Impact of Fibroblast-Derived SPARC on Invasiveness of Colorectal Cancer Cells

Immunohistochemical expression of SPARC in odontogenic keratocysts: a comparative study with other odontogenic cysts

BACKGROUND

Secreted protein acidic and rich in cysteine (SPARC) has been shown to modulate aggressive behavior in several benign and malignant tumors. Little is known about SPARC expression in odontogenic keratocyst (OKC), an odontogenic cyst with an aggressive nature. To the best of our knowledge, only one study has been investigated the expression of this protein in OKCs. This study aimed to characterize SPARC expression in OKCs. Additionally, to determine whether SPARC is associated with aggressive behavior in OKCs, SPARC expression in OKCs was compared with radicular cysts (RCs), dentigerous cysts (DCs) and calcifying odontogenic cysts (COCs). These odontogenic cysts showed no or less aggressive behavior.

METHODS

SPARC expression was evaluated in 38 OKCs, 39 RCs, 35 DCs and 14 COCs using immunohistochemistry. The percentages of positive cells and the intensities of immunostaining in the epithelial lining and the cystic wall were evaluated and scored.

RESULTS

Generally, OKCs showed similar staining patterns to RCs, DCs and COCs. In the epithelial lining, SPARC was not detected, except for ghost cells in all COCs. In the cystic wall, the majority of positive cells were fibroblasts. Compared between 4 groups of odontogenic cysts, SPARC expression in OKCs was significantly higher than those of RCs (P < 0.001), DCs (P < 0.001) and COCs (P = 0.001).

CONCLUSIONS

A significant increase of SPARC expression in OKCs compared with RCs, DCs and COCs suggests that SPARC may play a role in the aggressive behavior of OKCs.

Omics Overview of the SPARC Gene in Mesothelioma

The SPARC gene plays multiple roles in extracellular matrix synthesis and cell shaping, associated with tumor cell migration, invasion, and metastasis. The SPARC gene is also involved in the epithelial-mesenchymal transition (EMT) process, which is a critical phenomenon leading to a more aggressive cancer cell phenotype. SPARC gene overexpression has shown to be associated with poor survival in the mesothelioma (MESO) cohort from the TCGA database, indicating that this gene may be a powerful prognostic factor in MESO. Its overexpression is correlated with the immunosuppressive tumor microenvironment. Here, we summarize the omics advances of the SPARC gene, including the summary of SPARC gene expression associated with prognosis in pancancer and MESO, the immunosuppressive microenvironment, and cancer cell stemness. In addition, SPARC might be targeted by microRNAs. Notably, despite the controversial functions on angiogenesis, SPARC may directly or indirectly contribute to tumor angiogenesis in MESO. In conclusion, SPARC is involved in tumor invasion, metastasis, immunosuppression, cancer cell stemness, and tumor angiogenesis, eventually impacting patient survival. Strategies targeting this gene may provide novel therapeutic approaches to the treatment of MESO.

Three-dimensional heterotypic colorectal cancer spheroid models for evaluation of drug response

Colorectal cancer (CRC) is a leading cause of death worldwide. Improved preclinical tumor models are needed to make treatment screening clinically relevant and address disease mortality. Advancements in 3D cell culture have enabled a greater recapitulation of the architecture and heterogeneity of the tumor microenvironment (TME). This has enhanced their pathophysiological relevance and enabled more accurate predictions of tumor progression and drug response in patients. An increasing number of 3D CRC spheroid models include cell populations such as cancer-associated fibroblasts (CAFs), endothelial cells (ECs), immune cells, and gut bacteria to better mimic the in vivo regulation of signaling pathways. Furthermore, cell heterogeneity within the 3D spheroid models enables the identification of new therapeutic targets to develop alternative treatments and test TME-target therapies. In this mini review, we present the advances in mimicking tumor heterogeneity in 3D CRC spheroid models by incorporating CAFs, ECs, immune cells, and gut bacteria. We introduce how, in these models, the diverse cells influence chemoresistance and tumor progression of the CRC spheroids. We also highlight important parameters evaluated during drug screening in the CRC heterocellular spheroids.

Angiogenesis regulators S100A4, SPARC and SPP1 correlate with macrophage infiltration and are prognostic biomarkers in colon and rectal cancers

Introduction

Increasing evidence suggests that it is necessary to find effective and robust clinically validated prognostic biomarkers that can identify "high-risk" colorectal cancer (CRC) patients. Currently, available prognostic factors largely include clinical-pathological parameters and focus on the cancer stage at the time of diagnosis. Among cells of tumor microenvironment (TME) only Immunoscore classifier based on T lymphocytes showed high predictive value.

Methods

In the present study, we performed the complex analysis of mRNA and protein expression of crucial regulators of tumor angiogenesis and tumor progression, expressed by tumor-associated macrophages (TAMs): S100A4, SPP1 and SPARC. Colon and rectal cancer patients were investigated independently and in a combined cohort (CRC). For mRNA expression, we analyzed RNA sequencing data obtained from TCGA (N=417) and GEO (N=92) cohorts of colorectal cancer patients. For protein expression, we performed IHC digital quantification of tumor tissues obtained from 197 patients with CRC treated in the Department of abdominal oncology in Clinics of Tomsk NRMC.

Results

High S100A4 mRNA expression accurately predicted poor survival for patients with CRC independently of cancer type. SPARC mRNA level was independent prognostic factors for survival in colon but not in rectal cancer. SPP1 mRNA level had significant predictive value for survival in both rectal and colon cancers. Analysis of human CRC tissues revealed that S100A4, SPP1 and SPARC are expressed by stromal compartments, in particular by TAMs, and have a strong correlation with macrophage infiltration. Finally, our results indicate that chemotherapy-based treatment can change the predictive direction of S100A4 for rectal cancer patients. We found that S100A4 stromal levels were higher in patients with better response to neoadjuvant chemotherapy/chemoradiotherapy, and S100A4 mRNA levels predicted better DFS among non-responders.

Discussion

These findings can help improve the prognosis of patients with CRC based on S100A4, SPP1 and SPARC expression levels.

SPARC expression in tumor microenvironment induces partial epithelial-to-mesenchymal transition of esophageal adenocarcinoma cells via cooperating with TGF-β signaling

Secreted protein, acidic and rich in cysteine (SPARC) has been characterized as an oncoprotein in esophageal squamous cell carcinoma (ESCC), but its involvement in the pathological development of esophageal adenocarcinoma (ESAD) remains poorly understood. In this study, we aimed to explore the sources of SPARC in the tumor microenvironment (TME) and its functional role in ESAD. Bioinformatic analysis was conducted using data from The Cancer Genome Atlas (TCGA)-esophageal cancer (ESCA) and Genotype-Tissue Expression (GTEx). ESAD tumor cell line OE33 and OE19 cells were used as in vitro cell models. Results showed that SPARC upregulation was associated with unfavorable disease-specific survival (DSS) in ESAD. ESAD tumor cells (OE33 and OE19) had no detectable SPARC protein expression. In contrast, IHC staining in ESAD tumor tissues suggested that peritumoral stromal cells (tumor-associated fibroblasts and macrophages) were the dominant SPARC source in TME. Exogenous SPARC induced partial epithelial-to-mesenchymal transition of ESAD cells, reflected by reduced CDH1 and elevated ZEB1/VIM expression at both mRNA and protein levels. Besides, exogenous SPARC enhanced tumor cell invasion. When TGFBR2 expression was inhibited, the activation of TGF-β signaling induced by exogenous SPARC was impaired. However, the activating effects were rescued by overexpressing mutant TGFBR2 resistant to the shRNA sequence. Copresence of exogenous SPARC and TGF-β1 induced higher expression of mesenchymal markers and enhanced the invading capability of ESAD cells than TGF-β1 alone. In conclusion, this study suggests a potential cross-talk between ESAD tumor stromal cells and cancer cells via a SPARC-TGF-β1 paracrine network.

B cell expansion hinders the stroma-epithelium regenerative cross talk during mucosal healing

Therapeutic promotion of intestinal regeneration holds great promise, but defining the cellular mechanisms that influence tissue regeneration remains an unmet challenge. To gain insight into the process of mucosal healing, we longitudinally examined the immune cell composition during intestinal damage and regeneration. B cells were the dominant cell type in the healing colon, and single-cell RNA sequencing (scRNA-seq) revealed expansion of an IFN-induced B cell subset during experimental mucosal healing that predominantly located in damaged areas and associated with colitis severity. B cell depletion accelerated recovery upon injury, decreased epithelial ulceration, and enhanced gene expression programs associated with tissue remodeling. scRNA-seq from the epithelial and stromal compartments combined with spatial transcriptomics and multiplex immunostaining showed that B cells decreased interactions between stromal and epithelial cells during mucosal healing. Activated B cells disrupted the epithelial-stromal cross talk required for organoid survival. Thus, B cell expansion during injury impairs epithelial-stromal cell interactions required for mucosal healing, with implications for the treatment of IBD.

Functionalization of Covalent Organic Frameworks with Peptides by Polymer-Assisted Surface Modification and the Application for Protein Detection

Although covalent organic frameworks (COFs) have received extensive attention for biomedical research due to their unique properties, their application is still hindered by the challenges of incorporating COFs with functional biomolecules. Since peptides have shown advantages in biomedical applications, herein, we propose the functionalization of COFs with peptides by a polymer-assisted surface modification strategy. Furthermore, a method based on the peptide-functionalized COFs for protein detection has also been developed to demonstrate their application potential. With the help of the polymers, peptides and horseradish peroxidase are attached onto COFs with a high surface density, and the developed method has achieved simple and sensitive detection of the secreted protein acidic and rich in cysteine. We speculate that the facile method proposed in this work to prepare peptide-functionalized COFs can not only benefit protein detection but also promote more biomedical applications of COFs.

Contribution of endothelial cell-derived transcriptomes to the colon cancer based on bioinformatics analysis

Colon tumor endothelial cells (CTECs) plays substantial roles to induce immune invasion, angiogenesis and metastasis. Thus, identification of the CTECs-derived transcriptomes could be helpful for colon cancer diagnosis and potential therapy.

METHODS

By analysis of CTECs-derived gene expression profiling dataset, we identified differentially expressed genes (DEGs) between CTECs and colon normal endothelial cells (CNECs). In addition, we identified the significant pathways and protein-protein interaction (PPI) network that was significantly associated with the DEGs. Furthermore, we identified hub genes whose expression was significantly associated with prognosis and immune cell infiltrations in colon cancer. Finally, we identified the significant correlations between the prognostic hub genes and immune-inhibitory markers in colon cancer.

RESULTS

We identified 362 DEGs in CTECs relative to the CNECs, including117 up-regulated genes and 245 down-regulated genes in the CTECs. In addition, we identified significantly up-regulated pathways in CTECs that were mainly involved in cancer and immune regulation. Furthermore, we identified hub genes (such as SPARC, COL1A1, COL1A2 and IGFBP3) that are associated with prognosis and immune cells infiltrations in colon cancer. Interestingly, we found that prognosis-associated hub genes (SPARC, COL1A1, COL1A2 and IGFBP3) are positively correlated with immune-inhibitory markers of various immunosuppressive cells, including TAM, M2 macrophage, Tregs and T cell exhaustion. Finally, our findings revealed that prognosis-associated upregulated hub genes are positively correlated with immune checkpoint markers, including PD-L1 and PD-L2 and the immunosuppressive markers including TGFB1 and TGFBR1.

CONCLUSIONS

The identification of CTECs-specific transcriptomes may provide crucial insights into the colon tumor microenvironment that mediates the development of colon cancer.

Role of SPARC in the epithelial-mesenchymal transition induced by PTHrP in human colon cancer cells

Parathyroid hormone-related peptide (PTHrP) exerts its effects on cells derived from colorectal cancer (CRC) and tumor microenvironment and is involved in processes requiring the epithelial-mesenchymal transition (EMT). Here, we report that PTHrP modulates factors expression and morphological changes associated with EMT in HCT116 cells from CRC. PTHrP increased the protein expression of SPARC, a factor involved in EMT, in HCT116 cells but not in Caco-2 cells also from CRC but with less aggressiveness. PTHrP also increased SPARC expression and its subsequent release from endothelial HMEC-1 cells. The conditioned media of PTHrP-treated HMEC-1 cells induced early changes related to EMT in HCT116 cells. Moreover, SPARC treatment on HCT116 cells potentiated PTHrP modulation in E-cadherin expression and cell migration. In vivo PTHrP also increased SPARC expression and decreased E-cadherin expression. These results suggest a novel PTHrP action on CRC progression involving the microenvironment in the modulation of events associated with EMT.

MicroRNA‑592 promotes cell proliferation, migration and invasion in colorectal cancer by directly targeting SPARC

Colorectal cancer (CRC), one of the most common cancer types, causes a large number of cancer-related mortalities annually worldwide. Dysregulated microRNAs (miRNAs/miR) are closely associated with the malignant progression of CRC. Therefore, the present study aimed to investigate the expression and regulatory role of miR-592 in CRC. It was found that miR-592 expression was significantly elevated in CRC tissues and cell lines, and was associated with the prognosis of patients. Cellular phenotype assays demonstrated that miR-592 could promote CRC cell proliferation, migration and invasion. Bioinformatics analysis demonstrated that miR-592 mainly participated in the positive regulation of transcription, as well as the regulation of cell motility. Moreover, miR-592 targets were enriched in several signaling pathways, such as the ‘mTOR’ and ‘FoxO’ signaling pathways. In addition, secreted protein acidic and rich in cysteine (SPARC) was identified as a target of miR-592 in CRC. The present results suggested that miR-592 acts as an oncogene in CRC, in part, by directly inhibiting SPARC expression. Collectively, the present study provides a novel potential therapeutic strategy for CRC.

Fibroblast Subsets in Intestinal Homeostasis, Carcinogenesis, Tumor Progression, and Metastasis

Simple Summary

Colorectal cancer often develops via the adenoma–carcinoma sequence, a process which is accompanied by (epi) genetic alterations in epithelial cells and gradual phenotypic changes in fibroblast populations. Recent studies have made it clear that these fibroblast populations which, in the context of invasive cancers are termed cancer-associated fibroblasts (CAFs), play an important role in intestinal tumor progression. This review provides an overview on the emerging role of fibroblasts in various stages of colorectal cancer development, ranging from adenoma initiation to metastatic spread of tumor cells. As fibroblasts show considerable heterogeneity in subsets and phenotypes during cancer development, a better functional understanding of stage-specific (alterations in) fibroblast/CAF populations is key to increase the effectiveness of fibroblast-based prognosticators and therapies.

Abstract

In intestinal homeostasis, continuous renewal of the epithelium is crucial to withstand the plethora of stimuli which can damage the structural integrity of the intestines. Fibroblasts contribute to this renewal by facilitating epithelial cell differentiation as well as providing the structural framework in which epithelial cells can regenerate. Upon dysregulation of intestinal homeostasis, (pre-) malignant neoplasms develop, a process which is accompanied by (epi) genetic alterations in epithelial cells as well as phenotypic changes in fibroblast populations. In the context of invasive carcinomas, these fibroblast populations are termed cancer-associated fibroblasts (CAFs). CAFs are the most abundant cell type in the tumor microenvironment of colorectal cancer (CRC) and consist of various functionally heterogeneous subsets which can promote or restrain cancer progression. Although most previous research has focused on the biology of epithelial cells, accumulating evidence shows that certain fibroblast subsets can also importantly contribute to tumor initiation and progression, thereby possibly providing avenues for improvement of clinical care for CRC patients. In this review, we summarized the current literature on the emerging role of fibroblasts in various stages of CRC development, ranging from adenoma initiation to the metastatic spread of cancer cells. In addition, we highlighted translational and therapeutic perspectives of fibroblasts in the different stages of intestinal tumor progression.

Stromal Protein-Mediated Immune Regulation in Digestive Cancers

Simple Summary

Solid cancers are surrounded by a network of non-cancerous cells comprising different cell types, including fibroblasts, and acellular protein structures. This entire network is called the tumor microenvironment (TME) and it provides a physical barrier to the tumor shielding it from infiltrating immune cells, such as lymphocytes, or therapeutic agents. In addition, the TME has been shown to dampen efficient immune responses of infiltrated immune cells, which are key in eliminating cancer cells from the organism. In this review, we will discuss how TME proteins in particular are involved in this dampening effect, known as immunosuppression. We will focus on three different types of digestive cancers: pancreatic cancer, colorectal cancer, and gastric cancer. Moreover, we will discuss current therapeutic approaches using TME proteins as targets to reverse their immunosuppressive effects.

Abstract

The stromal tumor microenvironment (TME) consists of immune cells, vascular and neural structures, cancer-associated fibroblasts (CAFs), as well as extracellular matrix (ECM), and favors immune escape mechanisms promoting the initiation and progression of digestive cancers. Numerous ECM proteins released by stromal and tumor cells are crucial in providing physical rigidity to the TME, though they are also key regulators of the immune response against cancer cells by interacting directly with immune cells or engaging with immune regulatory molecules. Here, we discuss current knowledge of stromal proteins in digestive cancers including pancreatic cancer, colorectal cancer, and gastric cancer, focusing on their functions in inhibiting tumor immunity and enabling drug resistance. Moreover, we will discuss the implication of stromal proteins as therapeutic targets to unleash efficient immunotherapy-based treatments.

Expression of Extracellular Matrix-Related Genes and Their Regulatory microRNAs in Problematic Colorectal Polyps

Colorectal carcinoma usually evolves gradually, forming a spectrum of lesions, due to accumulation of genetic mutations and epigenetic alterations. Many early lesions are detected since the introduction of screening programs. The greatest challenge is to distinguish between adenomas with epithelial misplacement (AEM) and adenomas with early carcinoma (AEC), considering the diagnosis affects prognosis and treatment. We analyzed the expression of selected extracellular matrix (ECM)-related genes and proteins, and their regulatory microRNAs using RT-qPCR and immunohistochemistry in biopsies from 44 patients. Differences were observed in AEM in comparison to AEC for DCN, EPHA4, FN1, SPON2, and SPP1, reflecting inflammatory stromal reaction to traumatisation and misplacement of dysplastic glands in the submucosa in the former, and desmoplastic stromal reaction to true invasion of dysplastic glands in the submucosa in the latter. Expression of regulatory microRNAs hsa-miR-200c and hsa-miR-146a significantly negatively correlated with the expression of their regulated genes, while significant difference between AEM and AEC was observed only for hsa-miR-29c. The described expression patterns are too complex to be used in diagnostic work, but might contribute to better understanding ECM changes in colorectal carcinoma development, helping to find new markers in the future.

WGCNA reveals key gene modules regulated by the combined treatment of colon cancer with PHY906 and CPT11

Irinotecan (CPT11) is one of the most effective drugs for treating colon cancer, but its severe side effects limit its application. Recently, a traditional Chinese herbal preparation, named PHY906, has been proved to be effective for improving therapeutic effect and reducing side effects of CPT11. The aim of the present study was to provide novel insight to understand the molecular mechanism underlying PHY906-CPT11 intervention of colon cancer. Based on the GSE25192 dataset, for different three treatments (PHY906, CPT11, and PHY906-CPT11), we screened out differentially expressed genes (DEGs) and constructed a co-expression network by weighted gene co-expression network analysis (WGCNA) to identify hub genes. The key genes of the three treatments were obtained by merging the DEGs and hub genes. For the PHY906-CPT11 treatment, a total of 18 key genes including Eif4e, Prr15, Anxa2, Ddx5, Tardbp, Skint5, Prss12 and Hnrnpa3, were identified. The results of functional enrichment analysis indicated that the key genes associated with PHY906-CPT11 treatment were mainly enriched in ‘superoxide anion generation’ and ‘complement and coagulation cascades’. Finally, we validated the key genes by Gene Expression Profiling Interactive Analysis (GEPIA) and RT-PCR analysis, the results indicated that EIF4E, PRR15, ANXA2, HNRNPA3, NCF1, C3AR1, PFDN2, RGS10, GNG11, and TMSB4X might play an important role in the treatment of colon cancer with PHY906-CPT11. In conclusion, a total of 18 key genes were identified in the present study. These genes showed strong correlation with PHY906-CPT11 treatment in colon cancer, which may help elucidate the underlying molecular mechanism of PHY906-CPT11 treatment in colon cancer.

Pan-Cancer Analyses Reveal Prognostic Value of Osteomimicry Across 20 Solid Cancer Types

Background

Osteomimicry of cancer cells had been widely reported in prostate cancer and breast cancer. However, the prognostic value of osteomimicry in various cancer types remained unclear. We hypothesized that osteomimicry would result in remodeling of the tumor microenvironment and was eligible to predict patient prognosis.

Methods

A comprehensive transcriptomic analysis of the osteomimicry, which was characterized by mRNA expression of SPARC, SPP1, and BGLAP, across 20 solid tumors (7564 patients) using RNA-seq data from The Cancer Genome Atlas (TCGA) was conducted. Samples of each cancer type were classified into subgroups (high vs. low) based on median value of osteomimetic markers, the associations of these markers with clinical outcomes, immune cell infiltration and immune checkpoints expression were explored.

Results

Each osteomimetic marker harbored prognostic value in the pan-cancer analyses [SPARC: hazard ratio (HR) = 1.10, p = 0.028; SPP1: HR = 1.25, p < 0.001; BGLAP: HR = 1.13, p = 0.005]. Patients with high expression of all the three genes also had significantly unfavorable survival (HR = 1.61, p < 0.0001) compared with those of low expression. Correlation analyses demonstrated that osteomimicry was closely related to tumor purity, dendritic cells (DC) infiltration and expression of immune checkpoints.

Conclusion

Osteomimicry had prognostic value in various cancer types and the underlying mechanism might correlate to the trapping and dysfunction of DCs in the tumor microenvironment, revealing the potential of osteomimicry as a target of immunotherapy.

Low Levels of SPARC are Associated with Tumor Progression and Poor Prognosis in Human Endometrial Carcinoma

Background

SPARC (secreted protein acidic and rich in cysteine), also known as osteonectin, BM-40, and 43 K protein, is a matricellular protein associated with various tumor progressions. The aim of this research was to investigate the prognostic value of SPARC in endometrial carcinoma (EC) and its function in cancer cell invasion and metastasis.

Methods

From both mRNA and protein levels, SPARC expression in normal endometrial tissue and EC tissue, normal endometrial cells and 4 EC cell lines (KLE, HEC-1A, HEC-1B, Ishikawa) were evaluated by immunohistochemistry (IHC) or immunocytochemistry (ICC), quantitative real-time PCR (qRT-PCR) and Western blotting. RNA interference mediated by lentivirus was performed to get the stable SPARC down-expressing cells. The functional analysis techniques in vitro and in vivo were used to detect the effects of SPARC knockdown on EC cell proliferation, apoptosis, invasion and metastasis.

Results

The expressions of SPARC in EC tissues and cells were much lower than those in normal endometrial cells and tissues; meanwhile, its low expression was closely related to the malignant clinicopathological characteristics of EC. SPARC knockdown could inhibit apoptosis, promote the process of EMT and improve the proliferation and invasion capacities of EC cells in vitro and in vivo.

Conclusion

The low expression of SPARC was detected in EC tissues and cells, which was positively correlated with the poor prognosis of EC patients. SPARC acted as a tumor suppressor gene that hindered EC progression, which proposed a new therapeutic strategy for EC treatment.

SPARC-p53: The double agents of cancer

Cancer is a complex disease with high incidence and mortality rates. The important role played by the tumor microenvironment in regulating oncogenesis, tumor growth, and metastasis is by now well accepted in the scientific community. SPARC is known to participate in tumor-stromal interactions and impact cancer growth in ambiguous ways, which either enhance or suppress cancer aggressiveness, in a context-dependent manner. p53 transcription factor, a well-established tumor suppressor, has been reported to promote tumor growth in certain situations, such as hypoxia, thus displaying a duality in its action. Although both proteins are being tested in clinical trials, the synergistic relation between them is yet to be explored in clinical practice. In this review, we address the controversial roles of SPARC and p53 as double agents in cancer, briefly summarizing the interaction found between these two molecules and its importance in cancer.

Diffusion Kurtosis Imaging-A Superior Approach to Assess Tumor-Stroma Ratio in Pancreatic Ductal Adenocarcinoma

Extensive desmoplastic stroma is a hallmark of pancreatic ductal adenocarcinoma (PDAC) and contributes to tumor progression and to the relative resistance of tumor cells towards (radio) chemotherapy. Thus, therapies that target the stroma are under intense investigation. To allow the stratification of patients who would profit from such therapies, non-invasive methods assessing the stroma content in relation to tumor mass are required. In the current prospective study, we investigated the usefulness of diffusion-weighted magnetic resonance imaging (DW-MRI), a radiologic method that measures the random motion of water molecules in tissue, in the assessment of PDAC lesions, and more specifically in the desmoplastic tumor stroma. We made use of a sophisticated DW-MRI approach, the so-called diffusion kurtosis imaging (DKI), which possesses potential advantages over conventional and widely used monoexponential diffusion-weighted imaging analysis (cDWI). We found that the diffusion constant D from DKI is highly negatively correlated with the percentage of tumor stroma, the latter determined by histology. D performed significantly better than the widely used apparent diffusion coefficient (ADC) from cDWI in distinguishing stroma-rich (>50% stroma percentage) from stroma-poor tumors (≤50% stroma percentage). Moreover, we could prove the potential of the diffusion constant D as a clinically useful imaging parameter for the differentiation of PDAC-lesions from non-neoplastic pancreatic parenchyma. Therefore, the diffusion constant D from DKI could represent a valuable non-invasive imaging biomarker for assessment of stroma content in PDAC, which is applicable for the clinical diagnostic of PDAC.