ABSTRACT
Leukemia cell lines K562, KG1a, U937, HL60, Jurkat and solid tumor cell lines A549 and M4Beu are widely used in studies of cell cycle, apoptosis and adhesion mechanisms in cancer cells. Although the K562 and U937 cell lines were previously subjected to a detailed cytogenetic characterization, only a few molecular cytogenetic investigations have been performed on the other five cell lines. We combined several molecular cytogenetic techniques, such as fluorescence in situ hybridization (FISH), multicolor FISH (M-FISH), and comparative genomic hybridization (CGH) to demonstrate the precise genetic aberrations in tumor genomes of these seven cell lines. This information may be useful for multiple studies on these cell lines, providing a genetic basis for the interpretations of experimental findings.
Subject(s)
Chromosomes, Human/genetics , Cytogenetic Analysis/methods , Neoplasms/genetics , Neoplasms/pathology , Cell Line, Tumor , Chromosome Banding , DNA, Neoplasm/genetics , Humans , In Situ Hybridization, Fluorescence , K562 Cells , Karyotyping , Nucleic Acid Hybridization , U937 CellsABSTRACT
Benign and malignant thyroid tumors constitute a wide range of neoplasias showing recurrent chromosome abnormalities. Cytogenetic studies of thyroid hyperplasias and follicular adenomas revealed hyperdiplo d karyotypes with a characteristic sequence of trisomies (7, 5, 12, 14, 16, 17, 20 and 22) starting with trisomy 7. Comparative genomic hybridization (CGH) findings on thyroid oncocytic tumors showed similar chromosomal gains with no difference observed between adenomas and carcinomas. Follicular thyroid carcinomas exhibit losses of 3p25-pter predominantly or of 22,13 and 1p segments. Formation of fusion genes PAX8 - PPARgamma1 caused by a t(2;3)(q13;p25) has been observed in several cases of follicular carcinomas only. Loss of chromosome 22 has been found most frequently associated with widely invasive follicular carcinomas. Activation of the RET protooncogene through chromosome rearrangements involving subband 10q11.2 represent the most common and specific genetic alteration in papillary thyroid carcinoma. Several chimeric genes resulting in the fusion of the tyrosine kinase domain of RET with the 5' sequences of different genes have been described. Germline mutations in RET are associated with medullary thyroid carcinoma in multiple endocrine neoplasia type 2 (MEN2). Cytogenetics of thyroid tumors, using conventional and molecular methods (FISH, CGH) demonstrated that particular chromosome aberrations may be related to the clinical behavior of these tumors and may provide informations for their diagnosis or prognosis.
Subject(s)
Chromosome Aberrations , Thyroid Neoplasms/genetics , Adenoma/genetics , Carcinoma, Medullary/genetics , Carcinoma, Papillary/genetics , Humans , Hyperplasia/genetics , Thyroid Gland/pathologyABSTRACT
Since the establishment of human karyotype in 1956, human cytogenetic has quickly progressed. The description of the Philadelphia chromosome in 1960 led up to new applications of cytogenetic in the fields of hematology and oncology. The initial techniques allowed only uniform staining of chromosomes, limiting the detection of most structural rearrangements. Many approaches aimed to gain a better knowledge of chromosomal structure, a better understanding of rearrangements, and a better identification of the chromosomes were developed: autoradiography, banding techniques, electronic microscopy. Since 1980, new developments in clinical cytogenetic and molecular biology have occurred. In situ labeling using non-radioactive probes onto chromosomes and nuclei was developed: fluorescence in situ hybridization (Fish) was born. Fish allows detecting many chromosomal abnormalities of number and/or structure. The major limitation of this technique is that its use should be based on known indications for the choice of the probe. Multicolor karyotype (M-Fish or Sky), the most recent development of Fish on metaphase spreads, allows to overcome this limit. As shown here in three examples, M-Fish allows to describe precisely complex rearrangements in hematological malignancies and solid tumors. Finally, if no metaphase is available, comparative genomic hybridization (CGH) can be performed to detect and simultaneously localize on chromosomes gains or losses in genomic DNA.
