p53 overexpression in lymph node metastases predicts clinical outcome in ductal pancreatic cancer

Pancreatic cancer: promise for personalised medicine?

Pancreatic cancer has an infaust prognosis and is the fourth commonest cause of cancer related death in men. Design of rational treatment has been hampered by lack of insight into the pathogenesis of the disease. Recently more insight has been gained into a number of crucial aspects of pancreatic carcinogenesis, in particular the cell types that can give rise to oncological transformation in the pancreas, different modes of interaction between transformed pancreatic cells and the stroma that fosters further disease progression, the need of the pancreatic tumour cells to overcome the pressure of immune surveillance and the various changes in intercellular biochemistry that tumour cells employ to both sustain chemoresistance and metastasis. Although still largely incomplete, this new knowledge opens novel avenues on more successful treatment of the disease through personalised medicine.

Systematic review of immunohistochemical biomarkers to identify prognostic subgroups of patients with pancreatic cancer

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) carries a dismal prognosis. There is a need to identify prognostic subtypes of PDAC to predict clinical and therapeutic outcomes accurately, and define novel therapeutic targets. The purpose of this review was to provide a systematic summary and review of available data on immunohistochemical (IHC) prognostic and predictive markers in patients with PDAC.

METHODS

Relevant articles in English published between January 1990 and June 2010 were obtained from PubMed searches. Other articles identified from cross-checking references and additional sources were reviewed. The inclusion was limited to studies evaluating IHC markers in a multivariable setting.

RESULTS

Database searches identified 76 independent prognostic and predictive molecular markers implicated in pancreatic tumour growth, apoptosis, angiogenesis, invasion and resistance to chemotherapy. Of these, 11 markers (Ki-67, p27, p53, transforming growth factor β1, Bcl-2, survivin, vascular endothelial growth factor, cyclo-oxygenase 2, CD34, S100A4 and human equilibrative nucleoside transporter 1) provided independent prognostic or predictive information in two or more separate studies.

CONCLUSION

None of the molecular markers described can be recommended for routine clinical use as they were identified in small cohorts and there were inconsistencies between studies. Their prognostic and predictive values need to be validated further in prospective multicentre studies in larger patient populations. A panel of molecular markers may become useful in predicting individual patient outcome and directing novel types of intervention.

Meta-analysis of immunohistochemical prognostic markers in resected pancreatic cancer

BACKGROUND

The potential prognostic value of several commonly investigated immunohistochemical markers in resected pancreatic cancer is variably reported. The objective of this study was to conduct a systematic review of literature evaluating p53, p16, smad4, bcl-2, bax, vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) expression as prognostic factors in resected pancreatic adenocarcinoma and to conduct a subsequent meta-analysis to quantify the overall prognostic effect.

METHODS

Relevant literature was identified using Medline, EMBASE and ISI Web of Science. The primary end point was overall survival assessed on univariate analysis. Only studies analysing resected pancreatic adenocarcinoma were eligible for inclusion and the summary log(e) hazard ratio (logHR) and variance were pooled using an inverse variance approach. Evidence of heterogeneity was evaluated using the χ(2) test for heterogeneity and its impact on the meta-analysis was assessed by the I(2) statisic. Hazard ratios greater than one reflect adverse survival associated with positive immunostaining.

RESULTS

Vascular endothelial growth factor emerged as the most potentially informative prognostic marker (11 eligible studies, n=767, HR=1.51 (95% confidence interval, CI=1.18-1.92)) with no evidence of any significant publication bias (Egger's test, P=0.269). Bcl-2 (5 eligible studies, n=314, HR=0.51 (95% CI=0.38-0.68)), bax (5 studies, n=274, HR=0.63 (95% CI=0.48-0.83)) and p16 (3 studies, n=229, HR=0.63 (95% CI=0.43-0.92)) also returned significant overall survival differences, but in smaller patient series due to a lack of evaluable literature. Neither p53 (17 studies, n=925, HR=1.22 (95% CI=0.96-1.56)), smad4 (5 studies, n=540, HR=0.88 (95% CI=0.61-1.27)) nor EGFR (4 studies, n=250, HR=1.35 (95% CI=0.80-2.27)) was found to represent significant prognostic factors when analysing the pooled patient data. There was evidence of significant heterogeneity in four of the seven study groups.

CONCLUSION

These results support the case for immunohistochemical expression of VEGF representing a significant and reproducible marker of adverse prognosis in resected pancreatic cancer.

Predictive value of tumor proliferative indices in periampullary cancers: Ki-67, mitotic activity index (MI) and volume corrected mitotic index (M/V) using tissue microarrays

BACKGROUND

Morphometry [nuclear Ki-67 labelling, mitotic activity index (MI), and volume-corrected mitotic index (M/V)] for periampullary cancers using tissue microarrays has not been performed previously. The purpose of the study was to assess these indices on tissue microarray (TMA) sections constructed from patients with periampullary cancers and study their association with clinicopathological variables.

METHODS

Immunohistochemical staining for Ki-67 was performed on formalin-fixed pancreatic TMA sections. Expression of Ki-67 was assessed as the percentage of cancer cell nuclei expressing MIB1, MI as the mean percentage of Ki-67 from 10 random high-power fields, and M/V was calculated after standardizing MI for connective tissue volume and microscope parameters in the tumor using established protocols.

RESULTS

Patients > or =70 years with periampullary cancers had higher Ki-67 expression (>15) compared with patients <70 years of age (chi(2) = 3.9, P = 0.047). Ki-67 expression was higher in tumors > or =2 cm (chi(2) = 4.9, P = 0.028) compared with smaller tumors. Higher MI (>15) was clearly associated with worsening histological grade (chi(2) = 9.2, P = 0.010). The median survival for tumors of the pancreaticobiliary subtype (pancreatic ductal adenocarcinoma and cholangiocarcinoma) was 43 months in the group with an M/V score of <20, compared with 18 months for the group with a score > or =20 (P = 0.001). There was no statistically significant difference in survival, based on M/V score, for tumors of the intestinal subtype (ampullary and duodenal adenocarcinoma).

CONCLUSIONS

In periampullary cancers, Ki-67 and MI are proliferative indices predictive of tumor behavior. M/V was predictive of survival in tumors of the pancreaticobiliary subtype.

SMAD4 gene mutations are associated with poor prognosis in pancreatic cancer

PURPOSE

Recently, the majority of protein coding genes were sequenced in a collection of pancreatic cancers, providing an unprecedented opportunity to identify genetic markers of prognosis for patients with adenocarcinoma of the pancreas.

EXPERIMENTAL DESIGN

We previously sequenced more than 750 million base pairs of DNA from 23,219 transcripts in a series of 24 adenocarcinomas of the pancreas. In addition, 39 genes that were mutated in more than one of these 24 cancers were sequenced in a separate panel of 90 well-characterized adenocarcinomas of the pancreas. Of these 114 patients, 89 underwent pancreaticoduodenectomy, and the somatic mutations in these cancers were correlated with patient outcome.

RESULTS

When adjusted for age, lymph node status, margin status, and tumor size, SMAD4 gene inactivation was significantly associated with shorter overall survival (hazard ratio, 1.92; 95% confidence interval, 1.20-3.05; P = 0.006). Patients with SMAD4 gene inactivation survived a median of 11.5 months, compared with 14.2 months for patients without SMAD4 inactivation. By contrast, mutations in CDKN2A or TP53 or the presence of multiple (> or =4) mutations or homozygous deletions among the 39 most frequently mutated genes were not associated with survival.

CONCLUSIONS

SMAD4 gene inactivation is associated with poorer prognosis in patients with surgically resected adenocarcinoma of the pancreas.

Molecular prognostic markers in pancreatic cancer: a systematic review

Pancreatic cancer is one of the most lethal tumours of the gastrointestinal tract. The ability to predict which patients would benefit most from surgical intervention and/or chemotherapy would be a great clinical asset. Considerable research has focused on identifying molecular events in pancreatic carcinogenesis, and their correlation with clinicopathological variables of pancreatic tumours and survival. This systematic review examined evidence from published manuscripts looking at molecular markers in pancreatic cancer and their correlation with tumour stage and grade, response to chemotherapy and long-term survival. A literature search was undertaken using PubMed and MEDLINE search engines, using the keywords p53, p21, p16, p27, SMAD4, K-ras, cyclin D1, Bax, Bcl-2, EGFR, EGF, c-erbB2, HB-EGF, TGFbeta, FGF, MMP, uPA, cathepsin, heparanase, E-cadherin, laminins, integrins, TMSF, CD44, cytokines, angiogenesis, VEGF, IL-8, beta-catenin, DNA microarray, and gene profiling. A bewildering number of biomarkers are currently under evaluation. For the most part, the evidence regarding their application as prognostic indicators is conflicting. The advent of gene microarray and mass spectrometric protein profiling offers the potential to examine many different biomarkers simultaneously. This 'protein/gene signature' could revolutionise work in this field and allow researchers to develop accurate and reproducible predictions of survival based on protein or gene profiles.

Clinical significance of p16 protein expression loss and aberrant p53 protein expression in pancreatic cancer

Pancreatic cancer is a disease with poor prognosis mainly due to low resection rates and late diagnosis. To increase resectability and improve survival rates, a better understanding of pancreatic cancer pathogenesis and more effective screening techniques are required. New methods, such as genetic and molecular alterations, may suggest novel approaches for pancreatic cancer diagnosis and treatment. We immunohistochemically investigated 44 formalin-fixed, paraffin-embedded specimens of pancreatic ductal adenocarcinoma using monoclonal anti-p16 antibodies and monoclonal anti-p53 antibodies. The expressions of p16 and p53 proteins were compared using the Chi-square test with SPSS. Disease-free survival was analyzed using the Kaplan-Meier method, verified by the Log- Rank test. Loss of p16 expression was noted in 20 (45.5%) cases and aberrant p53 protein expression was detected in 14 (31.8%) cases. Loss of p16 expression was associated with a higher incidence of lymph node metastasis (p=0.040) and a more advanced stage (p=0.015), although there was no significant correlation between p16 expression and survival. Aberrant p53 protein expression correlated with histologic grade (p= 0.038). Disease-free survival rate was significantly lower in the aberrant p53 protein positive group compared to the negative group (p=0.029). From our results, we suggest that p53 is not a prognostic factor; however, p16 and p53 genes do play important roles in the progression of pancreatic ductal adenocarcinoma.

Clinicopathological significance and molecular regulation of maspin expression in ductal adenocarcinoma of the pancreas

We evaluated the biological relevance of maspin expression in pancreatic ductal adenocarcinoma and studied regulatory mechanisms of maspin gene activation in pancreatic carcinoma cell lines. Maspin expression was immunohistochemically detected in a series of 57 pancreatic ductal adenocarcinomas, 51 (90%) of which were classified as high-expressers. In lymph node metastases, maspin expression was somewhat decreasingly found in 39/49 (80%). Maspin high-expressers showed predominantly a low histological grade (p=0.013). Moreover, maspin expression was found in two mixed ductal-endocrine carcinomas, but not in 10 endocrine tumors and the surrounding normal pancreatic tissues. Using a luciferase reporter system, maspin promoter activity was induced in the maspin-positive pancreatic cancer cell lines as well as maspin-negative PANC-1 cells. Additionally, treatment with the DNA methyltransferase inhibitor, 5-aza-2' deoxycytidine, and histone deacetylase inhibitor, trichostatin A, led to re-expression of maspin mRNA in PANC-1 cells. Our results indicate that maspin expression is up-regulated in most if not all pancreatic ductal adenocarcinomas and may be related to the development and differentiation, and that DNA methylation and histone deacetylation may suppress maspin gene activation in pancreatic cancer cells.

The pancreas--hermit of the abdomen

The pancreas is almost impossible to palpate because it is located in the retroperitoneal space. Life-threatening lesions, therefore, often are not diagnosed until they are very advanced and encroaching on adjacent structures. The pancreas has a large endocrine and exocrine reserve, which also contributes to difficulty in diagnosing pancreatic disease. This article provides an in-depth analysis of the anatomy and physiology of the pancreas and endocrinopathies, allowing nurses to provide optimal care for patients with pancreatic abnormalities.

Immunotherapy for pancreatic cancer: current concepts

Despite advances in chemotherapy and surgical technique, patients with pancreatic cancer often succumb to local recurrence or metastatic spread. The need for new therapeutic strategies for this disease coupled with a better understanding of basic immunology have led to the development of novel anti-tumor vaccines. This review focuses on the historical development of tumor vaccines emphasizing the identification of potential pancreatic tumor antigens. The role of both B-cell and T-cell responses in tumor rejection will be reviewed. Methods for antigen presentation, including peptides, recombinant viral and bacterial vectors, dendritic cells, and whole cell approaches will be discussed. The use of immune adjuvants and improved methods of vaccine delivery will also be explored. The full potential for the immunotherapy of pancreatic cancer awaits the results of early phase clinical trials. The development of pancreatic cancer vaccines represents a useful paradigm for the translation of basic research into the clinical arena.

Innovative treatments for pancreatic cancer

Pancreatic cancer is the fifth leading cause of cancer deaths in the United States with little or no impact from conventional treatment options. Significant advances in understanding basic immunology have renewed interest in using immunotherapy to treat pancreatic cancer. Cancer immunotherapy, including humanized MAbs, cytokines, and potent vaccine strategies, has been successful in animal models and is being evaluated in clinical trials. Gene therapy is also being explored using methods to inactivate oncogenes, replace defective tumor suppressor genes, confer enhanced chemosensitivity to tumor cells, and increase immunogenicity of tumor cells. Angiogenesis, an essential step in the growth and metastasis of pancreatic cancer, has been targeted by many antiangiogenic agents. Several clinical trials have been initiated to evaluate the role of these innovative strategies in patients with pancreatic cancer with increasingly sophisticated correlative studies to learn more about the mechanisms of tumor rejection with these agents. The rapid translation of basic science discoveries to clinical trials should result in the development of new effective treatments for patients with pancreatic cancer.

Histone H3 mRNA in situ hybridization for identifying proliferating cells in human pancreas, with special reference to the ductal system

In general, the incidence of proliferating cells parallels that of carcinogenesis. We have investigated proliferating activity and phenotype expression in epithelial cells in normal tissue, mucinous metaplasia and ductal adenocarcinoma of the pancreas. Twenty-eight resected pancreases (15 cases of pancreatic ductal adenocarcinoma and 13 cases of other diseases) were examined. Formalin-fixed, paraffin-embedded tissue sections were examined for proliferating cell activity using histone H3 mRNA in situ hybridization and immunostaining for Ki-67. In the normal pancreas, the labelling indices for proliferating cells were low and no generating zone was found. The following progressive increase was found in the labelling indices: normal ductal epithelium < mucinous metaplasia without papillary hyperplasia < mucinous metaplasia with papillary hyperplasia < ductal carcinoma. In the pancreatic ductal adenocarcinomas, the S-phase fraction, as defined by the ratio H3-mRNA-labelling index/Ki-67-labelling index, increased as the degree of differentiation decreased. Mucinous metaplasia with papillary hyperplasia showed organoid differentiation toward pyloric mucosa. If used in combination with other proliferative markers on paraffin-embedded tissue sections, histone H3 mRNA in situ hybridization could open broader perspectives on the biology of cell proliferation in the pancreatic ductal system.