Biomarker Testing

Biomarker Testing is the use of a laboratory test to measure biomarkers found in blood, other body fluids, or tissue. Biomarker testing can be somatic or germline.

Carrier

A carrier is an individual who carries and is capable of passing on a genetic variant associated with a disease and may or may not display disease symptoms. Carriers are associated with diseases inherited as recessive traits. In order to have the disease, an individual must have inherited variant alleles from both parents. An individual having one normal allele and one variant allele does not have the disease. Two carriers may produce children with the disease.4
Carrier Illustration

Cytogenetics

The study of the structure, function, and abnormalities of human chromosomes.3

Fluorescence in situ hybridization (FISH)

Fluorescence in situ hybridization (FISH) is a laboratory technique for detecting and locating a specific DNA sequence on a chromosome. The technique relies on exposing chromosomes to a small DNA sequence called a probe that has a fluorescent molecule attached to it. The probe sequence binds to its corresponding sequence on the chromosome.4
Fluorescence in situ hybridization (FISH) Illustration

Germline Testing

The laboratory process of analyzing cells or tissue to look for changes in genes, chromosomes, or proteins that may be a sign of a disease or condition, such as cancer. These changes may also be a sign that a person has an increased risk of developing a specific disease or condition. 2

Immunohistochemistry (IHC)

A laboratory method that uses antibodies to check for certain antigens (markers) in a sample of tissue. The antibodies are usually linked to an enzyme or a fluorescent dye. After the antibodies bind to the antigen in the tissue sample, the enzyme or dye is activated, and the antigen can then be seen under a microscope. Immunohistochemistry is used to help diagnose diseases, such as cancer. It may also be used to help tell the difference between different types of cancer.2

Karyotype

A karyotype is an individual's collection of chromosomes. The term also refers to a laboratory technique that produces an image of an individual's chromosomes. The karyotype is used to look for abnormal numbers or structures of chromosomes.4
Karyotype Illustration

Liquid Biopsy
(also called circulating tumor DNA [ctDNA])

A test done on a sample of blood to look for cancer cells from a tumor that are circulating in the blood or for pieces of DNA from tumor cells that are in the blood. A liquid biopsy may be used to help find cancer at an early stage. It may also be used to help plan treatment or to find out how well treatment is working or if cancer has come back. Being able to take multiple samples of blood over time may also help doctors understand what kind of molecular changes are taking place in a tumor.2
Circulating Tumor DNA Illustration

Multi-Gene Panel Testing

A test done on a sample of blood to look for cancer cells from a tumor that are circulating in the blood or for pieces of DNA from tumor cells that are in the blood. A liquid biopsy may be used to help find cancer at an early stage. It may also be used to help plan treatment or to find out how well treatment is working or if cancer has come back. Being able to take multiple samples of blood over time may also help doctors understand what kind of molecular changes are taking place in a tumor.2

Next-Generation Sequencing (NGS)

A high-throughput method used to determine a portion of the nucleotide sequence of an individual’s genome. This technique utilizes DNA sequencing technologies that are capable of processing multiple DNA sequences in parallel. Also called massively parallel sequencing and NGS3.

Paired Somatic/Germline Testing

Genetic analysis of samples from the tumor (somatic) and normal (germline) in which the germline variants are subtracted from the somatic variants using bioinformatics resulting in a somatic-specific genomic tumor profile.18

Polygenic Risk Score

An assessment of the risk of a specific condition based on the collective influence of many genetic variants. These can include variants associated with genes of known function and variants not known to be associated with genes relevant to the condition.3
Calculating a Polygenic Risk Score

Sanger Sequencing

A low-throughput method used to determine a portion of the nucleotide sequence of an individual’s genome. This technique uses polymerase chain reaction (PCR) amplification of genetic regions of interest followed by sequencing of PCR products.3

Somatic Testing

The laboratory process of analyzing cells or tissue to look for changes in genes, chromosomes, or proteins that may be a sign of a disease or condition, such as cancer. Somatic testing may be done on tumor tissue to help diagnose cancer, plan treatment, or find out how well treatment is working. 2

Whole Exome Sequencing

A laboratory process that is used to determine the nucleotide sequence primarily of the exonic (or protein-coding) regions of an individual’s genome and related sequences, representing approximately 1% of the complete DNA sequence.3

Whole Genome Sequencing

A laboratory process that is used to determine nearly all of the approximately 3 billion nucleotides of an individual’s complete DNA sequence, including non-coding sequence.3