Extracellular Vesicle and Particle Biomarkers Define Multiple Human Cancers.

There is an unmet clinical need for improved tissue and liquid biopsy tools for cancer detection. We investigated the proteomic profile of extracellular vesicles and particles (EVPs) in 426 human samples from tissue explants (TEs), plasma, and other bodily fluids. Among traditional exosome markers, CD9, HSPA8, ALIX, and HSP90AB1 represent pan-EVP markers, while ACTB, MSN, and RAP1B are novel pan-EVP markers. To confirm that EVPs are ideal diagnostic tools, we analyzed proteomes of TE- (n = 151) and plasma-derived (n = 120) EVPs. Comparison of TE EVPs identified proteins (e.g., VCAN, TNC, and THBS2) that distinguish tumors from normal tissues with 90% sensitivity/94% specificity. Machine-learning classification of plasma-derived EVP cargo, including immunoglobulins, revealed 95% sensitivity/90% specificity in detecting cancer. Finally, we defined a panel of tumor-type-specific EVP proteins in TEs and plasma, which can classify tumors of unknown primary origin. Thus, EVP proteins can serve as reliable biomarkers for cancer detection and determining cancer type.

γδ T Cells Support Pancreatic Oncogenesis by Restraining αß T Cell Activation.

Inflammation is paramount in pancreatic oncogenesis. We identified a uniquely activated γδT cell population, which constituted ∼40% of tumor-infiltrating T cells in human pancreatic ductal adenocarcinoma (PDA). Recruitment and activation of γδT cells was contingent on diverse chemokine signals. Deletion, depletion, or blockade of γδT cell recruitment was protective against PDA and resulted in increased infiltration, activation, and Th1 polarization of αßT cells. Although αßT cells were dispensable to outcome in PDA, they became indispensable mediators of tumor protection upon γδT cell ablation. PDA-infiltrating γδT cells expressed high levels of exhaustion ligands and thereby negated adaptive anti-tumor immunity. Blockade of PD-L1 in γδT cells enhanced CD4(+) and CD8(+) T cell infiltration and immunogenicity and induced tumor protection suggesting that γδT cells are critical sources of immune-suppressive checkpoint ligands in PDA. We describe γδT cells as central regulators of effector T cell activation in cancer via novel cross-talk.

Tumour extracellular vesicles and particles induce liver metabolic dysfunction.

Cancer alters the function of multiple organs beyond those targeted by metastasis1,2. Here we show that inflammation, fatty liver and dysregulated metabolism are hallmarks of systemically affected livers in mouse models and in patients with extrahepatic metastasis. We identified tumour-derived extracellular vesicles and particles (EVPs) as crucial mediators of cancer-induced hepatic reprogramming, which could be reversed by reducing tumour EVP secretion via depletion of Rab27a. All EVP subpopulations, exosomes and principally exomeres, could dysregulate hepatic function. The fatty acid cargo of tumour EVPs-particularly palmitic acid-induced secretion of tumour necrosis factor (TNF) by Kupffer cells, generating a pro-inflammatory microenvironment, suppressing fatty acid metabolism and oxidative phosphorylation, and promoting fatty liver formation. Notably, Kupffer cell ablation or TNF blockade markedly decreased tumour-induced fatty liver generation. Tumour implantation or pre-treatment with tumour EVPs diminished cytochrome P450 gene expression and attenuated drug metabolism in a TNF-dependent manner. We also observed fatty liver and decreased cytochrome P450 expression at diagnosis in tumour-free livers of patients with pancreatic cancer who later developed extrahepatic metastasis, highlighting the clinical relevance of our findings. Notably, tumour EVP education enhanced side effects of chemotherapy, including bone marrow suppression and cardiotoxicity, suggesting that metabolic reprogramming of the liver by tumour-derived EVPs may limit chemotherapy tolerance in patients with cancer. Our results reveal how tumour-derived EVPs dysregulate hepatic function and their targetable potential, alongside TNF inhibition, for preventing fatty liver formation and enhancing the efficacy of chemotherapy.

Recurrence After Resection of Pancreatic Cancer: Can Radiomics Predict Patients at Greatest Risk of Liver Metastasis?

BACKGROUND: Liver metastasis (LM) after pancreatic ductal adenocarcinoma (PDAC) resection is common but difficult to predict and has grave prognosis. We combined preoperative clinicopathological variables and quantitative analysis of computed tomography (CT) imaging to predict early LM. METHODS: We retrospectively evaluated patients with PDAC submitted to resection between 2005 and 2014 and identified clinicopathological variables associated with early LM. We performed liver radiomic analysis on preoperative contrast-enhanced CT scans and developed a logistic regression classifier to predict early LM (< 6 months). RESULTS: In 688 resected PDAC patients, there were 516 recurrences (75%). The cumulative incidence of LM at 5 years was 41%, and patients who developed LM first (n = 194) had the lowest 1-year overall survival (OS) (34%), compared with 322 patients who developed extrahepatic recurrence first (61%). Independent predictors of time to LM included poor tumor differentiation (hazard ratio (HR) = 2.30; P < 0.001), large tumor size (HR = 1.17 per 2-cm increase; P = 0.048), lymphovascular invasion (HR = 1.50; P = 0.015), and liver Fibrosis-4 score (HR = 0.89 per 1-unit increase; P = 0.029) on multivariate analysis. A model using radiomic variables that reflect hepatic parenchymal heterogeneity identified patients at risk for early LM with an area under the receiver operating characteristic curve (AUC) of 0.71; the performance of the model was improved by incorporating preoperative clinicopathological variables (tumor size and differentiation status; AUC = 0.74, negative predictive value (NPV) = 0.86). CONCLUSIONS: We confirm the adverse survival impact of early LM after resection of PDAC. We further show that a model using radiomic data from preoperative imaging combined with tumor-related variables has great potential for identifying patients at high risk for LM and may help guide treatment selection.

The necrosome promotes pancreatic oncogenesis via CXCL1 and Mincle-induced immune suppression.

Neoplastic pancreatic epithelial cells are believed to die through caspase 8-dependent apoptotic cell death, and chemotherapy is thought to promote tumour apoptosis. Conversely, cancer cells often disrupt apoptosis to survive. Another type of programmed cell death is necroptosis (programmed necrosis), but its role in pancreatic ductal adenocarcinoma (PDA) is unclear. There are many potential inducers of necroptosis in PDA, including ligation of tumour necrosis factor receptor 1 (TNFR1), CD95, TNF-related apoptosis-inducing ligand (TRAIL) receptors, Toll-like receptors, reactive oxygen species, and chemotherapeutic drugs. Here we report that the principal components of the necrosome, receptor-interacting protein (RIP)1 and RIP3, are highly expressed in PDA and are further upregulated by the chemotherapy drug gemcitabine. Blockade of the necrosome in vitro promoted cancer cell proliferation and induced an aggressive oncogenic phenotype. By contrast, in vivo deletion of RIP3 or inhibition of RIP1 protected against oncogenic progression in mice and was associated with the development of a highly immunogenic myeloid and T cell infiltrate. The immune-suppressive tumour microenvironment associated with intact RIP1/RIP3 signalling depended in part on necroptosis-induced expression of the chemokine attractant CXCL1, and CXCL1 blockade protected against PDA. Moreover, cytoplasmic SAP130 (a subunit of the histone deacetylase complex) was expressed in PDA in a RIP1/RIP3-dependent manner, and Mincle--its cognate receptor--was upregulated in tumour-infiltrating myeloid cells. Ligation of Mincle by SAP130 promoted oncogenesis, whereas deletion of Mincle protected against oncogenesis and phenocopied the immunogenic reprogramming of the tumour microenvironment that was induced by RIP3 deletion. Cellular depletion suggested that whereas inhibitory macrophages promote tumorigenesis in PDA, they lose their immune-suppressive effects when RIP3 or Mincle is deleted. Accordingly, T cells, which are not protective against PDA progression in mice with intact RIP3 or Mincle signalling, are reprogrammed into indispensable mediators of anti-tumour immunity in the absence of RIP3 or Mincle. Our work describes parallel networks of necroptosis-induced CXCL1 and Mincle signalling that promote macrophage-induced adaptive immune suppression and thereby enable PDA progression.

Detailed Analysis of Margin Positivity and the Site of Local Recurrence After Pancreaticoduodenectomy.

BACKGROUND: The association between a positive surgical margin and local recurrence after resection of pancreatic adenocarcinoma (PDAC) has been reported. Assessment of the location of the a positive margin and the specific site of local recurrence has not been well described. METHODS: A prospectively maintained database was queried for patients who underwent R0/R1 pancreaticoduodenectomy for PDAC between 2000 and 2015. The pancreatic, posterior, gastric/duodenal, anterior peritoneal, and bile duct margins were routinely assessed. Postoperative imaging was reviewed for the site of first recurrence, and local recurrence was defined as recurrence located in the remnant pancreas, surgical bed, or retroperitoneal site outside the surgical bed. RESULTS: During the study period, 891 patients underwent pancreaticoduodenectomy, and 390 patients had an initial local recurrence with or without distant metastases. The 5-year cumulative incidence of local recurrence by site included the remnant pancreas (4%; 95% confidence interval [CI], 3-5%), the surgical bed (35%; 95% CI, 32-39%), and other regional retroperitoneal site (4%; 95% CI, 3-6%). In the univariate analysis, positive posterior margin (hazard ratio [HR], 1.50; 95% CI, 1.17-1.91; p = 0.001) and positive lymph nodes (HR, 1.36; 95% CI, 1.06-1.75; p = 0.017) were associated with surgical bed recurrence, and in the multivariate analysis, positive posterior margin remained significant (HR, 1.40; 95% CI, 1.09-1.81; p = 0.009). An isolated local recurrence was found in 197 patients, and a positive posterior margin was associated with surgical bed recurrence in this subgroup (HR, 1.51; 95% CI, 1.08-2.10; p = 0.016). CONCLUSION: In this study, the primary association between site of margin positivity and site of local recurrence was between the posterior margin and surgical bed recurrence. Given this association and the limited ability to modify this margin intraoperatively, preoperative assessment should be emphasized.

Early liver metastases after "failure" of adjuvant chemotherapy for stage III colorectal cancer: is there a role for additional adjuvant therapy?

BACKGROUND: The utility of adjuvant chemotherapy after resection of colorectal liver metastasis (CLM) in patients with rapid recurrence after adjuvant chemotherapy for their primary tumor is unclear. The aim of this study was to evaluate the oncologic benefit of adjuvant hepatic arterial plus systemic chemotherapy (HAIC + Sys) in patients with early CLM. METHODS: A retrospective analysis of patients with early CLM (≤12 months of adjuvant chemotherapy for primary tumor) who received either HAIC + Sys, adjuvant systemic chemotherapy alone (Sys), or active surveillance (Surgery alone) following resection of CLM was performed. Recurrence and survival were compared between treatment groups using Kaplan-Meier methods and Cox proportional hazards models. RESULTS: Of 239 patients undergoing resection of early CLM, 79 (33.1%) received HAIC + Sys, 77 (32.2%) received Sys, and 83 (34.7%) had Surgery alone. HAIC + Sys was independently associated with reduced risk of RFS events (adjusted hazard ratio [HRadj]: 0.64, 95%CI:0.44-0.94, p = 0.022) and all-cause mortality (HRadj: 0.54, 95%CI:0.36-0.81, p = 0.003) compared to Surgery alone patients. Largest tumor >5 cm (HRadj: 2.03, 95%CI: 1.41-2.93, p < 0.001) and right-sided colon tumors (HRadj: 1.93, 95%CI: 1.29-2.89, p = 0.002) were independently associated with worse OS. CONCLUSION: Adjuvant HAIC + Sys after resection of early CLM that occur after chemotherapy for node-positive primary is associated with improved outcomes.

Letter to the editor regarding "Variant anatomy of the biliary system as a cause of pancreatic and peri-ampullary cancers."

We suggest two potential theories that could explain how low union of the cystic and common hepatic duct may be related to heightened risk for pancreatic ductal adenocarcinoma, as observed by the study by Muraki et al.

Extracellular matrix proteins and carcinoembryonic antigen-related cell adhesion molecules characterize pancreatic duct fluid exosomes in patients with pancreatic cancer.

BACKGROUND: Exosomes are nanovesicles that have been shown to mediate carcinogenesis in pancreatic ductal adenocarcinoma (PDAC). Given the direct communication of pancreatic duct fluid with the tumor and its relative accessibility, we aimed to determine the feasibility of isolating and characterizing exosomes from pancreatic duct fluid. METHODS: Pancreatic duct fluid was collected from 26 patients with PDAC (n = 13), intraductal papillary mucinous neoplasm (IPMN) (n = 8) and other benign pancreatic diseases (n = 5) at resection. Exosomes were isolated by serial ultracentrifugation, proteins were identified by mass spectrometry, and their expression was evaluated by immunohistochemistry. RESULTS: Exosomes were isolated from all specimens with a mean concentration of 5.9 ± 1 × 108 particles/mL and most frequent size of 138 ± 9 nm. Among the top 35 proteins that were significantly associated with PDAC, multiple carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) and extracellular matrix (ECM) proteins were identified. Interestingly, CEACAM 1/5 expression by immunohistochemistry was seen only on tumor epithelia whereas tenascin C positivity was restricted to stroma, suggesting that both tumor and stromal cells contributed to exosomes. CONCLUSION: This is the first study showing that exosome isolation is feasible from pancreatic duct fluid, and that exosomal proteins may be utilized to diagnose patients with PDAC.

Adoptive immunotherapy of epithelial ovarian cancer with Vγ9Vδ2 T cells, potentiated by liposomal alendronic acid.

Adoptive immunotherapy using γδ T cells harnesses their natural role in tumor immunosurveillance. The efficacy of this approach is enhanced by aminobisphosphonates such as zoledronic acid and alendronic acid, both of which promote the accumulation of stimulatory phosphoantigens in target cells. However, the inefficient and nonselective uptake of these agents by tumor cells compromises the effective clinical exploitation of this principle. To overcome this, we have encapsulated aminobisphosphonates within liposomes. Expanded Vγ9Vδ2 T cells from patients and healthy donors displayed similar phenotype and destroyed autologous and immortalized ovarian tumor cells, following earlier pulsing with either free or liposome-encapsulated aminobisphosphonates. However, liposomal zoledronic acid proved highly toxic to SCID Beige mice. By contrast, the maximum tolerated dose of liposomal alendronic acid was 150-fold higher, rendering it much more suited to in vivo use. When injected into the peritoneal cavity, free and liposomal alendronic acid were both highly effective as sensitizing agents, enabling infused γδ T cells to promote the regression of established ovarian tumors by over one order of magnitude. Importantly however, liposomal alendronic acid proved markedly superior compared with free drug following i.v. delivery, exploiting the "enhanced permeability and retention effect" to render advanced tumors susceptible to γδ T cell-mediated shrinkage. Although folate targeting of liposomes enhanced the sensitization of folate receptor-α(+) ovarian tumor cells in vitro, this did not confer further therapeutic advantage in vivo. These findings support the development of an immunotherapeutic approach for ovarian and other tumors in which adoptively infused γδ T cells are targeted using liposomal alendronic acid.

Interleukin 17-producing γδT cells promote hepatic regeneration in mice.

BACKGROUND & AIMS: Subsets of leukocytes synergize with regenerative growth factors to promote hepatic regeneration. γδT cells are early responders to inflammation-induced injury in a number of contexts. We investigated the role of γδT cells in hepatic regeneration using mice with disruptions in Tcrd (encodes the T-cell receptor δ chain) and Clec7a (encodes C-type lectin domain family 7 member a, also known as DECTIN1). METHODS: We performed partial hepatectomies on wild-type C57BL/6, CD45.1, Tcrd(-/-), or Clec7a(-/-) mice. Cells were isolated from livers of patients and mice via mechanical and enzymatic digestion. γδT cells were purified by fluorescence-activated cell sorting. RESULTS: In mice, partial hepatectomy up-regulated expression of CCL20 and ligands of Dectin-1, which was associated with recruitment and activation of γδT cells and their increased production of interleukin (IL)-17 family cytokines. Recruited γδT cells induced production of IL-6 by antigen-presenting cells and suppressed expression of interferon gamma by natural killer T cells, promoting hepatocyte proliferation. Absence of IL-17-producing γδT cells or deletion of Dectin-1 prevented development of regenerative phenotypes in subsets of innate immune cells. This slowed liver regeneration and was associated with reduced expression of regenerative growth factors and cell cycle regulators. Conversely, exogenous administration of IL-17 family cytokines or Dectin-1 ligands promoted regeneration. More broadly, we found that γδT cells are required for inflammatory responses mediated by IL-17 and Dectin-1. CONCLUSIONS: γδT cells regulate hepatic regeneration by producing IL-22 and IL-17, which have direct mitogenic effects on hepatocytes and promote a regenerative phenotype in hepatic leukocytes, respectively. Dectin-1 ligation is required for γδT cells to promote hepatic regeneration.

Role of fatty-acid synthesis in dendritic cell generation and function.

Dendritic cells (DC) are professional APCs that regulate innate and adaptive immunity. The role of fatty-acid synthesis in DC development and function is uncertain. We found that blockade of fatty-acid synthesis markedly decreases dendropoiesis in the liver and in primary and secondary lymphoid organs in mice. Human DC development from PBMC precursors was also diminished by blockade of fatty-acid synthesis. This was associated with higher rates of apoptosis in precursor cells and increased expression of cleaved caspase-3 and BCL-xL and downregulation of cyclin B1. Further, blockade of fatty-acid synthesis decreased DC expression of MHC class II, ICAM-1, B7-1, and B7-2 but increased their production of selected proinflammatory cytokines including IL-12 and MCP-1. Accordingly, inhibition of fatty-acid synthesis enhanced DC capacity to activate allogeneic as well as Ag-restricted CD4(+) and CD8(+) T cells and induce CTL responses. Further, blockade of fatty-acid synthesis increased DC expression of Notch ligands and enhanced their ability to activate NK cell immune phenotype and IFN-γ production. Because endoplasmic reticulum (ER) stress can augment the immunogenic function of APC, we postulated that this may account for the higher DC immunogenicity. We found that inhibition of fatty-acid synthesis resulted in elevated expression of numerous markers of ER stress in humans and mice and was associated with increased MAPK and Akt signaling. Further, lowering ER stress by 4-phenylbutyrate mitigated the enhanced immune stimulation associated with fatty-acid synthesis blockade. Our findings elucidate the role of fatty-acid synthesis in DC development and function and have implications to the design of DC vaccines for immunotherapy.

Dendritic cells limit fibroinflammatory injury in nonalcoholic steatohepatitis in mice.

UNLABELLED: Nonalcoholic steatohepatitis (NASH) is the most common etiology of chronic liver dysfunction in the United States and can progress to cirrhosis and liver failure. Inflammatory insult resulting from fatty infiltration of the liver is central to disease pathogenesis. Dendritic cells (DCs) are antigen-presenting cells with an emerging role in hepatic inflammation. We postulated that DCs are important in the progression of NASH. We found that intrahepatic DCs expand and mature in NASH liver and assume an activated immune phenotype. However, rather than mitigating the severity of NASH, DC depletion markedly exacerbated intrahepatic fibroinflammation. Our mechanistic studies support a regulatory role for DCs in NASH by limiting sterile inflammation through their role in the clearance of apoptotic cells and necrotic debris. We found that DCs limit CD8(+) T-cell expansion and restrict Toll-like receptor expression and cytokine production in innate immune effector cells in NASH, including Kupffer cells, neutrophils, and inflammatory monocytes. Consistent with their regulatory role in NASH, during the recovery phase of disease, ablation of DC populations results in delayed resolution of intrahepatic inflammation and fibroplasia. CONCLUSION: Our findings support a role for DCs in modulating NASH. Targeting DC functional properties may hold promise for therapeutic intervention in NASH.

Multi-parametric atlas of the pre-metastatic liver for prediction of metastatic outcome in early-stage pancreatic cancer.

Metastasis occurs frequently after resection of pancreatic cancer (PaC). In this study, we hypothesized that multi-parametric analysis of pre-metastatic liver biopsies would classify patients according to their metastatic risk, timing and organ site. Liver biopsies obtained during pancreatectomy from 49 patients with localized PaC and 19 control patients with non-cancerous pancreatic lesions were analyzed, combining metabolomic, tissue and single-cell transcriptomics and multiplex imaging approaches. Patients were followed prospectively (median 3 years) and classified into four recurrence groups; early (<6 months after resection) or late (>6 months after resection) liver metastasis (LiM); extrahepatic metastasis (EHM); and disease-free survivors (no evidence of disease (NED)). Overall, PaC livers exhibited signs of augmented inflammation compared to controls. Enrichment of neutrophil extracellular traps (NETs), Ki-67 upregulation and decreased liver creatine significantly distinguished those with future metastasis from NED. Patients with future LiM were characterized by scant T cell lobular infiltration, less steatosis and higher levels of citrullinated H3 compared to patients who developed EHM, who had overexpression of interferon target genes (MX1 and NR1D1) and an increase of CD11B+ natural killer (NK) cells. Upregulation of sortilin-1 and prominent NETs, together with the lack of T cells and a reduction in CD11B+ NK cells, differentiated patients with early-onset LiM from those with late-onset LiM. Liver profiles of NED closely resembled those of controls. Using the above parameters, a machine-learning-based model was developed that successfully predicted the metastatic outcome at the time of surgery with 78% accuracy. Therefore, multi-parametric profiling of liver biopsies at the time of PaC diagnosis may determine metastatic risk and organotropism and guide clinical stratification for optimal treatment selection.

Dendritic cell populations with different concentrations of lipid regulate tolerance and immunity in mouse and human liver.

BACKGROUND & AIMS: Immune cells of the liver must be able to recognize and react to pathogens yet remain tolerant to food molecules and other nonpathogens. Dendritic cells (DCs) are believed to contribute to hepatic tolerance. Lipids have been implicated in dysfunction of DCs in cancer. Therefore, we investigated whether high lipid content in liver DCs affects induction of tolerance. METHODS: Mouse and human hepatic nonparenchymal cells were isolated by mechanical and enzymatic digestion. DCs were purified by fluorescence-activated cell sorting or with immunomagnetic beads. DC lipid content was assessed by flow cytometry, immune fluorescence, and electron microscopy and by measuring intracellular component lipids. DC activation was determined from surface phenotype and cytokine profile. DC function was assessed in T-cell, natural killer (NK) cell, and NKT cell coculture assays as well as in vivo. RESULTS: We observed 2 distinct populations of hepatic DCs in mice and humans based on their lipid content and expression of markers associated with adipogenesis and lipid metabolism. This lipid-based dichotomy in DCs was unique to the liver and specific to DCs compared with other hepatic immune cells. However, rather than mediate tolerance, the liver DC population with high concentrations of lipid was immunogenic in multiple models; they activated T cells, NK cells, and NKT cells. Conversely, liver DCs with low levels of lipid induced regulatory T cells, anergy to cancer, and oral tolerance. The immunogenicity of lipid-rich liver DCs required their secretion of tumor necrosis factor α and was directly related to their high lipid content; blocking DC synthesis of fatty acids or inhibiting adipogenesis (by reducing endoplasmic reticular stress) reduced DC immunogenicity. CONCLUSIONS: Human and mouse hepatic DCs are composed of distinct populations that contain different concentrations of lipid, which regulates immunogenic versus tolerogenic responses in the liver.

The impact of the stromal cell-derived factor-1-3'A and E-selectin S128R polymorphisms on breast cancer.

Breast cancer is prone to metastasis even in early stage disease. Stromal cell-derived factor-1 (SDF-1) is a chemokine that has been associated with the egress of cancer cells from the primary focus and homing to distant sites, while E-selectin has been implicated in their trans-endothelial migration. This study was performed to evaluate the association between SDF-1-3'A and E-selectin S128R-two polymorphisms associated with enhanced function-and the risk of breast cancer, as well as their influence on breast cancer outcome. A retrospective analysis was conducted on 261 patients and 480 healthy controls using PCR-RFLP. The frequencies for the wild-type (GG), GA and AA genotypes of SDF-1 were 43.7, 45.2, and 11.1 % in patients, and 51.5, 41.3, and 7.3 % in healthy controls, respectively, while the SDF-1-3'A allelic frequency was 33.7 % at patients and 27.9 % at controls. The SDF-1-3'A carrier group of patients and the A allele of SDF-1 were overrepresented among the breast cancer cases (p = 0.04 and 0.02, respectively). For the E-selectin S128R polymorphism, the frequencies for the wild-type (AA), AC and CC genotypes were 58.6, 38.3, and 3.1 % in patients and 63.8, 31.4, and 3.8 % in controls, respectively, while the C allelic frequency was 22.2 % for patients and 19.5 % for controls. The CC genotype was associated with poorer survival. Otherwise, no significant association was detected between examined genotypes and tumor characteristics. Overall, our findings support that the SDF-1-3'A confers increased susceptibility to breast cancer and that the E-selectin S128R CC genotype may be related to poorer prognosis. Investigation in bigger cohorts of patients is warranted.

The Liver Pre-Metastatic Niche in Pancreatic Cancer: A Potential Opportunity for Intervention.

Cancer-related mortality is primarily a consequence of metastatic dissemination and associated complications. Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies and tends to metastasize early, especially in the liver. Emerging evidence suggests that organs that develop metastases exhibit microscopic changes that favor metastatic growth, collectively known as "pre-metastatic niches". By definition, a pre-metastatic niche is chronologically established before overt metastatic outgrowth, and its generation involves the release of tumor-derived secreted factors that modulate cells intrinsic to the recipient organ, as well as recruitment of additional cells from tertiary sites, such as bone marrow-all orchestrated by the primary tumor. The pre-metastatic niche is characterized by tumor-promoting inflammation with tumor-supportive and immune-suppressive features, remodeling of the extracellular matrix, angiogenic modulation and metabolic alterations that support growth of disseminated tumor cells. In this paper, we review the current state of knowledge of the hepatic pre-metastatic niche in PDAC and attempt to create a framework to guide future diagnostic and therapeutic studies.