Evaluation of 06-methylguanine-DNA methyltransferase expression in children and adolescent pituitary adenoma

Abstract BackgroundTemozolomide can be used in the treatment of pituitary adenoma. Its efficacy can be evaluated by the expression of 06-methylguanine-DNA methyltransferase (MGMT). However, the previous study population was mainly adult. This study was the first to evaluate the expression of MGMT in children and adolescents with pituitary adenomas.MethodsThe clinical features and biological characteristics of 38 cases of pituitary adenoma in children and adolescents were analyzed retrospectively. The expression of MGMT, Ki-67, p53 was marked by immunohistochemical staining.ResultsIn this cohort, the expression of MGMT protein is 16/38 (42.11%). The low expression rate of MGMT in children and adolescent somatotroph adenomas was only 11.11%, which was much lower than that of adults. Ki-67 expression range of 1% -10%（mean 4.24 ± 2.71%）. The positive rate of p53 was 22/38 (57.89%). The statistical analysis showed that the expression of MGMT was related to the diameter of the tumor (P=0.01), the diameter of the tumor was large, and the expression of MGMT was high. The expression of MGMT was not associated with age, sex, tumor type, invasiveness, texture, apoplexy, recurrence, and expression of p53 and Ki-67.ConclusionSomatotroph adenomas, large-diameter children and adolescent pituitary adenomas may be not suitable for temozolomide treatment. To determine whether temozolomide responds to salvage therapy in children and adolescents with pituitary adenomas, MGMT expression should be assessed in all pituitary adenomas, the time span between specimen collection and temozolomide treatment needs to be considered because of the instability of MGMT protein expression.