目的　研究垂体瘤间期细胞遗传性畸变 ,探讨其异常与垂体瘤发生和发展的关系。方法　应用荧光原位杂交技术研究了 5 0例垂体瘤间期细胞核 7、8、11染色体数目的异常。结果　6 4 % (32 / 5 0 )的垂体瘤出现一个以上染色体数量的变异 ,其中以 11染色体的异常最为常见 2 8% (14 /5 0 ) ,其余依次为 7染色体 2 2 % (11/ 5 0 )、8染色体 2 0 % (10 / 5 0 )。 7、8染色体的异常与垂体瘤的临床病理特征未见明显相关 ,但 11号单体与垂体瘤的侵袭性密切相关。结论　垂体瘤 7、8、11染色体变异是频繁发生的。 7、8染色体的获得可能参与了肿瘤形成的起始阶段 ,而 11号染色体的丢失可能与肿瘤的演进及生物行为有关。 Objective To study the cytogenetic aberrations in pituitary adenomas and to explore the relationship between abnormalities and the occurrence and development of pituitary tumors. Methods Fluorescence in situ hybridization (FISH) was used to study the chromosomal abnormalities of chromosome 7, 8 and 11 in 50 pituitary tumors. Results Sixty-four percent (32/50) of pituitary tumors showed more than one chromosome variation, of which 11 were the most common chromosomes, 28% (14/50), and the rest were 7 2% 5 0), chromosome 8 0% (10/50). The abnormality of chromosome 7 and 8 has no obvious correlation with the clinicopathological features of pituitary tumor, but the number 11 monomer is closely related to the invasiveness of pituitary tumor. Conclusions 7, 8, 11 chromosomal variation of pituitary tumor is frequent. Obtaining of chromosome 7 and 8 may be involved in the initial stage of tumor formation. The loss of chromosome 11 may be related to the evolution and biological behavior of the tumor.