Influence of epidermal growth factor and gastrin on the cell proliferation of human meningiomas versus astrocytic tumors maintained as ex vivo tissue cultures

The hormone sensitivity of a tumor is traditionally based on the presence of steroid receptors. Other factors should be taken into consideration. Here, we studied the influence of 10 nM epidermal growth factor (EGF) or gastrin on the proliferation of human ex vivo tumor cultures by means of [3H]thymidine autoradiography. The immunohistochemical EGF-receptor expression was also quantified by means of computer-assisted microscopy. The results demonstrated that the proliferation of 6/11 astrocytic tumors and 3/16 meningiomas was sensitive to at least one factor tested, i.e. EGF or gastrin (P < 0.01), and 5 of these 9 'hormone-sensitive' tumors were sensitive to both factors. The immunohistochemical labeling index for the EGF receptor was higher than 80% in 15/16 meningiomas, but only in 6/11 gliomas (P < 0.01). These results suggest that EGF and gastrin are important for astrocytic tumor proliferation and significantly (P < 0.01) less important for meningiomas. Thus, astrocytic tumors may be steroid insensitive in term of cell growth, but are certainly not hormone insensitive.