Table of Contents
Definition / general | Clinical features | Uses by pathologists | Microscopic (histologic) images | Positive staining - normal | Positive staining - disease | Negative stainingCite this page: Pernick N. CD7. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/cdmarkerscd7.html. Accessed January 15th, 2021.
Definition / general
- T cell cell surface protein that plays important role in T cell-B cell interaction in early lymphoid development
- Member of immunoglobulin superfamily at 17q25.2-25.3
- Membrane expression early during T cell development, before TCR rearrangement; persists until terminal stages of T cell development (OMIM #186820)
- Has costimulatory activity for T cells (Immunol Res 2001;24:31)
- Binds galectin-1 and is essential for galectin-1-mediated T-cell death; loss of CD7 expression and altered cellular glycosylation may contribute to apoptosis resistance in mycosis fungoides (Mod Pathol 2003;16:543)
Clinical features
- Positive expression is a negative prognostic marker:
- Myeloid malignancies (Blood 2008;111:1067, Int J Hematol 2010;91:303)
- Epidermotropic CD8+ cytotoxic T cell lymphoma (Clin Exp Dermatol 2012;37:128)
- Loss of expression a negative prognostic marker:
- Acute myelogenous leukemia with FLT3/ITD mutation (Am J Clin Pathol 2008;129:624)
- Adult T cell leukemia / lymphoma (Histopathology 2009;54:214)
- Aggressive NK cell lymphoma (Korean J Lab Med 2009;29:491)
- HTLV1 (PLoS One 2013;8:e53728)
- Downregulated in infectious mononucleosis (Am J Clin Pathol 2003;120:49)
Uses by pathologists
- Marker for T-ALL
- CD7 and CD33 may be useful to quantify lymphocyte subsets (Cytometry A 2013;83:316)
Microscopic (histologic) images
Positive staining - normal
- Thymocytes, mature T cells (85%), NK cells (majority, Blood 2009;114:4823)
- Also monocytes, pluripotent hematopoietic progenitor cells, early myeloid cells, pre-B cells
Positive staining - disease
- T-ALL (very good marker) and other malignant immature T cells, CD7+ stem cell lymphoma (Am J Surg Pathol 2003;27:1366)
- NK lymphoma, but expression lost in aggressive NK cell lymphoma (Korean J Lab Med 2009;29:491)
- Chronic myelogenous leukemia, Down syndrome associated transient myeloproliferative disorder and AML (Am J Clin Pathol 2001;116:204), AML (some), lymphocyte rich thymoma (Am J Clin Pathol 2004;121:268)
- Cholangiocarcinoma, epithelioid sarcoma, pancreatic ductal carcinoma (Am J Clin Pathol 2003;120:64)
- T cells in classical Hodgkin lymphoma (Cytometry B Clin Cytom 2009;76:169), but Reed-Sternberg cells are negative (Mod Pathol 2005;18:1542)
- Rarely B cell lymphomas (Am J Clin Pathol 2001;115:396)
Negative staining
- Mature B cells, basophils, granulocytes
- B cell ALL, mycosis fungoides, adult T cell leukemia / lymphoma (Histopathology 2009;54:214)