垂体腺瘤中六氧-甲基鸟嘌呤-DNA-甲基转移酶的表达及其与垂体腺瘤侵袭性的关系

The Expression of MGMT in Pituitary Adenomas and its Association with Tumour Aggressiveness

目的通过检测垂体腺瘤中六氧-甲基鸟嘌呤-DNA-甲基转移酶(MGMT)的表达,了解MGMT在不同类型垂体腺瘤中的表达水平及其与垂体腺瘤侵袭性的关系。方法收集2011年10月至2012年8月在我院经病理证实的垂体腺瘤患者。采用免疫组织化学染色法检测肿瘤组织中MGMT的表达,并分析其在不同类型、不同功能垂体腺瘤中的表达差异。结果共138名患者纳入本项研究,其中大部分病变为无功能瘤(71%)和垂体大腺或巨大腺瘤(92.8%);43例(31.2%)病变为侵袭性垂体腺瘤,12例为复发性垂体腺瘤(8.7%)。79例病变判断为MGMT低表达,其表达与患者的性别、年龄,垂体腺瘤的大小、是否复发或侵袭生长无明显相关。MGMT在泌乳素瘤中低表达率明显高于无功能瘤组(P=0.025)和生长激素瘤组(P=0.043)。结论 MGMT的表达与垂体腺瘤侵袭性、有无复发无明显相关;其在泌乳素瘤中的低表达率明显高于其它类型垂体腺瘤,提示替莫唑胺可能是难治性泌乳素瘤的另一治疗方案。

Objective To determine the expression of O6-methylguanine-DNA methyltransferase （MGMT） in pituitary adenomas and its association with tumour aggressiveness. Methods From October 2011 to August 2012, all the patients with pathologically confirmed pituitary adenomas in our hospital were recruited for this study. The expression of MGMT in the tumor tissues was detected with immunohistochemistry. Results A total of 138 （including 71 male） patients participated in this study. The majority of the participants had nonfunctional （71%） and macroadenomas （92.8%）. Aggressive and relapsed pituitary adenomas accounted for 31.2% and 8.7% of the cases, respectively. Low MGMT expression was found in 79 cases. The MGMT expression had no significant associations with gender, age, aggressiveness and relapse of tumors. However, prolaetinomas were more likely to have low MGMT expression than nonfunctional adenomas （P=0. 025） and growth hormone adenomas （P=0. 043）. Conclusion The expression of MGMT has no associations with the aggressiveness and relapse of pituitary adenomas. Prolactinomas are more likely to have low expression of MGMT, which indicates that temozolomide might become an alternative treatment for aggressive and dopamine resistant prolactinomas.