SALL4

SALL4 is a protein that helps control the growth and development of cells, particularly during early human development. It is usually found in stem cells, which are special cells capable of turning into different types of tissues in the body. In adults, SALL4 is mostly seen in certain reproductive cells and tissues.

Why do pathologists test for SALL4?

Pathologists test for SALL4 to help identify specific types of tumours, particularly those that originate from germ cells (cells involved in reproduction). Testing for SALL4 helps distinguish these germ cell tumours from other tumours, aiding in accurate diagnosis and treatment planning.

How do pathologists test for SALL4?

Pathologists use a technique called immunohistochemistry to test for SALL4. In this test, a thin slice of tissue is placed on a microscope slide and treated with special antibodies that specifically attach to the SALL4 protein if it is present. A chemical reaction then produces a visible colour change. Under the microscope, pathologists determine if the cells show this colour change. Cells showing the presence of SALL4 are called “positive,” while those without it are described as “negative.”

What types of normal cells and tissues will be positive for SALL4?

In normal tissues, SALL4 is mainly found in germ cells, which are present in reproductive organs such as the ovaries and testicles. It is also found in embryonic stem cells, which play a role during early development. Generally, adult tissues outside of reproductive organs do not show SALL4 positivity.

What types of tumours will be positive for SALL4?

Tumours that originate from germ cells typically test positive for SALL4. Examples include germ cell tumours such as seminoma, embryonal carcinoma, yolk sac tumour, and dysgerminoma. Additionally, some non-germ cell cancers, such as certain liver cancers (hepatoblastoma) and rare tumours of the ovary or testicle, can also show SALL4 positivity. Tumours that do not arise from germ cells typically test negative for SALL4.