Molecular cytogenetic anomalies and phenotype alterations in a newly established cell line from Wilms tumor with diffuse anaplasia

The novel continuous cell line WT-Pe.1 was established in vitro from Wilms tumor with histological features of diffuse anaplasia. The cultures grew as poorly differentiated epithelial-like cells with pleomorphic polygonal shapes and formation of typical monolayers. WT-Pe.1 cells were immunoreactive for cytokeratin, vimentin, laminin, villin, CD10, and CD24 proteins. Conventional cytogenetic analysis by RHG-banding revealed a hypotriploid karyotype with numerous abnormalities including ring chromosomes, double-minutes, homogeneous staining regions, radial structures, dicentrics, and several marker chromosomes. Comparative genomic hybridization analysis revealed DNA copy numbers losses on chromosome segments 1 p, 3 p, 6q, 9q34.1∼q34.3, 11q24∼q25, 14q12∼qter, 16q, 18q, and 22q11∼q13; gain of genomic material was localized on chromosome arms 1q, 4 p, 6q, and 7p and the entire chromosome 12. With DNA from the original tumor, copy number losses were detected on chromosomes 1 p, 14q, 16q, 17q, and 22q and gains were observed on 1q, 4p, 8q, 12p, 12q, and chromosome 14 p. Copy number amplifications of distinct loci were found on 1q21.1 and 4p15.3, as well as an elevated copy number of cyclin D2 (CCND2) and cyclin D associated kinase (CDK4) genes on chromosome 12 (confirmed by fluorescence in situ hybridization).