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Background Despite efforts in localization of key proteins using immunohistochemistry, the complex proteomic composition of pleomorphic adenomas has not yet been characterized. Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI imaging) allows label-free and spatially resolved detection of hundreds of proteins directly from tissue sections and of histomorphological regions by finding colocalized molecular signals. Spatial segmentation of MALDI imaging data is an algorithmic method for finding regions of similar proteomic composition as functionally similar regions. Methods We investigated 2 pleomorphic adenomas by applying spatial segmentation to the MALDI imaging data of tissue sections. Results The spatial segmentation subdivided the tissue in a good accordance with the tissue histology. Numerous molecular signals colocalized with histologically defined tissue regions were found. Conclusion Our study highlights the cellular transdifferentiation within the pleomorphic adenoma. It could be shown that spatial segmentation of MALDI imaging data is a promising approach in the emerging field of digital histological analysis and characterization of tumors. © 2014 Wiley Periodicals, Inc. Head Neck 37: 1014–1021, 2015

The tumor suppressor p33ING1 is involved in DNA repair and cell cycle regulation. Furthermore, p33ING1 is a transcriptional silencer that recognizes the histone mark for trimethylated lysine 4 at histone H3. Interestingly, expression of p33ING1 and p33ING2 is able to induce premature senescence in primary human fibroblasts. The corepressor Alien is involved in gene silencing mediated by selected members of nuclear hormone receptors. In addition, Alien acts as a corepressor for E2F1, a member of the E2F cell cycle regulatory family. Furthermore, recent findings suggest that Alien is complexed with transcription factors participating in DNA repair and chromatin. Here, using a proteomic approach by surface-enhanced laser desorption ionization and mass spectrometry (SELDI-MS) combined with immunological techniques, we show that Alien interacts in vivo with the tumor suppressor p33ING1 as well as with the related tumor suppressor candidate p33ING2. The interaction of Alien with p33ING1 and p33ING2 was confirmed in vitro with GST-pull-down, suggesting a direct binding of Alien to these factors. The binding domain was mapped to a central region of Alien. Functionally, the expression of p33ING1 or p33ING2 enhances the Alien-mediated silencing, suggesting that the interaction plays a role in transcriptional regulation. Thus, the findings suggest that the identified interaction between Alien and the tumor suppressors p33ING1 and p33ING2 reveals a novel cellular protein network.

We analyzed 74 cryostat sections of central gastric tumor, tumor margin, and normal gastric epithelium using ProteinChip Arrays and SELDI-TOF MS. One peak was significantly down-regulated in tumor tissue (P = 1.43 × 10-6) and identified as pepsinogen C using MS/MS analysis and immunodepletion. This signal was further characterized by immunohistochemistry. This work demonstrates that differentially expressed signals can be identified and assessed using a proteomic approach comprising tissue-microdissection, protein profiling, and immunohistochemistry. Keywords: gastric cancer • proteomics • biomarker • ProteinChip technology • SELDI • microdissection • immunohistochemistry

Trotz Fortschritten in Diagnostik und Therapie konnte in den letzten Jahren keine deutliche Verbesserung der Tumorprognose für Patienten mit einem Plattenepithelkarzinom des oberen Aerodigestivtraktes erzielt werden. Eine neue Technologie stellt das ProteinChip®-Verfahren dar, das eine computergesteuerte Analyse der Expressionsmuster der unterschiedlichen Proteine als eigentliche Akteure der Zellsteuerung ermöglicht. Ziel unserer Studie war die Untersuchung der klinisch-prognostischen Bedeutung von Veränderungen des Expressionsmusters der Zellproteine für Patienten mit Karzinomen des oberen Aerodigestivtraktes.Von 1997-2001 wurden Gewebeproben aus dem Tumor und tumorfernen Normalgewebe von 51 Patienten (46 Männer, 5 Frauen) mit einem Plattenepithelkarzinom in Mundhöhle (n=16), Oropharynx (n=7), Hypopharynx (n=11) und Larynx (n=17) asserviert. Die Gewebsproben wurden zunächst mittels Laser-Mikrodissektion disseziert. Danach erfolgte die Untersuchung der gereinigten Proteinlysate der einzelnen Proben mittels ProteinChip®-Verfahren hinsichtlich der Proteinmuster. Alle Patienten wurden mindestens 3 Jahre nachkontrolliert. Das im Tumorgewebe signifikant vermehrt exprimierte Annexin V korrelierte mit einer Verschlechterung des tumorbezogenen Überlebens. Dieses Ergebnis erwies sich als statistisch signifikant in der COX-Analyse. Der Zusammenhang war am ausgeprägtesten bei größeren Tumoren und Tumoren der Lokalisationen Mundhöhle und Hypopharynx. Auffällig war auch die Korrelation zwischen dem Auftreten von Fernmetastasen und erhöhten Annexinwerten. Durch unsere Untersuchungen konnte erstmals ein klinischer Zusammenhang zwischen der erhöhten Expression von Annexin V im Proteom der Zelle und der Prognose der Tumorerkrankung darstellen.