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.