Identification of novel predictive markers for the prognosis of pancreatic ductal adenocarcinoma

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.

Systematic review of peri-operative prognostic biomarkers in pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) continues to be associated with a poor prognosis. This systematic review aimed to summarize the literature regarding potential prognostic biomarkers to facilitate validation studies and clinical application.

METHODS

A systematic review was performed (2004-2014) according to PRISMA guidelines. Studies were ranked using REMARK criteria and the following outcomes were examined: overall/disease free survival, nodal involvement, tumour characteristics, metastasis, recurrence and resectability.

RESULTS

256 biomarkers were identified in 158 studies. 171 biomarkers were assessed with respect to overall survival: urokinase-type plasminogen activator receptor, atypical protein kinase C and HSP27 ranked the highest. 33 biomarkers were assessed for disease free survival: CD24 and S100A4 were the highest ranking. 17 biomarkers were identified for lymph node involvement: Smad4/Dpc4 and FOXC1 ranked highest. 13 biomarkers were examined for tumour grade: mesothelin and EGFR were the highest ranking biomarkers. 10 biomarkers were identified for metastasis: p16 and sCD40L were the highest ranking. 4 biomarkers were assessed resectability: sCD40L, s100a2, Ca 19-9, CEA.

CONCLUSION

This review has identified and ranked specific biomarkers that should be a primary focus of ongoing validation and clinical translational work in PDAC.

Prognostic role of HER2 amplification based on fluorescence in situ hybridization (FISH) in pancreatic ductal adenocarcinoma (PDAC): a meta-analysis

Background

Previous studies have shown that human epidermal growth factor receptor 2 (HER2) may play an important role in the invasion and metastasis of pancreatic cancer, but the relationship between HER2 amplification level and prognosis of pancreatic cancer patients is still controversial. Therefore, we performed a meta-analysis to determine the prognostic significance of HER2 amplification based on fluorescence in situ hybridization (FISH) in patients with pancreatic cancer.

Methods

PubMed, EMBASE, and Web of Science (Jan 2001 to Jun 2015) were searched. Only articles that detect the HER2 amplification by FISH method were included. RevMan 5.3 and STATA version 12 were used to perform this meta-analysis. Pooled calculations were carried out on hazard ratio (HR) and 95 % confidence interval (CI) to assess the risk of disease.

Results

A total of six eligible studies were enrolled in meta-analysis. The univariate analysis results showed that HER2 amplification was not significantly associated with patients’ overall survival (pooled HR, 1.87, 95 % CI, 0.64–5.46, P = 0.25), which are maintained in one study of multivariate analysis (HR 0.51, 95 % CI, 0.12–2.14, P = 0.358). HER2 amplification also had no correlation with clinicopathological factors such as age, gender, lymph node metastasis, and tumor stage.

Conclusions

Our results showed that HER2 amplification based on FISH may not be a good prognostic factor for survival in patients with pancreatic cancer.

Reduced expression of caspase-8 and cleaved caspase-3 in pancreatic ductal adenocarcinoma cells

Pancreatic ductal adenocarcinoma (PDAC) is a rare neoplasm that affects the gastrointestinal system, and is characterized by a high mortality rate. It has been demonstrated that apoptosis has a significant role in the regulation of cancer cells. Therefore, the aim of the present study was to immunohistochemically assess the expression of proteins belonging to the caspase family, namely caspase-8, pro-caspase-3 and cleaved (active) caspase-3 in pancreatic cancer. The study group consisted of 29 patients exhibiting PDAC. Protein expression was evaluated by immunohistochemical methods. The expression of caspase-8 in normal cells was negative in 17.2% of cases and positive in 82.8% of cases. All cases demonstrated pro-caspase-3 expression in normal pancreatic cells, compared with 93.1% of cancer cells. Staining for activated caspase-3 was positive in 27 normal tissue cases, compared with positivity in only 10 cancer cases. Caspase-8 expression positively correlated with cleaved caspase-3 expression in the cytoplasm of cancer cells (P<0.002). Caspase-3 expression was identified to correlate with inflammatory peritumoral infiltration (P<0.015). No correlation was observed between caspase expression and any other clinicopathological parameters. The results of the present study demonstrated aberrant initiation of cancer cell apoptosis in PDAC via a decrease in caspase-8 expression, which may lead to disorders in the activation of effector caspase-3.

Prognosis Relevance of Serum Cytokines in Pancreatic Cancer

The overall survival of patients with pancreatic ductal adenocarcinoma is extremely low. Although gemcitabine is the standard used chemotherapy for this disease, clinical outcomes do not reflect significant improvements, not even when combined with adjuvant treatments. There is an urgent need for prognosis markers to be found. The aim of this study was to analyze the potential value of serum cytokines to find a profile that can predict the clinical outcome in patients with pancreatic cancer and to establish a practical prognosis index that significantly predicts patients' outcomes. We have conducted an extensive analysis of serum prognosis biomarkers using an antibody array comprising 507 human cytokines. Overall survival was estimated using the Kaplan-Meier method. Univariate and multivariate Cox's proportional hazard models were used to analyze prognosis factors. To determine the extent that survival could be predicted based on this index, we used the leave-one-out cross-validation model. The multivariate model showed a better performance and it could represent a novel panel of serum cytokines that correlates to poor prognosis in pancreatic cancer. B7-1/CD80, EG-VEGF/PK1, IL-29, NRG1-beta1/HRG1-beta1, and PD-ECGF expressions portend a poor prognosis for patients with pancreatic cancer and these cytokines could represent novel therapeutic targets for this disease.

Cyclin D1, p16(INK) (4A) and p27(Kip1) in pancreatic adenocarcinoma: assessing prognostic implications through quantitative image analysis

The prognostic significance of cyclin D1, p16(INK) (4A) and p27(Kip1) expression has been documented in several human malignancies; however, their prognostic potential in pancreatic adenocarcinoma is still unclear. This study aimed to assess the correlation of the aforementioned molecules with clinicopathological parameters and prognosis. Sixty patients with pancreatic ductal adenocarcinoma underwent surgical resection at a single institution; immunohistochemical staining of the studied markers was quantified by Ιmage analysis system. Cyclin D1 overexpression was positively associated with grade, neural infiltration and vascular invasion, whereas p27 positively correlated with age. Higher cyclin D1 expression indicated poorer survival (adjusted HR = 9.75, 95%CI: 1.48-64.31, p = 0.018, increment: one unit in H-score), whereas a marginal trend toward an association between p16 positivity and improved survival was observed (adjusted HR = 0.58, 95%CI: 0.32-1.05, p = 0.072 regarding positive vs negative cases). No significant association with overall survival was noted regarding p27. In conclusion, cyclin D1 overexpression and possibly p16 loss of expression in pancreatic adenocarcinoma seem to be adverse prognostic factors, whereas p27 expression did not seem to possess such prognostic properties. Further validation of the present findings in studies encompassing larger samples seems to be needed.

Frizzled-2: A potential novel target for molecular pancreatic cancer therapy

In the present study, pancreatic cancer cell proliferation was analyzed following the suppression of frizzled (Fz)2 expression. Reverse transcription polymerase chain reaction (PCR) was performed using RNA isolated from pancreatic cancer cell lines, PANC-1, NOR-P1, PK-45H, PK-1, PK-59, MIA-Paca2 and KP4. A surgical specimen of pancreatic cancer was immunostained with antibodies specific to Fz2. Cell proliferation assays were performed with MIA-Paca2 cells transfected with small interfering RNA (siRNA) or short hairpin RNA (shRNA) of Fz2. Fz2 was found to be expressed in all pancreatic cancer cell lines, with the exception of NOR-P1. Immunostaining revealed that Fz2 was not expressed in normal pancreatic tissues, while it was expressed in pancreatic cancer cells. The expression levels of cyclin D1 were analyzed by quantitative PCR. The proliferation and expression of cyclin D1 were suppressed with the siRNA and shRNA of Fz2 in the MIA-Paca2 cells. Therefore, Fz2 is a potential target for the molecular therapy of pancreatic cancer.

Clinicopathological and prognostic significance of myofibrillogenesis regulator-1 protein expression in pancreatic ductal adenocarcinoma

Myofibrillogenesis regulator-1 (MR-1) expression was detected in different malignancies and is associated with poor prognosis. However, its role in pancreatic ductal adenocarcinoma (PDAC) has not been fully elucidated. Thus, the aim of this study was to investigate the association of MR-1 expression with clinicopathologic features and prognosis in patients with PDAC. Immunohistochemistry was performed to investigate the protein expression of MR-1 and epithelial (E)-cadherin in 87 patients with PDAC. Results showed that MR-1 expression was correlated with histologic grade, tumor stage, and lymph node metastasis (all P <0.05). In addition, MR-1 expression showed a significant inverse correlation with E-cadherin expression (P = 0.002). Furthermore, the variables associated with prognosis were analyzed by Cox's proportional hazards model. Kaplan-Meier analysis was used to plot survival curves according to different expression levels of MR-1. Kaplan-Meier analysis revealed that MR-1 expression was significantly associated with worse disease-free survival (DFS) and overall survival (OS) rates in patients with PDAC (both P <0.001). Finally, multivariate analysis demonstrated that MR-1 expression, together with histologic grade, tumor stage, lymph node metastasis, was an independent prognostic factor for both DFS and OS rates in patients with PDAC. MR-1 overexpression was tightly associated with more aggressive tumor behavior and a poor prognosis, indicating that MR-1 is a valuable molecular biomarker for PDAC progression.