include tumor size and histological cancer staging.

Characteristics of a Surrogate Endpoint

A biomarker can be an indicator of a normal biological process, a pathogenic process, a pharmacologic response to a therapeutic intervention, or an interaction between a biological system and a health hazard.
Biomarkers can reflect pathophysiological effects, concentration of agents, or biological effects.

Biomarkers and Measurement Error

Measurement error occurs when there is a difference between the measured biomarker and the true exposure.
True exposure refers to the underlying biological or external factor that the biomarker is meant to measure.

Sources of Error in Biomarkers

Common sources of error in biomarkers include variability and/or error introduced during specimen collection, processing, and storage.

Biomarkers for Environmental and Occupational Research

Environmental agents include contaminants of the general environment, agents used in the personal environment, and toxic agents in specific environments.
Exposure to environmental agents can be unknown or un-sensed by individuals, making accurate documentation challenging.

Individual vs. Population Measurement of Present Exposures

Population level measurement involves an ecological approach, making assumptions about individual behaviors that influence exposure.
Individual measurement uses personal sensors and takes into account personal behavior, but may not be acceptable for prolonged periods of time.

Biomarkers in Daily Life

Biomarkers are increasingly being used in people's daily lives.

Role of Dose and Route of Exposure

The potential dose is the amount of a chemical ingested, inhaled, or applied to the skin.
The applied dose is the amount absorbed or deposited in the body.
The internal dose is the amount available for interaction with biologically significant molecular targets.
The biologically effective dose is the amount that has interacted with a target site and alters a physiologic function.

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Description

This quiz covers the different types of biomarkers, including endobiotic and xenobiotic biomarkers, and their applications in clinical research. Learn about diagnostic and prognostic biomarkers and how they are used in healthcare.