Application Of Conventional Cytogenetics And Fluorescence In Situ Hybridization In Lung Cancer

Objective: Lung cancer is a major cause of cancers related morbidity and mortality. To detect the chromosomal abnormalities of lung cancer, we apply the technique of conventional cytogenetics (CC), fluorescence in situ hybridization (FISH) and Spectral karyotyping (SKY) in this study, in order to disclose the essential pathogenesis of lung cancer(LC) and to provide reliable evidence for clinical diagnosis and prognosis.Materials and Methods: The research was divided into three parts. In part one, 24 fresh lung tumor specimens from surgery were done by overnight culture (OC). Using R-banding to analyses the chromosomal aberrations. In part two, using interphase FISH , six centromeric probes for chromosome 8, 11, 12, 17, X and Y were performed to detect the numerical abnormalities. In part three, SKY skill was used in meterphase from two samples, to identify the origin of the complicated structural chromosomal abnormalities.Results: Our research found out that the OC of 24 tumor samples allowed us to gain karyotype in 10 samples (10/24,41.67%). An clonal abnormal karyotype was observed in 9 of the 10 samples. CC study has revealed various numerical and structural chromosomal aberrations. The modal number of chromosomes for the most LC was in the range of near-diploidy and near-triploidy. The most frequent numerical alterations of chromosome in our study were the gains of an extra copy of chromosome 8, 12,17, X,7,11, and the loss of chromosome 3,Y,13,5,9, and some marker chromosomes which unable to differentiate. In addition,we also found structural alterations of chromosome 1,2, 3, 4, 9, 11, 15, 17, including in partly duplication, deletion and derivative chromosome. As far as numerical aberrations were concerned, interphase FISH not only confirmed the gains or loss of chromosome X,8,11,12,17 and Y in metaphase cells, but also detected the gains or loss which counld not be found out by CC. SKY skill analysised two samples, the changes were basiclly corresponding with CC, and the structural alterations were involved in chromosomes 1,2,3,4,6,8,12,13,15,17, et al. The translocation between chromosome 3 and 17 , and the translocation involving in chromosome 13, were found each in two cases. So SKY skill can elucidate some origin of the complicated structural chromosomal abnormalities which can not be detected by CC.Conclusions: The technique of CC can be used to study chromosomal changes of lung cancer, but the success rate in identifying clonal abnormal karyotypes is not high, due to the low mitotic activity, poor quality of chromosomes and the complicated karyotypic abnormalities. Comparing with CC, interphase FISH has many merits such as simplicity, accuracy and rapidity. In addtion, it can not only prove the results found by CC, but also detecte much changes which could not be found out by CC. Especially SKY skill can disclose the origin of the chromosomal translocations and marker chromosomes which are not detected by CC. Molecular cytogenetics can be used with CC to elucidate the biological characteristics of LC. Thus it should provide the new scientific evidences for early clinical diagnosis, treatment and prognosis of LC.