At a glance

Also known as

T-cell Gene Clonality; TCGR; TCR gene Rearrangement

Why get tested?
To help diagnose a T-cell lymphoma; sometimes to detect and evaluate residual cancer cells
 
When to get tested?
When a doctor thinks that you may have a T-cell lymphoma; when a doctor would like to assess whether treatment has been effective and/or whether lymphoma has recurred
 
Sample required?
bone marrow, tissue such as a lymph node (biopsy), or body fluid sample collected by your doctor; sometimes a blood sample drawn from a vein in your arm
 
Confused about genetics?
See our Genetics Information page

 

What is being tested?

This test detects characteristic changes (rearrangements) in specific genes in T-cells. This information can be helpful in diagnosing a T-cell lymphoma.

T-cells are a type of lymphocyte, one of the white blood cells (WBC) that helps protect the body against infection. There are two main types of lymphocytes, B-cells and T-cells. Whereas B-cells produce antibodies to attack bacteria, viruses and other foreign substances, one of the main jobs of T-cells is to destroy the body’s own cells that have been infected by viruses or bacteria or damaged for example by becoming cancerous.  Like almost all cells in the body, white blood cells contain DNA. As the cells mature, their DNA is modified in a process called gene rearrangement. These rearrangements allow for the development of a large repertoire of diverse cells enabling them to protect against many different kinds of infections. Rearrangements in parts of the DNA of T-cells called receptor genes are a normal part of their development. The final order in which the genes are rearranged is called a gene rearrangement profile. Within any normal population (sample) of T-cells, the cells and their gene rearrangement profiles are very diverse.

Lymphomas arise when an abnormal T-cell begins to produce numerous identical copies of itself (clones). The cloned cells grow and divide uncontrollably, crowding out normal cells. If someone has lymphoma, the T-cells in affected tissue (such as blood, lymph node, or skin) are identical and their gene rearrangement profiles are likewise identical.

A T-cell receptor gene rearrangement test evaluates the T-cells in a person's sample to determine whether the majority of T-cell rearrangement profiles are diverse or identical. This information, along with clinical signs and symptoms and results of other laboratory tests, can help clarify a person's diagnosis, or evaluate for persistent or recurrent lymphoma.

T-cell lymphoma is rare in Australia with B-cell Lymphoma being by far the most common type. There are many different types of T-cell Lymphoma and each of them is rare. Statistics from the American Cancer Society show that in the US 85 per cent of non-Hodgkin lymphomas are B-cell lymphomas with T-cell lymphomas accounting for the remaining 15 per cent.  In Australia, the figures can be expected to be similar.

For additional details about T-cells and this testing, read more.

 

How is the sample collected for testing?
A bone marrow, lymph node, or other tissue sample is collected through a biopsy procedure. Body fluid samples are obtained through collection of the fluid in a container by inserting a needle into the body cavity and aspirating a portion of the fluid with a syringe. Sometimes, a blood sample is obtained by inserting a needle into a vein in the arm. 
 
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
 

The Test

How is it used?

T-cell receptor gene rearrangement testing is used to help diagnose T-cell lymphomas and to evaluate for residual or recurrent disease after treatment.

Lymphomas arise when an abnormal T-cell begins to produce numerous identical copies of itself (clones). The cloned cells grow and divide uncontrollably, crowding out normal cells. There are many different types of T-cell lymphoma and each has different characteristics, prognosis, and a likely response to therapy. Several classification systems have been used to describe them. The most recent is the World Health Organization's. (For more on this, see the Lymphoma condition page.)

Testing for T-cell lymphomas is done in a step-wise fashion and typically starts with:

  1. Full Blood Count (FBC) and a WBC differential to evaluate the number, types, and maturity of white blood cells present in the blood. Results may reveal an increased number of lymphocytes and/or presence of abnormal lymphocytes.
  2. A pathology evaluation of blood filmbone marrow, lymph node, skin and/or other tissue biopsy samples is performed. These samples are examined under a microscope by a specialist pathologist or scientist.
  3. If indicated, immunophenotyping is performed on blood, bone marrow, or other tissue (such as an enlarged lymph node or tumour) using a method such as flow cytometry or immunohistochemistry. This test detects the presence or absence of certain markers on the membrane of the cells or inside the cells. These commonly used markers are called clusters of differentiation (CD) and are listed numerically. Patterns of antigens (presence or absence) can provide information as to whether the T-cells are clones (monoclonal) and can further help classify a T-cell lymphoma.

A proliferation of T-cells can be benign or malignant. If, after the above tests are performed, there is still no conclusion as to whether a person has a benign or malignant T-cell population, a T-cell receptor gene rearrangement test can be performed.

Testing may sometimes be performed to evaluate the effectiveness of lymphoma treatment - to detect residual or recurrent disease as evidenced by the continued presence of abnormal monoclonal T-cells.
 

When is it requested?

Testing is performed when a person has signs and symptoms that suggest a lymphoma, such as:
  • One or more swollen but painless lymph nodes—depending on the site of the affected lymph node, symptoms may involve areas of the chest, armpit, neck, abdomen, or groin area, for example.
  • Skin lesions
  • Enlarged spleen and/or liver
  • Fatigue
  • Fever
  • Night sweats
  • Unexplained weight loss

Findings from a FBC and differential may be the first indication that a person might have a lymphoma as symptoms may be absent, mild, or nonspecific.

Testing may be done when other laboratory tests indicate that a lymphoma may be present and/or when other tests are inconclusive. Some examples include:

Testing can also be ordered when someone has been treated for a lymphoma to evaluate the effectiveness of treatment and to detect residual or recurrent disease.

What does the test result mean?

Results of testing are typically interpreted by a haematologist – a pathologist who specialises in blood, blood cells, and bone marrow cells (haematopathology). Results must be interpreted in the context of clinical findings, and other test results including histopathology, immunophenotyping information. They must take into account the range of findings that can be found in a "normal" lymphocyte cell population.

This testing helps confirm whether a clonal population of T-cell lymphocytes is present and helps confirm and/or clarify a person's diagnosis. In general, if a significant clonal T-cell population is detected and other associated tests are in agreement, it is likely that the person tested has a T-cell lymphoma or that lymphoma has recurred.

Examples of lymphomas that may be detected by this testing include:

  • Adult T-cell leukemia/lymphoma (ATLL)
  • Anaplastic large-cell lymphoma
  • Angioimmunoblastic T-cell lymphoma
  • Enteropathy-associated T-cell lymphoma
  • Hepatosplenic T-cell lymphoma
  • Mycosis fungoides
  • Peripheral T-cell lymphoma, unspecified
  • Precursor T-cell neoplasm (T lymphoblastic leukemia/lymphoma)
  • Sézary syndrome
  • T-cell large granular lymphocytic leukemia
  • T-cell prolymphocytic leukemia

Is there anything else I should know?

In 2011, 5237 new cases of lymphoma were diagnosed in Australia. Non-Hodgkin lymphoma is more common, with 4631 new cases diagnosed in 2011, compared with 606 cases of Hodgkin lymphoma. The risk of being diagnosed with non-Hodgkin lymphoma by age 85 is 1 in 41. The risk of being diagnosed with Hodgkin lymphoma by age 85 is 1 in 412. The majority of these cases (about 85 per cent) will be due to B-cell lymphomas; almost 15 per cent will be T-cell lymphomas.

Testing may need to be repeated when the sample does not contain enough DNA to test or if the sample is not suitable for testing.

The detection of a clonal T-cell receptor gene rearrangement is not synonymous with the presence of T-cell lymphoma. Someone may have a clonal T-cell population and not have cancer. Conditions such as autoimmune disorders, certain infections, immune suppression, and immune deficiencies are sometimes associated with small clonal T-cell populations. This means that one or more groups of cloned T-cells may be present in a person's lymphocyte population without it being considered a lymphoma.

If someone is negative for a clonal T-cell receptor gene rearrangement, they may still have lymphoma. A test may also be negative if the test method is not sensitive enough to detect the rearrangement or if the clonal lymphocytes have mutations that are not detected by the test, or if the lymphoma is of the B-cell type.

Since false positive and false negative results can be associated with the testing, the results must be interpreted in the context of other clinical and pathologic findings.

Common Questions

Should everyone with a T-cell lymphoma have T-cell receptor gene rearrangement testing?

No. This testing is required only if routine diagnostic procedures are insufficient to make an accurate diagnosis.

Can results of testing be used to determine the course of the cancer (prognosis)?

No. A positive testing result only helps to confirm a diagnosis of T-cell lymphoma. The cancer progression and response to treatment is generally determined by the type of a person's lymphoma, but will also vary from person to person.

Where is T-cell receptor gene rearrangement testing performed?

This testing requires specialised equipment and interpretation. It is not offered by every laboratory and samples will often need to be sent to a reference laboratory.

Last Review Date: July 30, 2016