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Purpose: Pancreatic ductal adenocarcinoma (PDAC) is lethal cancer whose primary tumor is characterized by dense composition of cancer cells, stromal cells, and extracellular matrix (ECM) composed largely of collagen. Within the PDAC tumor microenvironment, activated pancreatic stellate cells (PSC) are the dominant stromal cell type and responsible for collagen deposition. Lumican is a secreted proteoglycan that regulates collagen fibril assembly. We have previously identified that the presence of lumican in the ECM surrounding PDAC cells is associated with improved patient outcome after multimodal therapy and surgical removal of localized PDAC. Experimental Design: Lumican expression in PDAC from 27 patients was determined by IHC and quantitatively analyzed for colocalization with PSCs. In vitro studies examined the molecular mechanisms of lumican transcription and secretion from PSCs (HPSCs and HPaSteC), and cell adhesion and migration assays examined the effect of lumican on PSCs in a collagen-rich environment. Results: Here we identify PSCs as a significant source of extracellular lumican production through quantitative IHC analysis. We demonstrate that the cytokine, TGF-β, negatively regulates lumican gene transcription within HPSCs through its canonical signaling pathway and binding of SMAD4 to novel SBEs identified within the promoter region. In addition, we found that the ability of HPSCs to produce and secrete extracellular lumican significantly enhances HPSCs adhesion and mobility on collagen. Conclusions: Our results demonstrate that activated pancreatic stellate cells within PDAC secrete lumican under the negative control of TGF-β; once secreted, the extracellular lumican enhances stellate cell adhesion and mobility in a collagen-rich environment. Clin Cancer Res; 22(19); 4934–46. ©2016 AACR.

PURPOSE: The ColoCare Study is an international cohort of men and women (>18 years age) newly diagnosed with stage I-IV colorectal cancer from seven centers in the United States and Germany. Study enrollment is currently ongoing. Here, we describe the clinical and demographic characteristics of this large cohort of prospectively followed colorectal cancer patients and describe differences in demographic, lifestyle, and clinical characteristics by age of onset and tumor site. METHODS: Data on demographics (sex, age, race, ethnicity) and lifestyle factors (smoking, body mass index) collected at baseline are included in this analysis, in addition to information on tumor characteristics (tumor stage and site), treatment (neoadjuvant and adjuvant therapy), and clinical outcomes (vital status, recurrence). Patients were categorized into early- ( RESULTS: Data on 1,933 stage I-IV colorectal cancer cases were included in this study, 19% of which were deceased at the time of this analysis. On average, patients were 60 years old, had a BMI of 29 kg/m2, and were predominantly diagnosed with stage II (25%) and stage III (33%) colorectal cancer. Fifty three percent of cases were diagnosed with colon cancer, while 47% were rectal cancer cases. Twenty percent (n=364) of patients were diagnosed before age 50 (i.e. early-onset cases). The early-onset group presented with a higher percentage of rectal cancer (52%) and more advanced disease (64% stage III-IV cancer) compared to late-onset cases (46% and 48%, respectively). Percentages of ever smokers were higher among late-onset compared to early-onset patients (51% vs. 38%), independent of tumor site. Early-onset cancers were more likely to originate in the rectum compared to colon, particularly among women (61% vs. 51%). Early-onset rectal cancer cases were more likely to be female as compared to late-onset rectal cancer cases (61% vs. 36%). Corresponding with national trends, early-onset cases received more aggressive adjuvant therapy after surgical resection compared to late-onset patients (54% vs. 40%). DISCUSSION: Within this large international multi-center cohort, patients with early-onset colorectal cancer were more likely to be diagnosed with rectal cancer and advanced stage disease. The majority of early-onset cases in the ColoCare Study were non-smokers. As expected, more aggressive treatment modalities were used in patients with early-onset disease. Citation Format: Caroline Himbert, Jane Figueiredo, Lyen Huang, Biljana Gigic, Courtney L. Scaife, Bartley Pickron, Laura Lambert, Jessica Cohan, Mary Bronner, Jolanta Jedrzkiewicz, Esther Herpel, Matthias Kloor, Johanna Nattenmueller, Hans-Ulrich Kauczor, Alexis Ulrich, Seth Felder, Julian Sanchez, Sophie Dessureault, Nathan Hinkle, Justin Monroe, Matthew Mutch, Cory Bernadt, Deyali Chatterjee, Mika Sinanan, Stacey Cohen, Ulrik Wallin, Deepti Reddi, Mukta Krane, Afshin E. Gabayan, David M. Hoffman, Yosef Y. Nasseri, Robert W. Decker, Karen Zaghiyan, Zuri A. Murrell, Andrew E. Hendifar, Jun Gong, Eiman Firoozmand, Alexandra Gangi, Beth A. Moore, Kyle G. Cologne, Maryliza El-Masry, William Grady, Martin Schneider, Stephanie L. Schmit, Erin Siegel, David Shibata, Adetunji Toriola, Christopher Li, Cornelia Ulrich, Sheetal Hardikar. Clinical characteristics and outcomes of colorectal cancer in the ColoCare Study: Differences by age of onset [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2364.

Neoadjuvant treatment (NAT) followed by total mesorectal excision is currently considered the standard of treatment for rectal adenocarcinoma. The degree of pathologic treatment response (pTR) correlates significantly with the recurrence free survival and overall survival (OS). However, it remains unclear which clinical and pathologic factors are associated with a more robust response to NAT, including showing pathologic complete response (pCR). Chemokine receptor 4 (CXCR4) overexpression has been associated with unfavorable OS in some studies. In this study, we sought to evaluate the clinicopathologic determinants of pTR in neoadjuvant treated rectal adenocarcinoma (NAT-RA). We retrospectively identified 91 patients who underwent pre-treatment diagnostic biopsy, NAT, and surgical resection at our institution. The archival slides were reviewed for pathologic features in the pre-treatment biopsies and for assessment of pTR in the resection specimens according to the current College of American Pathologist (CAP)'s guidelines. pCR was obtained in 16.5% of the cases, whereas 20.9% had near pCR, 30.8% had partial response, and 31.9% had a poor/no response. CXCR4 immunohistochemical analysis was also performed on the pre-treatment biopsies. Lower pre-treatment cT-stage (p = 0.019) and pre-treatment AJCC cTNM stage groups (p = 0.004), longer time interval between completion of NAT and resection (p = 0.022), and presence of tumor-infiltrating lymphocytes in the pre-treatment biopsies (p = 0.019) were significantly associated with a better pTR. CXCR4 nuclear expression was associated with a lower percentage of residual tumor (p = 0.036). Pre-treatment CEA levels, tumor differentiation, CAP treatment response groups and lower percentage of residual tumor were associated with a better OS.

In the setting of neoadjuvant therapy (NAT) for pancreatic ductual adenocarcinoma (PDAC), accurate measurement of tumor size, and consequently, staging based on AJCC eighth edition, is difficult. Attempts to address the limitations of tumor size in the NAT setting have included correlation of residual tumor percent with survival. However, only cases with complete pathologic response or minimal residual disease have shown better prognosis compared with all other groups. To date, no studies have simultaneously evaluated the prognostic value of tumor size and tumor regression in the setting of PDAC status post NAT (NAT-PDAC). Our aim was to study the prognostic value of residual tumor index (RTI), a metric combining residual tumor percent and tumor bed size as an interaction term (% residual tumor×tumor bed size [cm]). In a cohort of 105 cases of NAT-PDAC, we show that RTI supersedes the prognostic value of AJCC eighth edition T staging via multivariate cox regression. At a binary cutoff of 0.35 for RTI, the hazard ratio for recurrence-free survival is 3.26 (95% confidence interval, 1.51-7.04), P0.01. We further identified cutoffs of ≤0.2, 0.2 to 2 and2 that stratified our cases into 3 groups via RTI, which were statistically significant in Kaplan-Meier curve analysis of recurrence-free survival (P0.01) and overall survival (P0.01). RTI represents a novel metric for combining the prognostic value of tumor size and residual tumor in NAT-PDAC.

Granulite xenoliths preserve key geochemical and isotopic signatures of their mantle source regions. Mafic granulite and pyroxinite xenoliths within massif-type charnockitic rocks from the Eastern Ghats Belt have recently been reported by us. The mafic granulite xenoliths from the Chilka Lake granulite suite with abundant prograde biotite are geochemically akin to Oceanic Island Basalt (OIB). They can be distinguished from the hornblende-mafic granulite xenoliths with signatures of Arc-derived basalt occurring in the other suites of the Eastern Ghats Belt. These two groups of xenoliths in the Paleoproterozoic Eastern Ghats Province have quite distinct Nd-model ages- 1.9 Ga and 2.5 Ga respectively, which may be interpreted as their crustal residence ages. Strong positive Nb anomalies, indicating subducted oceanic crust in the source, LREE enrichment and strongly fractionated REE pattern are key geochemical signatures attesting to their origin as OIB-type magma. Also low Yb and Sc contents and high (La / Yb)N ratios can be attributed to melting in the presence of residual garnet and hence at great depths (> 80 km). The variable enrichment in radiogenic 87Sr, between 0.70052 and 0.71092 at 1.9 Ga and less radiogenic 143Nd between ε-1.54 and 7.46 are similar to those of the OIBs compared to MORBs. As OIBs commonly contain some recycled oceanic crust in their sources, we suggest that the residue of the oceanic crust from a previous melting event (~ 2.5 Ga) that produced the Arc-derived basalts (protoliths of hornblende-mafic granulite xenoliths) could have subducted to great depths and mechanically mixed with the mantle peridotite. A subsequent re-melting event of this mixed source might have occurred at ca. 1.9 Ga as testified by the crustal residence ages of the biotite-mafic granulite xenoliths of the Chilka Lake granulite suite.

Colorectal cancer is the second leading cause of cancer death in the United States. Significant limitations in screening and surveillance modalities continue to hamper early detection of primary cancers or recurrences after therapy. In this study, we describe a new registered ultrasound (US) and acoustic-resolution photoacoustic microscopy (AR-PAM) system and report its initial testing in ex vivo human colorectal tissue. A total of 8 colorectal specimens were imaged, which included 2 polyps, 4 malignant colon cancers, and 2 treated colorectal cancers. In each specimen, normal tissue was also imaged for internal control. Initial data have demonstrated the feasibility of identifying colorectal cancer imaging features and the invasion depth using co-registered US and an AR-PAM system. In normal tissue, we found that our system consistently demonstrates the multi-layer structure of normal colonic tissue while differentiating layers with elevated vascularity; these findings highly correlated with histologic findings of each specimen. For malignant colorectal samples, the tissue structure is highly disorganized as seen in US, and photoacoustic imaging revealed distorted vascular distribution inside the tumor. Notably, AR-PAM of tumor beds after complete tumor destruction by radiation and chemotherapy yielded a pattern identical to benign tissue. Quantitative analysis of photoacoustic spectral slope has demonstrated more high-frequency components in malignant tissue as compared to the normal colon tissue, which may be caused by significantly increased microvessel networks. In summary, we demonstrate the successful differentiation of benign and malignant colorectal tissue with our co-registered ultrasound and photoacoustic system.

A spatial frequency domain imaging (SFDI) was used to image ex vivo human colon tissues. Significant differences were observed between absorption, scattering, scatter slope, total hemoglobin and spatial heterogeneities of benign and malignant tissue groups.

Prostate cancer is the second leading cause of cancer-related death of men in the USA. TheTMPRSS2/ERG (T/E)fusion gene is present in approximately 50% of prostate cancers and promotes tumor progressionin vivo. The presence of theT/Efusion gene is strongly associated with the expression of ERG protein, but emerging evidence indicates a significant interfocal and intrafocal variability in the levels of ERG protein expression. We therefore analyzed ERG protein expression by image analysis to objectively quantitate the extent of such heterogeneity, and confirmed significant interfocal and intrafocal variability of ERG protein expression levels in cancer expressing ERG. To define the pathways associated with ERG and its variable expression in prostate cancer, we have analyzed the correlations of ERG expression, as evaluated by immunohistochemistry, with 46 key proteins associated with signal transduction, transcriptional control, and other processes using a large tissue microarray with more than 500 prostate cancers. We found a significant correlation of ERG expression with the markers of activation of the PI3K, MYC, and NFκB pathways, which had previously been linked directly or indirectly to ERG expression. We have also identified significant correlations with novel proteins that have not been previously linked to ERG expression, including serum response factor, the p160 coactivator SRC1, and Sprouty1. Notably, SKP2 only correlated with a high level of ERG protein expression. Thus ERG expression is variable in prostate cancer and is associated with activation of multiple pathways and proteins including several potentially targetable pathways.

The American Joint Committee for Cancer (AJCC) has adopted a size-based T stage system (8th edition) for pancreatic ductal adenocarcinoma (PDAC), defined as follows: pT1 ≤ 2 cm (pT1a ≤ 0.5 cm, pT1b > 0.5 cm and < 1 cm, and pT1c 1–2 cm); pT2 > 2 cm and ≤ 4 cm; and pT3 > 4 cm. However, the prognostic value of this new T staging system has not been validated in patients who underwent pancreaticoduodenectomy (PD) after neoadjuvant therapy. In this study, we analyzed 398 PDAC patients who underwent neoadjuvant therapy and PD at our institution from 1999 to 2012. The results were correlated with clinicopathologic parameters and survival. The new T stage correlated with lymph nodes metastasis (p0.05). In multivariate analysis, new ypT3 stage was associated with shorter OS (p=0.04), but not DFS (p=0.16). Our results show that the new ypT stage better stratify survival than the ypT stage in AJCC 7th edition for PDAC patients who received PD after neoadjuvant therapy, and that tumor size cut off of 1.0 cm work better for ypT2 than the proposed tumor size cut off of 2.0 cm in this group of patients.

Previous studies on the molecular alterations in ampullary adenocarcinoma (AA) are limited, and little is known about their clinical implications. The objective of this study is to examine the expression of p53, p21, cyclin D1, and Bcl2 and their clinical significance in patients with AA. Tissue microarrays were constructed using archival tissue from 92 patients with AA who underwent pancreaticoduodenectomy at our institution. Each tumor was sampled in triplicate with a 1.0-mm punch from representative areas. The expression of p53, p21, cyclin D1, and Bcl2 was evaluated by immunohistochemistry, and the staining results were correlated with clinicopathological features and survival. Among 92 cases studied, overexpression of p53, p21, cyclin D1, and Bcl2 was observed in 58.7%, 39.2%, 71.7%, and 5.4% of tumors, respectively. Patients whose tumor showed high level of cyclin D1 expression had higher risk of disease recurrence (P = .02) and worse recurrence-free and overall survivals after pancreaticoduodenectomy than did those with no or low cyclin D1 expression (P = .027 and P = .02, respectively). In multivariate analysis, cyclin D1 expression was an independent prognostic factor for both recurrence-free and overall survival (P.05). However, there was no significant correlation between p53, p21, or Bcl2 expression and survival (P.05). Our study showed that p53, p21, and cyclin D1, but not Bcl2, are frequently overexpressed in AAs. Cyclin D1 overexpression is associated with increased risk of disease recurrence and worse survival in patients with AA after resection.

pColorectal cancer is the second most common malignancy diagnosed globally. Critical gaps exist in diagnostic and surveillance imaging modalities for colorectal neoplasia. Although prior studies have demonstrated the capability of photoacoustic imaging techniques to differentiate normal from neoplastic tissue in the gastrointestinal tract, evaluation of deep tissue with a fast speed and a large field of view remains limited. To investigate the ability of photoacoustic technology to image deeper tissue, we conducted a pilot study using a real-time co-registered photoacoustic tomography (PAT) and ultrasound (US) system. A total of 23italicex vivo/italichuman colorectal tissue samples were imaged immediately after surgical resection. Co-registered photoacoustic images of malignancies showed significantly increased PAT signal compared to normal regions of the same sample. The quantitative relative total hemoglobin (rHbT) concentration computed from four optical wavelengths, the spectral features, such as the mean spectral slope, and 0.5-MHz intercept extracted from PAT and US spectral data, and image features, such as the first- and second-order statistics along with the standard deviation of the mean radon transform of PAT images, have shown statistical significance between untreated colorectal tumors and the normal tissue. Using either a logistic regression model or a support vector machine, the best set of parameters of rHbT and PAT intercept has achieved area-under-the-curve (AUC) values of 0.97 and 0.95 for both training and testing data sets, respectively, for prediction of histologically confirmed invasive carcinoma./p.

In the past few years, a better understanding of the genomic alterations in lung cancer has facilitated a targeted therapy. Lung adenocarcinomas with epidermal growth factor receptor mutations have a good response to tyrosine kinase inhibitors (TKIs). Osimertinib is a third-generation TKI approved by the Food and Drug Administration (FDA). Drug-induced liver injury is a well-known adverse effect of TKIs as a group and reported to show an autoimmune hepatitis-like picture. However, little is known about the histopathologic changes with osimertinib. We present a case of drug-induced liver injury secondary to osimertinib and discuss the histopathologic findings.

Background & Aims Obesity is a risk factor for pancreatic ductal adenocarcinoma (PDAC), but it is not clear how obesity contributes to pancreatic carcinogenesis. The oncogenic form of KRAS is expressed during early stages of PDAC development and is detected in almost all of these tumors. However, there is evidence that mutant KRAS requires an additional stimulus to activate its full oncogenic activity and that this stimulus involves the inflammatory response. We investigated whether the inflammation induced by a high-fat diet, and the accompanying up-regulation of cyclooxygenase-2 (COX2), increases Kras activity during pancreatic carcinogenesis in mice. Methods We studied mice with acinar cell−specific expression of KrasG12D (LSL-Kras/Ela-CreERT mice) alone or crossed with COX2 conditional knockout mice (COXKO/LSL-Kras/Ela-CreERT). We also studied LSL-Kras/PDX1-Cre mice. All mice were fed isocaloric diets with different amounts of fat, and a COX2 inhibitor was administered to some LSL-Kras/Ela-CreERT mice. Pancreata were collected from mice and analyzed for Kras activity, levels of phosphorylated extracellular-regulated kinase, inflammation, fibrosis, pancreatic intraepithelial neoplasia (PanIN), and PDACs. Results Pancreatic tissues from LSL-Kras/Ela-CreERT mice fed high-fat diets (HFDs) had increased Kras activity, fibrotic stroma, and numbers of PanINs and PDACs than LSL-Kras/Ela-CreERT mice fed control diets; the mice fed the HFDs also had shorter survival times than mice fed control diets. Administration of a COX2 inhibitor to LSL-Kras/Ela-CreERT mice prevented these effects of HFDs. We also observed a significant reduction in survival times of mice fed HFDs. COXKO/LSL-Kras/Ela-CreERT mice fed HFDs had no evidence for increased numbers of PanIN lesions, inflammation, or fibrosis, as opposed to the increases observed in LSL-Kras/Ela-CreERT mice fed HFDs. Conclusions In mice, an HFD can activate oncogenic Kras via COX2, leading to pancreatic inflammation and fibrosis and development of PanINs and PDAC. This mechanism might be involved in the association between risk for PDAC and HFDs.

Purpose: The most common genetic lesions in pancreatic ductal adenocarcinoma (PDAC) have been identified. However, significant gaps still exist in our understanding of how such genetic alterations act in concert to induce PDAC development. In this study, we investigated the mechanism of tumorigenic transformation in the immortalized human pancreatic ductal epithelial (HPDE) cell line by sequentially introducing PDAC signature alterations into this cell line. Experimental Design: The phenotype for stable expression of mutant K-ras, Her2, p16/p14shRNA, and Smad4shRNA in HPDE cells was examined by assays for cell proliferation, migration, invasion, soft agar, and orthotopic tumorigenesis. The mechanisms of tumorigenic transformation were further explored by gene expression profiling and pathway analyses. Results: The transformed cells exhibited enhanced proliferation, migration, and invasion, displayed anchorage-independent growth in soft agar, and grew orthotopic tumors with some histopathologic features of PDAC. We found that Smad4 played key roles in the tumorigenic transformation of HPDE cells. We further found that MDM2 and Bmi-1 were overexpressed in the tumorigenic HPDE cells and that Bmi-1 overexpression was regulated by Smad4. Ingenuity Pathway Analysis software analysis of microarray data revealed that dysregulation of integrin-linked kinase signaling and the cell cycle were the most significant changes involved in tumorigenic transformation. Altogether, this cell culture model closely recapitulated human pancreatic carcinogenesis from gene lesions, activation of specific signaling pathways, and some histopathologic features. Conclusion: The combination of activated K-ras and Her2 with inactivated p16/p14 and Smad4 was sufficient and essential to transform HPDE cells, thus revealing the potential tumorigenic mechanism. Clin Cancer Res; 19(3); 549–59. ©2012 AACR.

Purpose To determine the safety, tolerability and maximum tolerated dose (MTD) of addition of erlotinib to bevacizumab and capecitabine-based definitive chemoradiation (CRT) in unresectable pancreatic cancer. Methods Seventeen patients with CT-staged, biopsy-proven unresectable pancreatic cancer were enrolled between 3/2008 and 10/2010. Prior chemotherapy was permitted. Two patients each were enrolled at dose levels (DLs) 1–4 and 9 patients at DL 5. All patients received 50.4 Gy (GTV only) in 28 fractions with concurrent capecitabine, bevacizumab and erlotinib. Dose of each drug was escalated in 5 DLs using the continual reassessment method. Bevacizumab was escalated from 5mg/Kg q2weeks (DLs 1–4) to 10mg/Kg q2weeks (DL 5); daily erlotinib from 100mg/day (DLs 1–2) to 150 mg/Kg (DLs 3–5); and capecitabine from 400mg/m2 twice daily on days of radiation (DL 1) to 650mg/m2 (DLs 2–3) to 825 mg/m2 (DLs 4–5). Reassessment for potential resection was performed 6–8 weeks later. Results Sixteen patients received gemcitabine-based chemotherapy prior to CRT. With a median clinical follow-up of 10 months, no grade 3 toxicities were observed in DLs 1–4. Three (33%) patients at DL 5 developed a grade 3 acute toxicity (2 diarrhea, 1 rash). No grade 4 or 5 toxicities were seen. DL 4 was selected as the MTD; therefore, the recommended doses in combination with radiation are: bevacizumab, 5mg/Kg q2weeks; erlotinib, 150 mg/Kg daily; and capecitabine, 825mg/m2 BID. Median survival was 17.4 months. Of the five patients who underwent resection, 4 were originally deemed locally advanced and 1 was borderline resectable. Three patients had excellent pathological response (2 complete response and 20% viable tumor) at surgery, and the 2 patients with complete response are still alive at 61 and 67 months of follow up with no local or distant failures. Conclusions This chemoradiation regimen at the recommended dose levels is safe and tolerable for patients with unresectable pancreatic cancer and merits further evaluation.

Purpose: Protein phosphatase 4 (PP4) has been reported to be overexpressed in breast and lung cancers. PP4 plays an important role in the regulation of centrosome maturation, DNA repair, NF-κB, and c-jun-NH2-kinase (JNK) signaling pathways. However, the expression and functions of PP4 in pancreatic cancer have not been studied. Experimental Design: We examined the expression of PP4 catalytic subunit (PP4C) protein in 133 patients with stage II pancreatic ductal adenocarcinoma (PDAC) and their paired benign pancreatic samples (N = 113) by immunohistochemistry. To confirm the immunohistochemical results, we measured PP4C protein and mRNA levels by Western blotting and real-time reverse transcriptase PCR. Using univariate and multivariate analysis, we correlated PP4C expression with survival and other clinicopathologic features. Results: PP4C was overexpressed in 75 of 133 (56.4%) stage II PDAC samples, which was significantly higher than the paired benign pancreatic tissue (15%, 17 of 113). PP4C mRNA expression levels were also higher in PDAC samples than the paired benign pancreatic tissue. Overexpression of PP4C in PDAC samples was associated with higher frequencies of distant metastasis (P = 0.02) and poor disease-free and overall survivals in patients with stage II PDAC (P = 0.006 and 0.02) independent of tumor size, margin status, and lymph node status (stage). Conclusions: Our study showed that PP4C is overexpressed in PDAC. Overexpression of PP4C in PDAC samples is associated with poor prognosis in patients with stage II PDAC. Therefore, targeting PP4 signaling pathway may represent a new approach for the treatment of PDAC. Impact: Our study showed that PP4C is an independent prognostic factor in patients with stage II PDAC. Cancer Epidemiol Biomarkers Prev; 21(8); 1336–43. ©2012 AACR.

Lymphovascular invasion (LVI) is a prognostic factor in many types of human malignancies, including pancreatic ductal adenocarcinoma (PDAC). However, the prognostic significance of LVI in patients with PDAC who have received neoadjuvant therapy and pancreaticoduodenectomy is unclear. In this study, we analyzed LVI in 212 patients who had received neoadjuvant chemoradiation and subsequent pancreaticoduodenectomy at our institution between January 1999 and December 2007. LVI was present in 61.8% (131/212) of the patients. Of the 131 patients who were positive for LVI, 67 (31.6%) had tumor invasion into lymphovascular spaces without muscle layer (nonmuscular lymphovascular spaces), and 64 (30.2%) had tumor invasion into muscular vessels. Tumor invasion into muscular vessels correlated with higher frequencies of positive resection margin, lymph node metastasis, and locoregional/distant recurrence. Patients with tumor invasion into muscular vessels had significantly shorter disease-free survival and overall survival than did patients who had no LVI or who had tumor invasion of nonmuscular lymphovascular spaces (P

Perineural invasion (PNI) is one of the established prognostic factors in pancreatic ductal adenocarcinoma (PDAC). However, the prognostic significance of PNI in patients with PDAC who received neoadjuvant therapy and pancreaticoduodenectomy is not clear. In this study, we performed a detailed examination of neural invasion in pancreaticoduodenectomy specimens from 212 patients with PDAC who received neoadjuvant chemoradiation (treated group) and in 60 untreated patients at our institution between January 1999 and December 2007. The frequency of PNI was higher in the untreated group (80%, 48/60) than in the treated group (58%, 123/212). For the 123 treated cases that were positive for PNI, extratumoral PNI, intratumoral PNI, intrapancreatic PNI only, extrapancreatic PNI, and intraneural invasion were identified in 86 (69.9%), 37 (30.1%), 11 (8.9%), 112 (91.1%), and 35 cases (28.5%), respectively. The presence of PNI correlated with tumor size, margin status, lymph node metastasis, pathologic tumor, and American Joint Committee on Cancer stages in the treated group. Tumor involvement of nerves0.8 mm correlated with higher frequency of positive margin compared with tumors with PNI involving nerves ≤0.8 mm but not with other clinicopathologic parameters and survival. In the treated group, the presence of PNI or intraneural invasion correlated significantly with shorter disease-free survival and overall survival compared with no PNI or PNI only, respectively. PNI was an independent prognostic factor for both disease-free survival and overall survival in multivariate analysis. Our results showed that PNI plays an important role in the progression of PDAC and in predicting prognosis in this group of patients.

Sclerosing thymoma is an extremely rare entity described mostly in the recent past and, to our knowledge, described in only 14 cases, including one we recently diagnosed at our institution. The pathogenesis and biologic behavior of this relatively unknown entity is still largely uncertain. However, there are several consistent findings among the cases described so far. It is mostly asymptomatic or patients may present with shortness of breath or chest pain due to a large, well-circumscribed mass in the anterior mediastinum. It has a characteristic homogeneously white-tan, solid cut surface without any necrosis, hemorrhage, or cystic change. Microscopically, it is characterized by extensive sclerosis, hyalinization, and calcification. Only scant evidence of residual thymoma may be present to characterize this entity. Complete surgical resection has, so far, been curative. Knowledge of this rare entity in the general practice of surgical pathologists is important when considering the differential diagnosis of anterior mediastinal lesions.

There is substantial heterogeneity in the clinical behavior of pancreatic cancer and in its response to therapy. Some of this variation may be due to differences in delivery of cytotoxic therapies between patients and within individual tumors. Indeed, in 12 patients with resectable pancreatic cancer, we previously demonstrated wide inter-patient variability in the delivery of gemcitabine as well as in the mass transport properties of tumors as measured by computed tomography (CT) scans. However, the variability of drug delivery and transport properties within pancreatic tumors is currently unknown. Here, we analyzed regional measurements of gemcitabine DNA incorporation in the tumors of the same 12 patients to understand the degree of intra-tumoral heterogeneity of drug delivery. We also developed a volumetric segmentation approach to measure mass transport properties from the CT scans of these patients and tested inter-observer agreement with this new methodology. Our results demonstrate significant heterogeneity of gemcitabine delivery within individual pancreatic tumors and across the patient cohort, with gemcitabine DNA incorporation in the inner portion of the tumors ranging from 38 to 74% of the total. Similarly, the CT-derived mass transport properties of the tumors had a high degree of heterogeneity, ranging from minimal difference to almost 200% difference between inner and outer portions of the tumor. Our quantitative method to derive transport properties from CT scans demonstrated less than 5% difference in gemcitabine prediction at the average CT-derived transport value across observers. These data illustrate significant inter-patient and intra-tumoral heterogeneity in the delivery of gemcitabine, and highlight how this variability can be reproducibly accounted for using principles of mass transport. With further validation as a biophysical marker, transport properties of tumors may be useful in patient selection for therapy and prediction of therapeutic outcome.

Recurrence after resection of pancreatic ductal adenocarcinoma (PDAC) is common, thus postoperative surveillance is critical for detection and treatment of recurrent disease. The development of biologically based techniques for early recurrence detection may enable more timely and effective treatment of such recurrences. Tumor fragments derived from patients who underwent potentially curative resection of PDAC were heterotopically implanted into NOD/SCID mice. Engraftment success rates and growth parameters were matched to clinicopathologic data, preoperative treatment status, and oncologic outcomes to correlate disease-free survival (DFS) and overall survival. Seventy patients consented to participate with 56 (80 %) developing a mouse PDAC tumorgraft. Patients with successful engraftment had a shorter median DFS compared with patients whose tumorgrafts failed to engraft (9.8 vs. 40.9 mo, respectively; p

Purpose: To evaluate the relevance between lumican expression patterns and the clinical course of patients with pancreatic ductal adenocarcinoma (PDAC), and to investigate the role of lumican in PDAC progression. Experimental Design: One hundred thirty-one patient tumors were chosen for tissue microarray staining, and Cox regression analysis was used to test the associations between lumican expression and clinical, pathologic, and oncologic outcomes in all patients. Primary PDAC cells and recombinant human lumican protein were used to establish a working model to mimic the in vivo interactions between stromal lumican and PDAC cells. Using this model, we tested the effects of lumican on EGFR signaling via Akt and hypoxia-inducible factor-1α (HIF1α) and its subsequent influence on glucose consumption, lactate production, intracellular ATP, and apoptotic cell death. Results: Lumican was present in the stroma surrounding PDAC cells in roughly one-half of primary tumors and the direct xenografts. Patients with stromal lumican were associated with a profound reduction in metastatic recurrence after surgery and 3-fold longer survival than patients without stromal lumican. In PDAC cells, extracellular lumican reduced EGFR expression and phosphorylation through enhanced dimerization and internalization of EGFR and the resultant inhibition of Akt kinase activity. Lumican also reduced HIF1α expression and activity via Akt. PDAC cells with enhanced HIF1α activity were resistant to lumican-induced inhibition of glucose consumption, lactate production, intracellular ATP, and apoptosis. Conclusions: There is a positive association between stromal lumican in primary PDAC tumors and prolonged survival after tumor resection. Lumican plays a restrictive role in EGFR-expressing pancreatic cancer progression. Clin Cancer Res; 20(24); 6529–40. ©2014 AACR.

Expression of the cellular adhesion protein N-cadherin is a critical event during epithelial-mesenchymal transition (EMT). The SMAD4 protein has been identified as a mediator of transforming growth factor-β (TGF-β) superfamily signaling, which regulates EMT, but the mechanisms linking TGF-β signaling to N-cadherin expression remain unclear. When the TGF-β pathway is activated, SMAD proteins, including the common mediator SMAD4, are subsequently translocated into the nucleus, where they influence gene transcription via SMAD binding elements (SBEs). Here we describe a mechanism for control of CDH2, the gene encoding N-cadherin, through the canonical TGFβ–SMAD4 pathway. We first identified four previously undescribed SBEs within the CDH2 promoter. Using telomerase immortalized human pancreatic ductal epithelium, we found that TGF-β stimulation prompted specific SMAD4 binding to all four SBEs. Luciferase reporter and SMAD4-knockdown experiments demonstrated that specific SMAD4 binding to the SBE located at −3790 bp to −3795 bp within the promoter region of CDH2 was necessary for TGF-β-stimulated transcription. Expression of N-cadherin on the surface of epithelial cells facilitates motility and invasion, and we demonstrated that knockdown of SMAD4 causes decreased N-cadherin expression, which results in diminished migration and invasion of human pancreatic ductal epithelial cells. Similar reduction of cell motility was produced after CDH2 knockdown. Together, these findings suggest that SMAD4 is critical for the TGF-β-driven upregulation of N-cadherin and the resultant invasive phenotype of human pancreatic ductal epithelial cells during EMT.

Many commercially available cell lines have been in culture for ages, acquiring phenotypes that differ from the original cancers from which these cell lines were derived. Therefore, research on new cell lines could improve the success rates of translational research in cancer. We have developed methods for the isolation and culture of human pancreatic ductal adenocarcinoma (PDAC) cells from murine xenografts of human PDAC. We hypothesize that phenotypes of PDAC cells are modified by in vitro culture conditions over time and by in vivo implantation. Patient-derived xenografts were created in immunodeficient mice using surgically resected tumor specimens. These murine xenografts were then used to establish human PDAC cell lines in culture. Earlier (20) passage cell lines were evaluated separately regarding proliferation, cell cycle, genetic mutations, invasiveness, chemosensitivity, tumorigenesis, epithelial-mesenchymal transition (EMT) status, and proteomics. Later passage cells accelerated their doubling time and colony formation, and were more concentrated in the G0/G1 phase and less in the G2/M checkpoint phase. Later passage cells were more sensitive to gemcitabine and 5-fluorouracil than earlier passage cells, but all four new cell lines were more chemo-resistant compared to commercial ATCC cell lines. EMT induction was observed when establishing and passaging cell lines in vitro and furthermore by growing them as subcutaneous tumors in vivo. This study demonstrates a novel approach to the establishment of PDAC cell lines and observes a process by which newly established cell lines undergo phenotypic changes during in vitro culture and in vivo tumorigenesis. This may help explain differences of treatment effects often observed between experiments conducted in vitro, in vivo, and in human clinical trials.

The use of neoadjuvant therapy (NAC) for the treatment of potentially resectable pancreatic cancer remains controversial. In this study, we sought to evaluate cancer-specific endpoints in patients undergoing a NAC versus a surgery-first (SF) approach with specific emphasis on lymph node metastases. A total of 222 patients who underwent NAC and 85 patients who underwent SF were identified from 1990 to 2008 and compared for cancer-related endpoints. Peripancreatic lymph nodes from 135 neoadjuvant therapy patients were evaluated for histologic tumor regression. Patients who underwent NAC followed by surgery had improved overall survival and time to local recurrence compared with the SF approach. NAC patients were less likely to have lymph node metastases (p = 0.001), lymphovascular invasion (LVI), and had smaller tumors. On multivariate analysis, lymph node positivity was associated with SF, tumor size, and the presence of LVI. NAC patients with N0 disease had equivalent outcomes to patients with a low-LNR (0.01–0.15), whereas patients with a LNR >0.15 had reduced survival, and time to local and distant recurrence. Ten of 135 (7.4 %) NAC patients had evidence of tumor regression in at least one lymph node. Patients with potentially resectable PDAC selected to undergo NAC had improved survival and longer time to recurrence. Although some of these differences may be related to improvements in multimodality therapy completion rates, tumor regression in lymph node metastases exists and may demonstrate a biologic benefit of NAC compared with a SF approach.

We describe the use of an endoscopic modified Lothrop approach for clearance of an extensive sinonasal-type hemangiopericytoma of the nasal cavity and paranasal sinuses with bilateral frontal sinus involvement in a 44-year-old woman. The modified Lothrop approach is conventionally used to treat sinusitis, but with some slight modifications to the technique, it can also be used for tumor excision.

Background. The therapeutic resistance of pancreatic ductal adenocarcinoma (PDAC) is partly ascribed to ineffective delivery of chemotherapy to cancer cells. We hypothesized that physical properties at vascular, extracellular, and cellular scales influence delivery of and response to gemcitabine-based therapy. Methods. We developed a method to measure mass transport properties during routine contrast-enhanced CT scans of individual human PDAC tumors. Additionally, we evaluated gemcitabine infusion during PDAC resection in 12 patients, measuring gemcitabine incorporation into tumor DNA and correlating its uptake with human equilibrative nucleoside transporter (hENT1) levels, stromal reaction, and CT-derived mass transport properties. We also studied associations between CT-derived transport properties and clinical outcomes in patients who received preoperative gemcitabine-based chemoradiotherapy for resectable PDAC. Results. Transport modeling of 176 CT scans illustrated striking differences in transport properties between normal pancreas and tumor, with a wide array of enhancement profiles. Reflecting the interpatient differences in contrast enhancement, resected tumors exhibited dramatic differences in gemcitabine DNA incorporation, despite similar intravascular pharmacokinetics. Gemcitabine incorporation into tumor DNA was inversely related to CT-derived transport parameters and PDAC stromal score, after accounting for hENT1 levels. Moreover, stromal score directly correlated with CT-derived parameters. Among 110 patients who received preoperative gemcitabine-based chemoradiotherapy, CT-derived parameters correlated with pathological response and survival. Conclusion. Gemcitabine incorporation into tumor DNA is highly variable and correlates with multiscale transport properties that can be derived from routine CT scans. Furthermore, pretherapy CT-derived properties correlate with clinically relevant endpoints. Trial registration. Clinicaltrials.gov NCT01276613. Funding. Lustgarten Foundation (989161), Department of Defense (W81XWH-09-1-0212), NIH (U54CA151668, KCA088084).

Priyaveena Puvanakrishnan1, Jaesook Park1, Deyali Chatterjee2, Sunil Krishnan2, James W Tunnell11Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA; 2The UT MD Anderson Cancer Center, Houston, TX, USAAbstract: Gold nanoparticles (GNPs) have gained significant interest as nanovectors for combined imaging and photothermal therapy of tumors. Delivered systemically, GNPs preferentially accumulate at the tumor site via the enhanced permeability and retention effect, and when irradiated with near infrared light, produce sufficient heat to treat tumor tissue. The efficacy of this process strongly depends on the targeting ability of the GNPs, which is a function of the particle’s geometric properties (eg, size) and dosing strategy (eg, number and amount of injections). The purpose of this study was to investigate the effect of GNP type and dosing strategy on in vivo tumor targeting. Specifically, we investigated the in vivo tumor-targeting efficiency of pegylated gold nanoshells (GNSs) and gold nanorods (GNRs) for single and multiple dosing. We used Swiss nu/nu mice with a subcutaneous tumor xenograft model that received intravenous administration for a single and multiple doses of GNS and GNR. We performed neutron activation analysis to quantify the gold present in the tumor and liver. We performed histology to determine if there was acute toxicity as a result of multiple dosing. Neutron activation analysis results showed that the smaller GNRs accumulated in higher concentrations in the tumor compared to the larger GNSs. We observed a significant increase in GNS and GNR accumulation in the liver for higher doses. However, multiple doses increased targeting efficiency with minimal effect beyond three doses of GNPs. These results suggest a significant effect of particle type and multiple doses on increasing particle accumulation and on tumor targeting ability.Keywords: gold nanorods, gold nanoshells, tumor targeting, multiple dosing

Several grading schemes for the extent of residual tumor in posttreatment pancreaticoduodenectomy (PD) specimens have been proposed. However, the prognostic significance of these grading schemes is unknown.Histopathologic slides of 223 cases who received neoadjuvant chemoradiation and PD were reviewed. The extent of residual tumor was graded using both the College of American Pathologists (CAP) and the Evans grading systems. The grading results were correlated with clinicopathological parameters and survival.Among the 223 patients, 6 patients (2.7%) showed pathologic complete response (pCR; CAP grade 0 or Evans grade IV), 36 cases (16.1%) had minimal residual tumor (CAP grade 1 or Evans grade III), 124 cases (55.6%) had moderate response (CAP grade 2 or Evans grade IIb), and 57 cases (25.6%) had poor response (CAP grade 3, where 18 had Evans grade I and 39 had Evans grade IIa response). Patients with pCR or minimal residual tumor (response group 1) had better survival rates than those with moderate and poor response (response group 2). Response group 1 patients had lower posttherapy tumor and American Joint Committee on Cancer stages and lower rates of lymph node metastasis, positive resection margin, and recurrence and/or metastasis. Grading the extent of residual tumor is an independent prognostic factor for overall survival in multivariate analysis.pCR or minimal residual tumor in posttreatment PD specimens correlate with better survival in patients with pancreatic ductal adenocarcinoma who received neoadjuvant therapy and PD. Histologic grading of the extent of residual tumor in PD specimen is an important prognostic factor in patients with pancreatic ductal adenocarcinoma who received neoadjuvant therapies.

Cytomegalovirus infection is ubiquitous but often remains asymptomatic in affected patients. Symptomatic cytomegalovirus infection usually occurs in immunocompromised patients— patients who are infected with the Human Immunodeficiency Virus, have received organ transplantations, or are on immunosuppressive therapies. Cytomegalovirus colitis can present with abdominal pain, diarrhea and significant per rectal blood loss. It is a rare entity in immunocompetent patients and can often be missed unless one has a high index of suspicion. We describe a case of CMV colitis in a 78-year-old patient with no known risk factors for immunosuppression who was admitted for respiratory diseases and then subsequently developed transfusion dependent lower gastrointestinal bleeding. She ultimately required surgical resection of her colon. A literature review on CMV colitis, its myriad manifestations and therapeutic outcomes was conducted, with particular emphasis on its occurrence in immunocompetent patients.

Epidermal growth factor receptor (EGFR) acts as a cell response mediator to a range of extracellular factors, including allergens. Eosinophilic esophagitis (EoE) is an allergen-mediated, clinicopathological condition affecting the esophagus. EGFR expression in EoE has not been studied to date. Our objective of this study was to characterize the EGFR expression in EoE. In this retrospective study involving esophageal …

Figure 1. Characterization of different MDSCs subsets in healthy controls and RAC patients. (A) Flow cytometric profile of peripheral blood (upper and mid rows) and tumor cells (lower row) from healthy control and RAC patient. X100 light microscopy image of representative cell in each subset is presented. (B) Flow cytometric analysis of different circulating MDSCs subsets in healthy controls and RAC patients. The figure represents 3 different subjects in each group; *-P

250 Background: Studies by comparative genomic hybridization have demonstrated that the 18q chromosomal region is frequently lost in gastrointestinal neuroendocrine tumors (GI-NET). However, the impact of DPC/SMAD4 loss, which is located 18q21, in the pathogenesis of GI-NET remains controversial. In this study, we sought to determine the protein expression of SMAD4 in GI-NET and the impact on oncologic outcomes. Methods: To investigate the role of SMAD4 in GI-NET, a tissue microarray consisting of 33 GI-NET was constructed and analyzed by immunohistochemistry for SMAD4 expression. SMAD4 expression was classified as negative, SMAD4-low (≤10% cells +) or SMAD4-high (>10% cells+). Staining results were correlated clinicopathologic features and overall survival. Results: Of the 33 tumors examined, 93% were low- or intermediate-grade and 7% high-grade. 35% of GI-NET were negative for SMAD4, 45% were SMAD4-low and 15% SMAD4-high. Expression of Chromogranin was observed in 91% of all tumors, synaptophysin in 94%, CDX2 in 64%, and CK19 in 55%. We were unable to identify any association between loss of SMAD4 and stage or tumor grade. There was an inverse correlation between loss of SMAD4 and CK19 expression, whereby 75% of SMAD4-neg tumors expressed CK19 and only 32% of SMAD4+ expressed CK19 (p=0.01). At a median follow-up of 123 months, median overall survival was 203 months. Survival differences related to SMAD4 status resulted in clinically meaningful, although statistically non-significant, differences in overall survival (SMAD4-low: 132 months vs. SMAD4-high: 203 months, p=0.058). Conclusions: Differences in SMAD4 expression result in clinically important differences in overall survival, although this cohort may be underpowered to detect a statistically-significant difference. Future studies with larger patient populations may be critical to evaluate the importance of SMAD4 in the pathogenesis of GI-NET.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal human malignancies with less than 5% five-year survival rate. Despite significant improvements in medical and surgical oncology and postoperative mortality rate, the overall survival for patients with pancreatic cancer has not changed significantly in the last four decades. Neoadjuvant chemoradiation therapy (NCT) is increasingly used to treat patients with potentially resectable PDAC, especially for patients with borderline resectable disease. However, analysis of prognostic factors is limited for patients with PDAC treated with NCT and pancreaticoduodenectomy. We systemically examined the pancreaticoduodenectomy specimens from 240 consecutive patients with PDAC who received NCT and pancreaticoduodenectomy between 1999 and 2007 at our institution. We found that posttreatment pathologic stage, pathologic tumor response grading, tumor involvement of the superior mesenteric/portal vein, tumor invasion into the muscular vessels, and perineural invasion are significant prognostic factors in our patient population. Therefore careful pathologic evaluation of the pancreatectomy specimens plays a key role in predicting prognosis of patients with PDAC who received NCT and pancreaticoduodenectomy.

Obesity is a risk factor for Pancreatic Ductal Adenocarcinoma (PDAC), but the molecular mechanisms involved are unclear. Oncogenic mutation of K-Ras occurs early and nearly universally in patients with this disease. However, recent evidence indicates that oncogenic Ras is not fully active and for activity to surpass the threshold required to engage a Ras-inflammation feed-forward loop, it requires a stimulus. We hypothesized that high-fat intake acts as an inflammatory stimulus, increasing K-Ras activity and that cyclooxygenase -2 (COX2) expression is required in the inflammatory loop. LSL-K-Ras mice were crossed with elastase-CreER (acinar cell-specific) or Pdx1-Cre (pancreatic cell-specific) to “knock-in” expression of oncogenic K-Ras. Additionally, acinar cell-specific -Ras mice were crossed with COX2 conditional knockout mice. All mice were fed isocaloric diets with different amounts of fat and a COX2 inhibitor was administered to some acinar cell-specific -Ras mice. Pancreata were analyzed for Ras activity, Phospho-ERK levels, inflammation, fibrosis, PanIN and PDAC development. We observed that consumption of a high fat diet (HFD) led to increased K-Ras activity, PanIN formation, fibrotic stroma and PDAC development compared to a control diet. Additionally, we observed a significant reduction in the survival of mice fed a HFD. Genetic deletion of COX2 in acinar cells and COX2 systemic inhibition prevented the HFD-induced effects in acinar cell-specific -Ras mice. These findings indicated that a HFD stimulates activation of oncogenic K-Ras and initiates an inflammatory feed-forward loop requiring the expression of COX2 leading to pancreatic inflammation, fibrosis, PanINs and PDAC. This mechanism may explain the PDAC risks associated with consumption of a HFD. Citation Format: Bincy Philip, Christina L. Roland, Jarek Daniluk, Yan Liu, Deyali Chatterjee, Sobeyda Berenice Gomez, Baoan Ji, Huang Haojie, Huamin Wang, Jason B. Fleming, Craig D. Logsdon, Zobeida Cruz-Monserrate. High fat triggers oncogenic K-Ras activity and a COX2 dependent feed-forward loop to induce pancreatic ductal adenocarcinoma development. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr C61.

Background: PP4 has been reported to be overexpressed in breast and lung cancers. While previous studies have identified the role of PP4 in activating NFκB and JNK signaling pathway, the expression and functions of PP4 in pancreatic cancer has not been studied in detail. Methods: We examined the expression of PP4 protein in 133 patient samples of stage II pancreatic ductal adenocarcinoma (PDA) samples by immunohistochemistry (IHC). To confirm our IHC results, we measured the expression levels of PP4 mRNA in 15 PDA samples and 15 benign pancreatic tissue sample by real time RT-PCR. We also measured PP4 protein levels in in 9 fresh frozen PDA samples and their paired benign pancreatic tissues by Western blot. Using univariate and multivariate analysis, we correlated PP4 expression with survival and other clinicopathologic features. Results: PP4 was overexpressed in 75 of 133 (56%) stage II PDA samples by immunohistochemistry. Compared to benign pancreatic tissue, PP4 protein levels were higher in 9 of 9 PDA samples by Western blot analysis. PP4 mRNA expression levels in PDA samples were significantly higher than benign pancreatic tissue, suggesting that overexpression of PP4 in PDA is due to increase mRNA expression. PP4 overexpression was associated with higher frequencies of distant metastasis (p=0.02) and poor overall and recurrence-free survivals (p = 0.002 and 0.005) independent of tumor size, margin status, and lymph node status (stage) in patients with stage II PDAs. Conclusions: Our study shows that PP4 is frequently overexpressed in PDA samples and is associated with poor prognosis in patients with stage II PDA. Therefore, targeting PP4 signaling pathway may represent a new approach for the treatment of PDA. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5527. doi:1538-7445.AM2012-5527