The association of ability to grow in vitro, non-random chromosome abnormalities, DNA ploidy and oncogene amplification with prognosis may lead to a better understanding of the biology of neuroblastomas. In a pilot study fresh tumour tissue was obtained from 4 consecutive patients at the Department of Paediatric Surgery, Rigshospitalet, Denmark. Chromosome abnormalities were detected in 3 out of 3 successfully karyotyped tumours, and one or more aneuploid stem lines were detected in 4 out of 4 tumours using flow cytometry. The N-myc oncogene was amplified in 1 out of 3 tumours tested. Continuous cell lines could be established from all 3 advanced stage tumours. This pilot study has shown that fresh tumour tissue can be obtained and successfully studied for various fundamental aspects of the biology of neuroblastomas.