Background: Papillary renal cell tumours (RCT) have been described as a genetic entity. Recently, papillary RCTs are divided into small (type 1) and large (type 2) cell tumours. Subsequent DNA analyses resulted in controversial data regarding putative genetic changes marking type 1 and type 2 tumours.
Aim: The aim of this study was to improve our original description, that papillary RCT is a genetic entity regardless of the phenotypic variation.
Methods: We have analysed DNA from 163 papillary RCTs including 82 multiplex tumours from 8 hereditary cases for copy number changes by chromosomal CGH and/or for allelic changes at chromosome 7 and 17 by microsatellites and compared the results of genetic analysis to the cytological characteristics of tumours.
Results: We have detected alterations of chromosome 7 and 17 at similar frequency in papillary RCTs from small to large cell characteristics, from nuclear grade 1 to 3 and from 3 mm to 16 cm in diameter in size.
Conclusion: Trisomies of chromosomes 7 and 17 are specific genetic alterations in papillary RCTs irrespectively of their size, grade and cellular differentiation.