SOX11 is a protein that works inside the nucleus of a cell to switch other genes on and off. Pathologists test for SOX11 mainly to help diagnose mantle cell lymphoma, a type of lymphoma made of small B cells. SOX11 is especially helpful in the small number of mantle cell lymphomas that do not show the usual marker, cyclin D1.
This article explains what SOX11 is, how pathologists use it to diagnose mantle cell lymphoma and other tumors, and what a SOX11 result in your pathology report means.
SOX11 is a protein that controls which genes are active in a cell, a type of protein called a transcription factor. It plays an important role before birth, helping the brain, nerves, and skeleton develop. Most mature cells in the adult body, including normal lymphocytes, do not make SOX11. This is why finding SOX11 in a group of lymphocytes is unusual and can point toward a specific type of lymphoma.
Pathologists test for SOX11 using immunohistochemistry, which uses antibodies to detect specific proteins in a thin slice of tissue. Cells that make SOX11 show a brown color inside the nucleus under the microscope. Normal lymphocytes in the same sample stay unstained, which helps the pathologist see whether the abnormal cells are positive.
SOX11 helps diagnose mantle cell lymphoma because, in most cases, the cancer cells express SOX11, while most other small B-cell lymphomas do not. The pathologist usually looks at SOX11 together with CD5, CD23, and cyclin D1. Typical patterns include:
Mantle cell lymphoma can be negative for SOX11 in one specific form. This form, called leukemic non-nodal mantle cell lymphoma, mainly involves the blood, bone marrow, and spleen rather than the lymph nodes. It often grows more slowly than typical mantle cell lymphoma. If your report describes a SOX11-negative mantle cell lymphoma, your doctor can explain whether this form applies to you.
SOX11 can also be positive in a few other blood cancers and some solid tumors, so the pathologist always interprets it alongside other markers. Examples include:
A SOX11 result in your report describes whether the abnormal cells make this protein. Your report may describe the result in one of a few ways: