Immunohistochemical detection of prothymosin alpha in pituitary adenomas - A new marker of tumor recurrence?

Abstract

Forty pituitary adenomas were immunostained with an antibody raised against the C-terminal fragment (101-109) of human prothymosin alpha (PTα). The strong positive immunostaining was found in the subpopulation of cell nuclei and intratumoral vessel walls, while the cytoplasm of adenoma cells was slightly immunopositive. The significantly higher percentage of PTα-positive cell nuclei was found in recurrent pituitary adenomas as compared with primary tumors. However, there was no correlation between the percentage of PTα-positive cell nuclei and Ki-67 indices. Gonadotropinomas were characterized by higher nuclear PTα expression in comparison to other pituitary adenomas, which is probably linked with the high recurrence rate of these tumors. It is suggested that PTα immunostaining may be helpful in predicting the pituitary tumor recurrence. However, this conclusion needs to be confirmed in further prospective studies. Moreover, PTα may be also useful as an immunohistochemical marker of the intratumoral microvasculature. © Polish Histochemical et Cytochemical Society.