Molecular cytogenetic characterization of nasopharyngeal carcinoma cell lines and xenografts by comparative genomic hybridization and spectral karyotyping

Nasopharyngeal carcinoma (NPC) cell lines and xenografts represent valuable models for functional and therapeutic studies on this common malignancy in Southeast Asia. The karyotypic information in most NPC cell lines and xenografts, however, remains largely unclear to date. We have characterized the chromosomal aberrations in six commonly used human NPC cell lines and xeno-rafts using the molecular cytogenetic technique of comparative genomic hybridization (CGH). Genomic imbalances identified in cell lines were further correlated with structural abnormalities indicated from spectral karyotyping (SKY) analysis. CGH revealed consistent overrepresentations of 8q (Six Out Of Six cases) with a smallest overlapping region identified on 8q21.1similar toq22. Other common gains included 7p (4/6 cases), 7q (4/6 cases). 12q (4/6) and 20q (4/6 cases), where minimal overlapping regions were suggested on 7p15similar top14 7q11.2similar toq21, and 12q22similar toq24.1. Common losses were detected on 3p12similar top21 (4/6 cases) and 11q14similar toqter (4/6 cases). Although SKY analysis on cell lines revealed predominantly unbalanced rearrangements, reciprocal translocations that involved chromosome 2 [i.e., t(1;2), t(2:3). and t(2;4)] were suggested. Furthermore, SKY examination illustrated additional breakpoints on a number of apparently balanced chromosomes. These breakpoints included 3p21, 3q26, 5q31, 6p21.1similar top25, 7p14similar top22. and 8q22. Our finding of regional gains and losses and breakpoints represents information that may contribute to NPC studies in vitro. (C) 2003 Elsevier Science Inc. All rights reserved.