Superficial fibromas with CTNNB1 mutation.

Superficial fibromas are a group of mesenchymal spindle cell lesions with pathomorphological heterogeneity and diverse molecular backgrounds. In part, they may be indicators of an underlying syndrome. Among the best-known entities of superficial fibromas is Gardner fibroma, a plaque-like benign tumor, which is associated with APC germline mutations and occurs in patients with familial adenomatosis polyposis (Gardner syndrome). Affected patients also have an increased risk to develop desmoid fibromatosis (DTF), a locally aggressive neoplasm of the deep soft tissue highly prone to local recurrences. Although a minority of DTFs occur in the syndromic context and harbor APC germline mutations, most frequently their underlying molecular aberration is a sporadic mutation in Exon 3 of the CTNNB1 gene. Up to date, a non-syndromic equivalent to Gardner fibroma carrying a CTNNB1 mutation has not been defined. Here, we present two cases of (sub-)cutaneous tumors with a hypocellular and collagen-rich Gardner fibroma-like appearance and pathogenic, somatic CTNNB1 mutations. We aim to differentiate these tumors from other fibromas according to their histological appearance, immunohistochemical staining profile and underlying somatic CTNNB1 mutations. Furthermore, we distinguish them from locally aggressive desmoid fibromatosis regarding their biological behavior, prognosis and indicated therapeutic strategies. Consequently, we call them CTNNB1-mutated superficial fibromas as a sporadic counterpart lesion to syndromic Gardner fibromas.

A genome scale RNAi screen identifies GLI1 as a novel gene regulating vorinostat sensitivity.

Vorinostat is an FDA-approved histone deacetylase inhibitor (HDACi) that has proven clinical success in some patients; however, it remains unclear why certain patients remain unresponsive to this agent and other HDACis. Constitutive STAT (signal transducer and activator of transcription) activation, overexpression of prosurvival Bcl-2 proteins and loss of HR23B have been identified as potential biomarkers of HDACi resistance; however, none have yet been used to aid the clinical utility of HDACi. Herein, we aimed to further elucidate vorinostat-resistance mechanisms through a functional genomics screen to identify novel genes that when knocked down by RNA interference (RNAi) sensitized cells to vorinostat-induced apoptosis. A synthetic lethal functional screen using a whole-genome protein-coding RNAi library was used to identify genes that when knocked down cooperated with vorinostat to induce tumor cell apoptosis in otherwise resistant cells. Through iterative screening, we identified 10 vorinostat-resistance candidate genes that sensitized specifically to vorinostat. One of these vorinostat-resistance genes was GLI1, an oncogene not previously known to regulate the activity of HDACi. Treatment of vorinostat-resistant cells with the GLI1 small-molecule inhibitor, GANT61, phenocopied the effect of GLI1 knockdown. The mechanism by which GLI1 loss of function sensitized tumor cells to vorinostat-induced apoptosis is at least in part through interactions with vorinostat to alter gene expression in a manner that favored apoptosis. Upon GLI1 knockdown and vorinostat treatment, BCL2L1 expression was repressed and overexpression of BCL2L1 inhibited GLI1-knockdown-mediated vorinostat sensitization. Taken together, we present the identification and characterization of GLI1 as a new HDACi resistance gene, providing a strong rationale for development of GLI1 inhibitors for clinical use in combination with HDACi therapy.

Tissue eosinophilia in acute and chronic atopic dermatitis: a morphometric approach using quantitative image analysis of immunostaining.

BACKGROUND: The frequency and amount of tissue eosinophilia in spontaneous lesions of acute and chronic atopic dermatitis (AD) are still a matter of controversy, and little is known about the distribution of eosinophilia in skin. OBJECTIVES: To give a quantitative description of tissue eosinophilia in spontaneous lesions of acute and chronic AD based on morphometric data. METHODS: Thirty-one lesional skin biopsies of AD were evaluated using our recently described method for the quantitative assessment of eosinophilic granule protein (EGP) deposition by image analysis of immunostaining using the antibodies EG1, EG2, MBP, EPO and neutrophil elastase (NE). The frequency, amount and distribution of protein deposition including extracellular EGP deposition as an indicator of complete activation and degranulation of eosinophils were determined. Eosinophil count was performed in addition. Histopathological parameters of acute dermatitis (spongiosis) and chronic dermatitis (epidermal hyperplasia) were scored to look for a correlation with tissue eosinophilia. RESULTS: Tissue eosinophilia was found in nearly all biopsies (30 of 31). The most protein was detected by EG2, followed by EG1, MBP and EPO, with very small amounts of NE. A superficial tissue distribution of eosinophilia was found, with < 10% of total EGP deposition below a depth of 1.39 mm from the epidermis. Eosinophils were involved in acute, spongiotic dermatitis, but more tissue eosinophilia including EGP deposition was detected in lesions with pronounced epidermal hyperplasia than in biopsies without. CONCLUSIONS: These data provide further evidence for the involvement of activated eosinophils in acute and chronic AD by a new quantitative in situ approach. Pronounced tissue eosinophilia, especially EGP deposition as the result of complete activation of eosinophils, is found in chronic AD and may be involved in the development or maintenance of chronicity.

Quantification of eosinophilic granule protein deposition in biopsies of inflammatory skin diseases by automated image analysis of highly sensitive immunostaining.

Eosinophilic granulocytes are major effector cells in inflammation. Extracellular deposition of toxic eosinophilic granule proteins (EGPs), but not the presence of intact eosinophils, is crucial for their functional effect in situ. As even recent morphometric approaches to quantify the involvement of eosinophils in inflammation have been only based on cell counting, we developed a new method for the cell-independent quantification of EGPs by image analysis of immunostaining. Highly sensitive, automated immunohistochemistry was done on paraffin sections of inflammatory skin diseases with 4 different primary antibodies against EGPs. Image analysis of immunostaining was performed by colour translation, linear combination and automated thresholding. Using strictly standardized protocols, the assay was proven to be specific and accurate concerning segmentation in 8916 fields of 520 sections, well reproducible in repeated measurements and reliable over 16 weeks observation time. The method may be valuable for the cell-independent segmentation of immunostaining in other applications as well.

Temperature dependence of forward and reverse electron transfer from A1-, the reduced secondary electron acceptor in photosystem I.

Electron-transfer reactions following the formation of P700(+)A1- have been studied in isolated Photosystem I complexes from Synechococcus elongatus between 300 and 5 K by flash absorption spectroscopy. (1) In the range from 300 to 200 K, A1- is reoxidized by electron transfer to the iron-sulfur cluster FX. The rate slows down with decreasing temperature, corresponding to an activation energy of 220 +/- 20 meV in this temperature range. Analyzing the temperature dependence of the rate in terms of nonadiabatic electron-transfer theory, one obtains a reorganization energy of about 1 eV and an edge-to-edge distance between A1 and FX of about 8 A assuming the same distance dependence of the electron-transfer rate as in purple bacterial reaction centers. (2) At temperatures below 150 K, different fractions of PS I complexes attributed to frozen conformational substates can be distinguished. A detailed analysis at 77 K gave the following results: (a) In about 45%, flash-induced electron transfer is limited to the formation and decay of the secondary pair P700(+)A1-. The charge recombination occurs with a t1/2 of about 170 micros. (b) In about 20%, the state P700(+)FX- is formed and recombines with complex kinetics (t1/2 = 5-100 ms). (c) In about 35%, irreversible formation of P700(+)FA- or P700(+)FB- is possible. (3) The transition from efficient forward electron transfer at higher temperatures to heterogeneous photochemistry at low temperatures has been investigated in different glass-forming solvents. The yield of forward electron transfer to the iron-sulfur clusters decreases in a narrow temperature interval. The temperature of the half-maximal effect varies between different solvents and appears to be correlated with their liquid to glass transition. It is proposed that reorganization processes in the surroundings of the reactants which are required for the stabilization of the charge-separated state become arrested near the glass transition. This freezing of protein motions and/or solvent reorganization may affect electron-transfer reactions through changes in the free-energy gap and the reorganization energy. (4) The rate of charge recombination between P700(+) and A1- increases slightly (about 1.5-fold) when the temperature is decreased from 300 to 5 K. This charge recombination characterized by a large driving force is much less influenced by the solvent properties than the forward electron-transfer steps from A1- to FX and FA/B.

Inverted papilloma in a 10-year-old boy.

Inverted nasal papillomas are rare tumors in children. Four large series include only a single patient (of a total of 269) younger than 20 years. We report the occurrence of an inverted nasal papilloma in a 10-year-old boy; this tumor exhibited clinical and histopathologic features identical to those of similar neoplasms in adults. Inverted papillomas in children should be treated by wide local excision, usually using a lateral rhinotomy approach. The rationale for such aggressive surgery is based on the high rate of recurrence (25% to 75%) and a propensity for the development of carcinomas (5% to 15%) as associated lesions.

Adult epiglottitis, cellulitis, and Streptococcus pneumoniae bacteremia.

Described is an adult with acute epiglottitis, cellulitis of the neck and chest, and Streptococcus pneumoniae bacteremia. Although this syndrome is usually associated with Haemophilus influenzae type b, this case illustrates that in adults a similar syndrome can be produced by S. pneumoniae. The failure to determine an etiologic agent in approximately two thirds of reported adult cases of epiglottitis raises the question as to whether S. pneumoniae, a common adult respiratory pathogen, might fill this etiological void. To establish such an association between S. pneumoniae and acute epiglottitis would be further impetus to immunize patients against S. pneumoniae.