Higher Postoperative Mortality and Inferior Survival After Right-Sided Liver Resection for Perihilar Cholangiocarcinoma: Left-Sided Resection is Preferred When Possible

BACKGROUND

A right- or left-sided liver resection can be considered in about half of patients with perihilar cholangiocarcinoma (pCCA), depending on tumor location and vascular involvement. This study compared postoperative mortality and long-term survival of right- versus left-sided liver resections for pCCA.

METHODS

Patients who underwent major liver resection for pCCA at 25 Western centers were stratified according to the type of hepatectomy-left, extended left, right, and extended right. The primary outcomes were 90-day mortality and overall survival (OS).

RESULTS

Between 2000 and 2022, 1701 patients underwent major liver resection for pCCA. The 90-day mortality was 9% after left-sided and 18% after right-sided liver resection (p < 0.001). The 90-day mortality rates were 8% (44/540) after left, 11% (29/276) after extended left, 17% (51/309) after right, and 19% (108/576) after extended right hepatectomy (p < 0.001). Median OS was 30 months (95% confidence interval [CI] 27-34) after left and 23 months (95% CI 20-25) after right liver resection (p < 0.001), and 33 months (95% CI 28-38), 27 months (95% CI 23-32), 25 months (95% CI 21-30), and 21 months (95% CI 18-24) after left, extended left, right, and extended right hepatectomy, respectively (p < 0.001). A left-sided resection was an independent favorable prognostic factor for both 90-day mortality and OS compared with right-sided resection, with similar results after excluding 90-day fatalities.

CONCLUSIONS

A left or extended left hepatectomy is associated with a lower 90-day mortality and superior OS compared with an (extended) right hepatectomy for pCCA. When both a left and right liver resection are feasible, a left-sided liver resection is preferred.

Adipose tissue macrophage dysfunction is associated with a breach of vascular integrity in NASH

BACKGROUND & AIMS

In non-alcoholic fatty liver disease (NAFLD), monocytes infiltrate visceral adipose tissue promoting local and hepatic inflammation. However, it remains unclear what drives inflammation and how the immune landscape in adipose tissue differs across the NAFLD severity spectrum. We aimed to assess adipose tissue macrophage (ATM) heterogeneity in a NAFLD cohort.

METHODS

Visceral adipose tissue macrophages from lean and obese patients, stratified by NAFLD phenotypes, underwent single-cell RNA sequencing. Adipose tissue vascular integrity and breaching was assessed on a protein level via immunohistochemistry and immunofluorescence to determine targets of interest.

RESULTS

We discovered multiple ATM populations, including resident vasculature-associated macrophages (ResVAMs) and distinct metabolically active macrophages (MMacs). Using trajectory analysis, we show that ResVAMs and MMacs are replenished by a common transitional macrophage (TransMac) subtype and that, during NASH, MMacs are not effectively replenished by TransMac precursors. We postulate an accessory role for MMacs and ResVAMs in protecting the adipose tissue vascular barrier, since they both interact with endothelial cells and localize around the vasculature. However, across the NAFLD severity spectrum, alterations occur in these subsets that parallel an adipose tissue vasculature breach characterized by albumin extravasation into the perivascular tissue.

CONCLUSIONS

NAFLD-related macrophage dysfunction coincides with a loss of adipose tissue vascular integrity, providing a plausible mechanism by which tissue inflammation is perpetuated in adipose tissue and downstream in the liver.

IMPACT AND IMPLICATIONS

Our study describes for the first time the myeloid cell landscape in human visceral adipose tissue at single-cell level within a cohort of well-characterized patients with non-alcoholic fatty liver disease. We report unique non-alcoholic steatohepatitis-specific transcriptional changes within metabolically active macrophages (MMacs) and resident vasculature-associated macrophages (ResVAMs) and we demonstrate their spatial location surrounding the vasculature. These dysfunctional transcriptional macrophage states coincided with the loss of adipose tissue vascular integrity, providing a plausible mechanism by which tissue inflammation is perpetuated in adipose tissue and downstream in the liver. Our study provides a theoretical basis for new therapeutic strategies to be directed towards reinstating the endogenous metabolic, homeostatic and cytoprotective functions of ResVAMs and MMacs, including their role in protecting vascular integrity.

Predicting futility of upfront surgery in perihilar cholangiocarcinoma: Machine learning analytics model to optimize treatment allocation

BACKGROUND

While resection remains the only curative option for perihilar cholangiocarcinoma, it is well known that such surgery is associated with a high risk of morbidity and mortality. Nevertheless, beyond facing life-threatening complications, patients may also develop early disease recurrence, defining a "futile" outcome in perihilar cholangiocarcinoma surgery. The aim of this study is to predict the high-risk category (futile group) where surgical benefits are reversed and alternative treatments may be considered.

METHODS

The study cohort included prospectively maintained data from 27 Western tertiary referral centers: the population was divided into a development and a validation cohort. The Framingham Heart Study methodology was used to develop a preoperative scoring system predicting the "futile" outcome.

RESULTS

A total of 2271 cases were analyzed: among them, 309 were classified within the "futile group" (13.6%). American Society of Anesthesiology (ASA) score ≥ 3 (OR 1.60; p = 0.005), bilirubin at diagnosis ≥50 mmol/L (OR 1.50; p = 0.025), Ca 19-9 ≥ 100 U/mL (OR 1.73; p = 0.013), preoperative cholangitis (OR 1.75; p = 0.002), portal vein involvement (OR 1.61; p = 0.020), tumor diameter ≥3 cm (OR 1.76; p < 0.001), and left-sided resection (OR 2.00; p < 0.001) were identified as independent predictors of futility. The point system developed, defined three (ie, low, intermediate, and high) risk classes, which showed good accuracy (AUC 0.755) when tested on the validation cohort.

CONCLUSIONS

The possibility to accurately estimate, through a point system, the risk of severe postoperative morbidity and early recurrence, could be helpful in defining the best management strategy (surgery vs. nonsurgical treatments) according to preoperative features.

Histopathological growth patterns and tumor-infiltrating lymphocytes in breast cancer liver metastases

Liver is the third most common organ for breast cancer (BC) metastasis. Two main histopathological growth patterns (HGP) exist in liver metastases (LM): desmoplastic and replacement. Although a reduced immunotherapy efficacy is reported in patients with LM, tumor-infiltrating lymphocytes (TIL) have not yet been investigated in BCLM. Here, we evaluate the distribution of the HGP and TIL in BCLM, and their association with clinicopathological variables and survival. We collect samples from surgically resected BCLM (n = 133 patients, 568 H&E sections) and post-mortem derived BCLM (n = 23 patients, 97 H&E sections). HGP is assessed as the proportion of tumor liver interface and categorized as pure-replacement ('pure r-HGP') or any-desmoplastic ('any d-HGP'). We score the TIL according to LM-specific guidelines. Associations with progression-free (PFS) and overall survival (OS) are assessed using Cox regressions. We observe a higher prevalence of 'any d-HGP' (56%) in the surgical samples and a higher prevalence of 'pure r-HGP' (83%) in the post-mortem samples. In the surgical cohort, no evidence of the association between HGP and clinicopathological characteristics is observed except with the laterality of the primary tumor (p value = 0.049) and the systemic preoperative treatment before liver surgery (p value = .039). TIL is less prevalent in 'pure r-HGP' as compared to 'any d-HGP' (p value = 0.001). 'Pure r-HGP' predicts worse PFS (HR: 2.65; CI: (1.45-4.82); p value = 0.001) and OS (HR: 3.10; CI: (1.29-7.46); p value = 0.011) in the multivariable analyses. To conclude, we demonstrate that BCLM with a 'pure r-HGP' is associated with less TIL and with the worse outcome when compared with BCLM with 'any d-HGP'. These findings suggest that HGP could be considered to refine treatment approaches.

PD-1- CD45RA+ effector-memory CD8 T cells and CXCL10+ macrophages are associated with response to atezolizumab plus bevacizumab in advanced hepatocellular carcinoma

The combination of atezolizumab plus bevacizumab (atezo/bev) has dramatically changed the treatment landscape of advanced HCC (aHCC), achieving durable responses in some patients. Using single-cell transcriptomics, we characterize the intra-tumoural and peripheral immune context of patients with aHCC treated with atezo/bev. Tumours from patients with durable responses are enriched for PDL1+ CXCL10+ macrophages and, based on cell-cell interaction analysis, express high levels of CXCL9/10/11 and are predicted to attract peripheral CXCR3+ CD8+ effector-memory T cells (CD8 TEM) into the tumour. Based on T cell receptor sharing and pseudotime trajectory analysis, we propose that CD8 TEM preferentially differentiate into clonally-expanded PD1- CD45RA+ effector-memory CD8+ T cells (CD8 TEMRA) with pronounced cytotoxicity. In contrast, in non-responders, CD8 TEM remain frozen in their effector-memory state. Finally, in responders, CD8 TEMRA display a high degree of T cell receptor sharing with blood, consistent with their patrolling activity. These findings may help understand the possible mechanisms underlying response to atezo/bev in aHCC.

Same-session double EUS-guided bypass versus surgical gastroenterostomy and hepaticojejunostomy: an international multicenter comparison

BACKGROUND AND AIMS

Gastric outlet and biliary obstruction are common manifestations of GI malignancies and some benign diseases for which standard treatment would be surgical gastroenterostomy and hepaticojejunostomy (ie, "double bypass"). Therapeutic EUS has allowed for the creation of an EUS-guided double bypass. However, same-session double EUS-guided bypass has only been described in small proof-of-concept series and lacks a comparison with surgical double bypass.

METHODS

A retrospective multicenter analysis was performed of all consecutive same-session double EUS-guided bypass procedures performed in 5 academic centers. Surgical comparators were extracted from these centers' databases from the same time interval. Efficacy, safety, hospital stay, nutrition and chemotherapy resumption, long-term patency, and survival were compared.

RESULTS

Of 154 identified patients, 53 (34.4%) received treatment with EUS and 101 (65.6%) with surgery. At baseline, patients undergoing EUS exhibited higher American Society of Anesthesiologists scores and a higher median Charlson Comorbidity Index (9.0 [interquartile range {IQR}, 7.0-10.0] vs 7.0 [IQR, 5.0-9.0], P < .001). Technical success (96.2% vs 100%, P = .117) and clinical success rates (90.6% vs 82.2%, P = .234) were similar when comparing EUS and surgery. Overall (11.3% vs 34.7%, P = .002) and severe adverse events (3.8% vs 19.8%, P = .007) occurred more frequently in the surgical group. In the EUS group, median time to oral intake (0 days [IQR, 0-1] vs 6 days [IQR, 3-7], P < .001) and hospital stay (4.0 days [IQR, 3-9] vs 13 days [IQR, 9-22], P < .001) were significantly shorter.

CONCLUSIONS

Despite being used in a patient population with more comorbidities, same-session double EUS-guided bypass achieved similar technical and clinical success and was associated with fewer overall and severe adverse events when compared with surgical gastroenterostomy and hepaticojejunostomy.

Coronary covered stents in the management of late-onset arterial complications post-hepato-pancreato-biliary surgery

PURPOSE

To retrospectively evaluate the safety, efficacy, and late clinical outcome of coronary covered stent placement for the treatment of late-onset arterial complications after hepato-pancreato-biliary surgery.

MATERIALS AND METHODS

Consecutive patients presenting with post-hepato-pancreato-biliary surgery-related arterial lesions and subsequently treated with a covered coronary stent in the authors institution between January 2012 and November 2021 were included. Primary endpoints were technical and clinical success; secondary endpoints were covered stent patency and end-organ perfusion of the affected artery.

RESULTS

The study included 22 patients (13 men and 9 women) with a mean age of 67 years ± 9.6 years. Initial surgery included pancreaticoduodenectomy (n = 15; 68%), liver transplantation (n = 2; 9%), left hepatectomy (n = 1; 5%), bile duct resection (n = 1; 5%), hepatogastrostomy (n = 1; 5%), and segmental enterectomy (n = 1; 5%). Technically, coronary covered stents were successfully placed in n = 22 patients (100%) without immediate complication. Definitive bleeding control was observed in n = 18 patients (81.1%) with recurrent bleeding within 30 days postintervention in n = 5 patients (23%). No ischemic liver or biliary complications occurred during the follow-up period. The 30-day mortality rate was 0%.

CONCLUSION

Coronary covered stents are a safe and efficient treatment option in most of the patients presenting with late-onset postoperative arterial injuries following hepato-pancreato-biliary surgery and are associated with an acceptable recurrent bleeding rate and no late, ischemic, parenchymal complications.

Multivariable prediction model for both 90-day mortality and long-term survival for individual patients with perihilar cholangiocarcinoma: does the predicted survival justify the surgical risk?

BACKGROUND

The risk of death after surgery for perihilar cholangiocarcinoma is high; nearly one in every five patients dies within 90 days after surgery. When the oncological benefit is limited, a high-risk resection may not be justified. This retrospective cohort study aimed to create two preoperative prognostic models to predict 90-day mortality and overall survival (OS) after major liver resection for perihilar cholangiocarcinoma.

METHODS

Separate models were built with factors known before surgery using multivariable regression analysis for 90-day mortality and OS. Patients were categorized in three groups: favourable profile for surgical resection (90-day mortality rate below 10 per cent and predicted OS more than 3 years), unfavourable profile (90-day mortality rate above 25 per cent and/or predicted OS below 1.5 years), and an intermediate group.

RESULTS

A total of 1673 patients were included. Independent risk factors for both 90-day mortality and OS included ASA grade III-IV, large tumour diameter, and right-sided hepatectomy. Additional risk factors for 90-day mortality were advanced age and preoperative cholangitis; those for long-term OS were high BMI, preoperative jaundice, Bismuth IV, and hepatic artery involvement. In total, 294 patients (17.6 per cent) had a favourable risk profile for surgery (90-day mortality rate 5.8 per cent and median OS 42 months), 271 patients (16.2 per cent) an unfavourable risk profile (90-day mortality rate 26.8 per cent and median OS 16 months), and 1108 patients (66.2 per cent) an intermediate risk profile (90-day mortality rate 12.5 per cent and median OS 27 months).

CONCLUSION

Preoperative risk models for 90-day mortality and OS can help identify patients with resectable perihilar cholangiocarcinoma who are unlikely to benefit from surgical resection. Tailored shared decision-making is particularly essential for the large intermediate group.

Prospective cohort study on short-term outcomes of 3D-laparoscopic pancreaticoduodenectomy with stented pancreaticogastrostomy

BACKGROUND

Minimally invasive pancreaticoduodenectomy, either laparoscopic or robotic, is a high-risk procedure with demanding learning curve. The aim of this prospective cohort study was to evaluate short-term clinical and oncologic outcomes of 3D-laparoscopic pancreaticoduodenectomy (3dLPD) with stented pancreaticogastrostomy (sPG) and Roux-en-Y gastroenterostomy (ryGES).

METHODS

Between March 2016 and July 2021, 347 consecutive patients underwent 3dLPD for confirmed or suspected pancreatic or periampullary tumors. Pancreatic duct diameter measured 3 mm or less in 221 (64%) and pancreatic texture was soft in 191 (55%) patients. Simultaneous resection of the superior mesenteric or portal vein was performed in 52 (15%) patients.

RESULTS

Postoperative complications were observed in 189 (54%) patients, with severe complications (Clavien-Dindo grade > 2) in 68 (20%) including 4 (1.2%) deaths. Clinically relevant pancreatic fistula (cPOPF) occurred in 88 (25%), hemorrhage in 25 (7%), and bile leakage in 10 (3%) patients. Clinical pancreatic fistula was strongly associated with soft pancreatic texture and small pancreatic duct diameter (p < 0.001) and managed by endoscopic trans-gastric drainage in 34 (38.6%) patients, reoperation in 12 (13.6%), and ICU admission in 11 (12.5%). The remaining 31 (35%) patients with cPOPF were managed without invasive intervention. Median length of hospital stay after surgery was 13 (range 5-112; IQR 8-18) days. In pancreatic adenocarcinoma (PDAC) the R0-resection rate was 66/186 (36%), R1-indirect 95/186 (51%), and R1-direct 25 (13%). Median number of locoregional lymph nodes retrieved in PDAC was 21 (IQR 15-28). R0-resection rate for malignancy other than PDAC was 78/86 (91%) with a median of 16 (IQR 12-22) locoregional lymph nodes retrieved.

CONCLUSION

3dLPD with sPG and ryGES is associated with 1.2% mortality and 25% cPOPF. About two-third of patients with cPOPF were managed with some type of invasive intervention, whereas the intraoperatively placed drains sufficed in one-third of patients.

CLINICAL TRIAL REGISTRY

Clinicaltrials.gov NCT02671357.

Bile duct injury in laparoscopic cholecystectomy with a posterior infundibular approach

Aims: Bile duct injury (BDI) in laparoscopic cholecystectomy (LC) has a significant impact on morbidity and mortality. Although the critical view of safety (CVS) concept is the most widely supported approach to prevent BDI, alternative approaches are used as well. The aim was to evaluate the incidence, severity, and management of bile duct injury in LC, using a posterior infundibular approach. Methods: This retrospective, monocentric cohort study includes patients who underwent LC for gallstone disease. Data were collected in a prospectively maintained database. Patients with BDI were identified and were analyzed in-depth. Results: Between 1999 and 2018, 8389 consecutive patients were included (M/F 3288/5101; mean age 55 (standard deviation; SD ± 17) years). Mean length of postoperative hospital stay was two days (SD ± 4). Fourteen patients died after LC and 21 patients were identified with BDI. Seventeen BDI (81%) patients were managed minimally invasive (14 endoscopic, 3 laparoscopic), and 4 patients via laparotomy (3 hepaticojejunostomy, 1 primary suture). Severe complications (Clavien-Dindo ≥3) after BDI repair were observed in 6 patients. There was no BDI-related mortality. Median follow-up time was 113 months (range 5–238). Conclusion: A posterior infundibular approach in LC was associated with a low incidence of BDI and no BDI-related mortality.

Survival After Minimally Invasive vs Open Surgery for Pancreatic Adenocarcinoma

IMPORTANCE

Only a few high-volume centers have reported on long-term oncologic outcomes after minimally invasive pancreatic surgery (MIPS) for pancreatic adenocarcinoma, but none of them have shown superior long-term overall survival (OS) compared with open pancreatic surgery (OPS).

OBJECTIVE

To study long-term survival after MIPS and OPS with curative intent among patients with pancreatic adenocarcinoma.

DESIGN, SETTING, AND PARTICIPANTS

This comparative effectiveness study used a retrospective analysis of a prospectively maintained electronic database of patient data collected between January 2010 and December 2019. Consecutive patients from a high-volume pancreatic cancer referral center were included. Data analysis was conducted from March to October 2022. Median follow-up time was 56.8 months.

EXPOSURES

Patients were matched using propensity score models to study long-term survival.

MAIN OUTCOMES AND MEASURES

Survival outcomes were analyzed using the Cox proportional hazards model. Variables used for propensity score correction were TNM stage, tumor dimension, lymph node status, type of operation, simultaneous vascular resection, neoadjuvant chemotherapy, adjuvant chemotherapy, sex, age, and American Society of Anesthesiologists score. Additional corrections were made for year of surgery and type of adjuvant chemotherapy.

RESULTS

After propensity score matching the sample of 396 patients, there were 198 patients in the MIPS group (89 [44.9%] men; median [range] age, 68 [32-87] years) and 198 in the OPS group (94 [47.5%] men; median [range] age, 67 [39-84] years). Median OS in the MIPS group was 30.7 (95% CI, 26.2-36.8) months compared with 20.3 (95% CI, 17.6-23.5) months after OPS (hazard ratio [HR], 0.70; 95% CI, 0.56-0.87; P = .002). Median disease-free survival (DFS) after MIPS vs OPS was 14.8 (95% CI, 11.8-17.0) months vs 10.7 (95% CI, 9.0-12.1) months (HR, 0.71; 95% CI, 0.57-0.89; P = .003). Additional corrections for year of surgery and type of adjuvant chemotherapy showed better OS (year of surgery: HR, 0.74; 95% CI, 0.57-0.96; P = .02; adjuvant chemotherapy: HR, 0.71; 95% CI, 0.56-0.90; P = .005) and DFS (year of surgery: HR, 0.77; 95% CI, 0.59-0.99; P = .04; adjuvant chemotherapy: HR, 0.72; 95% CI, 0.57-0.92; P = .009) for patients undergoing minimally invasive vs open surgery.

CONCLUSIONS AND RELEVANCE

In this study of 396 patients with borderline resectable and resectable pancreatic adenocarcinoma, MIPS was associated with better OS and DFS than OPS. Centralization of MIPS should be stimulated, and pancreatic surgeons should be encouraged to pass the learning curve before implementing MIPS for pancreatic adenocarcinoma in daily clinical practice.

Multi-institutional expert update on the use of laparoscopic bile duct exploration in the management of choledocholithiasis: Lesson learned from 3950 procedures

BACKGROUND

Recently there has been a growing interest in the laparoscopic management of common bile duct stones with gallbladder in situ (LBDE), which is favoring the expansion of this technique. Our study identified the standardization factors of LBDE and its implementation in the single-stage management of choledocholithiasis.

METHODS

A retrospective multi-institutional study among 17 centers with proven experience in LBDE was performed. A cross-sectional survey consisting of a semi-structured pretested questionnaire was distributed covering the main aspects on the use of LBDE in the management of choledocholithiasis.

RESULTS

A total of 3950 LBDEs were analyzed. The most frequent indication was jaundice (58.8%). LBDEs were performed after failed ERCP in 15.2%. The most common approach used was the transcystic (63.11%). The overall series failure rate of LBDE was 4% and the median rate for each center was 6% (IQR, 4.5-12.5). Median operative time ranged between 60-120 min (70.6%). Overall morbidity rate was 14.6%, with a postoperative bile leak and complications ≥3a rate of 4.5% and 2.5%, respectively. The operative time decreased with experience (P = .03) and length of hospital stay was longer in the presence of a biliary leak (P = .04). Current training of LBDE was defined as poor or very poor by 82.4%.

CONCLUSION

Based on this multicenter survey, LBDE is a safe and effective approach when performed by experienced teams. The generalization of LBDE will be based on developing training programs.

Abstract C077: Evidence for a tumoral temperature driven chemoresistance pathway in pancreatic cancer

Tumor growth is inevitably accompanied by changes in the tumor-microenvironment to which cancer cells have to adapt in order to thrive. Alterations in metabolism and blood perfusion of solid tumors have been suggested to drive a spontaneous increase in tumoral temperature. However, it is currently unknown if this phenomenon affects cancer biology. We found increased temperature in human pancreatic ductal adenocarcinoma (PDAC) tumors. By mimicking this observation in PDAC cell lines, we found that cancer cells adapt to tumoral temperature by altering the cellular lipidome and accordingly evade ferroptosis, a lipid-dependent form of cell death. We found evidence that tumoral temperature-induced ferroptosis evasion depends on p38-MAPK deactivation and ultimately drives resistance to the chemotherapeutic drug gemcitabine. Collectively, our findings suggest a direct role for p38-dependend ferroptosis evasion in gemcitabine resistance, and we identify tumoral temperature as a pathophysiological driver of this process. Our discovery unveils temperature as an unexplored hallmark of the tumor-microenvironment.

Citation Format: Vincent de Laat, Halit Topal, Jonas Dehairs, Xander Spotbeen, Ali Talebi, Frank Vanderhoydonc, Tessa Ostyn, Tania Roskams, Baki Topal, Johan Swinnen. Evidence for a tumoral temperature driven chemoresistance pathway in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr C077.

Abstract 3100: XenoSarc: patient-derived xenograft (PDX) models of soft tissue sarcoma (STS) and their histopathological and molecular characterization

STS constitutes a family of rare mesenchymal tumors with more than 70 subtypes described. The limited treatment options available for advanced STS patients underline the need for reliable preclinical models to test new therapeutic approaches. We established a panel of PDX models (XenoSarc) by subcutaneous implantation of fresh tumor specimens in athymic mice (nu/nu NRMI). Once tumor growth was observed, pieces of tumor were re-transplanted to next generations of animals. At each passage tumor fragments were collected for histopathological and molecular characterization. In an ongoing effort 493 STS samples from 414 consenting patients treated at the University Hospitals, Leuven (Belgium) have been transplanted. A total of 67 PDX models from 20 STS subtypes have been established, meaning they have stable morphological, immunohistochemical and genetic characteristics over at least 2 passages. The PDX platform includes more common STS subtypes such as myxofibrosarcoma (n=12 models), gastrointestinal stromal tumors (9), dedifferentiated liposarcoma (10), and leiomyosarcoma (8), as well as models from ultra-rare subtypes, e.g. pulmonary intimal sarcoma, extraskeletal osteosarcoma, mesenchymal chondrosarcoma, myxoinflammatory fibroblastic sarcoma and others. All relevant details about the donor patient and tumor characteristics, including sensitivity to the standard treatments, are known for every model. The models are well-characterized, with availability of molecular information on genomic profile (by low-coverage whole genome sequencing), and expression profile (by RNA sequencing). Xenografts are accompanied by ready to use tissue microarrays (TMA) from the models, which can be exploited for target identification and model selection for preclinical studies. Ex-mouse material can also be used to establish primary cell cultures and 3D organoids for in vitro screening purposes. The XenoSarc platform offers opportunities for studying the biology of various sarcoma subtypes including ultra-rare entities and was found to be a very reliable tool for early drug screening in STS in preparation of clinical testing of novel compounds. The platform is available for collaborative preclinical projects with academic and industrial partners.

Citation Format: Agnieszka Wozniak, Luna De Sutter, Lore De Cock, Britt Van Renterghem, Che-Jui Lee, Yannick Wang, Ulla Vanleeuw, Kimberly Verbeeck, Daphne Hompes, Friedl Sinnaeve, Hazem Wafa, Baki Topal, Joris Jaekers, Dirk Van Raemdonck, Maria Debiec-Rychter, Raf Sciot, Patrick Schöffski. XenoSarc: patient-derived xenograft (PDX) models of soft tissue sarcoma (STS) and their histopathological and molecular characterization [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 3100.

Macrophage scavenger receptor 1 mediates lipid-induced inflammation in non-alcoholic fatty liver disease

BACKGROUND & AIMS

Obesity-associated inflammation is a key player in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). However, the role of macrophage scavenger receptor 1 (MSR1, CD204) remains incompletely understood.

METHODS

A total of 170 NAFLD liver biopsies were processed for transcriptomic analysis and correlated with clinicopathological features. Msr1^-/- and wild-type mice were subjected to a 16-week high-fat and high-cholesterol diet. Mice and ex vivo human liver slices were treated with a monoclonal antibody against MSR1. Genetic susceptibility was assessed using genome-wide association study data from 1,483 patients with NAFLD and 430,101 participants of the UK Biobank.

RESULTS

MSR1 expression was associated with the occurrence of hepatic lipid-laden foamy macrophages and correlated with the degree of steatosis and steatohepatitis in patients with NAFLD. Mice lacking Msr1 were protected against diet-induced metabolic disorder, showing fewer hepatic foamy macrophages, less hepatic inflammation, improved dyslipidaemia and glucose tolerance, and altered hepatic lipid metabolism. Upon induction by saturated fatty acids, MSR1 induced a pro-inflammatory response via the JNK signalling pathway. In vitro blockade of the receptor prevented the accumulation of lipids in primary macrophages which inhibited the switch towards a pro-inflammatory phenotype and the release of cytokines such as TNF-ɑ. Targeting MSR1 using monoclonal antibody therapy in an obesity-associated NAFLD mouse model and human liver slices resulted in the prevention of foamy macrophage formation and inflammation. Moreover, we identified that rs41505344, a polymorphism in the upstream transcriptional region of MSR1, was associated with altered serum triglycerides and aspartate aminotransferase levels in a cohort of over 400,000 patients.

CONCLUSIONS

Taken together, our data suggest that MSR1 plays a critical role in lipid-induced inflammation and could thus be a potential therapeutic target for the treatment of NAFLD.

LAY SUMMARY

Non-alcoholic fatty liver disease (NAFLD) is a chronic disease primarily caused by excessive consumption of fat and sugar combined with a lack of exercise or a sedentary lifestyle. Herein, we show that the macrophage scavenger receptor MSR1, an innate immune receptor, mediates lipid uptake and accumulation in Kupffer cells, resulting in liver inflammation and thereby promoting the progression of NAFLD in humans and mice.

Targeting the bicarbonate transporter SLC4A4 overcomes immunosuppression and immunotherapy resistance in pancreatic cancer

Solid tumors are generally characterized by an acidic tumor microenvironment (TME) that favors cancer progression, therapy resistance and immune evasion. By single-cell RNA-sequencing analysis in individuals with pancreatic ductal adenocarcinoma (PDAC), we reveal solute carrier family 4 member 4 (SLC4A4) as the most abundant bicarbonate transporter, predominantly expressed by epithelial ductal cells. Functionally, SLC4A4 inhibition in PDAC cancer cells mitigates the acidosis of the TME due to bicarbonate accumulation in the extracellular space and a decrease in lactate production by cancer cells as the result of reduced glycolysis. In PDAC-bearing mice, genetic or pharmacological SLC4A4 targeting improves T cell-mediated immune response and breaches macrophage-mediated immunosuppression, thus inhibiting tumor growth and metastases. In addition, Slc4a4 targeting in combination with immune checkpoint blockade is able to overcome immunotherapy resistance and prolong survival. Overall, our data propose SLC4A4 as a therapeutic target to unleash an antitumor immune response in PDAC.

Endothelial Zeb2 preserves the hepatic angioarchitecture and protects against liver fibrosis

Aims

Hepatic capillaries are lined with specialized liver sinusoidal endothelial cells (LSECs) which support macromolecule passage to hepatocytes and prevent fibrosis by keeping hepatic stellate cells (HSCs) quiescent. LSEC specialization is co-determined by transcription factors. The zinc-finger E-box-binding homeobox (Zeb)2 transcription factor is enriched in LSECs. Here, we aimed to elucidate the endothelium-specific role of Zeb2 during maintenance of the liver and in liver fibrosis.

Methods and results

To study the role of Zeb2 in liver endothelium we generated EC-specific Zeb2 knock-out (EC^KO) mice. Sequencing of liver EC RNA revealed that deficiency of Zeb2 results in prominent expression changes in angiogenesis-related genes. Accordingly, the vascular area was expanded and the presence of pillars inside EC^KO liver vessels indicated that this was likely due to increased intussusceptive angiogenesis. LSEC marker expression was not profoundly affected and fenestrations were preserved upon Zeb2 deficiency. However, an increase in continuous EC markers suggested that Zeb2-deficient LSECs are more prone to dedifferentiation, a process called ‘capillarization’. Changes in the endothelial expression of ligands that may be involved in HSC quiescence together with significant changes in the expression profile of HSCs showed that Zeb2 regulates LSEC–HSC communication and HSC activation. Accordingly, upon exposure to the hepatotoxin carbon tetrachloride (CCl₄), livers of EC^KO mice showed increased capillarization, HSC activation, and fibrosis compared to livers from wild-type littermates. The vascular maintenance and anti-fibrotic role of endothelial Zeb2 was confirmed in mice with EC-specific overexpression of Zeb2, as the latter resulted in reduced vascularity and attenuated CCl₄-induced liver fibrosis.

Conclusion

Endothelial Zeb2 preserves liver angioarchitecture and protects against liver fibrosis. Zeb2 and Zeb2-dependent genes in liver ECs may be exploited to design novel therapeutic strategies to attenuate hepatic fibrosis.

Comprehensive targeted next-generation sequencing approach in the molecular diagnosis of gastrointestinal stromal tumor

Mutational analysis guides therapeutic decision making in patients with advanced-stage gastrointestinal stromal tumors (GISTs). We evaluated three targeted next-generation sequencing (NGS) assays, consecutively used over 4 years in our laboratory for mutational analysis of 162 primary GISTs: Agilent GIST MASTR, Illumina TruSight 26 and an in-house developed 96 gene panels. In addition, we investigated the feasibility of a more comprehensive approach by adding targeted RNA sequencing (Archer FusionPlex, 11 genes) in an attempt to reduce the number of Wild Type GISTs. We found KIT or PDGFRA mutations in 149 out of 162 GISTs (92.0%). Challenging KIT exon 11 alterations were initially missed by different assays in seven GISTs and typically represented deletions at the KIT intron 10-exon 11 boundary or large insertions/deletions (>24 base pairs). Comprehensive analysis led to the additional identification of driver alterations in 8/162 GISTs (4.9%): apart from BRAF and SDHA mutations (one case each), we found five GISTs harboring somatic neurofibromatosis type 1 (NF1) alterations (3.1%) and one case with an in-frame TRIM4-BRAF fusion not reported in GIST before. Eventually, no driver alteration was found in two out of 162 GISTs (1.2%) and three samples (1.9%) failed analysis. Our study shows that a comprehensive targeted NGS approach is feasible for routine mutational analysis of GIST, thereby substantially reducing the number of Wild Type GISTs, and highlights the need to optimize assays for challenging KIT exon 11 alterations.

Predictors of survival after surgery with curative intent for perihilar cholangiocarcinoma

Background

Several clinicopathological predictors of survival after curative surgery for perihilar cholangiocarcinoma (pCCA) have been identified; however, conflicting reports remain. The aim was to analyse clinical and oncological outcomes after curative resection of pCCA and to determine prognostic factors.

Methods

Eighty-eight consecutive patients with pCCA underwent surgery with curative intent between 1998 and 2017. Survival curves were estimated using the Kaplan-Meier method and compared using the log-rank test. Twenty-one prognostic factors were evaluated using multivariate Cox regression models.

Results

Postoperative complications were observed in 73 (83%) patients of which 41 (47%) were severe complications (therapy-oriented severity grading system (TOSGS) grade > 2), including a 90-day mortality of 9% (n = 8). Overall survival (OS) and disease-free survival (DFS) rates at 5 and 10 years after surgery were 33% and 19%, and 37% and 30%, respectively. Independent predictors of OS were locoregional lymph node metastasis (LNM) (risk ratio (RR) 2.12, confidence interval (CI) 1.19–3.81, p = 0.011), patient American Society of Anesthesiologists (ASA) physical status classification system > 2 (RR 2.10, CI 1.03–4.26, p = 0.043), and depth of tumour penetration (pT) > 2 (RR 2.58, CI 1.03–6.30, p = 0.043). The presence of locoregional LNM (RR 2.95, CI 1.51–5.90, p = 0.002) and caudate lobe resection (RR 2.19, CI 1.01–5.14, p = 0.048) were found as independent predictors of DFS.

Conclusions

Curative surgery for pCCA carries high risks with poor long-term survival. Locoregional LNM was the only predictor for both OS and DFS.

Abstract 1117: XenoSarc: Patient-derived xenograft (PDX) models of soft tissue sarcoma (STS) and their histopathological and molecular characterization

Background: STS constitutes a rare family of mesenchymal tumors with more than 70 subtypes classified by WHO (2013). The limited treatment options available for advanced STS underline the need for reliable preclinical models, especially from ultra-rare subtypes, to test novel therapeutic strategies.

Methods: A panel of PDX models was established by subcutaneous implantation of fresh tumor specimens in immunodeficient, athymic nude NMRI mice. Once tumor growth was observed, pieces of tumor were re-transplanted to next generations of mice. At each passage tumor fragments were collected for histopathological and molecular characterization. A model was considered “established” after observing stable histological and molecular features for at least two passages. Furthermore, ex-mouse tumor tissue samples were stored, further characterized by immunocytology and flow cytometry and cultured to be used for in vitro drug testing.

Results: Between September 2011 and November 2019, 375 STS samples from 325 consenting patients treated at the University Hospitals, Leuven, Belgium have been transplanted. A total of 56 PDX models were established, maintaining the histopathological and molecular features of the original tumor. Detailed clinical information about the donor patient and tumor characteristics (including sensitivity to standard and experimental agents), is known for every model.

At present the XenoSarc platform includes ready to use models of dedifferentiated liposarcoma (11 models), gastrointestinal stromal tumor (8), myxofibrosarcoma (8), leiomyosarcoma (7), malignant peripheral nerve sheath tumor (3), synovial sarcoma (2), pulmonary artery intimal sarcoma (2), epithelioid hemangioendothelioma (1), mesenchymal chondrosarcoma (1), pleomorphic rhabdomyosarcoma (1), CIC-rearranged round cell sarcoma (1), myxoinflammatory fibroblastic sarcoma (1), rhabdomyosarcoma not otherwise specified (NOS) (1), telangiectatic extraskeletal osteosarcoma (1), extraskeletal osteosarcoma (1) and high-grade undifferentiated pleomorphic sarcoma (7). These models are well-characterized, including molecular information on copy number changes (by low-coverage whole genome sequencing), gene expression profile (by RNA-Seq) and targeted sequencing to detect mutations in genes involved in tumorigenesis. In addition, we have constructed tissue microarrays (TMA) from the xenografts which are used for target identification and model selection for preclinical studies. We are using the xenografts for in vivo testing of novel agents, including targeted and cytotoxic (pro-)drugs, and results already served as rationale for a number of prospective clinical trials. A total of 27 other xenografts are still in early stages of engraftment, not yet fulfilling our criteria of an “established” model.

Conclusion: The XenoSarc platform offers a lot of opportunities for studying the biology of a variety of important sarcoma subtypes including ultra-rare entities, and has proven efficiency for early drug screening in STS in preparation of clinical testing of novel compounds. The platform is well maintained and continuously expanded, and available to collaborators from academia and industry.

Citation Format: Agnieszka Wozniak, Britt Van Renterghem, Jasmien Cornillie, Yannick Wang, Che-Jui Lee, Jasmien Wellens, Ulla Vanleeuw, Madita Nysen, Daphne Hompes, Friedl Sinnaeve, Hazem Wafa, Baki Topal, Tom Verbelen, Maria Debiec-Rychter, Raf Sciot, Patrick Schöffski. XenoSarc: Patient-derived xenograft (PDX) models of soft tissue sarcoma (STS) and their histopathological and molecular characterization [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 1117.

3D-laparoscopic pancreaticoduodenectomy with superior mesenteric or portal vein resection for pancreatic cancer

BACKGROUND

Minimally invasive pancreaticoduodenectomy with synchronous vein resection for pancreatic cancer is controversial. The aim of this study was to evaluate outcomes and describe the surgical technique of 3d-laparoscopic pylorus-resecting pancreaticoduodenectomy (3dLPD) with venous resection for pancreatic cancer.

METHODS

A retrospective cohort analysis was performed with 26 patients [male/female 11/15; median age 68 (range 45-83) years] who underwent 3dLPD with stented pancreaticogastrostomy and superior mesenteric or portal vein resection for pancreatic adenocarcinoma between November 2016 and June 2019. Median follow-up time after surgery was 12 months (range 3-32).

RESULTS

Median operating time was 340 min (range 240-420) and intra-operative blood loss was 100 mL (range 0-1000). Type of venous resection and reconstruction was wedge-resection with primary closure (n = 22), wedge-resection with reconstruction using a peritoneal patch (n = 3), and segmental resection with primary end-to-end reconstruction (n = 1). Laparoscopy was converted to open surgery in 4 (15%) patients. Postoperative complications occurred in 10 (38%) patients including severe complications (Clavien-Dindo grade > 2) in 4 (15%). Postoperative mortality was zero. R0 resection was achieved in 21 (81%) patients. Median number of lymph nodes retrieved was 25 (range 10-45). Venous patency was observed in 23 (88%) patients with a median patency duration of 11 months (range 0-31).

CONCLUSIONS

3dLPD with simultaneous venous resection for pancreatic cancer results in acceptable reconstruction patency and adequacy of surgical oncology without compromising clinical outcomes.

Unraveling the transcriptional determinants of liver sinusoidal endothelial cell specialization

Liver sinusoidal endothelial cells (LSECs) are the first liver cells to encounter waste macromolecules, pathogens, and toxins in blood. LSECs are highly specialized to mediate the clearance of these substances via endocytic scavenger receptors and are equipped with fenestrae that mediate the passage of macromolecules toward hepatocytes. Although some transcription factors (TFs) are known to play a role in LSEC specialization, information about the specialized LSEC signature and its transcriptional determinants remains incomplete.Based on a comparison of liver, heart, and brain endothelial cells (ECs), we established a 30-gene LSEC signature comprising both established and newly identified markers, including 7 genes encoding TFs. To evaluate the LSEC TF regulatory network, we artificially increased the expression of the 7 LSEC-specific TFs in human umbilical vein ECs. Although Zinc finger E-box-binding protein 2, homeobox B5, Cut-like homolog 2, and transcription factor EC (TCFEC) had limited contributions, musculoaponeurotic fibrosarcoma (C-MAF), GATA binding protein 4 (GATA4), and MEIS homeobox 2 (MEIS2) emerged as stronger inducers of LSEC marker expression. Furthermore, a combination of C-MAF, GATA4, and MEIS2 showed a synergistic effect on the increase of LSEC signature genes, including liver/lymph node-specific ICAM-3 grabbing non-integrin (L-SIGN) (or C-type lectin domain family member M (CLEC4M)), mannose receptor C-Type 1 (MRC1), legumain (LGMN), G protein-coupled receptor 182 (GPR182), Plexin C1 (PLXNC1), and solute carrier organic anion transporter family member 2A1 (SLCO2A1). Accordingly, L-SIGN, MRC1, pro-LGMN, GPR182, PLXNC1, and SLCO2A1 protein levels were elevated by this combined overexpression. Although receptor-mediated endocytosis was not significantly induced by the triple TF combination, it enhanced binding to E2, the hepatitis C virus host-binding protein. We conclude that C-MAF, GATA4, and MEIS2 are important transcriptional regulators of the unique LSEC fingerprint and LSEC interaction with viruses. Additional factors are however required to fully recapitulate the molecular, morphological, and functional LSEC fingerprint.NEW & NOTEWORTHY Liver sinusoidal endothelial cells (LSECs) are the first liver cells to encounter waste macromolecules, pathogens, and toxins in the blood and are highly specialized. Although some transcription factors are known to play a role in LSEC specialization, information about the specialized LSEC signature and its transcriptional determinants remains incomplete. Here, we show that Musculoaponeurotic Fibrosarcoma (C-MAF), GATA binding protein 4 (GATA4), and Meis homeobox 2 (MEIS2) are important transcriptional regulators of the unique LSEC signature and that they affect the interaction of LSECs with viruses.

Gemcitabine Recruits M2-Type Tumor-Associated Macrophages into the Stroma of Pancreatic Cancer

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a very lethal disease that can develop therapy resistance over time. The dense stroma in PDAC plays a critical role in tumor progression and resistance. How this stroma interacts with the tumor cells and how this is influenced by chemotherapy remain poorly understood. METHODS: The backbone of this study is the parallel transcriptome analysis of human tumor and mouse stroma in two molecular and clinical representative patient-derived tumor xenografts models. Mice (8 animals per group) were treated for 4 weeks with gemcitabine or control. We studied tumor growth, RNA expression in the stroma, tumor-associated macrophages (TAMs) with immunofluorescence, and cytokines in the serum. RESULTS: A method for parallel transcriptome analysis was optimized. We found that the tumor (differentiation, gene expression) determines the infiltration of macrophages into the stroma. In aggressive PDAC (epithelial-to-mesenchymal transition high), we find more M2 polarized TAMs and the activation of cytokines and growth factors (TNFα, TGFβ1, and IL6). There are increased stromal glycolysis, reduced fatty acid oxidation, and reduced mitochondrial oxidation (tricarboxylic acid cycle and oxidative phosphorylation). Treatment with gemcitabine results in a shift of innate immune cells, especially additional infiltration of protumoral M2 TAMs (P < .001) and metabolic reprogramming. CONCLUSIONS: Gemcitabine treatment of PDAC xenografts stimulates a protumoral macrophage phenotype, and this, in combination with a shift of the tumor cells to a mesenchymal phenotype that we reported previously, contributes to tumor progression and therapeutic resistance. Targeting M2-polarized TAMs may benefit PDAC patients at risk to become refractory to current anticancer regimens.

An Integrated Gene Expression Landscape Profiling Approach to Identify Lung Tumor Endothelial Cell Heterogeneity and Angiogenic Candidates

Heterogeneity of lung tumor endothelial cell (TEC) phenotypes across patients, species (human/mouse), and models (in vivo/in vitro) remains poorly inventoried at the single-cell level. We single-cell RNA (scRNA)-sequenced 56,771 endothelial cells from human/mouse (peri)-tumoral lung and cultured human lung TECs, and detected 17 known and 16 previously unrecognized phenotypes, including TECs putatively regulating immune surveillance. We resolved the canonical tip TECs into a known migratory tip and a putative basement-membrane remodeling breach phenotype. Tip TEC signatures correlated with patient survival, and tip/breach TECs were most sensitive to vascular endothelial growth factor blockade. Only tip TECs were congruent across species/models and shared conserved markers. Integrated analysis of the scRNA-sequenced data with orthogonal multi-omics and meta-analysis data across different human tumors, validated by functional analysis, identified collagen modification as a candidate angiogenic pathway.

XenoSarc: A comprehensive platform of patient-derived xenograft (PDX) models of soft tissue sarcoma (STS) for early drug testing

37

Background: STS is a family of rare, heterogeneous tumors with > 70 subtypes. There is an urgent need for reliable preclinical models, especially for orphan subtypes of STS, given the limited treatment options. Methods: A panel of PDX models was established by s.c. implantation of fresh tumor specimens in athymic NMRI mice. Growing pieces of tumor were re-transplanted to next generations of mice. At each passage fragments were collected for histological/molecular characterization. A model was considered “established” after observing stable features for at least 2 passages. Ex-mouse tissue samples were stored, characterized by immunohistochemistry/flow cytometry and used for in vitro drug testing. Results: Between 2011-2019, 329 samples from 301 consenting patients were transplanted; 56 models are established, 16 additional models are in early passaging. Clinical information about donor and tumor (including sensitivity to standard and experimental agents) is available. The platform includes models of dedifferentiated lipo- (10 models), myxofibro- (8), leiomyo- (7), synovial (2), intimal (2), CIC-positive round cell (1), mesenchymal chondro- (1), extraskeletal osteo- (1), myxoid lipo- (1), myxoinflammatory fibroblastic (1), rhabdomyo- (2) and high-grade undifferentiated pleomorphic sarcoma (7), as well as GIST (8), MPNST (4) and epithelioid hemangioendothelioma (1). Models are well-characterized, with molecular information on copy number changes (low-coverage whole genome sequencing) and gene expression profile (RNA-Seq) available. We also constructed tissue microarrays from the xenografts which are used for target identification and model selection for preclinical studies. Xenografts are available for in vivo testing of novel agents, and results already served as a rationale for a number of prospective clinical trials. Conclusions: XenoSarc offers opportunities for studying the biology of a variety of sarcoma subtypes including ultra-rare entities and is a valuable tool for early drug screening in preparation of clinical STS trials. The platform is well maintained and continuously expanded, and available to collaborators from academia and industry.

Laparoscopic versus open major hepatectomy: a systematic review and meta-analysis of individual patient data

BACKGROUND

The role of laparoscopy for major hepatectomies remains a matter of development to be further assessed. The purpose of this study is to compare the short- and long-term outcomes between laparoscopic and open major hepatectomies meta-analyzing individual patient data from published comparative studies.

METHODS

All retrospective studies comparing between laparoscopic and open major hepatectomies published until March 2017 were identified independently by 2 reviewers by searching in PubMed and Cochrane Central Register of Controlled Trials. Individual patient data were sought from all selected studies. Postoperative outcomes, including intraoperative blood loss, operative time, hospital stay, postoperative complications, mortality rates, and long-term survival were analyzed.

RESULTS

A total of 917 patients were divided into the laparoscopic (427) and open (490) groups from 8 selected studies. The hospital stay was significantly shorter, and the total morbidity was lower in the laparoscopic group. When classified by severity, the incidence of postoperative minor complications was lower; however, that of major complications was not significantly different. The operative time was longer in the laparoscopic group; however, intraoperative blood loss, perioperative mortality, and blood transfusions were comparable between the 2 groups. The overall survival in the patients with colorectal liver metastases and hepatocellular carcinoma was not significantly different between the 2 groups.

CONCLUSION

Laparoscopic major hepatectomies offer some perioperative advantages, including fewer complications and shorter hospital stay, without increasing the blood loss volume and mortality. Whether these results can anticipate the outcomes in future randomized controlled trials has not been determined.

The PDGFRα-laminin B1-keratin 19 cascade drives tumor progression at the invasive front of human hepatocellular carcinoma

Human hepatocellular carcinomas (HCCs) expressing the biliary/hepatic progenitor cell marker keratin 19 (K19) have been linked with a poor prognosis and exhibit an increase in platelet-derived growth factor receptor α (PDGFRα) and laminin beta 1 (LAMB1) expression. PDGFRα has been reported to induce de novo synthesis of LAMB1 protein in a Sjogren syndrome antigen B (La/SSB)-dependent manner in a murine metastasis model. However, the role of this cascade in human HCC remains unclear. This study focused on the functional role of the PDGFRα-La/SSB-LAMB1 pathway and its molecular link to K19 expression in human HCC. In surgical HCC specimens from a cohort of 136 patients, PDGFRα expression correlated with K19 expression, microvascular invasion and metastatic spread. In addition, PDGFRα expression in pre-operative needle biopsy specimens predicted poor overall survival during a 5-year follow-up period. Consecutive histological staining demonstrated that the signaling components of the PDGFRα-La/SSB-LAMB1 pathway were strongly expressed at the invasive front. K19-positive HCC cells displayed high levels of α2β1 integrin (ITG) receptor, both in vitro and in vivo. In vitro activation of PDGFRα signaling triggered the translocation of nuclear La/SSB into the cytoplasm, enhanced the protein synthesis of LAMB1 by activating its internal ribosome entry site, which in turn led to increased secretion of laminin-111. This effect was abrogated by the PDGFRα-specific inhibitor crenolanib. Importantly LAMB1 stimulated ITG-dependent focal adhesion kinase/Src proto-oncogene non-receptor tyrosine kinase signaling. It also promoted the ITG-specific downstream target Rho-associated coiled-coil containing protein kinase 2, induced K19 expression in an autocrine manner, invadopodia formation and cell invasion. Finally, we showed that the knockdown of LAMB1 or K19 in subcutaneous xenograft mouse models resulted in significant loss of cells invading the surrounding stromal tissue and reduced HepG2 colonization into lung and liver after tail vein injection. The PDGFRα-LAMB1 pathway supports tumor progression at the invasive front of human HCC through K19 expression.

Cytoreductive surgery and Hyperthermic intra-operative peritoneal chemotherapy with Cisplatin for gastric peritoneal Carcinomatosis Monocentric phase-2 nonrandomized prospective clinical trial

Background

Cytoreductive surgery (CRS) plus hyperthermic intra-operative peritoneal chemotherapy (HIPC) for gastric peritoneal carcinomatosis (PC) is controversial, and selection criteria for this treatment modality are lacking.

Methods

Thirty-two patients (F/M ratio 12/20; median (range) age 58 (32-75) years) underwent CRS + HIPC with cisplatin for PC from gastric adenocarcinoma in 2010-2014. This monocentric phase-2 nonrandomized prospective study with a power of 90% aimed to improve the 1-year overall survival (OS) rate with 40% (historical reference of 52% to 72%). Median PCI score was 8 (range 1-20), number of regions involved was 6 (range 1-11). The impact of 16 prognostic factors on survival was evaluated using univariable and multivariable Cox regression models. Follow-up was complete in all patients, and closed 2 years after patient inclusion.

Results

All patients had complete cytoreduction (CCR-0) and histopathological R0 resection. PCI </= 12 without PC on any small bowel region with 4 or more non-small bowel regions resulted in a median OS time of 24.7 months (15.6–29.4), and 1, 2, 5-year OS rates of 90%, 55%, 5.6%, respectively. Independent predictors of OS were PC on the small bowel combined with PC on 4 or more non-small bowel regions (p = 0.0004), number of regions involved (p = 0.0029), and overall PCI score (p = 0.0104).

Conclusions

CRS + HIPC with cisplatin to treat gastric PC, providing complete cytoreduction and R0 resection, should be restricted to patients with PCI of 12 or less. Patients having PC on any small bowel region with 4 or more non-small bowel regions should be refused for CRS + HIPC.

Trial registration number

Registration number: NCT01116791. Registration date: May 5, 2010.

Gastric cancer

Gastric cancer is one of the leading causes of cancer-related death worldwide. Many patients have inoperable disease at diagnosis or have recurrent disease after resection with curative intent. Gastric cancer is separated anatomically into true gastric adenocarcinomas and gastro-oesophageal-junction adenocarcinomas, and histologically into diffuse and intestinal types. Gastric cancer should be treated by teams of experts from different disciplines. Surgery is the only curative treatment. For locally advanced disease, adjuvant or neoadjuvant therapy is usually implemented in combination with surgery. In metastatic disease, outcomes are poor, with median survival being around 1 year. Targeted therapies, such as trastuzumab, an antibody against HER2 (also known as ERBB2), and the VEGFR-2 antibody ramucirumab, have been introduced. In this Seminar, we present an update of the causes, classification, diagnosis, and treatment of gastric cancer.

Successful application of endoscopic ultrasound-guided fine needle biopsy to establish pancreatic patient-derived tumor xenografts: a pilot study

Background and study aim: Typically, pancreatic patient-derived tumor xenografts (PDXs) are established by transplanting large tumor biopsies obtained through invasive surgery approaches into immunocompromised mice. We aimed to develop pancreatic PDXs by transplanting tumor tissue acquired by endoscopic ultrasound (EUS)-guided fine needle biopsies (FNB), assess take rates compared to surgery-derived PDXs, and demonstrate the histological and genetic resemblance to the original tumor. Patients and methods: Biopsies of untreated pancreatic carcinoma were collected at surgery and during EUS and processed to generate PDXs. Results: By centrifugation of FNB-derived tissue prior to engraftment, we achieved an engraftment rate of 60 % (6/10). Despite a decrease in stromal tissue, the general morphology of FNB-derived PDXs was conserved as assessed by histopathology. At the genetic level, somatic mutation and copy number profiles were largely similar to the primary tumor. Conclusion: We show that it is technically feasible to establish pancreatic PDXs using a minimally invasive sampling technique, such as EUS-FNB. Although only a limited amount of tumor tissue was acquired, we obtained results similar to those from surgery-derived PDXs.

Abstract A26: The successful application of endoscopic ultrasound guided fine needle biopsy to establish pancreatic patient-derived tumor xenografts

Introduction: Pancreatic cancer is one of the most lethal cancer types with an overall 5-year survival rate of less than 5%. The vast majority of the patients are diagnosed late in their disease onset with already locally advanced setting or when metastasized to regional lymph nodes or other organs and are therefore excluded from surgery. Over the last decades no major advances have been made in the treatment of this disease, at least partly due to the lack of preclinical in vivo models reliably recapitulating the clinic. Patient-derived tumor xenografts (PDX) are currently used as reliable preclinical in vivo models to study tumor biology, accelerate biomarker discovery and preclinical drug screening. However, at present, large tumor biopsies obtained by invasive surgical approaches are still a prerequisite to successfully establish pancreatic PDXs thereby limiting this technique to patients that are eligible for surgery. The objective of the study was to establish pancreatic PDXs by transplanting tumor tissue acquired by endoscopic ultrasound (EUS) fine needle biopsies (FNB) and compare them to surgery-derived PDXs. Secondly, we aimed to demonstrate that EUS-derived PDXs of locally advanced or metastatic pancreatic cancer reflect the original tumors, at the histologic and genetic level.

Method: Biopsies of chemo-naive primary pancreatic carcinoma were collected at surgery and EUS. After localization of the tumor using a linear echoendoscope, a FNB on patients (n=10) with suspected malignant pancreas tumor was performed using a 22G needle. Concentration of the EUS-derived FNB occurred by centrifugation of the sample prior to engraftment. Surgical samples (n=4) on confirmed pancreatic adenocarcinoma were obtained at the time of tumor resection. Via a standardized aseptic technique transplantation was performed in nude mice upon propagation. To asses preservation of general tumor morphology and other tumor-specific characteristics as growth pattern and vascular-stromal composition, H&E and immunohistochemistry (cytokeratin-7, human-vimentin, CD31) were performed. To determine conservation of the mutation profile, copy number alterations and transcription profile, whole exome sequencing (WES), whole-genome low-coverage sequencing and RNA sequencing were executed.

Results: Using the adapted protocol of EUS-derived FNB, we achieved an engraftment rate of 60% whereas all surgical samples were successfully transplanted. Despite a decrease in desmoplastic stromal reaction, the general morphology of EUS-derived FNB PDXs, as assessed by histology, was conserved compared to that of the primary tumor. Also at the genetic level, there was no obvious difference compared to surgery-derived xenografts. In particular, despite some heterogeneity, somatic mutation and copy number profiles were largely shared between xenografts regardless of whether they were obtained by EUS or surgery.

Conclusion: We show that it is technically feasible to establish pancreatic PDXs from patients with locally advanced or metastatic disease by a minimal-invasive sampling technique such as EUS FNB. By acquiring a limited amount of tumor tissue, we demonstrated that tumor morphology, differentiation grade and genetic profile are largely maintained across the different passages suggesting that EUS-derived FNB xenografts may be useful to study pancreatic tumor biology and develop novel therapies in this patient population with a high clinical need. In addition, our approach could potentially be translated to establish PDXs in other unresectable tumor types.

Citation Format: Els Hermans, Schalk Van der Merwe, Jeroen Depreeuw, Jeroen Dekervel, Enrico Radaelli, Baki Topal, Diether Lambrechts, Frédéric Amant. The successful application of endoscopic ultrasound guided fine needle biopsy to establish pancreatic patient-derived tumor xenografts. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr A26.

Prognostic relevance of molecular subtypes and master regulators in pancreatic ductal adenocarcinoma

Background

Pancreatic cancer is poorly characterized at genetic and non-genetic levels. The current study evaluates in a large cohort of patients the prognostic relevance of molecular subtypes and key transcription factors in pancreatic ductal adenocarcinoma (PDAC).

Methods

We performed gene expression analysis of whole-tumor tissue obtained from 118 surgically resected PDAC and 13 histologically normal pancreatic tissue samples. Cox regression models were used to study the effect on survival of molecular subtypes and 16 clinicopathological prognostic factors. In order to better understand the biology of PDAC we used iRegulon to identify transcription factors (TFs) as master regulators of PDAC and its subtypes.

Results

We confirmed the PDAssign gene signature as classifier of PDAC in molecular subtypes with prognostic relevance. We found molecular subtypes, but not clinicopathological factors, as independent predictors of survival. Regulatory network analysis predicted that HNF1A/B are among thousand TFs the top enriched master regulators of the genes expressed in the normal pancreatic tissue compared to the PDAC regulatory network. On immunohistochemistry staining of PDAC samples, we observed low expression of HNF1B in well differentiated towards no expression in poorly differentiated PDAC samples. We predicted IRF/STAT, AP-1, and ETS-family members as key transcription factors in gene signatures downstream of mutated KRAS.

Conclusions

PDAC can be classified in molecular subtypes that independently predict survival. HNF1A/B seem to be good candidates as master regulators of pancreatic differentiation, which at the protein level loses its expression in malignant ductal cells of the pancreas, suggesting its putative role as tumor suppressor in pancreatic cancer.

Trial registration

The study was registered at ClinicalTrials.gov under the number NCT01116791 (May 3, 2010).

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2540-6) contains supplementary material, which is available to authorized users.

Laminin-332 sustains chemoresistance and quiescence as part of the human hepatic cancer stem cell niche

BACKGROUND & AIMS

Cancer stem cells (CSCs) are thought to be persistent in tumours due to their chemoresistance and to cause relapse and metastasis. Hepatic carcinomas displaying hepatic progenitor cell (HPC) features have been associated with a poor prognosis, though it remains unclear how CSCs relate to these different histological subtypes.

METHODS

Candidate CSCs were isolated using the side population (SP) technique from primary tissue samples diagnosed as keratin(K)19-negative or -positive hepatocellular carcinoma (HCC) or as combined hepatocellular/cholangiocarcinoma and analysed for gene and protein expression. The effect of laminin-332 was analysed in vitro by using HCC cell lines and in vivo using a xenograft mouse model.

RESULTS

The size of the SP correlated with the degree of HPC features found in human hepatic cancer, and also showed an elevated mRNA expression of biliary/HPC markers and the extracellular matrix marker LAMC2, the gene encoding the laminin γ2-chain. Immunopositivity for the γ2-chain of laminin-332 was seen in the extracellular matrix surrounding small HPC-like tumour cells with a low proliferation rate. In vitro, laminin-332 increased K19 expression, phosphorylated mTOR and decreased phospho-histone H3 expression, indicating reduced cell mitosis. The effect of laminin-332 was enhanced upon mTORC1 inhibition and diminished when inhibiting mTORC1+C2. Resistance to doxorubicin and sorafenib treatment, and the SP fraction increased in the coated condition. In vivo, laminin-332 reduced tumour growth and sustained K19 expression.

CONCLUSIONS

In this study we identified a prominent role for laminin-332 as part of the specialised CSC niche in maintaining and supporting cell 'stemness', which leads to chemoresistance and quiescence.

Yttrium-90 radioembolization for the treatment of chemorefractory colorectal liver metastases: Technical results, clinical outcome and factors potentially influencing survival

BACKGROUND

The purpose of this study was to retrospectively assess the technical and clinical outcomes, overall survival and prognostic factors for prolonged survival after yttrium-90 ((90)Y) radioembolization as a salvage therapy for patients with chemorefractory liver-only or liver-dominant colorectal metastases.

MATERIAL AND METHODS

From January 2005 to January 2014, all the patients selected for (90)Y radioembolization to treat chemorefractory colorectal liver metastases were identified. Demographic, laboratory, imaging and dosimetry data were collected. Post-treatment technical and clinical outcomes were analyzed as well as overall survival; finally several factors potentially influencing survival were analyzed.

RESULTS

In total 88 patients were selected for angiographic workup; 71 patients (81%) finally underwent catheter-directed (90)Y microsphere infusion into the hepatic artery 25 days (standard deviation 13 days) after angiographic workup. Median infused activity was 1809 MBq; 30-day toxicity included: fatigue (n = 39; 55%), abdominal discomfort (n = 33; 47%), nausea (n = 5; 7%), fever (n = 14; 20%), diarrhea (n = 6; 9%), liver function abnormalities and elevated bilirubin (transient) (n = 3; 4%). Gastric ulcer was found in five patients (7%). A late complication was radioembolization-induced portal hypertension (REIPH) in three patients (4%). Median time to progression in the liver was 4.4 months. Estimated survival at six and 12 months was 65% and 30%, respectively, with a 50% estimated survival after 8.0 months in this group of chemorefractory patients. Prognostic factors for worse survival were high preprocedural bilirubin, alkaline phosphatase and tumor volume levels.

CONCLUSION

(90)Y microsphere radioembolization for chemorefractory colorectal liver metastases has an acceptable safety profile with a 50% estimated survival after 8.0 months. Pretreatment high bilirubin, alkaline phosphatase and tumor volume levels were associated with early death.

Association of Adipose Tissue Inflammation With Histologic Severity of Nonalcoholic Fatty Liver Disease

BACKGROUND & AIMS

The prevalence of nonalcoholic fatty liver disease (NAFLD) has increased with the obesity pandemic. We analyzed the transcriptional profiles of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT), and phenotypes and functional characteristics of adipocyte tissue macrophages (ATMs), in obese patients undergoing bariatric surgery.

METHODS

We collected anthropometric data; plasma samples; and SAT, VAT, and liver tissues from 113 obese patients undergoing bariatric surgery at academic hospitals in Europe (Antwerp and Leuven) and South Africa. Based on clinical and histologic features, patients were assigned to the following groups: obese, NAFLD, nonalcoholic steatohepatitis (NASH), or NASH with fibrosis. Microarray analyses were performed to identify genes expressed differentially among groups. We measured levels of cytokines and chemokines in plasma samples and levels of RNAs in adipose tissues by quantitative reverse-transcription polymerase chain reaction. ATMs were isolated from patients and 13 lean individuals undergoing cholecystectomy (controls), analyzed by flow cytometry, and cultured; immunophenotypes and levels of cytokines and chemokines in supernatants were determined.

RESULTS

We observed increased expression of genes that regulate inflammation in adipose tissues from patients with NAFLD and NASH; expression of these genes increased as disease progressed from NAFLD to NASH. We found 111 genes associated with inflammation that were expressed differentially between VAT and SAT. Serum levels of interleukin 8, chemokine (C-C motif) ligand 3, and tumor necrosis factor-α correlated with liver inflammation and NAFLD activity score. We developed 2 models that could be used to determine patients' liver histology based on gene expression in VAT and SAT. Flow cytometry showed increased proportions of CD11c+CD206+ and CCR2+ macrophages in VAT from patients with NASH, and supernatants of cultured macrophages had increased levels of cytokines and chemokines compared with controls.

CONCLUSIONS

VAT and SAT from patients with NAFLD and NASH have an increased expression of genes that regulate inflammation, and ATM produce increased levels of inflammatory cytokines, compared with adipose tissues from controls. We identified an expression profile of 5 genes in SAT that accurately predict liver histology in these patients. Transcript profiling: accession numbers: GSE58979 and GSE59045.

The impact of liver transplantation after surgical treatment of hepatocellular carcinoma

Background: The impact of liver transplantation (LTx) after surgical treatment for hepatocellular carcinoma (HCC) remains undefined. The aim of the current study was to assess the impact of LTx and of selection criteria for LTx on the survival of patients who underwent surgery for HCC.

Methods: Between 2004 and 2009, 119 patients underwent surgical treatment for HCC. Cirrhosis was present in 85 patients. Of all patients, 77 fulfilled the Milan criteria, 88 the UCSF and 87 the up-to-7 criteria. Finally, 35 patients received an LTx, of whom 31 met the Milan, 33 the UCSF, and 33 the up-to-7 criteria. The relation between LTx and survival was evaluated using a Cox regression model with LTx as a time-dependent factor.

Results: Median [95% confidence interval (CI)] disease-free survival (DFS) and overall survival (OS) of the entire patient population was 9.4 (7–12.2) and 49.1 (37.7–64) months, respectively. The 1, 3, and 5-year DFS vs. OS rates were 36, 3, and 0% vs. 84.7, 61.7, and 39.6%, respectively. Patients fulfilling the Milan criteria had a significantly better OS and DFS than those who had tumors beyond the Milan criteria (p < 0.047). No significant differences were observed in terms of OS between patients within vs. beyond the UCSF or up-to-7 criteria (p > 0.130). In multivariable analysis, cirrhotic patients who received an LTx had a better OS, with a hazard ratio equal to 0.25 (95% CI: 0.08–0.74; p < 0.01). LTx after surgery had a beneficial impact on both DFS and OS of patients in all the three selection criteria models of LTx (p < 0.031).

Conclusion: LTx after primary surgery seems to offer the best long-term survival for patients suffering from HCC in cirrhosis as well as for them who fulfill the Milan, UCSF, and up-to-7 criteria.

Meox2/Tcf15 heterodimers program the heart capillary endothelium for cardiac fatty acid uptake

BACKGROUND

Microvascular endothelium in different organs is specialized to fulfill the particular needs of parenchymal cells. However, specific information about heart capillary endothelial cells (ECs) is lacking.

METHODS AND RESULTS

Using microarray profiling on freshly isolated ECs from heart, brain, and liver, we revealed a genetic signature for microvascular heart ECs and identified Meox2/Tcf15 heterodimers as novel transcriptional determinants. This signature was largely shared with skeletal muscle and adipose tissue endothelium and was enriched in genes encoding fatty acid (FA) transport-related proteins. Using gain- and loss-of-function approaches, we showed that Meox2/Tcf15 mediate FA uptake in heart ECs, in part, by driving endothelial CD36 and lipoprotein lipase expression and facilitate FA transport across heart ECs. Combined Meox2 and Tcf15 haplodeficiency impaired FA uptake in heart ECs and reduced FA transfer to cardiomyocytes. In the long term, this combined haplodeficiency resulted in impaired cardiac contractility.

CONCLUSIONS

Our findings highlight a regulatory role for ECs in FA transfer to the heart parenchyma and unveil 2 of its intrinsic regulators. Our insights could be used to develop new strategies based on endothelial Meox2/Tcf15 targeting to modulate FA transfer to the heart and remedy cardiac dysfunction resulting from altered energy substrate usage.

The FINISH-3 trial: a phase 3, international, randomized, single-blind, controlled trial of topical fibrocaps in intraoperative surgical hemostasis

BACKGROUND

This Phase 3, international, randomized, single-blind, controlled trial (FINISH-3) compared the efficacy and safety of Fibrocaps, a ready-to-use, dry-powder fibrin sealant containing human plasma-derived thrombin and fibrinogen, vs gelatin sponge alone for use as a hemostat for surgical bleeding in 4 indications (ie, spinal, hepatic, vascular, soft tissue dissection).

STUDY DESIGN

Adults with mild to moderate surgical bleeding (randomized 2:1; Fibrocaps vs gelatin sponge) were treated at a single bleeding site (day 1). Time to hemostasis (TTH) during 5 minutes was compared (log-rank statistic) within each indication. Safety follow-up continued to day 29.

RESULTS

Patients were treated (Fibrocaps, n = 480; gelatin sponge, n = 239) when undergoing spinal (n = 183), vascular (n = 175), hepatic (n = 180), or soft-tissue (n = 181) procedures. Fibrocaps was applied by spray device in 53% of all procedures (94% of hepatic and soft-tissue procedures). Fibrocaps significantly reduced TTH compared with gelatin sponge; estimated hazard ratios were 3.3, 2.1, 2.3, and 3.4 for the 4 surgical indications, respectively (each p < 0.001; primary end point). Fibrocaps significantly reduced median TTH for each indication (p < 0.001) and was superior for secondary efficacy end points of restricted mean TTH (p < 0.001) and probability of hemostasis at 3 (p < 0.001) and 5 (p ≤ 0.002) minutes. Adverse event incidences were generally similar between treatment arms. Non-neutralizing, anti-thrombin antibodies developed in 2% of Fibrocaps-treated and 3% of gelatin sponge-treated patients.

CONCLUSIONS

Fibrocaps was well tolerated and significantly reduced TTH relative to gelatin sponge alone in all 4 surgical indications. These findings demonstrate the broad utility of Fibrocaps as a hemostatic agent for mild to moderate surgical bleeding.

Endothelial deficiency of L1 reduces tumor angiogenesis and promotes vessel normalization

While tumor blood vessels share many characteristics with normal vasculature, they also exhibit morphological and functional aberrancies. For example, the neural adhesion molecule L1, which mediates neurite outgrowth, fasciculation, and pathfinding, is expressed on tumor vasculature. Here, using an orthotopic mouse model of pancreatic carcinoma, we evaluated L1 functionality in cancer vessels. Tumor-bearing mice specifically lacking L1 in endothelial cells or treated with anti-L1 antibodies exhibited decreased angiogenesis and improved vascular stabilization, leading to reduced tumor growth and metastasis. In line with these dramatic effects of L1 on tumor vasculature, the ectopic expression of L1 in cultured endothelial cells (ECs) promoted phenotypical and functional alterations, including proliferation, migration, tubulogenesis, enhanced vascular permeability, and endothelial-to-mesenchymal transition. L1 induced global changes in the EC transcriptome, altering several regulatory networks that underlie endothelial pathophysiology, including JAK/STAT-mediated pathways. In particular, L1 induced IL-6-mediated STAT3 phosphorylation, and inhibition of the IL-6/JAK/STAT signaling axis prevented L1-induced EC proliferation and migration. Evaluation of patient samples revealed that, compared with that in noncancerous tissue, L1 expression is specifically enhanced in blood vessels of human pancreatic carcinomas and in vessels of other tumor types. Together, these data indicate that endothelial L1 orchestrates multiple cancer vessel functions and represents a potential target for tumor vascular-specific therapies.

Keratin 19: a key role player in the invasion of human hepatocellular carcinomas

OBJECTIVE

Keratin (K)19, a biliary/hepatic progenitor cell (HPC) marker, is expressed in a subset of hepatocellular carcinomas (HCC) with poor prognosis. The underlying mechanisms driving this phenotype of K19-positive HCC remain elusive.

DESIGN

Clinicopathological value of K19 was compared with EpCAM, and α-fetoprotein, in a Caucasian cohort of 242 consecutive patients (167 surgical specimens, 75 needle biopsies) with different underlying aetiologies. Using microarrays and microRNA profiling the molecular phenotype of K19-positive HCCs was identified. Clinical primary HCC samples were submitted to in vitro invasion assays and to side population analysis. HCC cell lines were transfected with synthetic siRNAs against KRT19 and submitted to invasion and cytotoxicity assays.

RESULTS

In the cohort of surgical specimens, K19 expression showed the strongest correlation with increased tumour size (p<0.01), decreased tumour differentiation (p<0.001), metastasis (p<0.05) and microvascular invasion (p<0.001). The prognostic value of K19 was also confirmed in a set of 75 needle biopsies. Profiling showed that K19-positive HCCs highly express invasion-related/metastasis-related markers (eg, VASP, TACSTD2, LAMB1, LAMC2, PDGFRA), biliary/HPC markers (eg, CD133, GSTP1, NOTCH2, JAG1) and members of the miRNA family 200 (eg, miR-141, miR-200c). In vitro, primary human K19-positive tumour cells showed increased invasiveness, and reside in the chemoresistant side population. Functionally, K19/KRT19 knockdown results in reduced invasion, loss of invadopodia formation and decreased resistance to doxorubicin, 5-fluorouracil and sorafenib.

CONCLUSIONS

Giving the distinct invasive properties, the different molecular profile and the poor prognostic outcome, K19-positive HCCs should be considered as a seperate entity of HCCs.

Keratin 19: a key role player in the invasion of human hepatocellular carcinomas

OBJECTIVE

Keratin (K)19, a biliary/hepatic progenitor cell (HPC) marker, is expressed in a subset of hepatocellular carcinomas (HCC) with poor prognosis. The underlying mechanisms driving this phenotype of K19-positive HCC remain elusive.

DESIGN

Clinicopathological value of K19 was compared with EpCAM, and α-fetoprotein, in a Caucasian cohort of 242 consecutive patients (167 surgical specimens, 75 needle biopsies) with different underlying aetiologies. Using microarrays and microRNA profiling the molecular phenotype of K19-positive HCCs was identified. Clinical primary HCC samples were submitted to in vitro invasion assays and to side population analysis. HCC cell lines were transfected with synthetic siRNAs against KRT19 and submitted to invasion and cytotoxicity assays.

RESULTS

In the cohort of surgical specimens, K19 expression showed the strongest correlation with increased tumour size (p<0.01), decreased tumour differentiation (p<0.001), metastasis (p<0.05) and microvascular invasion (p<0.001). The prognostic value of K19 was also confirmed in a set of 75 needle biopsies. Profiling showed that K19-positive HCCs highly express invasion-related/metastasis-related markers (eg, VASP, TACSTD2, LAMB1, LAMC2, PDGFRA), biliary/HPC markers (eg, CD133, GSTP1, NOTCH2, JAG1) and members of the miRNA family 200 (eg, miR-141, miR-200c). In vitro, primary human K19-positive tumour cells showed increased invasiveness, and reside in the chemoresistant side population. Functionally, K19/KRT19 knockdown results in reduced invasion, loss of invadopodia formation and decreased resistance to doxorubicin, 5-fluorouracil and sorafenib.

CONCLUSIONS

Giving the distinct invasive properties, the different molecular profile and the poor prognostic outcome, K19-positive HCCs should be considered as a seperate entity of HCCs.

Human pancreatic cancer contains a side population expressing cancer stem cell-associated and prognostic genes

In many types of cancers, a side population (SP) has been identified based on high efflux capacity, thereby enriching for chemoresistant cells as well as for candidate cancer stem cells (CSC). Here, we explored whether human pancreatic ductal adenocarcinoma (PDAC) contains a SP, and whether its gene expression profile is associated with chemoresistance, CSC and prognosis. After dispersion into single cells and incubation with Hoechst dye, we analyzed human PDAC resections specimens using flow cytometry (FACS). We identified a SP and main population (MP) in all human PDAC resection specimens (n = 52) analyzed, but detected immune (CD45⁺) and endothelial (CD31⁺) cells in this fraction together with tumor cells. The SP and MP cells, or more purified fractions depleted from CD31⁺/CD45⁺ cells (pSP and pMP), were sorted by FACS and subjected to whole-genome expression analysis. This revealed upregulation of genes associated with therapy resistance and of markers identified before in putative pancreatic CSC. pSP gene signatures of 32 or 10 up- or downregulated genes were developed and tested for discriminatory competence between pSP and pMP in different sets of PDAC samples. The prognostic value of the pSP genes was validated in a large independent series of PDAC patients (n = 78) using nCounter analysis of expression (in tumor versus surrounding pancreatic tissue) and Cox regression for disease-free and overall survival. Of these genes, expression levels of ABCB1 and CXCR4 were correlated with worse patient survival. Thus, our study for the first time demonstrates that human PDAC contains a SP. This tumor subpopulation may represent a valuable therapeutic target given its chemoresistance- and CSC-associated gene expression characteristics with potential prognostic value.