野生型胃肠道间质瘤的研究进展

胃肠道间质瘤(GIST)是最常见的消化道间叶组织来源肿瘤,约10%的GIST患者分子检测无KIT/PDGFRA基因突变,称为野生型GIST。根据是否有琥珀酸脱氢酶B(SDHB)表达缺失,野生型GIST可分为SDH缺陷型和非SDH缺陷型,SDH缺陷型包括无综合征相关性、Carney三联征相关性及Carney-stratakis综合征相关性GIST;非SDH缺陷型包括BRAF突变、Ⅰ型神经纤维瘤病相关性、K/N-RAS突变及四重野生型GIST等。野生型GIST的发生发展、临床病理特征和治疗原则均与KIT或PDGFRA突变的GIST有较大差异。本文就野生型GIST的分子机制和临床诊疗进展做一综述。     

腹腔镜"蘑菇状"剜除术治疗外生性肾血管平滑肌脂肪瘤的临床应用

目的对比研究腹腔镜下外生性肾血管平滑肌脂肪瘤"蘑菇状"剜除与标准肾部分切除术的安全性及有效性，为肾血管平滑肌脂肪瘤腹腔镜下"蘑菇状"剜除术术式的建立提供临床依据。 方法选取海南医学院第二附属医院与解放军总医院2018年1月至2019年5月期间，接受腹腔镜手术的肾血管平滑肌脂肪瘤患者53例，其中25例沿肿瘤假包膜行"蘑菇状"剜除术(A组)、28例行肾部分切除术(B组)。比较两组手术患者的肾动脉阻断时间、手术时间、术中出血量、术后24 h血红蛋白、术后eGFR(estimated glomerular filtration rate,估计肾小球率过滤)的变化、术后住院时间和术后肿瘤复发率。 结果53例手术无术中转开放，无死亡病例。肾动脉阻断时间：A组(11.9±2.2)min、B组(21.5±6.5) min(P<0.001)。手术时间：A组(87.9±24.8)min、B组(114.3±38.9) min(P<0.001)。术中出血量：A组20 ml(20～40)ml、B组50 ml(50～100)ml(P<0.001)。术后24 h血红蛋白变化：A组(7.4±4.3) g/L、B组(12.4±8.8) g/L(P＝0.013)。术后24 h eGFR变化：A组(6.2±7.2 )ml(min·1.73 m²)，B组(12.7±12.8)ml(min·1.73 m²)(P＝0.027)。术后6个月eGFR变化：A组(1.5±3.7)ml(min·1.73 m²)、B组(6.5±5.6)ml(min·1.73 m²)(P<0.001)。术后住院时间：A组4.0 d(3～4)d、B组4.5 d(3～6)d(P＝0.023)。术后随访两组术后肿瘤均无复发。 结论采用腹腔镜"蘑菇状"剜除术治疗外生性肾血管平滑肌脂肪瘤在肾动脉阻断时间、术中出血量、术后24 h血红蛋白、术后eGFR变化、术后住院时间等方面均优于传统肾部分切除术，两组术后肿瘤均无复发；该方法安全、有效，适于临床推广。     

Agminated fibroblastic connective tissue nevus in a 1‐year‐old boy

Fibroblastic connective tissue nevus (FCTN) is a benign cutaneous mesenchymal lesion characterized by proliferation of CD34‐positive fibroblastic/myofibroblastic spindle‐shaped cells. We report a case of agminated FCTN on the right lower abdomen of a 1‐year‐old boy.     

Relationship between MLH1, PMS2, MSH2 and MSH6 gene-specific alterations and tumor mutational burden in 1057 microsatellite instability-high solid tumors

Microsatellite instability-high (MSI-H) and tumor mutational burden (TMB) are predictive biomarkers for immune-checkpoint inhibitors (ICIs). Still, the relationship between the underlying cause(s) of MSI and TMB in tumors remains poorly defined. We investigated associations of TMB to mismatch repair (MMR) protein expression patterns by immunohistochemistry (IHC) and MMR mutations in a diverse sample of tumors. Hypothesized differences were identified by the protein/gene affected/mutated and the tumor histology/primary site. Overall, 1057 MSI-H tumors were identified from the 32 932 tested. MSI was examined by NGS using 7000+ target microsatellite loci. TMB was calculated using only nonsynonymous missense mutations sequenced with a 592-gene panel; a subset of MSI-H tumors also had MMR IHC performed. Analyses examined TMB by MMR protein heterodimer impacted (loss of MLH1/PMS2 vs. MSH2/MSH6 expression) and gene-specific mutations. The sample was 54.6% female; mean age was 63.5 years. Among IHC tested tumors, loss of co-expression of MLH1/PMS2 was more common (n = 544/705, 77.2%) than loss of MSH2/MSH6 (n = 81/705, 11.5%; P < .0001), and was associated with lower mean TMB (MLH1/PMS2: 25.03 mut/Mb vs MSH2/MSH6 46.83 mut/Mb; P < .0001). TMB also varied by tumor histology: colorectal cancers demonstrating MLH1/PMS2 loss had higher TMBs (33.14 mut/Mb) than endometrial cancers (20.60 mut/Mb) and other tumors (25.59 mut/Mb; P < .0001). MMR gene mutations were detected in 42.0% of tumors; among these, MSH6 mutations were most common (25.7%). MSH6 mutation patterns showed variability by tumor histology and TMB. TMB varies by underlying cause(s) of MSI and tumor histology; this heterogeneity may contribute to differences in response to ICI.     

A perivascular niche in the bone marrow hosts quiescent and proliferating tumorigenic colorectal cancer cells

Disseminated tumor cells (dTCs) can frequently be detected in the bone marrow (BM) of colorectal cancer (CRC) patients, raising the possibility that the BM serves as a reservoir for metastatic tumor cells. Identification of dTCs in BM aspirates harbors the potential of assessing therapeutic outcome and directing therapy intensity with limited risk and effort. Still, the functional and prognostic relevance of dTCs is not fully established. We have previously shown that CRC cell clones can be traced to the BM of mice carrying patient-derived xenografts. However, cellular interactions, proliferative state and tumorigenicity of dTCs remain largely unknown. Here, we applied a coculture system modeling the microvascular niche and used immunofluorescence imaging of the murine BM to show that primary CRC cells migrate toward endothelial tubes. dTCs in the BM were rare, but detectable in mice with xenografts from most patient samples (8/10) predominantly at perivascular sites. Comparable to primary tumors, a substantial fraction of proliferating dTCs was detected in the BM. However, most dTCs were found as isolated cells, indicating that dividing dTCs rather separate than aggregate to metastatic clones—a phenomenon frequently observed in the microvascular niche model. Clonal tracking identified subsets of self-renewing tumor-initiating cells in the BM that formed tumors out of BM transplants, including one subset that did not drive primary tumor growth. Our results indicate an important role of the perivascular BM niche for CRC cell dissemination and show that dTCs can be a potential source for tumor relapse and tumor heterogeneity.     

营养风险与腹膜后肿瘤患者住院时间的相关性研究

目的 探讨营养风险与腹膜后肿瘤患者住院时间的相关性。方法 采用回顾性研究，选取2012年1月至2018年12月四川大学华西医院血管外科新入院腹膜后肿瘤患者60例，采用营养风险筛查表评估患者营养风险，收集患者体质指数、围术期血红蛋白和白蛋白水平、住院天数、术后恶心呕吐发生情况、术后排气、排便时间和首次进食时间。采用单因素分析比较不同患者住院时间，采用多重线性逐步回归分析患者住院时间的影响因素。结果 纳入的60例腹膜后肿瘤患者中，40例患者（66.7%）术前存在营养风险，52例患者（86.7%）术后存在营养风险；单因素分析显示，患者术前、术后营养风险 （术前P<0.001，术后P=0.043）、术前白蛋白 （P=0.019）、术后血红蛋白 （P=0.019）、术后白蛋白（P=0.025） 水平以及术后恶心呕吐 （P=0.001） 均会影响患者的住院时间；患者住院时间与围术期营养风险筛查工具评分、术后首次进食时间、术后排气时间和排便时间具有相关性，且相关性强（r=0.759~0.770； P<0.01）；多因素分析显示术前营养风险是腹膜后肿瘤患者住院时间的重要预测因素（β=0.399）。结论 术前营养风险是腹膜后肿瘤患者住院时间的预测因子。     

Emerging from their burrow: Hedgehog pathway inhibitors for cancer

Introduction: Cancer treatment is moving away from conventional cytotoxic drugs and towards agents that target specific proteins and mechanisms important to cancer development or survival. The Hedgehog Pathway (HhP) is a signal transduction pathway and its constitutive activation is tumorigenic in basal cell carcinoma (BCC). The HhP enables phenotypic flexibility, and channels tumor-stroma interactions. As a result, it is over-expressed in numerous cancers as well as in the tumor microenvironment and may represent a promising therapeutic target.

Areas covered: In this article, we review the rationale for targeting HhP and its role as an oncogenic driver, in tumor epithelial-to-mesenchymal transition (EMT), and in the tumor microenvironment and describe the results of preclinical and clinical studies involving HhP inhibitors.

Expert opinion: HhP activation plays an important role in both the tumor microenvironment and tumor EMT which can lead to treatment resistance for a number of different malignancies. In addition to standard use in BCC, several HhP inhibitors are in preclinical, early, and mid-stage clinical development for other solid and hematologic malignancies.     

Reflection of neuroblastoma intratumor heterogeneity in the new OHC-NB1 disease model

Accurate modeling of intratumor heterogeneity presents a bottleneck against drug testing. Flexibility in a preclinical platform is also desirable to support assessment of different endpoints. We established the model system, OHC-NB1, from a bone marrow metastasis from a patient diagnosed with MYCN-amplified neuroblastoma and performed whole-exome sequencing on the source metastasis and the different models and passages during model development (monolayer cell line, 3D spheroid culture and subcutaneous xenograft tumors propagated in mice). OHC-NB1 harbors a MYCN amplification in double minutes, 1p deletion, 17q gain and diploid karyotype, which persisted in all models. A total of 80–540 single-nucleotide variants (SNVs) was detected in each sample, and comparisons between the source metastasis and models identified 34 of 80 somatic SNVs to be propagated in the models. Clonal reconstruction using the combined copy number and SNV data revealed marked clonal heterogeneity in the originating metastasis, with four clones being reflected in the model systems. The set of OHC-NB1 models represents 43% of somatic SNVs and 23% of the cellularity in the originating metastasis with varying clonal compositions, indicating that heterogeneity is partially preserved in our model system.     

NRP-1单克隆抗体对乳腺癌裸鼠移植瘤生长的影响

 目的 探讨NRP-1单克隆抗体（NRP-1 MAb）的特异性，以及不同剂量的NRP-1 MAb治疗乳腺癌裸鼠移植瘤的疗效。方法 Western blot和共聚焦免疫荧光法检测NRP-1 MAb是否识别MCF7细胞上NRP-1蛋白。将MCF7细胞接种于BALB/c裸鼠皮下建立乳腺癌细胞移植瘤模型，并进行瘤组织传代。传代的肿瘤体积生长至300~500 mm3时，随机分为对照组、NRP-1 MAb低剂量组、中剂量组和高剂量组，每组6只，给药7次。观察荷瘤裸鼠一般状况，测量瘤体大小及裸鼠体重。实验结束时剥离瘤体称重，提取组织蛋白，Western blot检测组织中VEGF蛋白和NRP-1蛋白的表达量。结果 NRP-1MAb成功识别MCF7细胞上的NRP-1蛋白；NRP-1 MAb能够有效抑制MCF7细胞裸鼠移植瘤的生长，低剂量组（1 mg/kg）抑瘤率为47.01%，中剂量组（5 mg/kg）抑瘤率为65.70%，高剂量组（10 mg/kg）抑瘤率为69.19%。。结论 NRP-1 MAb能够识别并有效结合MCF7细胞膜上的NRP-1蛋白，且可抑制MCF7细胞移植瘤的生长，NRP-1 MAb抑制移植瘤的增长可能与下调NRP-1和VEGF表达有关。