Differential cell cycle and proliferation marker expression in ductal pancreatic adenocarcinoma and pancreatic intraepithelial neoplasia (PanIN)

Combined utility of Ki-67 index and tumor grade to stratify patients with pancreatic ductal adenocarcinoma who underwent upfront surgery

OBJECTIVE

To investigate the prognostic prediction of a new indicator, combined by tumor grade and Ki-67, in patients with resected pancreatic ductal adenocarcinoma (PDAC).

METHODS

Data were retrospectively collected from consecutive patients who underwent primary resection of pancreas from December 2012 to December 2017. Tumor grade and Ki-67 were reviewed from routine pathological reports. G-Ki67 was classified as three categories as I (G1/2 and Ki-67 < 40%), II (G1/2 and Ki-67 ≥ 40%), and III(G3/4 and all Ki-67).

RESULTS

Cox regression analyses revealed that tumor stage (II vs. I: hazard ratio (HR), 3.781; 95% confidence index (CI), 2.844-5.025; P < 0.001; III vs. I: HR, 7.476; 95% CI, 5.481-10.20; P < 0.001) and G-Ki67 (II vs. I: HR, 1.299; 95% CI, 1.038-1.624; P = 0.022; III vs. I: HR, 1.942; 95% CI, 1.477-2.554; P < 0.001) were independent prognostic factors in the developing cohort. The result was rectified in the validation cohort. In subgroups analysis, G-Ki67 (II vs. I: HR, 1.866 ; 95% CI, 1.045-3.334; P = 0.035; III vs. I: HR, 2.333 ; 95% CI, 1.156-4.705; P = 0.018) also had a high differentiation for survival prediction.

CONCLUSION

Our findings indicate that three-categories of G-Ki67 in resectable PDAC according to the routine pathological descriptions provided additional prognostic information complementary to the TNM staging system.

Downregulation of ZNF395 Drives Progression of Pancreatic Ductal Adenocarcinoma through Enhancement of Growth Potential

BACKGROUND

Progression of pancreatic intraepithelial neoplasia (PanIN) to invasive carcinoma is a critical factor impacting the prognosis of patients with pancreatic tumors. However, the molecular mechanisms involved are not fully understood. We have reported that the process frequently involves loss of chromosome 8p, causing downregulation of DUSP4, thus conferring invasive ability on cancer cells. Here, we focus on ZNF395, whose expression was also found to be decreased by 8p loss and was predicted to be a growth suppressor gene.

METHODS

Pancreatic cancer cell lines inducibly expressing ZNF395 were established to assess the functional significance of ZNF395 in pancreatic carcinogenesis. Immunohistochemistry was also performed to analyze the expression levels of ZNF395 in pancreatic cancer tissues.

RESULTS

Induction of ZNF395 in pancreatic cancer cells resulted in marked activation of JNK and suppression of their proliferation through a delay in cell cycle progression. Immunohistochemistry revealed that ZNF395 was expressed ubiquitously in both normal pancreatic ducts and PanINs but was significantly reduced in invasive cancers, especially those showing poor differentiation.

CONCLUSION

ZNF395 acts as a novel tumor suppressor gene. Its downregulation caused by 8p loss in intraepithelial cells accelerates their proliferation through dysregulation of the cell cycle, leading to progression to invasive cancer.

Tumor budding assessed according to the criteria of the International Tumor Budding Consensus Conference determines prognosis in resected esophageal adenocarcinoma

Only few studies examined the prognostic effect of tumor budding in esophageal adenocarcinomas so far. However, different quantification approaches were used, so results cannot be directly compared. Recently, the International Tumor Budding Consensus Conference (ITBCC) published consensus criteria for the evaluation of tumor budding in colorectal cancer, which we applied in our study. Hematoxylin and eosin (H&E) and cytokeratin (AE1/AE3) stained whole tissue slides of 104 resected esophageal adenocarcinomas were evaluated. The mean count of tumor buds was analyzed in one high power field according to the ITBCC criteria and assigned to budding groups Bd1-3. Tumor budding was significantly associated with a worse overall survival. Regardless of the quantification approach, an increased number of tumor buds was significantly associated with reduced overall survival (OS) (H&E: HR = 1.05 (95% CI 1.029-1.073), p < 0.001; cytokeratin: HR = 1.073 (95% CI 1.045-1.101), p < 0.001). In multivariable analysis tumor budding according to ITBCC criteria on H&E stained slides was an independent prognostic factor. Tumor budding, according to ITBCC criteria, is an independent prognostic factor in resected esophageal adenocarcinoma. Prospective studies using ITBCC criteria are useful in the near future to validate our results.

Different shades of pancreatic ductal adenocarcinoma, different paths towards precision therapeutic applications

BACKGROUND

Different histological and molecular subtypes of pancreatic ductal adenocarcinoma (PDAC), with different molecular composition and survival statistics, have recently been recognised.

MATERIALS AND METHODS

This review describes the currently available studies regarding molecular and histological subtypes in PDAC. Studies from major cohorts such as International Cancer Genome Consortium as well as smaller cohorts are reviewed. We discuss where the described subtypes overlap, where the discrepancies are and which paths forward could be taken regarding diagnosis, ontogeny and therapy.

RESULTS

Four molecular subtypes with strong overlap among the different studies can be found, next to a list of mixed findings. Two of the four subtypes (epithelial classical and mesenchymal basal-like) were represented in every study and were often discriminated in other solid tumours as well. These two subtypes differ substantially in prognosis. One biomarker has been discovered, only discriminating these two subtypes, and insights into subtype-specific therapeutic vulnerabilities are scarce.

CONCLUSION

Subtypes can be reproducibly detected in cohorts of PDAC patients and two of them directly relate with prognosis. A consensus on the subtypes is warranted. Further discovery and validation studies are needed to identify strong biomarkers, to comprehend subtype ontogeny and to define strategies for precision medicine.

Proteomic and genomic profiling of pancreatic cancer

Pancreatic cancer remains the most fatal human tumor type. The aggressive tumor biology coupled with the lack of early detection strategies and effective treatment are major reasons for the poor survival rate. Collaborative research efforts have been devoted to understand pancreatic cancer at the molecular level. Large-scale genomic studies have generated important insights into the genetic drivers of pancreatic cancer. In the post-genomic era, protein sequencing of tumor tissue, cell lines, pancreatic juice, and blood from patients with pancreatic cancer has provided a fundament for the development of new diagnostic and prognostic biomarkers. The integration of mass spectrometry and genomic sequencing strategies may help characterize protein identities and post-translational modifications that relate to a specific mutation. Consequently, proteomic and genomic techniques have become a compulsory requirement in modern medicine and health care. These types of proteogenomic studies may usher in a new era of precision diagnostics and treatment in patients with pancreatic cancer.

p16, p21, and p53 proteins play an important role in development of pancreatic intraepithelial neoplastic

BACKGROUND

Deregulation of cell cycle takes place during the development of many cancers as well as pancreatic ductal adenocarcinoma (PDA), which develops from precursor lesions, most frequently including pancreatic intraepithelial neoplasia (PanIN).

AIMS

The aim of this study was to evaluate and compare the expression of p16, p21, and p53 proteins taking part in the regulation of the cell cycle in normal pancreatic ducts and pancreatic intraepithelial neoplasia at its various advancing stages.

METHODS

The expressions of p16, p21, and p53 were assessed immunohistochemically in 70 patients with different pancreatic diseases (pancreatic ductal adenocarcinoma, pancreatitis, and pancreatic cysts), showing also pancreatic intraepithelial neoplasia. The results correlated with chosen clinicopathological parameters.

RESULTS

Our study revealed a difference in p16, p21, and p53 expressions between normal pancreatic ducts and various stages of PanIN. p16 expression progressively decreased, whereas p21 and p53 increased from normal pancreas to PanIN 1, 2, and 3. The expression of p21 was associated with age, p53 with PanIN location in the pancreas and p16 with the type of primary diseases. Simultaneously, we observed a directly proportional relationship between the expression of p21 and p53 proteins and inversely proportional between the p16 and the p21 and p53 proteins.

CONCLUSIONS

p16, p21, and p53 proteins play an important role in the deregulation of the cell cycle and participate in the development of pancreatic intraepithelial neoplasia. Immunohistochemical evaluation of their expressions may be helpful in the diagnosis of PanIN.

Expression of chosen cell cycle and proliferation markers in pancreatic intraepithelial neoplasia

Introduction

Pancreatic ductal adenocarcinoma is one of the most aggressive tumours that develops from precursor lesions, most frequently including pancreatic intraepithelial neoplasia (PanIN). Deregulation of the cell cycle, responsible for uncontrolled cell proliferation, is an important phenomenon in the development of this cancer.

Aim

To evaluate the cell cycle and the expression of proliferation markers, namely Ki67, PCNA, and cyclin D1 in pancreatic intraepithelial neoplasia at its different stages of progression.

Material and methods

The study group consisted of 70 patients with different pancreatic diseases (pancreatic ductal adenocarcinoma, pancreatitis, and pancreatic cysts), who also had pancreatic intraepithelial neoplasia. Expression of Ki67, PCNA, and Cyclin D1 was analysed immunohistochemically using appropriate antibodies.

Results

Statistically significant differences were demonstrated in Ki67, PCNA, and Cyclin D1 expression between normal pancreatic ducts and various stages of PanIN (p < 0.001). Expression of these proteins increased from normal pancreas to PanIN 1, 2, and 3. Expression of these proteins was higher in stages PanIN 1, 2, and 3 compared to normal pancreas. The expression of Ki67, PCNA, and cyclin D1 was associated with age (p < 0.001), Ki67 and PCNA with sex (p < 0.001), and PCNA with the type of primary disease (p = 0.031). Simultaneously, a directly proportional relationship was established between the expression of all proteins examined (p < 0.001).

Conclusions

An increase in the expression of Ki67, PCNA, and cyclin D1 suggests that these proteins may enhance epithelial cell proliferation and may influence the development of pancreatic intraepithelial neoplasia. Moreover, immunohistochemical assessment of Ki67, PCNA, and cyclin D1 expression may be helpful in the differential diagnosis of PanIN.

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.

The roles of FOXM1 in pancreatic stem cells and carcinogenesis

Pancreatic ductal adenocarcinoma (PDAC) has one of the poorest prognoses among all cancers. Over the past several decades, investigators have made great advances in the research of PDAC pathogenesis. Importantly, identification of pancreatic cancer stem cells (PCSCs) in pancreatic cancer cases has increased our understanding of PDAC biology and therapy. PCSCs are responsible for pancreatic tumorigenesis and tumor progression via a number of mechanisms, including extensive proliferation, self-renewal, high tumorigenic ability, high propensity for invasiveness and metastasis, and resistance to conventional treatment. Furthermore, emerging evidence suggests that PCSCs are involved in the malignant transformation of pancreatic intraepithelial neoplasia. The molecular mechanisms that control PCSCs are related to alterations of various signaling pathways, for instance, Hedgehog, Notch, Wnt, B-cell-specific Moloney murine leukemia virus insertion site 1, phosphoinositide 3-kinase/AKT, and Nodal/Activin. Also, authors have reported that the proliferation-specific transcriptional factor Forkhead box protein M1 is involved in PCSC self-renewal and proliferation. In this review, we describe the current knowledge about the signaling pathways related to PCSCs and the early stages of PDAC development, highlighting the pivotal roles of Forkhead box protein M1 in PCSCs and their impacts on the development and progression of pancreatic intraepithelial neoplasia.

Expression of cell cycle regulatory proteins in eyelid sebaceous gland carcinoma: low p27 expression predicts poor prognosis

Prognosis of eyelid sebaceous gland carcinoma is largely unpredictable and there are few practically available markers for predicting patients' prognosis. Dysregulation of cell cycle progression is strongly associated with the development of cancer and the cancer prognosis. We investigated the expression of cell cycle regulatory proteins in eyelid sebaceous gland carcinoma and estimate their value as prognostic predictors. Forty-three cases of eyelid sebaceous gland carcinoma were included in this study. Immunohistochemistry for the p53, p21, p27, cyclin E, p16, cyclin D1, and phosphorylated Rb (pRb) proteins was performed using archival paraffin blocks. Correlations between clinical features and protein expression were evaluated statistically. Nine patients showed lymph node or distant metastasis, and the remaining patients showed localized disease. High expression of p21, p27, cyclin E, and p16 was found in the majority of tumor cell nuclei, whereas these proteins were rarely expressed in the normal sebaceous glands. However, pRb was focally lost in a subset of cases. Patients showing diffuse p27 expression developed metastasis less commonly than those with negative or focal p27 expression (log-rank test, p = 0.008). Aberrant expression of cell cycle regulatory proteins was observed in eyelid sebaceous gland carcinoma, suggesting that cell cycle dysregulation is involved in the pathogenesis of this tumor. Decreased p27 expression is a predictive biomarker of an unfavorable prognosis of eyelid sebaceous gland carcinoma.

Phenethyl isothiocyanate inhibits proliferation and induces apoptosis in pancreatic cancer cells in vitro and in a MIAPaca2 xenograft animal model

Pancreatic cancer is often diagnosed at an advanced stage and it has a poor prognosis that points to an increased need to develop effective chemoprevention strategies for this disease. We examined the ability of phenethyl isothiocyanate (PEITC), a naturally occurring isothiocyanate found in cruciferous vegetables, to inhibit the growth of pancreatic cancer cells in vitro and in a MIAPaca2 xenograft animal model. Exposure to PEITC inhibited pancreatic cancer cell growth in a dose-dependent manner, with an IC50 of approximately 7 μmol/L. PEITC treatment induced G2/M phase cell cycle arrest, downregulated the antiapoptotic proteins Bcl-2 and Bcl-XL, upregulated the proapoptotic protein Bak, and suppressed Notch 1 and 2 levels. In addition, treatment with PEITC induced cleavage of poly-(ADP-ribose) polymerase and led to increased cytoplasmic histone-associated DNA fragmentation and subdiploid (apoptotic) fraction in pancreatic cancer cells. Oral administration of PEITC suppressed the growth of pancreatic cancer cells in a MIAPaca2 xenograft animal model. Our data show that PEITC exerts its inhibitory effect on pancreatic cancer cells through several mechanisms, including G2/M phase cell cycle arrest and induction of apoptosis, and supports further investigation of PEITC as a chemopreventive agent for pancreatic cancer.

Prognostic significance of L-type amino-acid transporter 1 expression in surgically resected pancreatic cancer

BACKGROUND

The expression of L-type amino-acid transporter 1 (LAT1) is tumour-specific and has been shown to have essential roles in cell growth and survival. However, little is known regarding the clinical significance of LAT1 expression in pancreatic cancer. This study was conducted to determine the prognostic significance of LAT1 expression.

METHODS

A total of 97 consecutive patients with surgically resected pathological stage I-IV pancreatic ductal adenocarcinoma were retrospectively reviewed. Tumour sections were stained by immunohistochemistry for LAT1, CD98, Ki-67 and vascular endothelial growth factor (VEGF), and microvessel density was determined by CD34 and p53.

RESULTS

L-type amino-acid transporter 1 and CD98 were highly expressed in 52.6% (51/97) and 56.7% (55/97) of cases, respectively (P=0.568). The expression of LAT1 within pancreatic cancer cells was significantly associated with disease stage, tumour size, Ki-67, VEGF, CD34, p53 and CD98. L-type amino-acid transporter 1 expression was confirmed to be a significant prognostic factor for predicting poor outcome by multivariate analysis.

CONCLUSION

L-type amino-acid transporter 1 expression is a promising pathological marker for the prediction of outcome in patients with pancreatic cancer.

A novel survival-based tissue microarray of pancreatic cancer validates MUC1 and mesothelin as biomarkers

BACKGROUND

One-fifth of patients with seemingly 'curable' pancreatic ductal adenocarcinoma (PDA) experience an early recurrence and death, receiving no definable benefit from a major operation. Some patients with advanced stage tumors are deemed 'unresectable' by conventional staging criteria (e.g. liver metastasis), yet progress slowly. Effective biomarkers that stratify PDA based on biologic behavior are needed. To help researchers sort through the maze of biomarker data, a compendium of ∼2500 published candidate biomarkers in PDA was compiled (PLoS Med, 2009. 6(4) p. e1000046).

METHODS AND FINDINGS

Building on this compendium, we constructed a survival tissue microarray (termed s-TMA) comprised of short-term (cancer-specific death <12 months, n = 58) and long-term survivors (>30 months, n = 79) who underwent resection for PDA (total, n = 137). The s-TMA functions as a biological filter to identify bona fide prognostic markers associated with survival group extremes (at least 18 months separate survival groups). Based on a stringent selection process, 13 putative PDA biomarkers were identified from the public biomarker repository. Candidates were tested against the s-TMA by immunohistochemistry to identify the best markers of tumor biology. In a multivariate model, MUC1 (odds ratio, OR = 28.95, 3+ vs. negative expression, p = 0.004) and MSLN (OR = 12.47, 3+ vs. negative expression, p = 0.01) were highly predictive of early cancer-specific death. By comparison, pathologic factors (size, lymph node metastases, resection margin status, and grade) had ORs below three, and none reached statistical significance. ROC curves were used to compare the four pathologic prognostic features (ROC area = 0.70) to three univariate molecular predictors (MUC1, MSLN, MUC2) of survival group (ROC area = 0.80, p = 0.07).

CONCLUSIONS

MUC1 and MSLN were superior to pathologic features and other putative biomarkers as predicting survival group. Molecular assays comparing cancers from short and long survivors are an effective strategy to screen biomarkers and prioritize candidate cancer genes for diagnostic and therapeutic studies.

MicroRNA-375 and MicroRNA-221: Potential Noncoding RNAs Associated with Antiproliferative Activity of Benzyl Isothiocyanate in Pancreatic Cancer

The deregulated presence or absence of microRNAs (miRNAs) might play an important role in molecular pathways leading to neoplastic transformation. At present, it is also thought that the approaches to interfere miRNA functions should be helpful for developing novel therapeutic opportunities for human cancer. In this study, we provide evidence that the anticancer agent benzyl isothiocyanate (BITC) has the ability to modulate the level of miRNAs such as miR-221 and miR-375, known to be abnormally expressed in pancreatic cancer patients. Interestingly, ectopic expression of miR-375 or the enforced silencing of miR-221 in cultured pancreatic cancer cells attenuates cell viability and sensitizes antiproliferative action of BITC. We also show that the expression of putative tumor suppressor miR-375 is more abundant in nonpathological mice pancreata than those with Kras(G12D)-driven pancreatic intraepithelial neoplasia (PanIN). To the contrary, the expression of oncogenic miR-221 is significantly elevated in the mouse pancreas with PanIN lesions. Although miR-375 has been shown to be aberrantly expressed in pancreatic cancer patients, there has not been a comprehensive study to investigate the molecular pathways targeted by this miRNA in pancreatic cancer cells. Further analysis by gene expression microarray revealed that IGFBP5 and CAV-1, potential biomarkers of pancreatic cancer, were significantly downregulated in cells transfected with miR-375. Correlatively, elevated expression of IGFBP5 and CAV-1 was evident in the mouse pancreas with preneoplastic lesions in which the expression of miR-375 wanes. Taken together, our findings suggest that anticancer agent BITC might target the expression of miR-221 and miR-375 to switch hyperproliferative pancreatic cancer cells to a hypoproliferative state.

Skp2 is required for incretin hormone-mediated β-cell proliferation

The glucoincretin hormone glucagon-like peptide-1 (GLP-1) and its analog exendin-4 (Ex-4) promote β-cell growth and expansion. Here we report an essential role for Skp2, a substrate recognition component of SCF (Skp, Cullin, F-box) ubiquitin ligase, in promoting glucoincretin-induced β-cell proliferation by regulating the cellular abundance of p27. In vitro, GLP-1 treatment increases Skp2 levels, which accelerates p27 degradation, whereas in vivo, loss of Skp2 prevents glucoincretin-induced β-cell proliferation. Using inhibitors of phosphatidylinositol 3-kinase and Irs2 silencing RNA, we also show that the effects of GLP-1 in facilitating Skp2-dependent p27 degradation are mediated via the Irs2-phosphatidylinositol-3 kinase pathway. Finally, we show that down-regulation of p27 occurs in islets from aged mice and humans, although in these islets, age-dependent accumulation of p16(Ink4a) prevent glucoincretin-induced β-cell proliferation; however, ductal cell proliferation is maintained. Taken together, these data highlight a critical role for Skp2 in glucoincretin-induced β-cell proliferation.

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.