Growth patterns, ultrastructure, and chromosomal constitution of normal kidney and nephroblastoma cells in short-term...

Nephrectomies were performed on four children with nephroblastomas (Wilms' tumor). Tumor tissue and normal kidney tissue were taken from each patient and were cultured. The in vitro characteristics of the cultured cells were then compared with their known in vivo characteristics. The normal kidney cells showed uniform cell morphology, had a relatively slow and orderly growth pattern and had the usual diploid chromosomal constitution. The tumor cells on the other hand were irregular in morphology and had a rapid and disorderly growth pattern. Electron microscopic examination confirmed the variation in the tumor cell morphology. In addition, microfilaments were seen to be abnormally abundant in many of the cells and some cells contained membrane-bound granules. Desmosomes were absent. Chromosome analyses showed cells from three of the nephroblastoma samples to maintain a constant hyperdiploid karyotype during the first few passages in vitro, whereas the normal kidney cells continued to have the normal diploid karyotype. Our study suggests that nephroblastoma and normal kidney cells are stable in culture, that is they retain most of their cellular characteristics in vitro and do not undergo rapid dedifferentitation in short-term culture.