Expression of leukemia inhibitory factor in craniopharyngioma

It has recently been reported that overexpression of leukemia inhibitory fa ctor (LIF) in mice transgenic for LIF causes invagination of the anterior w a II of Rathke's pouch reading to the formation of cysts lined by LIF immun oreactive epithelial cells. Strong immunoreactivity was also found in human Rathke's cleft cysts. Because such cysts and craniopharyngiomas share a co mmon histogenesis, we raised the question of whether LIF is also expressed in craniopharyngioma. Fourteen histologically verified craniopharyngiomas of adamantinomatous typ e were examined for LIF immunoreactivity using the streptavidin-biotin-pero xidase complex method, Rabbit-anti-LIF antibody dilution 1:40) was applied to tissues having undergone antigen retrieval (microwaving in citrate buffe r at pH 6). For positive control, nontumorous pituitary tissues were used. Primary anti body substituted with phosphate-buffered saline served as a ne gative control. By immunocytochemistry, the epithelial cells of all 14 craniopharyngiomas w ere LIF immunoreactive, showing varying degrees of staining intensity. In c omparison, the connective tissue components of the tumors were immunonegati ve. Our study provides evidence that LIF is expressed in the epithelial cells o f craniopharyngioma. Further investigation is required to elucidate the pos sible role of LIF in the development and progression of craniopharyngiomas.