Estramustine-binding protein (
EMBP) is a
glycoprotein shown to be expressed in the cytoplasm of
astrocytoma cells. Originally, it was found in rat prostatic tissue and described as a secretory
protein. Its expression has been demonstrated to positively correlate with the degree of neoplastic transformation in
astrocytoma tissue.
EMBP has been proposed to be responsible for a specific and high affinity binding of
estramustine in
astrocytoma tumor tissue. In this study the expression of
EMBP was evaluated by immunohistochemistry and radioimmunoassay in a series of
astrocytoma of different grades. Staining intensity and the number of stained cells increased with the degree of
malignancy. The levels of
EMBP were 1.3-6.2 ng/g
tumor tissue with higher levels in
tumors of grade III to IV compared to grade I and II. It was found that a high expression of
EMBP always implied a short survival of the patients. On the other hand, a low expression of
EMBP did not always assure a favorable prognosis. It is proposed that
EMBP might have a value to predict survival in patients with
astrocytoma, especially if
estramustine is to be included in the treatment schedule. However, further extended studies are needed before final conclusions can be made.