恶性外周神经鞘瘤中PTEN表达及DNA倍体分析的意义

The Significance of PTEN Expression and DNA Ploidy Analysis in Malignant Peripheral Nerve Sheath Tumors

目的:通过检测第10号染色体上磷酸酶和张力蛋白同源缺失基因(PTEN)在恶性外周神经鞘瘤(malignant peripheral nerve sheath tumors,MPNST)中的表达,佐以流式细胞术对MPNST进行DNA倍体分析,研究两者与其临床生物学行为之间的关系。方法:对65例良、恶性外周神经肿瘤石蜡包埋组织应用免疫组化进行PTEN的检测,兼以流式细胞术行DNA倍体分析。结果:PTEN在良、恶性外周神经肿瘤中阳性表达有显著差异(χ2=17.628,P<0.001);PTEN阳性表达强度与MPNST的分化程度无相关性(rs=0.067,P=0.699)。MPNST发生异倍体4例,均为低异倍体(DI值<0.90);SPF、PI值在良、恶性外周神经肿瘤中有显著差别(χ2=28.674,P<0.001;χ2=23.730,P<0.001),且与MPNST病理组织学分级呈正相关(rs=0.418,P<0.01;rs=0.347,P<0.05);PTEN的阳性表达以及阳性表达强度与DNA倍体分析3项指标均无关联。结论:PTEN可以作为鉴别良、恶性外周神经肿瘤以及判断外周神经鞘瘤恶性程度高低的一个有价值的指标;异倍体的出现以及SPF、PI值的增高是判断MPNST恶性程度(演进与异质化)的重要标志。

Objective：Through studying the expressions of PTEN in malignant peripheral nerve sheath tumors （MPNST） and analyzing the DNA ploidy by the flow cytometry from the level of single cell, to explor the relations between them and the bio logic behaviors of MPNST. Methods： Using the method of immunohistochemistry, 65 cases of benign or malignant peripheral nerve sheath tumors were selected to examine PTEN indicator, all the samples were paraffin embedded. At the same time, the DNA ploidy of all these samples by flow cytometry were analyzed. Results： PTEN was expressed differently between benign and malignant peripheral nerve tumors and the difference was significant （X^2 = 17. 628, P〈0. 001 ）. The stronger expression of PTEN was positively related to the degree of the malignancy of MPNST （rs= 0. 067,P = 0. 699）. There were 4 aneuploidy in 42 cases of MPNST, and all the aneuploidy was low aneuploidy（DI〈0.90） ; SPF and PI index were also different between the benign and malignant peripheral nerve tumors, the differences were significant （ X^2 = 28. 674, P 〈 0. 001 ; X^2 = 23. 730, P 〈 0. 001）; SPF and PI index were also positive correlations with the histological grade of MPNST（rs = 0. 418,P〈0. 01;rs = 0. 347,P〈0.05） ; The degree and intension of the expression of PTEN was positively correlated to the three indexes of DNA ploidy analysis. Conclusion..PTEN can be used as a worthy factor to estimate the property of benign and malignant peripheral tumors and as a valuable indicator to estimate the degree of malignancy of MPNST. The appearance of the aneuploidy and high SPF,PI index can predict the malignant degree（progression and heterogeneity） of MPNST.