皮肤黑色素瘤基因突变类型及基因拷贝数变异分析

目的:对比肢端黑色素瘤(acral melanoma,AM)与非肢端黑色素瘤(non-acral melanoma,NAM)的基因突变类型及基因拷贝数变异(copy number variation,CNV)的差异,讨论并分析其基因突变类型及拷贝数变异的意义。方法:收集2018年1月至2021年1月新疆医科大学附属肿瘤医院收治的73例皮肤黑色素瘤患者的资料,所有患者均采用二代测序技术对46个癌症相关基因进行了全面的基因组检测。根据解剖部位分为肢端组(AMs)和非肢端组(NAMs),比较并讨论两组患者的临床病理特征、基因突变类型及CNV的差异。结果:两组患者在性别、年龄、肿瘤厚度、溃疡、淋巴结状态和分期等方面无显著性差异(P>0.05)。73例患者最常见的基因突变类型为BRAF突变(20.5%)、KRAS/NRAS突变(17.8%)、KIT突变(13.7%)。与AMs相比,NAMs的BRAF突变频率呈显著性差异(P<0.05)。年龄≤65岁的患者BRAF突变率与年龄>65岁的患者相比呈显著性差异(P<0.05)。此外,无溃疡的黑色素瘤比有溃疡的黑色素瘤更易出现BRAF突变(P<0.05)。两组患者中KRAS/NRAS和KIT突变率无显著性差异(P>0.05)。影响细胞周期畸变基因(CDK4/6、CCND1/2、CDKN2A)、受体酪氨酸激酶基因(EGFR、MET、ERBB2、ERBB3、PDGFRA)及抗细胞凋亡基因(BIRC2/3/5)的CNV在AMs和NAMs之间呈显著性差异(P=0.019、0.002、0.027)。结论:通过对AMs和NAMs基因突变类型及CNV的分析,能为深入了解皮肤恶性黑色素瘤致癌模式和临床病理特征提供帮助。

Primary Mg_(2)Si phase and Mg_(2)Si/α-Mg interface modified by Sn and Sb elements in a Mg-5Sn-2Si-1.5Al-1Zn-0.8Sb alloy

The microstructure of primary Mg_(2)Si and the interface of Mg_(2)Si/α-Mg modified by Sn and Sb elements in an as-cast Mg-5Sn-2Si-1.5Al-1Zn-0.8Sb(wt.%) alloy were investigated.In the primary Mg_(2)Si phase not only the Si atoms but also the Mg atoms could be substituted by Sn and Sb atoms,resulting in the slightly reduced lattice constant a of 0.627 nm.An OR of Mg_(2)Si phase and α-Mg in the form of[001]Mg_(2)Si‖[01■1]α,(220)Mg_(2)Si‖(0■12)αwas discovered.Between primary Mg_(2)Si phase and α-Mg matrix two transitional nano-particle layers were formed.In the rim region of primary Mg_(2)Si particle,Mg_(2)Sn precipitates sizing from 5 nm to 50 nm were observed.Adjacent to the boundary of primary Mg_(2)Si particle,luxuriant columnar crystals of primary Mg_(2)Sn phase with width of about 25 nm and length of about100 nm were distributed on the α-Mg matrix.The lattice constant of the Mg_(2)Sn precipitate in primary Mg_(2)Si particle was about 0.756 nm.Three ORs between Mg_(2)Sn and Mg_(2)Si were found,in which the Mg_(2)Sn precipitates had strong bonding interfaces with Mg_(2)Si phase.Three new minor ORs between Mg_(2)Sn phase and α-Mg were found.The lattice constant of primary Mg_(2)Sn phase was enlarged to 0.813 nm owing to the solution of Sn and Sb atoms.Primary Mg_(2)Sn had edge-to-edge interfaces with α-Mg.Therefore,the primary Mg_(2)Si particle and α-Mg were united and the interfacial adhesion was improved by the two nano-particles layers of Mg_(2)Sn phase.

Permian tectonic evolution and continental accretion in the eastern Central Asian Orogenic Belt:A perspective from the intrusive rocks

The tectonic evolution and history of continental accretion of the eastern Central Asian Orogenic Belt(CAOB)are not yet fully understood.In this study,we investigate Permian intrusive rocks from the Jiamusi Block of the eastern CAOB to constrain the tectonic evolution and continental accretion of this region during the late-stage evolution of the Paleo-Asian Ocean.Our new data show that Early Permian gabbro-diorites were derived from the partial melting of depleted mantle metasomatized by oceanic-slab-released fluids.Middle Permian adakitic granites have low Na2O and MgO and high K2O contents,indicating a thickened-lower-crust source.Late Permian S-type granites were derived from the partial melting of continental crust.A compilation of the available geochronological data for Permian intrusive rocks(including adakitic and A-,S-,and I-type granites and mafic rocks)from the eastern CAOB reveals that the A-type granites formed mainly during the Early–Middle Permian,S-type and adakitic granites mostly during the Middle–Late Permian,and I-type granites and mantle-derived mafic rocks throughout the Permian.The A-type granites,which are proposed to have been sourced from thinned continental crust,indicate an extensional setting in the eastern CAOB during the Early Permian.The Middle–Late Permian adakitic granites imply a thickened continental crust,which indicates a compressional setting.Therefore,the eastern CAOB underwent a transition from extension to compression during the Middle Permian,which was probably triggered by the late-stage subduction of Paleo-Asian oceanic crust.Considering the petrogenesis of the intrusive rocks and inferred regional tectonic evolution of the eastern CAOB,we propose that vertical underplating of mantle-and oceanic-slabderived magmas contributed the materials for continental crust accretion.