MALIGNANT SCHWANNOMA-DERIVED CELLS SUPPORT HUMAN SKIN MAST-CELL SURVIVAL IN-VITRO

We have recently observed mast cell infiltration in malignant schwanno ma (MS) arising in the patient with von Recklinghausen's disease. To d etermine the cell to cell interactions between human skin mast cell (H SMC) and MS cell, we investigated the HSMC survival and the morphologi cal changes when cultured with MS-derived cells isolated from the pati ent. Partially purified HSMCs obtained from normal adult skin and cuta neous neurofibroma by enzymatic digestion were cocultured with MS-deri ved cells on the coverslips. The number of HSMCs stained with crystal violet were directly counted by light microscope. HSMCs cocultured wit h MS-derived cell feeder layer revealed significantly increased HSMC s urvival compared to that with normal human skin fibroblast layer at 1 and 2 weeks. Conditioned medium of cultured MS-derived cell did not in fluence HSMC survival. In the morphology HSMCs cultured with MS-derive d cells demonstrated spindle form in close contact with the adjacent M S-derived cells, suggesting cell to cell interactions. We failed to de tect stem cell factor (SCF) mRNA in cultured MS-derived cell by RT-PCR . These results suggest that MS-derived cell is capable by supporting HSMC survival in vitro. Some factor(s) other than SCF, which is associ ated with direct contact between HSMCs and MS-derived cells, might rel ate to these observations. (C) 1998 Elsevier Science Ireland Ltd.