Tenascin C, Fibronectin, and Tumor-Stroma Ratio in Pancreatic Ductal Adenocarcinoma.

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.

Toll-like receptors 2, 4 and 9 and hypoxia markers HIF-1alpha and CAIX in pancreatic intraepithelial neoplasia.

Pancreatic cancer arises from precursor lesions called pancreatic intraepithelial neoplasia (PanIN) characterized by inflammatory microenvironment. In pancreatic cancer, strong innate immunity and hypoxia responses are typical. Occurrence and relationship of these responses in human PanINs is unknown. We have studied the expression of toll-like receptors (TLR) TLR2, TLR4 and TLR9, and hypoxia markers HIF-1alpha and Carbonic anhydrase IX (CAIX) in normal and inflamed pancreatic ducts, in PanINs and in cancers. The samples of 69 surgically resected pancreatic ductal adenocarcinoma patients were stained using immunohistochemistry. We found TLR2, TLR9, HIF-1alpha and CAIX to be prominently expressed in pancreatic intraepithelial neoplasia. Expression of TLR2 showed a linear increase from PanIN1 to PanIN3, while the highest TLR4 expression was detected in inflamed ducts, and TLR9 expression in PanIN1 lesions. Within the PanIN1-group, nuclear HIF-1alpha correlated with membranous and cytoplasmic TLR2 expression (ρ = 0.982 and 0.815; p < 0.001 and p = 0.025, respectively), and in the PanIN2-group nuclear HIF-1alpha correlated with nuclear TLR9 expression 0.636, p = 0.026). Our findings show that the expression of TLRs 2, 4 and 9, and hypoxia markers HIF-1alpha and CAIX is abnormal in pancreatic intraepithelial neoplasia suggesting that both the innate immunity activation and hypoxia response are involved in early pancreatic carcinogenesis. However, these processes might be independent.

Weak HIF-1alpha expression indicates poor prognosis in resectable pancreatic ductal adenocarcinoma.

BACKGROUND: HIF-1alpha and CAIX proteins are commonly expressed under hypoxic conditions, but other regulatory factors have been described as well. Pancreatic ductal adenocarcinoma (PDAC) is characterized by hypoxia and strong stromal reaction and has a dismal prognosis with the currently available treatment modalities. METHODS: We investigated the expression and prognostic role of HIF-1alpha and CAIX in PDAC series from Northern Finland (n = 69) using immunohistochemistry. RESULTS: In our PDAC cases, 95 and 85% showed HIF-1alpha and CAIX expression, respectively. Low HIF-1alpha expression correlated with poor prognosis, and multivariate analysis identified weak HIF-1alpha intensity as an independent prognostic factor for PDAC-specific deaths (HR 2.176, 95% CI 1.216-3.893; p = 0.009). There was no correlation between HIF-1alpha and CAIX expression levels, and the latter did not relate with survival. CONCLUSIONS: Our findings are in contrast with previous research by finding an association between low HIF-1alpha and poor prognosis. The biological mechanisms remain speculative, but such an unexpected relation with prognosis and absence of correlation between HIF-1alpha and CAIX suggests that the prognostic association of HIF-1alpha may not directly be linked with hypoxia. Accordingly, the role of HIF-1alpha might be more complex than previously thought and the use of this marker as a hypoxia-related prognostic factor should be addressed with caution.

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

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.

KDM4D Predicts Recurrence in Exocrine Pancreatic Cells of Resection Margins from Patients with Pancreatic Adenocarcinoma.

BACKGROUND/AIM: The role of histone demethylators, such as Jumonji domain 2 (JMJD2/KDM4) proteins, and histone deacetylases, such as sirtuins (SIRT) is poorly characterized in pancreatic carcinomas while they have a major role in the carcinogenesis of several other tumours. MATERIALS AND METHODS: We assessed retrospectively with immunohistochemistry the expressions of KDM4A, KDM4B and KDM4D in 81 and SIRT1-4 in 102 pancreatic adenocarcinomas. Immunostaining was evaluated separately in benign pancreatic tissues and in malignant cells. RESULTS: High nuclear KDM4D expression in benign pancreatic tissue from resection margins associated with dismal disease-free survival (DFS) (OR=8.00; 95%CI=1.87-33.9; p=0.005), even more significantly than tumour size and lymph node involvement. High cytoplasmic SIRT2 expression in benign pancreatic tissues also associated with a shorter DFS, but only in univariate analysis (p=0.026). CONCLUSION: Nuclear KDM4D and SIRT2 expression deviated from that of benign pancreatic tissue thus putatively influencing gene expression of tumor cells. Regardless, none of the enzymes studied had a decisive role in the spread of pancreatic cancer. A high nuclear expression of KDM4D in samples of pancreatic resection margins significantly and independently predicted an earlier recurrence and could thus be used in the assessment of risk of relapse in clinical practice.

High toll-like receptor (TLR) 9 expression is associated with better prognosis in surgically treated pancreatic cancer patients.

Pancreatic cancer remains one of the deadliest malignancies in the world. Inflammatory response and tumor environment are thought to play a major role in its pathogenesis. Knowledge on TLR expression and impact on patient survival in pancreatic cancer is limited. The study's aim was to clarify the role of different TLRs in pancreatic cancer. TLR2, TLR4, and TLR9 expression was investigated in 65 surgically resected pancreatic ductal adenocarcinoma specimens by immunohistochemistry. The association between TLR expression, clinical parameters, and local inflammatory response to the tumor was assessed using chi-square test. Relation between patient survival and TLR expression was calculated with multivariable Cox regression, adjusted for age, sex, and tumor stage. We found TLR2, TLR4, and TLR9 to be expressed in pancreatic cancer. There was no association between TLR expression and tumor stage, tumor size, lymph node metastasis, or tumor necrosis. Contrary to our initial hypothesis, high cytoplasmic TLR9 expression was associated with longer patient survival, and multivariate analysis identified low TLR9 expression as an independent risk factor for cancer-specific death (HR 3.090, 95% CI 1.673-5.706). The results suggest that high TLR9 expression in pancreatic ductal adenocarcinoma indicates improved prognosis. The prognostic effect of TLR9 might be associated with bacterial exposure, but this needs further evidence.

Loss of Peroxiredoxin Expression Is Associated with an Aggressive Phenotype in Pancreatic Adenocarcinoma.

BACKGROUND: The role of the redox-regulating peroxiredoxin (Prx) enzymes I-VI in pancreatic carcinoma is poorly characterized. MATERIALS AND METHODS: The expression of Prxs I, II, III, V and VI was immunohistochemically evaluated in benign pancreas and in 69 pancreatic adenocarcinoma samples. RESULTS: Cytoplasmic Prx I expression was significantly greater in cancer cells than in benign pancreas (p=0.002) and Prx I expression in adenocarcinoma cells was associated with a larger tumour (p=0.005). Stronger cytoplasmic Prx III expression was associated with node negativity (p=0.007) and better tumor differentiation (p=0.033). Greater cytoplasmic Prx V expression was associated with smaller tumours (p=0.029) and negative nodal status (p=0.003). Among patients with T3-4 tumours, stronger intensity of cytoplasmic Prx I was associated with longer relapse-free survival (p=0.041). In patients with tumours of T3-4 class only, cytoplasmic Prx VI expression was associated with longer disease-free survival (p=0.0037). CONCLUSION: Peroxiredoxins appear to be promising prognostic factors in cases of pancreatic adenocarcinoma, and this may be related to their potential as tumour suppressors.

Keap1 expression has independent prognostic value in pancreatic adenocarcinomas.

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. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/4220521801406476.