Establishment of an epithelioid malignant schwannoma cell line (YST-1)

A novel cell line, YST-1, was established from an epithelioid malignant schwannoma (EMS) that occurred in the upper arm of an 8-year-old girl. YST-1 cells were polygonal and stellate in shape, contained abundant free ribosomes, mitochondria, lysosomes and rough-surfaced endoplasmic reticulum, and grew stably with a population doubling time of 40 h. Immunohistochemically, vimentin, S100 protein and S100 protein beta subunit were positive in the cytoplasm. The xeno-transplanted tumor in nude mice was composed of cells with an epithelioid arrangement similar to the original tumor. The borders of the tumor cells were connected intimately without desmosomal junctions, and there were abundant organelles in the cytoplasm. YST-1 cells were considered to be of value for studying the nature and histogenesis of EMS.