The expression of growth hormone and insulin-like growth factor I recepter mRNAs in brai]tumors and tumor proliferation

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The expression of growth hormone(GH) and insulin-like growth factor I(IGF-I) receptor mRNAs in brain tumors, and tumor proliferation.The relationship between the expression of GH receptor (GH-R) and IGF-I receptor (IGF-I R)mRNAs, and tumor proliferation has not been elucidated in human brain tumors. We investigated the expression of these receptors in 22 cases of astrocytic tumor and 20 cases of meningioma using not only reverse transcription-PCR(RT-PCR) but also immunohistochemical technique. In 22 case of astrocytic tumor, 11 cases were low grade astrocytoma and the rest were high grade one. Using RT-PCR,GH-R mRNA was found in 95% of meningiomas and in 86.4% of astrocytic trumors. IGF-I-R mRNA was found in 80% of meningiomas and in 91.0% of astrocytic tumors. GH-R and IGF-I-R mRNA in astrocytic tumors were expressed not only in high grade astrocytomas but also in low grade astrocytomas. Statistically, there were no significant relationship between the expression of these mRNAs and histological grade. In immunohistochemical study using frozen tissue, the distribution of IGF-I-R was diffusely recognized in the cytoplasm of meningioma cells and astrocytic tumor cells. On the other hand, IGF-I-R could not be detected in the tumor cells using paraffin embedded tissue. These results demonstrated the existence of IGF-I-R and GH-R in human astrocytic tumors and meningiomas. These receptors may play a role in the tumor cell proliferation and growth, and it is possible that not only IGF-I-R but also GH itself are one of growth accelerating factors in astrocytic tumors and meningiomas.We are now investigating the distribution of GH-R and IGF-I-R mRNAs in brain tumors using in site hybridization technique.