Gastrointestinal stromal tumours (GISTs) negative for KIT (CD117 antigen) immunoreactivity

Gastrointestinal stromal tumours (GISTs) are currently defined as mesenchymal tumours of the gastrointestinal tract that express KIT receptor tyrosine kinase. However, a small subgroup of tumours that fulfil the clinical and morphological criteria for GISTs lack KIT expression. So far, the biological features of these tumours have rarely been addressed. The present study describes seven gastrointestinal stromal neoplasms that presented clinicopathological features typical of GISTs but showed absence of CD117 expression as detected by immunohistochemistry. The tumours originated from the stomach (n = 5), duodenum (n = 1), and colon (n = 1), showing histologically either predominantly epithelioid (n = 3), mixed spindled and epithelioid (n = 2), or anaplastic/spindle cell (n = 2) type features. CD34 and alpha-smooth muscle actin (alpha-SMA) positivity was present in four and three tumours, respectively. Chromosomal analysis was performed in two cases, both showing losses of chromosomes 14, 22, and 1p, which is the characteristic feature of GISTs. Dual-colour interphase fluorescence in situ hybridization (FISH) analysis, utilizing chromosome 1p-, 14-, and 22-specific probes, revealed a similar cytogenetic profile in the remaining five tumour specimens. Mutational analysis of exons 9, 11, 13, and 17 of KIT, and exons 12 and 18 of PDGFRA was performed in all cases by denaturing high-pressure liquid chromatography (DHPLC) pre-screening, followed by direct sequencing. None of the tumours showed KIT mutant isoforms. Three tumours harboured PDGFRA exon 18 activating mutations; two were Asp --> Val(842) missense substitutions and one was a DIM842-844 amino acid deletion. KIT and PKC theta (protein activated in interstitial cells of Cajal and GISTs) expression was determined by western immunoblotting of the total cell lysates from three tumour biopsies. None of these three tumours expressed KIT, while all specimens showed expression of PKC theta protein. These findings indicate that there is a subgroup of KIT-negative GISTs that exhibit the same morphological, cytogenetic, and molecular features as KIT-positive tumours. While intragenic PDGFRA activating mutations are present in some of these tumours, the oncogenic events underlying the pathogenesis of the others remain unknown.     

细胞遗传学检查在诊断闭经患者中的作用

目的 分析闭经患者的染色体核型,了解闭经与染色体异常的相关性,为临床治疗提供科学依据。方法 对158例闭经患者进行外用血淋巴细胞染色体棱型分析。结果 158例患者中有染色体异常者40例,占受检者25.3％(40/158)。原发性闭经患者中染色体异常检出率26.6%(33/124);继发性闭经患者中检出率为20.6％(7/34),染色体异常类型包括:X染色体数目异常13例,结构异常5例,嵌合体11例,含Y染色体13例。结论 性染色体决定着女性性腺及生殖器官的发育,性染色体异常是导致闭经的重要原因。对于闭经患者常规行染色体检查是必要的。     

High-Density SNP genotyping defines 17 distinct haplotypes of the TNF block in the Caucasian population: implications for haplotype tagging

The region spanning the tumor necrosis factor (TNF) cluster in the human major histocompatibility complex (MHC) has been implicated in susceptibility to numerous immunopathological diseases, including type 1 diabetes mellitus and rheumatoid arthritis. However, strong linkage disequilibrium across the MHC has hampered the identification of the precise genes involved. In addition, the observation of "blocks" of DNA in the MHC within which recombination is very rare, limits the resolution that may be obtained by genotyping individual SNPs. Hence a greater understanding of the haplotypes of the block spanning the TNF cluster is necessary. To this end, we genotyped 32 human leukocyte antigen (HLA)-homozygous workshop cell lines and 300 healthy control samples for 19 coding and promoter region SNPs spanning 45 kb in the central MHC near the TNF genes. The workshop cell lines defined 11 SNP haplotypes that account for approximately 80% of the haplotypes observed in the 300 control individuals. Using the control individuals, we defined a further six haplotypes that account for an additional 10% of donors. We show that the 17 haplotypes of the "TNF block" can be identified using 15 SNPs.     

Influence of local inflammation of the peritoneal membrane on diuresis and residual renal function in patients treated with peritoneal dialysis

The aim of this study was to investigate the connection between local inflammation of the peritoneal membrane and diuresis, as well as the residual renal function (RRF) in patients treated with continuous ambulatory peritoneal dialysis (CAPD). Twenty patients treated with CAPD participated in this cross-sectional study. To determine the influence of local inflammation of the peritoneal membrane, effluent interleukin-6 (IL-6) and soluble interleukin-6 receptor (sIL-6R) levels were measured. The level of IL-6, in the group as a whole, was significantly higher in effluent (7.87 pg/mL) than in serum (1.29 pg/mL). There was a significant correlation between effluent and serum IL-6 (r = 0.608; P = 0.002). There was also a significant relationship between effluent and serum IL-6 and duration of CAPD treatment, respectively (r = 0.577; P = 0.004; r = 0.528; P = 0.008). Further, there was a significant negative correlation between effluent IL-6 and daily diuresis (r = −0.533; P = 0.008), but there was no significant correlation between effluent IL-6 and RRF (r = −0.339, P = 0.072). On the other hand, the concentrations of effluent IL-6 were significantly higher in patients with RRF <2 mL/min than in those with RRF ≥2 mL/min (P = 0.039). In conclusion, local inflammation has a significant impact on the amount of diuresis and probably on RRF in patients on CAPD.     

Biallelic inactivation of NF1 in a sporadic plexiform neurofibroma

Plexiform neurofibromas are a major cause of morbidity in individuals with neurofibromatosis type 1 (NF1). Sporadically, these tumors appear as an isolated feature without other signs of NF1. A role for the NF1 gene in solitary plexiform neurofibromas has never been described. In this study, we report a 13-year-old boy who was diagnosed with a plexiform neurofibroma, without other NF1 diagnostic criteria. The tumor was partially resected and analyzed using different techniques: karyotyping, fluorescence in situ hybridization (FISH), and microarray comparative genomic hybridization (aCGH). Tumor Schwann cell culture and subsequent karyotyping showed a rearrangement involving chromosomes 1 and 17, namely an insertion of chromosomal bands 1p36-35 at 17q11.2. FISH demonstrated that the insertion interrupted the NF1 gene. In addition, a deletion was detected affecting the other NF1 allele. Whole-genome aCGH analysis of the resected tumor confirmed the presence of an 8.28 Mb deletion including the NF1 gene locus in ～15-20% of tumor cells. We conclude that biallelic NF1 inactivation was at the origin of the isolated plexiform neurofibroma in this patient. The insertion is most likely the "first hit" and the large deletion the "second hit."     

Endometriosis is associated with a decreased risk of pre-eclampsia

BACKGROUND: We postulated that impaired endometrial differentiation in women with pelvic endometriosis predisposes for pre-eclampsia. METHODS: A retrospective case-control study set at the University of Ghent IVF centre. The incidence of pre-eclampsia and pregnancy-induced hypertension (PIH) following the clinical and/or laparoscopic diagnosis of endometriosis-associated infertility (case group; n = 245 pregnancies) was compared with the incidence of these obstetric complications in pregnancies following treatment for male-factor infertility (control group; n = 274 pregnancies). Pregnancy data were obtained by searching electronic databases and postal questionnaires. The case and control groups were matched for age, parity and multiple pregnancies. RESULTS: The incidence of pre-eclampsia was significantly lower in the case group (0.8%) when compared with control group (5.8%) (P = 0.002; odds ratio (OR) = 7.5, 95% confidence interval (CI): 1.7-33.3). Analysis of obstetric outcome in the subgroup of patients with laparoscopic data confirmed the lower risk of pre-eclampsia in the case (1.2%) versus control (7.4%) groups (P = 0.032; OR = 6.6, 95% CI: 1.2-37). PIH occurred in 3.5% and 8.7% of case and control pregnancies, respectively (P = 0.018; OR = 2.6, 95% CI: 1.2-6.0). The odds of developing pre-eclampsia were 5.67 times higher in the control group than in pregnancies following endometriosis-associated infertility. In multiple pregnancies, the odds of developing pre-eclampsia increased 1.93 times per additional child, with or without endometriosis. CONCLUSIONS: We found no evidence that endometriosis predisposes for pre-eclampsia. Instead, the risk of hypertensive disorder in pregnancy is significantly reduced in women with endometriosis-associated infertility.     

The KAT6B‐related disorders genitopatellar syndrome and Ohdo/SBBYS syndrome have distinct clinical features reflecting distinct molecular mechanisms

Genitopatellar syndrome (GPS) and Say–Barber–Biesecker–Young–Simpson syndrome (SBBYSS or Ohdo syndrome) have both recently been shown to be caused by distinct mutations in the histone acetyltransferase KAT6B (a.k.a. MYST4/MORF). All variants are de novo dominant mutations that lead to protein truncation. Mutations leading to GPS occur in the proximal portion of the last exon and lead to the expression of a protein without a C‐terminal domain. Mutations leading to SBBYSS occur either throughout the gene, leading to nonsense‐mediated decay, or more distally in the last exon. Features present only in GPS are contractures, anomalies of the spine, ribs and pelvis, renal cysts, hydronephrosis, and agenesis of the corpus callosum. Features present only in SBBYSS include long thumbs and long great toes and lacrimal duct abnormalities. Several features occur in both, such as intellectual disability, congenital heart defects, and genital and patellar anomalies. We propose that haploinsufficiency or loss of a function mediated by the C‐terminal domain causes the common features, whereas gain‐of‐function activities would explain the features unique to GPS. Further molecular studies and the compilation of mutations in a database for genotype–phenotype correlations (www.LOVD.nl/KAT6B) might help tease out answers to these questions and understand the developmental programs dysregulated by the different truncations. Hum Mutat 33:1520–1525, 2012. © 2012 Wiley Periodicals, Inc.     

Systemic inhibition of BMP1-3 decreases progression of CCl4-induced liver fibrosis in rats

Liver fibrosis is a progressive pathological process resulting in an accumulation of excess extracellular matrix proteins. We discovered that bone morphogenetic protein 1-3 (BMP1-3), an isoform of the metalloproteinase Bmp1 gene, circulates in the plasma of healthy volunteers and its neutralization decreases the progression of chronic kidney disease in 5/6 nephrectomized rats. Here, we investigated the potential role of BMP1-3 in a chronic liver disease. Rats with carbon tetrachloride (CCl₄)-induced liver fibrosis were treated with monoclonal anti-BMP1-3 antibodies. Treatment with anti-BMP1-3 antibodies dose-dependently lowered the amount of collagen type I, downregulated the expression of Tgfb1, Itgb6, Col1a1, and Acta2 and upregulated the expression of Ctgf, Itgb1, and Dcn. Mehanistically, BMP1-3 inhibition decreased the plasma levels of transforming growth factor beta 1(TGFβ1) by prevention of its activation and lowered the prodecorin production further suppressing the TGFβ1 profibrotic effect. Our results suggest that BMP1-3 inhibitors have significant potential for decreasing the progression of fibrosis in liver cirrhosis.