New PLAG1-fusion transcripts in the spectrum of pediatric fibrotic, lipofibrotic, and mature lipomatous tumors.

The histomorphology of liboblastoma is highly variable and comprises different patterns that are found admixed or in pure form within a tumor. The most important features - mature lipomatous, fibrotic, lipofibrous, and myxoid - overlap with the histomorphology of several other pediatric tumor entities. Regarding the morphologic overlaps, molecular diagnostics with identification of fusion transcripts involving PLAG1 or HMGA2 is essential to identify lipoblastomas. This paper describes the diagnostic procedure in general and two new fusion transcripts of lipoblastoma, MEG3-PLAG1 and COL1A1-PLAG1. In conclusion, the algorithm to diagnose lipoblastomas among this group of pediatric fibrotic, lipofibrous and mature lipomatous tumors essentially includes histomorphology, immunohistochemistry, and molecular diagnostics.

Small intestinal mucosa expression of putative chaperone fls485.

BACKGROUND: Maturation of enterocytes along the small intestinal crypt-villus axis is associated with significant changes in gene expression profiles. fls485 coding a putative chaperone protein has been recently suggested as a gene involved in this process. The aim of the present study was to analyze fls485 expression in human small intestinal mucosa. METHODS: fls485 expression in purified normal or intestinal mucosa affected with celiac disease was investigated with a molecular approach including qRT-PCR, Western blotting, and expression strategies. Molecular data were corroborated with several in situ techniques and usage of newly synthesized mouse monoclonal antibodies. RESULTS: fls485 mRNA expression was preferentially found in enterocytes and chromaffine cells of human intestinal mucosa as well as in several cell lines including Rko, Lovo, and CaCo2 cells. Western blot analysis with our new anti-fls485 antibodies revealed at least two fls485 proteins. In a functional CaCo2 model, an increase in fls485 expression was paralleled by cellular maturation stage. Immunohistochemistry demonstrated fls485 as a cytosolic protein with a slightly increasing expression gradient along the crypt-villus axis which was impaired in celiac disease Marsh IIIa-c. CONCLUSIONS: Expression and synthesis of fls485 are found in surface lining epithelia of normal human intestinal mucosa and deriving epithelial cell lines. An interdependence of enterocyte differentiation along the crypt-villus axis and fls485 chaperone activity might be possible.

Are H19 variants associated with Silver-Russell syndrome?

Opposite (epi)mutations affecting the imprinted region 11p15 are associated with Silver-Russell (SRS) and Beckwith-Wiedemann syndrome (BWS). Apart from other disturbances more than 35% of patients with SRS show hypomethylation at the imprinting control region 1 (ICR1) in 11p15. ICR1 is paternally methylated and regulates the expression of the paternally expressed growth factor IGF2 and the maternally expressed gene H19. The exact function of the non-coding RNA H19 is still unknown. However, the finding that this gene is highly conserved in mammals indicates profound functional relevance. Due to the supposed function of H19 in the regulation of the imprinted region 11p15 we searched for mutations in the transcribed sequence and the CTCF binding sites of H19 in 44 patients with SRS. In two cases different 3 base-pair (bp) deletions in exon 1 could be identified. A third patient carried a 39 bp duplication affecting exon 2 and intron 2. These three variants were not detected in 100 controls and 42 patients with isolated growth retardation. One of the patients carrying a mutation also showed hypomethylation at the ICR1 in 11p15. Splicing studies in HEK cells transfected with constructs carrying the three different variants revealed a deviation from the normal H19 splicing pattern in two of these individuals. However, analysis of lymphocytes of one of these two patients did not verify an altered expression pattern of H19. Nevertheless, our results indicate a relevant role of H19 in the aetiology of SRS: functional effects of these variants on chromatin restructuring of the ICR1, or altered function of H19 as a posttranslational modifying factor (microRNA/antisense RNA) are conceivable.