Test Catalog

Test ID: FOXP3    
FOXP3 Immunostain, Technical Component Only

Useful For Suggests clinical disorders or settings where the test may be helpful

Classification of leukemias and lymphomas

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

FOXP3 is a transcription factor implicated in T-cell regulation, activation, and differentiation. FOXP3 has been shown to be a master control gene for the development and function of CD4+/CD25+ regulatory T cells. In normal lymphoid tissues, a T-cell subset in interfollicular areas shows nuclear staining. FOXP3 is a specific marker for adult T-cell leukemia/lymphoma (ATLL).

Interpretation Provides information to assist in interpretation of the test results

This test includes only technical performance of the stain (no pathologist interpretation is performed). Mayo Clinic cannot provide an interpretation of tech only stains outside the context of a pathology consultation. If an interpretation is needed, refer to PATHC / Pathology Consultation for a full diagnostic evaluation or second opinion of the case. All material associated with the case is required. Additional specific stains may be requested as part of the pathology consultation, and will be performed as necessary at the discretion of the Mayo pathologist.


The positive and negative controls are verified as showing appropriate immunoreactivity and documentation is retained at Mayo Clinic Rochester. If a control tissue is not included on the slide, a scanned image of the relevant quality control tissue is available upon request. Contact 855-516-8404.


Interpretation of this test should be performed in the context of the patient's clinical history and other diagnostic tests by a qualified pathologist.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

No significant cautionary statements

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Katho M, Katoh M: Human FOX gene family. Int J Oncol 2004 November;25(5):1495-1500

2. Karube K, Ohshima K, Tsuchiya T, et al: Expression of FOXP3, a key molecule in CD4CD25 regulatory T cells, in adult T-cell leukaemia/lymphoma cells. Br J Haematol 2004 July;126(1):81-84

3. Roncador G, Garcia JF, Garcia JR, et al: FOXP3, a selective marker for a subset of adult T-cell leukaemia/lymphoma. Leukemia 2005 December;19(12):2247-2253