IGF2BP3 as a Prognostic Biomarker in Well-Differentiated/Dedifferentiated Liposarcoma

BACKGROUND

Although IGF2BP3 has been implicated in tumorigenesis and poor outcomes in multiple cancers, its role in soft-tissue sarcoma (STS) remains unknown. Preliminary data have suggested an association with IGF2BP3 expression among patients with well-differentiated/dedifferentiated liposarcoma (WD/DD LPS), a disease where molecular risk stratification is lacking.

METHODS

We examined the survival associations of IGF2BP3 via univariate and multivariate Cox regression in three unique datasets: (1) the Cancer Genome Atlas (TCGA), (2) an in-house gene microarray, and (3) an in-house tissue microarray (TMA). A fourth dataset, representing an independent in-house TMA, was used for validation.

RESULTS

Within the TCGA dataset, IGF2BP3 expression was a poor prognostic factor uniquely in DD LPS (OS 1.6 vs. 5.0 years, p = 0.009). Within the microarray dataset, IGF2BP3 expression in WD/DD LPS was associated with worse survival (OS 7.7 vs. 21.5 years, p = 0.02). IGF2BP3 protein expression also portended worse survival in WD/DD LPS (OS 3.7 vs. 13.8 years, p < 0.001), which was confirmed in our validation cohort (OS 2.7 vs. 14.9 years, p < 0.001). In the multivariate model, IGF2BP3 was an independent risk factor for OS, (HR 2.55, p = 0.034).

CONCLUSION

IGF2BP3 is highly expressed in a subset of WD/DD LPS. Across independent datasets, IGF2BP3 is also a biomarker of disease progression and worse survival.

Laparoscopic compared to open approach for distal gastrectomy may reduce pneumonia risk for patients with gastric cancer

Background

Whether laparoscopic approach to gastrectomy for gastric cancer (GC) reduces the risk of pneumonia remains unknown. In this study, we compared pneumonia outcomes for patients with GC who underwent either laparoscopic gastrectomy (LG) or open gastrectomy (OG).

Methods

The ACS NSQIP database was queried to identify patients with GC who underwent LG or OG between Jan 2012 - Dec 2018. Outcomes were compared using regression models. A post-hoc analysis was performed for elderly patients.

Results

The study cohort included 2661 patients, 23.4 % undergoing LG. Laparoscopic approach lowered pneumonia risk (OR 0.47, p = .028) and reduced hospital length of stay, (5.3 vs 7.1 days, p < .001). Elderly patients undergoing LG demonstrated similar benefits. Risk factors for pneumonia included advanced age, dyspnea and weight-loss, whereas laparoscopic approach reduced this risk.

Conclusions

LG in patients with GC has both statistically and clinically significant advantages over OG with respect to pneumonia. Further studies are needed to validate the relationship between postoperative pneumonia and surgical approach for gastrectomy.

Lifelong Imaging Surveillance is Indicated for Patients with Primary Retroperitoneal Liposarcoma

BACKGROUND

Surveillance imaging of patients with retroperitoneal liposarcoma (RP-LPS) after surgical resection is based on a projected risk of locoregional and distant recurrence. The duration of surveillance is not well defined because the natural history of RP-LPS after treatment is poorly understood. This study evaluated the long-term risk of recurrence and disease-specific survival (DSS) for a cohort of patients with at least 10 years of progression-free survival (10yr-PFS) from their primary resection.

METHODS

The prospective University of California, Los Angeles (UCLA) Sarcoma Database identified RP-LPS patients with 10yr-PFS after initial resection. The patients in the 10yr-PFS cohort were subsequently evaluated for recurrence and DSS. The time intervals start at date of initial surgical resection. Cox proportional hazards models were used to determine factors associated with recurrence and DSS.

RESULTS

From 1972 to 2010, 76 patients with RP-LPS had at least 10 years of follow-up evaluation. Of these 76 patients, 39 (51%) demonstrated 10yr-PFS. The median follow-up period was 15 years (range 10-33 years). Among the 10yr-PFS patients, 49% (19/39) experienced a recurrence at least 10 years after surgery. Of those who experienced recurrence, 42% (8/19) died of disease. Neither long-term recurrence nor DSS were significantly associated with age, sex, tumor size, LPS subtype, surgical margin, or perioperative treatment with radiation or chemotherapy.

CONCLUSION

Patients who have primary RP-LPS treated with surgical resection ± multimodality therapy face a long-term risk of recurrence and disease-specific death unacknowledged by current surveillance imaging guidelines. Among the patients with 10yr-PFS, 49% experienced a recurrence, and 42% of those died of disease. These findings suggest a need for lifelong surveillance imaging for patients with RP-LPS.

Abstract 3490: IGF2BP3 (IMP3) expression is associated with worse survival in well-differentiated/dedifferentiated (WD/DD) liposarcoma

Background: Liposarcoma (LPS) is an understudied form of soft tissue sarcoma (STS). The well-differentiated (WD) and de-differentiated (DD) subtypes of LPS are associated with indolent and aggressive disease courses, respectively, but this histologic stratification fails to fully capture disease heterogeneity. Molecular approaches may help refine prognostication and inform treatment intensification. Insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3 or IMP3), is an RNA-binding protein that regulates gene expression by controlling mRNA stability and has been implicated in tumorigenesis and poor prognosis in many cancers. We hypothesized IGF2BP3 would refine the prognostication of LPS beyond its WD/DD histologic status.

Methods: We examined the association between IGF2BP3 gene or protein expression and clinical data in four datasets: (1) patients with STS subtypes (n=206) in the cancer genome atlas (TCGA) database, (2) an in-house gene microarray of lipomatous tumors (n=71), LPS cell lines (n=3) and patient-derived xenografts (PDX, n=3), (3) an in-house tissue microarray (TMA) of lipomatous tumors (n=115), LPS cell lines (n=3) and PDXs (n=3) and (4) an in-house TMA of WD/DD LPS (n=71). IGF2BP3 protein expression in TMAs was quantified by immunohistochemistry (IHC). IGF2BP3 gene and protein expression values from identical samples were compared by Pearson correlation (n=43). The Kaplan-Meier method and log-rank test were used to compare survival outcomes.

Results: In the TCGA cohort, which does not include WD LPS, IGF2BP3 expression was a poor prognostic factor solely in DD LPS (n=50, median overall survival (mOS): 1.6 vs 5.0 years, p=0.009). Among gene microarray samples, IGF2BP3 expression was highest in DD LPS (n=18) compared to WD LPS (n=29) and lipoma (n=7) by paired t-tests (p=0.03 and 0.002, respectively) and IGF2BP3 expression was associated with worse survival in WD/DD LPS (mOS 7.7 vs 21.5 years, p=0.02). In both TMAs, IGF2BP3 expression (&gt;25% cell positivity/core) portended worse survival in WD/DD LPS (mOS (3): 3.7 vs 13.8 years, p&lt;0.001 and mOS (4): 2.7 vs 14.9 years, p&lt;0.001). IGF2BP3 was not expressed in myxoid LPS (n=21) or lipoma (n=8) samples. Gene and protein expression of IGF2BP3 were positively correlated in WD/DD LPS (r2 = 0.69). IGF2BP3 expression was more strongly associated with survival than LPS differentiation status (mOS: 7.0 (DD) vs 15.2 years (WD), p=0.02). Furthermore, all LPS cell lines and PDXs demonstrated high gene and protein expression of IGF2BP3.

Conclusion: IGF2BP3 is highly expressed in a subset of LPS. Across independent datasets, IGF2BP3 is also a biomarker of disease progression and worse survival, and may stratify patients more effectively than histologic differentiation. Mechanistic studies of IGF2BP3 in LPS tumorigenesis and progression using aforementioned LPS cell lines and PDX models are ongoing.

Citation Format: Kyle D. Klingbeil, Jack Pengfei Tang, Sarah M. Dry, Fritz C. Eilber, Dinesh S. Rao, Brian E. Kadera, Anusha Kalbasi. IGF2BP3 (IMP3) expression is associated with worse survival in well-differentiated/dedifferentiated (WD/DD) liposarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3490.

Gastrointestinal Luminal Stenting: The Early US Experience with the Duodenal HANAROSTENT

Self-expandable metal stents (SEMSs) are frequently utilized for palliation of malignant gastric and/or duodenal outlet obstruction (GDOO). Re-establishing luminal patency with accurate SEMS positioning while limiting migration and adjacent tissue injury is an important technical consideration and aim. The duodenal HANAROSTENT^® was introduced in the USA in 2019 and developed with these challenges in mind. As the first center in the USA to deploy the duo-denal HANAROSTENT^® in clinical practice, we herein examine our early experience with its use. Specifically, we describe 7 consecutive cases of malignant GDOO in which a duodenal HANAROSTENT^® was placed for on-label use, defined as palliative treatment of malignant gastric and/or duodenal obstruction. All stents were 22 mm in diameter, with 5 being 90 mm and 2 being 120 mm in length. Technical and clinical success with duodenal HANAROSTENT^® placement were achieved in all 7 cases (100%). In no case was stent adjustment required post-deployment. There were no stent-related adverse events, and no subsequent endoscopic procedures were necessary in any of the patients during a mean follow-up of 5 months (range 1-12 months). In summary, the duodenal HANAROSTENT^® appears to perform well and be a promising alternative to other available duodenal SEMSs. As experience in the USA with this newly introduced duodenal SEMS grows, multicenter prospective data should be collected to better establish its relative safety and efficacy.

Recurrence and disease-specific survival after 10-year disease-free interval in patients with primary retroperitoneal liposarcoma: Implications for long-term surveillance

11546

Background: Surveillance imaging of patients with retroperitoneal liposarcoma (RP-LPS) following surgical resection is based on a projected risk of locoregional and distant recurrence. The duration of surveillance is not well defined as the long-term natural history of RP-LPS after treatment is poorly understood. We evaluate a cohort of RP-LPS patients—without evidence of disease 10 years following initial resection—to assess the long-term risk of recurrence and disease-specific survival (DSS). Methods: The prospectively maintained UCLA Sarcoma Database was used to identify RP-LPS patients who demonstrated 10-year progression-free survival (10yr-PFS) after initial diagnosis and treatment. Patients in the 10yr-PFS cohort were subsequently evaluated for recurrence and DSS. Time intervals start at date of initial surgical resection. Cox proportional hazards models were used to determine factors associated with recurrence and DSS. Results: From 1972-2010, 76 patients with RP-LPS had at least 10 years of follow-up. Of these, 37 (49%) demonstrated 10yr-PFS. Median follow-up was 15 years (range 10-35 years). Among the 10yr-PFS patients, 43% (16/37) developed a recurrence >10 years after the initial surgery, and 19% (7/37) died of disease. Neither long-term recurrence nor DSS were significantly associated with age, sex, tumor size, LPS subtype, surgical margin, or peri-operative treatment with radiation or chemotherapy (Table). Conclusions: Patients with primary RP-LPS treated with surgical resection +/- multimodality therapy have a long-term risk of recurrence and disease-specific death that is unacknowledged by current surveillance imaging guidelines. Among the patients with a 10yr-PFS, 43% developed a recurrence and 19% died of disease. These findings suggest a need for lifelong surveillance imaging in patients with RP-LPS.[Table: see text]

Chemotherapy-Induced Inflammatory Gene Signature and Protumorigenic Phenotype in Pancreatic CAFs via Stress-Associated MAPK

Pancreatic ductal adenocarcinoma (PDAC) has a characteristically dense stroma comprised predominantly of cancer-associated fibroblasts (CAF). CAFs promote tumor growth, metastasis, and treatment resistance. This study aimed to investigate the molecular changes and functional consequences associated with chemotherapy treatment of PDAC CAFs. Chemoresistant immortalized CAFs (R-CAF) were generated by continuous incubation in gemcitabine. Gene expression differences between treatment-naïve CAFs (N-CAF) and R-CAFs were compared by array analysis. Functionally, tumor cells (TC) were exposed to N-CAF- or R-CAF-conditioned media and assayed for migration, invasion, and viability in vitro Furthermore, a coinjection (TC and CAF) model was used to compare tumor growth in vivo R-CAFs increased TC viability, migration, and invasion compared with N-CAFs. In vivo, TCs coinjected with R-CAFs grew larger than those accompanied by N-CAFs. Genomic analysis demonstrated that R-CAFs had increased expression of various inflammatory mediators, similar to the previously described senescence-associated secretory phenotype (SASP). In addition, SASP mediators were found to be upregulated in response to short duration treatment with gemcitabine in both immortalized and primary CAFs. Inhibition of stress-associated MAPK signaling (P38 MAPK or JNK) attenuated SASP induction as well as the tumor-supportive functions of chemotherapy-treated CAFs in vitro and in vivo These results identify a negative consequence of chemotherapy on the PDAC microenvironment that could be targeted to improve the efficacy of current therapeutic regimens.

IMPLICATIONS

Chemotherapy treatment of pancreatic cancer-associated fibroblasts results in a proinflammatory response driven by stress-associated MAPK signaling that enhances tumor cell growth and invasiveness. Mol Cancer Res; 14(5); 437-47. ©2016 AACR.

Abstract A53: Chemotherapy treated pancreatic cancer tumor-associated fibroblasts are protumorigenic

Introduction: The dense tumor-associated stroma (TAS) characteristic of pancreatic ductal adenocarcinoma (PDAC) plays an important role in disease progression and treatment resistance. PDAC tumor-associated fibroblasts (TAFs), the predominant cell type of the TAS, enhance tumor growth, invasion, metastasis, and chemoresistance. However, the impact of cytotoxic chemotherapy on TAF biology has not yet been reported.

Methods: Immortalized human TAFs were grown in either standard media or media containing IC50 doses of gemcitabine (GEM) for 4 weeks to generate chemotherapy-naïve and chemotherapy-resistant lines. Conditioned media (CM) was produced from both naïve and resistant TAFs. MTT assay was used to assess tumor cell (TC) viability in naïve versus resistant CM. TC migration and invasion as well as endothelial cell migration were assessed using modified Boyden chambers with naïve or resistant CM. For in vivo studies, TCs were subcutaneously co-implanted with naïve or resistant TAFs in immunodeficient mice. Gene expression microarray analysis was performed to compare naïve and chemoresistant TAFs. Expression of selected targets was confirmed by qRT-PCR and/or antibody-based cytokine array. IL-8 expression was quantified by ELISA. Expression of phospo- and total forms of ATM, AKT, and S6 were assessed by immunofluorescence and/or Western blot.

Results:TCs (Miapaca-2 and Panc1) demonstrated increased viability when grown in the presence of resistant as compared to naïve TAF CM (p&lt;0.001). TCs also showed increased migration (Miapaca-2, p&lt;0.001 and Panc1, p=0.002) and invasion (Panc-1, p&lt;0.001) in the presence of resistant CM. In addition, resistant TAF CM increased endothelial cell migration (p=0.01). In vivo, TCs (Miapaca-2) implanted along with chemoresistant TAFs grew larger tumors compared to those implanted with naïve TAFs (p&lt;0.05). Microarray analysis demonstrated that TAFs undergo a large number of molecular changes in response to GEM. Molecules involved in important TAF functions such as stellate cell activation, cellular movement, extracellular matrix production and remodeling, and cytokine signaling were altered. Of note, the expression of multiple protumorigenic inflammatory molecules was increased. Cytokine array and qRT-PCR confirmed elevated levels of multiple inflammatory cytokines (IL-6, IL-8, CXCL-1, SPP1) in chemoresistant TAFs. Furthermore, ELISA demonstrated that IL-8 concentration was 6-fold higher in chemoresistant TAF CM compared to naïve TAF CM. TAFs activated a DNA damage response (DDR) upon treatment with GEM as evidence by phosphorylation of ATM. Treatment with NVP-BEZ235, a pan-PI3K related kinase (PIKK) inhibitor that inhibits the DDR effector kinases ATM and ATR as well as PI3K and mTOR, attenuated the induction of inflammatory factors by GEM.

Conclusions: Chemotherapy treated TAFs support tumorigenesis and angiogenesis in vitro and in vivo via paracrine signaling. After treatment with GEM, TAFs activate a DDR and manifest a pro-inflammatory gene expression signature. Inhibition of PIKK attenuates this inflammatory response to chemotherapy in TAFs.

Citation Format: Paul A. Toste, Andrew H. Nguyen, Brian E. Kadera, Mindy Duong, Luyi Li, Timothy R. Donahue. Chemotherapy treated pancreatic cancer tumor-associated fibroblasts are protumorigenic. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Innovations in Research and Treatment; May 18-21, 2014; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2015;75(13 Suppl):Abstract nr A53.

p85α is a microRNA target and affects chemosensitivity in pancreatic cancer

BACKGROUND

We previously identified a correlation between increased expression of the phosphoinositide 3-kinase (PI3K) regulatory subunit p85α and improved survival in human pancreatic ductal adenocarcinoma (PDAC). The purpose of this study was to investigate the impact of changes in p85α expression on response to chemotherapy and the regulation of p85α by microRNA-21 (miR-21).

MATERIALS AND METHODS

PDAC tumor cells overexpressing p85α were generated by viral transduction, and the effect of p85α overexpression on sensitivity to gemcitabine was tested by MTT assay. Primary human PDAC tumors were stained for p85α and miR-21 via immunohistochemistry and in situ hybridization, respectively. Additionally, PDAC cells were treated with miR-21 mimic, and changes in p85α and phospho-AKT were assessed by Western blot. Finally, a luciferase reporter assay system was used to test direct regulation of p85α by miR-21.

RESULTS

Higher p85α expression resulted in increased sensitivity to gemcitabine (P < 0.01), which correlated with decreased PI3K-AKT activation. Human tumors demonstrated an inverse correlation between miR-21 and p85α expression levels (r = -0.353, P < 0.001). In vitro, overexpression of miR-21 resulted in decreased levels of p85α and increased phosphorylation of AKT. Luciferase reporter assays confirmed the direct regulation of p85α by miR-21 (P < 0.01).

CONCLUSIONS

Our results demonstrate that p85α expression is a determinant of chemosensitivity in PDAC. Additionally, we provide novel evidence that miR-21 can influence PI3K-AKT signaling via its direct regulation of p85α. These data provide insight into potential mechanisms for the known relationship between increased p85α expression and improved survival in PDAC.

Low expression of the E3 ubiquitin ligase CBL confers chemoresistance in human pancreatic cancer and is targeted by epidermal growth factor receptor inhibition

PURPOSE

Expression of CBL, an ubiquitin ligase, is decreased in 60% of human pancreatic ductal adenocarcinomas (PDAC) and is associated with shorter overall survival. We sought to determine how low CBL directly contributes to clinically more aggressive PDAC.

EXPERIMENTAL DESIGN

Human PDACs were stained for CBL, pEGFR, and EGFR. CBL-low was modeled in PDAC cells (Panc-1, L3.6pl, and AsPC-1) via transient transfection (siRNA) or stable knockdown (shRNA). Cell viability and apoptosis were measured by MTT assays and FACS. Immunoblot and a phospho-receptor tyrosine kinase (pRTK) array were used to probe signal transduction. NOD-scid-IL2Rγ(null) mice were subcutaneously implanted with PDAC or PDAC(CBL-low) cells on opposite flanks and treated with gemcitabine ± erlotinib for ≥4 weeks.

RESULTS

There was an inverse correlation between CBL and pEGFR protein expression in 12 of 15 tumors. CBL knockdown increased PDAC resistance to gemcitabine and 5-fluorouracil (5-FU) by upregulating pEGFR (Y1068), pERK, and pAKT. A pRTK array of PDAC(CBL-low) cells revealed additional activated tyrosine kinases but all to a much lower magnitude than EGFR. Increased chemoresistance from low CBL was abrogated by the EGFR inhibitor erlotinib both in vitro and in vivo. Erlotinib+gemcitabine-treated PDAC(CBL-low) cells exhibited greater apoptosis by cleaved PARP, caspase-3, and Annexin V/PI.

CONCLUSIONS

Low CBL causes chemoresistance in PDAC via stress-induced EGFR activation that can be effectively abrogated by EGFR inhibition. These results suggest that dysregulation of ubiquitination is a key mechanism of EGFR hyperactivation in PDAC and that low CBL may define PDAC tumors likely to respond to erlotinib treatment.

Locally advanced pancreatic cancer: association between prolonged preoperative treatment and lymph-node negativity and overall survival

IMPORTANCE

Treatment of patients with locally advanced/borderline resectable (LA/BR) pancreatic ductal adenocarcinoma (PDAC) is not standardized.

OBJECTIVE

To (1) perform a detailed survival analysis of our institution's experience with patients with LA/BR PDAC who were downstaged and underwent surgical resection and (2) identify prognostic biomarkers that may help to guide a decision for the use of adjuvant therapy in this patient subgroup.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective observational study of 49 consecutive patients from a single institution during 1992-2011 with American Joint Committee on Cancer stage III LA/BR PDAC who were initially unresectable, as determined by staging computed tomography and/or surgical exploration, and who were treated and then surgically resected.

MAIN OUTCOMES AND MEASURES

Clinicopathologic variables and prognostic biomarkers SMAD4, S100A2, and microRNA-21 were correlated with survival by univariate and multivariate Cox proportional hazard modeling.

RESULTS

All 49 patients were deemed initially unresectable owing to vascular involvement. After completing preoperative chemotherapy for a median of 7.1 months (range, 5.4-9.6 months), most (75.5%) underwent a pylorus-preserving Whipple operation; 3 patients (6.1%) had a vascular resection. Strikingly, 37 of 49 patients were lymph-node (LN) negative (75.5%) and 42 (85.7%) had negative margins; 45.8% of evaluable patients achieved a complete histopathologic (HP) response. The median overall survival (OS) was 40.1 months (range, 22.7-65.9 months). A univariate analysis of HP prognostic biomarkers revealed that perineural invasion (hazard ratio, 5.5; P=.007) and HP treatment response (hazard ratio, 9.0; P=.009) were most significant. Lymph-node involvement, as a marker of systemic disease, was also significant on univariate analysis (P=.05). Patients with no LN involvement had longer OS (44.4 vs 23.2 months, P=.04) than LN-positive patients. The candidate prognostic biomarkers, SMAD4 protein loss (P=.01) in tumor cells and microRNA-21 expression in the stroma (P=.05), also correlated with OS. On multivariate Cox proportional hazard modeling of HP and prognostic biomarkers, only SMAD4 protein loss was significant (hazard ratio, 9.3; P=.004).

CONCLUSIONS AND RELEVANCE

Our approach to patients with LA/BR PDAC, which includes prolonged preoperative chemotherapy, is associated with a high incidence of LN-negative disease and excellent OS. After surgical resection, HP treatment response, perineural invasion, and SMAD4 status should help determine who should receive adjuvant therapy in this select subset of patients.

MicroRNA-21 in pancreatic ductal adenocarcinoma tumor-associated fibroblasts promotes metastasis

INTRODUCTION

Pancreatic ductal adenocarcinoma (PDAC) is projected to rise to the second leading cause of U.S. cancer-related deaths by 2020. Novel therapeutic targets are desperately needed. MicroRNAs (miRs) are small noncoding RNAs that function by suppressing gene expression and are dysregulated in cancer. miR-21 is overexpressed in PDAC tumor cells (TC) and is associated with decreased survival, chemoresistance and invasion. Dysregulation of miR regulatory networks in PDAC tumor-associated fibroblasts (TAFs) have not been previously described. In this study, we show that miR-21 expression in TAFs promotes TC invasion.

METHODS

In-situ hybridization for miR-21 was performed on the 153 PDAC patient UCLA tissue microarray and 23 patient-matched lymph node metastases. Stromal and TC histoscores were correlated with clinicopathologic parameters by univariate and multivariate Cox regression. miR-21 positive cells were further characterized by immunofluorescence for mesenchymal/epithelial markers. For in vitro studies, TAFs were isolated from freshly resected human PDAC tumors by the outgrowth method. miR-21 was overexpressed/inhibited in fibroblasts and then co-cultured with GFP-MiaPaCa TCs to assess TC invasion in modified Boyden chambers.

RESULTS

miR-21 was upregulated in TAFs of 78% of tumors, and high miR-21 significantly correlated with decreased overall survival (P = 0.04). Stromal miR-21 expression was also significantly associated with lymph node invasion (P = 0.004), suggesting that it is driving TC spread. Co-immunofluorescence revealed that miR-21 colocalized with peritumoral fibroblasts expressing α-smooth muscle actin. Moreover, expression of miR-21 in primary TAFs correlated with miR-21 in TAFs from patient-matched LN metastases; evidence that PDAC tumor cells induce TAFs to express miR-21. miR-21 expression in TAFs and TCs promotes invasion of TCs and is inhibited with anti-miR-21.

CONCLUSIONS

miR-21 expression in PDAC TAFs is associated with decreased overall survival and promotes TC invasion. Anti-miR-21 may represent a novel therapeutic strategy for dual targeting of both tumor and stroma in PDAC.

Impact of tumor grade on pancreatic cancer prognosis: validation of a novel TNMG staging system

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) patients demonstrate highly variable survival within each stage of the American Joint Committee on Cancer (AJCC) staging system. We hypothesize that tumor grade is partly responsible for this variation. Recently our group developed a novel tumor, node, metastasis, grade (TNMG) classification system utilizing Surveillance Epidemiology and End Results (SEER) data in which the presence of high tumor grade results in advancement to the next higher AJCC stage. This study's objective was to validate this TNMG staging system utilizing single-institution data.

METHODS

All patients with PDAC who underwent resection at UCLA between 1990 and 2009 were identified. Clinicopathologic data reviewed included age, sex, node status, tumor size, grade, and stage. Grade was redefined as a dichotomous variable. The impact of grade on survival was assessed by Cox regression analysis. Disease was restaged into the TNMG system and compared to the AJCC staging system.

RESULTS

We identified 256 patients who underwent resection for PDAC. Patients with low-grade tumors experienced a 13-month improvement in median survival compared to those with high-grade tumors. On multivariate analysis, tumor grade was the strongest predictor of survival with a hazard ratio of 2.02 (p = 0.0005). Restaging disease according to the novel TNMG staging system resulted in improved survival discrimination between stages compared to the current AJCC system.

CONCLUSIONS

We were able to demonstrate that grade is one of the strongest independent prognostic factors in PDAC. Restaging with our novel TNMG system demonstrated improved prognostication. This system offers an effective and convenient way of adding grade to the current AJCC staging system.

Remission of type 2 diabetes after Roux-en-Y gastric bypass is associated with greater weight loss

BACKGROUND

Physiologic studies in rodents and preliminary human studies have suggested that Roux-en-Y gastric bypass (RYGB) improves type 2 diabetes mellitus (T2DM) by way of metabolic changes, long before the bariatric or weight loss effects occur, leading to the concept of "metabolic surgery." To test this hypothesis, we studied patients with insulin-dependent T2DM who underwent RYGB to determine whether T2DM remission in this treatment-resistant subgroup occurred independent of weight loss.

METHODS

Of all the patients undergoing RYGB from 2000 to 2006 (n = 1546) with >/=12 months of follow-up, 318 had T2DM (21%), and 75 (24%) of these were insulin dependent. Of the 75 patients, 4 were found to have T1DM (5.3%) and were excluded, leaving a study population of 71 patients. The patients who achieved remission, defined as a cessation of diabetic medications with a hemoglobin A1c level of <7%, were compared with those who did not achieve remission. Statistical significance was set at P < .05, using the Student t test, chi-square test, and logistic regression analysis, as appropriate.

RESULTS

After RYGB, all 71 patients with insulin-dependent T2DM had achieved a reduction in the dose and/or number of medications at 29.6 +/- 17.0 months. Of these 71 patients, 35 (49%) demonstrated a remission of T2DM. The preoperative body mass index, age, number of medications, and hemoglobin A1c level did not differentiate between those who attained remission and those who still required diabetic medication. From the multivariate analysis, the significant factors associated with remission were the preoperative insulin dose and the percentage of excess weight loss. The percentage of excess weight loss was greater in the remission patients as early as 3 months postoperatively (P = .04) and also at 6, 12, 18, and 24 months.

CONCLUSION

RYGB uniformly improved the medication requirements of patients with insulin-dependent T2DM. Although physiologic mechanisms likely contributed, early rapid weight loss was associated with the remission of T2DM.