Emerging novel prognostic markers in pancreatic ductal adenocarcinoma

Abstract Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive cancers, the 5-year survival rate being less than 5%. At the time of diagnosis, 90% of PDACs extend beyond the pancreas and distant metastases are often present. Due to aggressive growth, local expansion and early appearance of metastasis, primary PDAC tumours are local enough for curative surgical resection in only 10–20% of the cases. Adjuvant chemotherapy is indicated in these curative-treated cases, with slight improvement in survival. PDAC is considered to represent a heterogeneous group of biologically and prognostically different malignancies. Characterization of these subgroups is essential and there is an urgent need for more accurate biomarkers and targeted treatments in PDAC. In the current work, we immunohistochemically investigated the expression levels and prognostic values of oxidative stress markers (8-OHdG, Keap1, Prx I, II, III, V and VI), epigenetic histone modifiers (KDM4A, KDM4B, KDM4D and SIRT1–4), and cell-cycle regulators (p16, Rb, CDK4) and DNA-repair enzymes (FEN1 and MGMT) in the cohort of surgically treated PDAC patients. We found that Keap1 expression was associated with better pancreatic cancer-specific survival. Expression of antioxidative peroxiredoxins I, III, V and VI was also connected with a more favourable tumour characteristics and Prx I and VI showed prognostic value. When considering the biology of PDAC, we noticed that pivotal epigenetic regulation also occurred in exocrine pancreatic tissue adjacent to resection margins. Overexpression of the cell-cycle regulator CDK4 and the DNA-repair enzyme FEN1 in the whole population, and elevated expression level of MGMT in the most high-risk patients were connected with worse prognosis. The results of the study can be utilized in the future when individualized therapies are being designed for PDAC patients. Due to occurrence of the epigenetic regulation also in exocrine pancreatic tissue adjacent to resection margins, it could be evaluated in future for routine diagnostics and treatment optimization. The potential role of MGMT in the development of PDAC chemoresistance should be studied in the future.Tiivistelmä Haiman duktaalinen adenokarsinooma (PDAC) on yksi aggressiivisimmista syöpäsairauksista. Viiden vuoden elossaoloennuste on vain lähellä 5 prosenttia. Diagnoosihetkellä 90% haiman adenokarsinoomista yltää haiman ulkopuolelle ja usein kasvain on jo lähettänyt etäpesäkkeitä. Kasvutaipumuksen sekä metastasoinnin takia kuratiivinen kirurginen hoito on mahdollista vain 10–20% tapauksista. Liitännäissolunsalpaajahoito on aiheellista näissä kuratiivistavoitteisesti hoidetuissa tapauksissa. Kuitenkin vaikutus kokonaiselossaoloaikaan on melko vähäinen. Uusimman tutkimustiedon valossa PDAC:aa pidetäänkin heterogeenisenä ryhmänä biologisesti ja ennusteellisesti erilaisia tautiryhmiä. Näiden tautiryhmien tunteminen ja tunnistaminen riittävän tarkkojen merkkiaineiden avulla olisi ensiarvoisen tärkeää, jotta hoitoja voitaisiin kohdentaa niistä hyötyville potilaille. Väitöskirjatutkimuksessa selvitimme immunohistokemiallisin menetelmin oksidatiivisen stressin merkkiaineiden (8-OHdG, Keap1, Prx I, II, III, V ja VI), epigeneettisten histonimodifikaattorien (KDM4A, KDM4B, KDM4D ja SIRT1–4) sekä solusyklin säätelijöiden (p16, Rb, CDK4) ja DNA-korjausentsyymien (FEN1 ja MGMT) ilmentymistä ja ennusteellista arvoa kirurgisesti hoidetuilla PDAC-potilailla. Tutkimuksessamme totesimme, että kasvainkudoksen Keap1-ilmentymä yhdistyi parempiennusteiseen taudinkuvaan. Antioksidatiivisten peroksiredoksiinien I, III, V ja VI ilmentyminen yhdistyi niin ikään suotuisampaan kasvaimen fenotyyppiin ja Prx I ja VI osoittivat ennusteellista arvoa. Havaitsimme lisäksi, että PDAC:n biologiaan keskeistesti vaikuttavaa epigeneettistä säätelyä tapahtuu myös malignin haimakudoksen viereisessä eksokriinisessä haimakudoksessa. Solusyklin säätelijä CDK4:n ja DNA-korjausentsyymi FEN1:n voimakas ilmentyminen koko tutkimuspopulaatiossa sekä kohonnut MGMT:n ilmentyminen korkeimman riskin potilailla yhdistyivät huonompaan taudin ennusteeseen. Väitöskirjatyön tutkimustuloksia voidaan tulevaisuudessa hyödyntää, kun tutkitaan yksilöllisiä hoitomuotoja PDAC-potilailla. Koska epigeneettistä säätelyä tapahtuu myös syövän viereisessä eksokriinisessa haimakudoksessa, voidaan tulevaisuudessa tämän kudoksen arviointia mahdollisesti käyttää rutiinisti diagnostiikassa sekä hoidon optimoinnissa. MGMT:n mahdollinen rooli PDAC:n kemoresistenssin kehittymisessä tulisi tulevaisuudessa selvittää

Keap1 expression has independent prognostic value in pancreatic adenocarcinomas

Abstract Background: Oxidative stress and redox-regulating enzymes may potentially accelerate pancreatic carcinogenesis and also affect chemoresistance. Recently major antioxidant response regulator NF-E2-related factor 2 (Nrf2) has been linked to poor prognosis in pancreatic cancer. Nrf2 activity is strictly regulated by oxidative stress sensor Kelch-like ECH-associated protein 1 (Keap1). Oxidative DNA damage can be estimated e.g. by 8-hydroxy-2′-deoxyguanosine (8-OHdG) expression. The aim of this study was to evaluate the expression and possible prognostic role of Keap1 and 8-OHdG in pancreatic cancer. Methods: We assessed immunohistochemically the expression of 8-OHdG and Keap1 in precisely characterized material of 69 pancreatic adenocarcinoma patients. Results: Nuclear 8-OHdG associated with cytoplasmic Keap1 expression (p = 0.031) and was overexpressed in patients with smaller tumors (p = 0.016) and in tumors without lymph node involvement (p = 0.051). Cytoplasmic 8-OHdG expression associated with higher differentiation (p = 0.023). Cytoplasmic Keap1 immunostaining associated with N0-staging (p = 0.0009) and the absence of distant metastases (p = 0.018). Membranous Keap1 associated with longer relapse-free survival (p = 0.041) and pancreatic cancer-specific survival (median survival 14 vs. 32 months; p = 0.029) and was in multivariate analysis an independent prognostic factor of pancreatic cancer-related death (HR 2.66, 95%CI 1.23–5.75). Conclusions: Oxidative stress and main redox regulators may participate in pancreatic carcinogenesis and Keap1 appears as a promising prognostic factor in pancreatic cancer. Future studies should also concentrate on potential link between redox regulation and chemoresistance in pancreatic cancer

Proteins of the retinoblastoma pathway, FEN1 and MGMT are novel potential prognostic biomarkers in pancreatic adenocarcinoma

Abstract Background: We studied the expression of some major proteins involved in cell-cycle regulation and DNA repair, the roles of which are not well known in pancreatic ductal adenocarcinoma (PDAC), but which have a significant impact on carcinogenesis of many other cancers. Methods: We immunohistochemically assessed expression levels of the cell-cycle regulators Rb1, p16 and cyclin-dependent kinase 4 (CDK4), and the DNA repair enzymes O6-methylguanine-DNA-alkyltransferase (MGMT) and flap endonuclease-1 (FEN1) separately in malignant tissue and benign tissue from resection margins in 102 cases of PDAC. Nearly all (95.1%) patients had undergone pancreaticoduodenectomy. Results: The studied proteins showed wide but somewhat variable expression in both benign and malignant pancreatic tissues. Strong CDK4 expression in islets of Langerhans predicted poor relapse-free survival (RFS) (HR 2.874; 95% CI 1.261–6.550; p = .012) and within T3–4 tumors CDK4 expression in adenocarcinoma cells also predicted poor disease-free survival (DFS) (RR 2.148; 95% CI 1.081–4.272; p = .029). Strong MGMT expression was associated in N1 patients with weak local relapse-free survival (RFS), DFS and overall survival; all significantly in Cox regression analysis. FEN1 was also an independent predictor of decreased DFS (in the whole study population) and worse RFS (in the patients with T3–4 tumors). Conclusions: Major cell-cycle regulator also have predictive significance, but further studies are required to evaluate this

Distributed Whiteboard

As the electronic whiteboards is getting more spread and more brands are created, the demands of a standard is growing. Still no standard is made for electronic whiteboards towards application programmers. This paper describes a framework to gain loose coupling and a standard to interact with electronic whiteboard events. It builds a framework follows a specific pattern to standardlize implementation in application. The electronic whiteboards are still very small units. A collection of whiteboards has to be handled due to many of those electronic whiteboards are somewhat small and several whiteboards should be able to act like one for the participants. Projection utilities is needed to hide those differences in manufacturers drivers or if there is no projection provided in those drivers. This paper also discusses the technical users, non technical users and student view of having a projected or un-projected whiteboards.Validerat; 20101217 (root

Additional file 3: of Weak HIF-1alpha expression indicates poor prognosis in resectable pancreatic ductal adenocarcinoma

Table S2. Multivariate analysis for the contribution of clinical factors of pancreatic ductal adenocarcinoma to mortality after controlling for other variables. Tested explanatory variables were nuclear HIF-1alpha score (weak and strong), age at the time of diagnosis (< 65 or ≥ 65 years), sex (male or female) and tumor stage (I, II or III-IV). (DOCX 14 kb

Additional file 1: of Weak HIF-1alpha expression indicates poor prognosis in resectable pancreatic ductal adenocarcinoma

Figure S1. Positive and negative controls for HIF-1alpha staining. The HIF-1alpha staining pattern in ischemic colon sample is nuclear and shows an increase in intensity towards the surface in the mucosal epithelium (a.). PDAC sample with high nuclear HIF-1alpha intensity stained with CD3 antibody for negative control (b.). CD3 staining is located in the lymphocytes but not in the cancer cells. (TIF 5034 kb

Tenascin C, fibronectin, and tumor-stroma ratio in pancreatic ductal adenocarcinoma

Abstract Objectives: Pancreatic ductal adenocarcinoma (PDAC) is characterized by abundant stroma with increased expression of tenascin C and fibronectin. Their role and tumor-stroma ratio in PDAC are not well known. The aim of this study was to evaluate tenascin C and fibronectin expression and tumor-stroma ratio and their prognostic relevance in PDAC. Methods: Ninety-five resected PDACs were immunohistochemically stained for tenascin C and fibronectin, and the expression was separately assessed in tumor bulk and front. Tumor-stroma ratio was determined with sections stained with hematoxylin-eosin. Results: Tenascin C and fibronectin were abundantly expressed in the stroma of PDAC, but absent in adjacent normal pancreatic tissue. Fibronectin expression of the bulk was associated with high T class (P = 0.045). In the main analysis, tenascin C and fibronectin expression and tumor-stroma ratio were not associated with patient survival. In a subgroup analysis of early-stage PDAC (T1–T2 tumors), high tenascin C expression in the tumor bulk was associated with poor prognosis (hazard ratio, 8.23; 95% confidence interval, 2.71–24.96). Conclusions: Tenascin C and fibronectin are abundantly expressed in PDAC, but they seem to have no major association with patient survival. However, in early-stage PDAC, tenascin C expression of the tumor bulk may have prognostic impact. Tumor-stroma ratio has no prognostic value in PDAC