Yamada K, Kasama M, Kondo T, Shinoura N, Yoshioka M
Division of Genetics, National Medical Center Hospital, Tokyo, Japan.
Cancer Genet Cytogenet. 1994 Mar;73(1):46-52. doi: 10.1016/0165-4608(94)90180-5.
Chromosome analysis was performed on 70 brain tumors. Thirty-six tumors showed clonal karyotypes characterized by many autosomal abnormalities; 20 meningiomas revealed monosomy 22 as a consistent abnormality, and 12 gliomas showed various abnormalities frequently involving chromosomes 3, 7, and 22. Of the remaining 34 tumors, 24 had normal karyotypes and 10 had clonal cells with loss and/or an extra sex chromosome with single trisomy of chromosomes 3, 6, 7, or 14. Sex chromosome aneuploidy was mostly due to loss of the Y or an X chromosome and was observed in 25 tumors, usually together with autosomal abnormalities. In these tumors the average frequency of cells with sex chromosome aneuploidy was 52%, with a range from 12% to 100%. Loss of the Y was found significantly more frequently in tumors of aged patients. Chromosome analysis in materials subcultured for a long period showed a tendency for cellular selection in which clonal cells with many autosomal abnormalities disappeared rapidly and karyotypes having loss or an extra sex chromosome and/or trisomy 7 were present in an increasing proportion with advance of cell generations in vitro. We infer that the cells having loss of one sex chromosome or trisomy 7 have a proliferative advantage. And that cells bearing only these abnormalities may exist in normal brain tissue more abundantly than in any other body tissue. The possibility of tissue-specific aneuploid mosaicism in the normal tissue would allow an alternative interpretation for simple autosomal trisomy in solid tumors.
对70例脑肿瘤进行了染色体分析。36例肿瘤显示出以许多常染色体异常为特征的克隆核型；20例脑膜瘤显示22号染色体单体性为一致的异常，12例胶质瘤显示出各种异常，常涉及3号、7号和22号染色体。在其余34例肿瘤中，24例核型正常，10例有克隆细胞，伴有性染色体丢失和/或额外的性染色体，以及3号、6号、7号或14号染色体的单三体性。性染色体非整倍性主要是由于Y或X染色体的丢失，在25例肿瘤中观察到，通常与常染色体异常同时存在。在这些肿瘤中，具有性染色体非整倍性的细胞的平均频率为52%，范围为12%至100%。在老年患者的肿瘤中，Y染色体丢失的情况明显更常见。对长期传代培养的材料进行染色体分析显示出细胞选择的趋势，即具有许多常染色体异常的克隆细胞迅速消失，而具有性染色体丢失或额外的性染色体和/或7号染色体三体性的核型在体外细胞传代过程中所占比例越来越高。我们推断，丢失一条性染色体或7号染色体三体性的细胞具有增殖优势。而且，仅具有这些异常的细胞可能在正常脑组织中比在任何其他身体组织中更丰富地存在。正常组织中组织特异性非整倍体嵌合体的可能性将为实体瘤中单纯常染色体三体性提供另一种解释。
