Abstract
Karyotyping was performed in 46 human renal cell carcinomas of various histological grades. Controls included chromosome analysis of normal renal parenchymal cells from the same patients. Various numerical chromosome aberrations were found as well as marker chromosomes. They are specific of the individual tumor but no single marker was identified occurring in all tumors tested. Only trisomy 3 was found in different tumors (31%),suggesting a more general character of this aberration. Histological dedifferentiation and large tumor size correlate with focusing of the karyotype towards distinct chromosomal modes indicative of distinct tumor cell subclones within these tumors. Their rapid growth, reflecting biological agressiveness, is most probably responsible for the patients’ poor prognosis.