The nature of neural invasion by pancreatic cancer

Adjuvant therapy for intermediate risk factors in oral cancer: Can we reach a consensus?

Oral carcinoma is a common disease that poses challenges in treatment management, especially for advanced cases. Adjuvant therapies, such as radiation and chemoradiation therapy, are typically used for advanced oral cancer patients. However, there is uncertainty regarding the use of adjuvant therapy for early-stage patients with certain soft histological parameters. The UICC manual of clinical oncology suggests that adjuvant therapy for such parameters is desirable but not essential. These parameters include perineural invasion, lymphovascular invasion, single nodal positivity, and patterns of invasion, which complicate the decision-making process for including adjuvant therapy. This review aims to provide evidence-based literature for effectively managing this patient group and developing treatment protocols based on current evidence.

Perineural invasion score system and clinical outcomes in resected pancreatic cancer patients

BACKGROUND/OBJECTIVES

Perineural invasion (PNI), classified according to its presence or absence in tumor specimens, is recognized as a poor prognostic factor in pancreatic ductal adenocarcinoma (PDAC) patients. Herein, we identified five histological features of PNI and investigated their impact on survival outcomes of PDAC resected patients.

METHODS

Five histopathological features of PNI (diameter, number, site, sheath involvement, and mitotic figures within perineural invasion) were combined in an additional final score (ranging from 0 to 8), and clinical data of PDAC patients were retrospectively analyzed. PNI + patients were stratified in two categories according to the median score value (<6 and ≥ 6, respectively). Impact of PNI on disease-free survival (DFS) and overall survival (OS) were analyzed.

RESULTS

Forty-five patients were enrolled, of whom 34 with PNI (PNI+) and 11 without PNI (PNI-). The DFS was 11 months vs. not reached (NR) (p = 0.258), while the OS was 19 months vs. NR (p = 0.040) in PNI+ and PNI- patients, respectively. A ≥6 PNI was identified as an independent predictor of worse OS vs. <6 PNI + patients (29 vs. 11 months, p < 0.001) and <6 PNI+ and PNI- patients (43 vs. 11 months, p < 0.001). PNI ≥6 was an independent negative prognostic factor of DFS vs. <6 PNI+ and PNI- patients (13 vs. 6 months, p = 0.022).

CONCLUSIONS

We report a PNI scoring system that stratifies surgically-treated PDAC patients in a graded manner that correlates with patient prognosis better than the current dichotomous (presence/absence) definition. However, further and larger studies are needed to support this PNI scoring system.

Molecular pathway of pancreatic cancer-associated neuropathic pain

The pancreas is a heterocrine gland that has both exocrine and endocrine parts. Most pancreatic cancer begins in the cells that line the ducts of the pancreas and is called pancreatic ductal adenocarcinoma (PDAC). PDAC is the most encountered pancreatic cancer type. One of the most important characteristic features of PDAC is neuropathy which is primarily due to perineural invasion (PNI). PNI develops tumor microenvironment which includes overexpression of fibroblasts cells, macrophages, as well as angiogenesis which can be responsible for neuropathy pain. In tumor microenvironment inactive fibroblasts are converted into an active form that is cancer-associated fibroblasts (CAFs). Neurotrophins they also increase the level of Substance P, calcitonin gene-related peptide which is also involved in pain. Matrix metalloproteases are the zinc-associated proteases enzymes which activates proinflammatory interleukin-1β into its activated form and are responsible for release and activation of Substance P which is responsible for neuropathic pain by transmitting pain signal via dorsal root ganglion. All the molecules and their role in being responsible for neuropathic pain are described below.

Clinical Evaluation of the Pancreatic Cancer Microenvironment: Opportunities and Challenges

Advances in our understanding of pancreatic ductal adenocarcinoma (PDAC) and its tumor microenvironment (TME) have the potential to transform treatment for the hundreds of thousands of patients who are diagnosed each year. Whereas the clinical assessment of cancer cell genetics has grown increasingly sophisticated and personalized, current protocols to evaluate the TME have lagged, despite evidence that the TME can be heterogeneous within and between patients. Here, we outline current protocols for PDAC diagnosis and management, review novel biomarkers, and highlight potential opportunities and challenges when evaluating the PDAC TME as we prepare to translate emerging TME-directed therapies to the clinic.

Involvement of neuronal factors in tumor angiogenesis and the shaping of the cancer microenvironment

Emerging evidence suggests that nerves within the tumor microenvironment play a crucial role in regulating angiogenesis. Neurotransmitters and neuropeptides released by nerves can interact with nearby blood vessels and tumor cells, influencing their behavior and modulating the angiogenic response. Moreover, nerve-derived signals may activate signaling pathways that enhance the production of pro-angiogenic factors within the tumor microenvironment, further supporting blood vessel growth around tumors. The intricate network of communication between neural constituents and the vascular system accentuates the potential of therapeutically targeting neural-mediated pathways as an innovative strategy to modulate tumor angiogenesis and, consequently, neoplastic proliferation. Hereby, we review studies that evaluate the precise molecular interplay and the potential clinical ramifications of manipulating neural elements for the purpose of anti-angiogenic therapeutics within the scope of cancer treatment.

The significance of peri-neural invasion in patients with resected hilar cholangiocarcinoma: A single-center experience in China

BACKGROUND

The significance of peri-neural invasion (PNI) in resected patients with hilar cholangiocarcinoma (HCCA) has been rarely explored. Our study was performed to evaluate the significance of PNI in resected HCCA patients in terms of tumor biological features and long-term survival.

METHODS

We retrospectively reviewed surgically-treated HCCA patients between June, 2000 and June 2018. SPSS 25.0 software was used for statistical analysis.

RESULTS

A total of 239 resected HCCA patients were included (No. PNI: 138). PNI indicated more aggressive tumor biological features. Major vascular reconstruction was more frequently performed in patients with PNI (34.8% vs 24.8%, P = 0.064). Patients with PNI shared a significantly higher percentage of surgical margin width <5 mm (29.0% vs 16.8%, P = 0.02). The proportion of patients with T1-2 disease (31.2% vs 40.6%, P = 0.085) or I-II disease (21% vs 34.7%, P = 0.014) was significantly lower in patients with PNI. The overall morbidity rate was significantly higher in patients with PNI (P = 0.042). A much worse overall survival (OS) (P = 0.0003) or disease-free survival (DFS) (P = 0.0011) in patients with PNI. Even after matching vital prognostic factors, a significantly worse OS (P = 0.0003) or DFS (P = 0.0002) was still observed in patients with PNI. PNI was an independent prognostic factor in both OS (P = 0.011) and DFS (P = 0.024).

CONCLUSION

PNI indicated more aggressive tumor biological features and more advanced tumor stage in patients with resected HCCA. PNI can be an independent prognostic factor in both OS and DFS. Future multi-center studies covering various races or populations are required for further validation.

Targeting the Cancer-Neuronal Crosstalk in the Pancreatic Cancer Microenvironment

Pancreatic ductal adenocarcinoma (PDAC) represents one of the most aggressive solid tumors with a dismal prognosis and an increasing incidence. At the time of diagnosis, more than 85% of patients are in an unresectable stage. For these patients, chemotherapy can prolong survival by only a few months. Unfortunately, in recent decades, no groundbreaking therapies have emerged for PDAC, thus raising the question of how to identify novel therapeutic druggable targets to improve prognosis. Recently, the tumor microenvironment and especially its neural component has gained increasing interest in the pancreatic cancer field. A histological hallmark of PDAC is perineural invasion (PNI), whereby cancer cells invade surrounding nerves, providing an alternative route for metastatic spread. The extent of PNI has been positively correlated with early tumor recurrence and reduced overall survival. Multiple studies have shown that mechanisms involved in PNI are also involved in tumor spread and pain generation. Targeting these pathways has shown promising results in alleviating pain and reducing PNI in preclinical models. In this review, we will describe the mechanisms and future treatment strategies to target this mutually trophic interaction between cancer cells to open novel avenues for the treatment of patients diagnosed with PDAC.

Survival Benefit after Shifting from Upfront Surgery to Neoadjuvant Treatment in Borderline Resectable Pancreatic Cancer

According to the 2016 National Comprehensive Cancer Network (NCCN) guidelines, patients with borderline resectable pancreatic cancer (BRPC) should receive chemotherapy as the first-line treatment. This study examined the real-world survival benefits of modifying BRPC treatment guidelines. Patients treated for BRPC at a single institution from 2013 to 2015 (pre-guideline group) and 2017 to 2019 (post-guideline group) were retrospectively reviewed. According to the treatment method used, patients were classified into upfront surgery (US), surgery after neoadjuvant treatment (NAT), and chemotherapy only (CO) groups. Overall survival (OS) was compared according to period and treatment type. Factors associated with OS were analyzed using a Cox regression model. Among the 165 patients, 63 were in the pre-guideline group and 102 patients were in the post-guideline group. The median OS was significantly improved in the post-guideline group compared to the pre-guideline group (29 vs. 13 months, p < 0.001). According to the treatment method, the median OS of the NAT group was significantly longer than that of the US and CO groups (40 vs. 16 vs. 15 months, respectively, p < 0.001). In multivariate analysis, tumor size, differentiation, NAT, and perineural invasion were significant prognostic factors. NAT is an important treatment option for BRPC and increased patient survival in the real world.

Quantification of perineural invasion in pancreatic ductal adenocarcinoma: proposal of a severity score system

Perineural invasion (PNI) is a common feature in pancreatic ductal adenocarcinoma (PDAC) and correlates with an aggressive tumor behavior already at early stages of disease. PNI is currently considered as a "present vs. absent" feature, and a severity score system has not yet been established. The aim of the present study was thus to develop and validate a score system for PNI and to correlate it with other prognostic features. In this monocentric retrospective study, 356 consecutive PDAC patients (61.8% upfront surgery patients, 38.2% received neoadjuvant therapy) were analyzed. PNI was scored as follows: 0: absent; 1: the presence of neoplasia along nerves < 3 mm in caliber; and 2: neoplastic infiltration of nerve fibers ≥ 3 mm and/or massive perineural infiltration and/or the presence of necrosis of the infiltrated nerve bundle. For every PNI grade, the correlation with other pathological features, disease-free survival (DFS), and disease-specific survival (DSS) were analyzed. Uni- and multivariate analysis for DFS and DSS were also performed. PNI was found in 72.5% of the patients. Relevant trends between PNI score and tumor differentiation grade, lymph node metastases, vascular invasion, and surgical margins status were found. The latter was the only parameter statistically correlated with the proposed score. The agreement between pathologists was substantial (Cohen's K 0.61). PNI severity score significantly correlated also with decreased DFS and DSS at univariate analysis (p < 0.001). At multivariate analysis, only the presence of lymph node metastases was an independent predictor of DFS (HR 2.235 p < 0.001). Lymph node metastases (HR 2.902, p < 0.001) and tumor differentiation grade (HR 1.677, p = 0.002) were independent predictors of DSS. Our newly developed PNI score correlates with other features of PDAC aggressiveness and proved to have a prognostic role though less robust than lymph nodes metastases and tumor differentiation grade. A prospective validation is needed.

Multiperspective quantitative tumor-stroma ratio reveals histological areas associated with poor outcomes in oral squamous cell carcinoma

AIMS

Different regions of oral squamous cell carcinoma (OSCC) have particular histopathological characteristics, and the individual histological characteristics of the tumors are poorly understood. Therefore, calculating the proportion of tumor cells in different regions that allow assessment of the prognostic outcomes for OSCC patients would be of great clinical significance.

METHODS AND RESULTS

We established an open-source software-based analytic pipeline that defines the inner tumor and invasive tumor front (ITF) in pancytokeratin-stained whole slide images (WSIs) and quantifies the tumor-stroma ratio (TSR) within the two regions. We applied this method to 114 patients with OSCC and predicted patient prognosis by the TSR. The proportion of tumor area in the inner tumor was generally higher than that in the ITF (p < 0.0001). TSR was an independent prognostic factor for overall survival (OS) (p = 0.016), disease-free survival (DFS) (p = 0.026), and relapse-free survival (RFS) (p = 0.037) in inner tumor, and TSR was an independent prognostic factor for OS (p = 0.00052), DFS (p = 0.035), and metastasis-free survival (MFS) (p = 0.038) in the ITF. Tumor-low status was associated with poorer prognosis. There was a significant correlation between the TSR and perineural invasion (PNI) in the inner tumor (p = 0.009).

CONCLUSIONS

The histopathological characteristics of different regions of OSCC may be used to develop the potential prognostic markers. The TSR of the inner tumor is more targeted in predicting prognosis and accurately assesses the risk of PNI+.

Prognostic Impact of Gastroduodenal Artery Involvement in Cancer of the Pancreatic Head

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) contacting major arteries such as the celiac, common hepatic, and superior mesenteric artery is linked to poor prognosis and classified as borderline resectable. Although PDAC involving the gastroduodenal artery (GDA) is considered resectable, the prognostic impact of GDA involvement remains unclear. Here we investigated the prognostic impact of GDA involvement in PDAC after resection.

METHODS

This study included 105 patients with resectable PDAC or borderline resectable with portal vein involvement. Patients were divided into two groups: those with tumor-GDA contact ≤ 180° and those with GDA contact > 180°. We evaluated the prognostic impact of GDA involvement between these groups.

RESULTS

Both recurrence-free and overall survival after the surgery were significantly poorer with GDA contact > 180° than ≤ 180°. The poorer prognosis with GDA contact > 180° was verified by multivariate analysis and propensity score matching analysis to match patient backgrounds between the groups. The frequency of postoperative distant metastasis was also significantly higher in patients with GDA contact > 180°.

CONCLUSIONS

GDA involvement is an independent factor significantly associated with postoperative survival in PDAC, and the poorer prognosis with GDA involvement may be linked to the development of postoperative distant metastasis.

Tissue clearing and 3D reconstruction of digitized, serially sectioned slides provide novel insights into pancreatic cancer

Pancreatic cancer is currently the third leading cause of cancer death in the United States. The clinical hallmarks of this disease include abdominal pain that radiates to the back, the presence of a hypoenhancing intrapancreatic lesion on imaging, and widespread liver metastases. Technologies such as tissue clearing and three-dimensional (3D) reconstruction of digitized serially sectioned hematoxylin and eosin-stained slides can be used to visualize large (up to 2- to 3-centimeter cube) tissues at cellular resolution. When applied to human pancreatic cancers, these 3D visualization techniques have provided novel insights into the basis of a number of the clinical characteristics of this disease. Here, we describe the clinical features of pancreatic cancer, review techniques for clearing and the 3D reconstruction of digitized microscope slides, and provide examples that illustrate how 3D visualization of human pancreatic cancer at the microscopic level has revealed features not apparent in 2D microscopy and, in so doing, has closed the gap between bench and bedside. Compared with animal models and 2D microscopy, studies of human tissues in 3D can reveal the difference between what can happen and what does happen in human cancers.

An Overview of the Molecular Cues and Their Intracellular Signaling Shared by Cancer and the Nervous System: From Neurotransmitters to Synaptic Proteins, Anatomy of an All-Inclusive Cooperation

We propose an overview of the molecular cues and their intracellular signaling involved in the crosstalk between cancer and the nervous system. While "cancer neuroscience" as a field is still in its infancy, the relation between cancer and the nervous system has been known for a long time, and a huge body of experimental data provides evidence that tumor-nervous system connections are widespread. They encompass different mechanisms at different tumor progression steps, are multifaceted, and display some intriguing analogies with the nervous system's physiological processes. Overall, we can say that many of the paradigmatic "hallmarks of cancer" depicted by Weinberg and Hanahan are affected by the nervous system in a variety of manners.

Nomenclature and Lymphatic Drainage Patterns of Abdominal Lymph Nodes

The lymphatic system provides a route for the spread of inflammation and malignancies. The identification of nodal stations and lymphatic pathways of tumor spread is important for tumor staging, choice of therapy, and the prediction of the prognosis of patients with malignant diseases. Because lymph node metastasis is common in primary intra-abdominal malignant tumors, its detection is essential for radiologists to understand the pattern of disease spread. Using schematic pictures and color-coded CT images, this pictorial essay describes the locations and nomenclature of the abdominal lymph nodes. Furthermore, the lymphatic drainage pathways of the upper and lower gastrointestinal tracts, liver, gallbladder, bile duct, and pancreas have been highlighted. In addition, lymph nodes belonging to the regional lymph nodes in malignant tumors arising from each organ are described, and certain cases are presented with images from patients.

Impact of resection margin status on survival after operation for pancreatic head cancer with extrapancreatic nerve plexus invasion

BACKGROUND

Extrapancreatic nerve plexus (PL) invasion of pancreatic ductal adenocarcinoma (PDAC) is an important factor for determining resectability and surgical method. We sought to clarify the characteristics of PDAC with PL invasion and clinical impact of the resection margin status on prognosis for PDAC with PL invasion.

METHODS

A total of 242 patients with pancreatic head cancer who underwent pancreatectomy were evaluated. Clinicopathological data and patient survival were analyzed.

RESULTS

Pathological PL invasion was observed in 68 patients (28.1%). Patients with PL invasion had significantly shorter disease-free survival (DFS) and showed trends toward worse overall survival (OS) than those without PL invasion. While multivariate analysis revealed that PL invasion was not an independent prognostic factor, PL invasion was associated with extensive venous invasion and a high percentage of lymph node metastases, both of which were independent factors affecting DFS and OS. Among patients with PL invasion, there was no significant difference in DFS and OS between the R0 and R1 resection groups.

CONCLUSIONS

PL invasion is a common pathological feature of aggressive PDAC with high propensity for invasiveness and metastatic potential. The microscopic resection margin status may not affect the survival of pancreatic head cancer patients with PL invasion.

Implications of Perineural Invasion on Disease Recurrence and Survival After Pancreatectomy for Pancreatic Head Ductal Adenocarcinoma

OBJECTIVE

To describe PNI and to evaluate its impact on disease-free (DFS) and overall survival (OS) in patients with resected pancreatic ductal adenocarcinoma (PDAC).

SUMMARY OF BACKGROUND DATA

Although PNI is a prognostic factor for survival in many GI cancers, there is limited knowledge regarding its impact on tumor recurrence, especially in ''early stage disease'' (PDAC ≤20 mm, R0/ N0 PDAC).

METHODS

This multicenter retrospective study included patients undergoing PDAC resection between 2009 and 2014. The association of PNI with DFS and OS was analyzed using Cox proportional-hazards models.

RESULTS

PNI was found in 87% of 778 patients included in the study, with lower rates in PDAC ≤20 mm (78.7%) and in R0/N0 tumors (70.6%). PNI rate did not differ between patients who underwent neoadjuvant therapy and upfront surgery (88% vs 84%, P = 0.08). Although not significant at multivariate analysis ( P = 0.07), patients with PNI had worse DFS at univariate analysis (median DFS: 20 vs 15 months, P < 0.01). PNI was the only independent predictor of DFS in R0/N0 tumors (hazard ratio [HR]: 2.2) and in PDAC ≤ 20 mm (HR: 1.8). PNI was an independent predictor of OS in the entire cohort (27 vs 50 months, P = 0.01), together with G3 tumors, pN1 status, carbohydrate antigen (CA) 19.9 >37 and pain.

CONCLUSIONS

PNI represents a major determinant of tumor recurrence and patients' survival in pancreatic cancer. The role of PNI is particularly relevant in early stages, supporting the hypothesis that invasion of nerves by cancer cells has a driving role in pancreatic cancer progression.

Perineural Invasion in Pancreatic Ductal Adenocarcinoma (PDAC): A Saboteur of Curative Intended Therapies?

(1) Background: Perineural invasion (PNI) is a common characteristic of pancreatic ductal adenocarcinoma (PDAC) and is present in most resection margins. We hypothesized that curative pancreatic tumor resection with long-term survival could only be achieved in PNI-negative patients. (2) Material and Methods: A retrospective investigation of PDAC patients who underwent curative-intended surgery during the period 2008 to 2019 was performed at our institution. (3) Results: We identified 571 of 660 (86.5%) resected patients with well-annotated reports and complete datasets. Of those, 531 patients (93%) exhibited tumors with perineural invasion (Pn1), while 40 (7%) were negative for PNI (Pn0). The majority of patients in the Pn1 group presented advanced tumor stage and positive lymph node infiltration. Patients in the Pn0 group showed an improved disease-free and long-term survival compared to the Pn1 group (p < 0.001). Subgroup analysis of all R0-resected patients indicated improved long-term survival and disease-free survival of R0 Pn0 patients when compared to R0 Pn1 patients (p < 0.001). (4) Conclusion: Our study confirmed that Pn0 improves the long-term survival of PDAC-resected cancer patients. Furthermore, PNI significantly challenges the long-term survival of formally curative (R0) resected patients. We provide new insights into the dynamics of PNI in pancreatic cancer patients which are needed to define subgroups of patients for risk stratification and multimodal treatment strategies.

Prognostic impact of splenic vessel involvement and tumor size in distal pancreatectomy for adenocarcinoma: a retrospective multicentric cohort study

PURPOSE

Splenic vessel involvement occurs frequently in pancreatic ductal adenocarcinoma (PDAC) of the body and the tail (B/T) but the impact on survival is unknown. We assessed the influence of radiological and pathologic involvement of splenic artery (p-SA +) and vein (p-SV +) on patient outcomes after distal pancreatectomy (DP) for PDAC.

METHODS

From 2013 to 2019, all DP for PDAC in five centers were included. Factors associated with overall (OS) and disease-free (DFS) survival were identified.

RESULTS

Among the 76 patients included, 5 (6.6%) had p-SA + only, 11 (14.5%) had p-SV + only, and 24 (31.6%) had both p-SA + and p-SV + . The preoperative CT-scan accuracy to predict p-SV + and p-SA + was high (sensitivity: 91.4% and 82.8%, respectively; negative predictive value: 89.7% and 88.3%, respectively). The 5-year OS and DFS rates were 3.9% and 8.3%, respectively. Multivariate analysis identified splenic vessel involvement (i.e., p-SA + or p-SV + , or both p-SA + and p-SV +) as the only independent factor influencing DFS (HR 4.04; 95% CI [1.22-13.44], p = 0.023). Tumor size ≥ 30 mm was the only independent factor influencing OS (HR 4.04; 95% CI [1.26-12.95], p = 0.019) and was associated with a high risk of p-SA + (p = 0.001) and p-SV + (p < 0.001).

CONCLUSION

Tumor size ≥ 30 mm and splenic vessel involvement occurred in more than half of the patients who underwent DP for PDAC and had negative impact on long-term survival. Preoperative CT-scan was reliable to identify splenic vessel involvement in B/T PDAC. Large tumor size and radiological splenic vessel involvement could be taken into account to propose a neoadjuvant treatment.

Microscopic Invasion of Nerve Is Associated With Aggressive Behaviors in Pancreatic Neuroendocrine Tumors

Objectives

The role of neural invasion has been reported in cancers. Few studies also showed that neural invasion was related to survival rate in patients with pancreatic neuroendocrine tumor (PNET). The aim of this study is to explore the association between neural invasion and aggressive behaviors in PNET.

Methods

After excluding those patients with biopsy and with missing histological data, a total 197 patients with PNET who underwent surgery were retrospectively analyzed. The demographic data and histological data were obtained. Aggressive behavior was defined based on extra-pancreatic extension including vascular invasion, organ invasion and lymph node metastases. Logistic regression analyses were used to identify risk factor for aggressive behavior. Receiver operating characteristic (ROC) curves were performed to show the performance of nomograms in evaluating aggressive behavior of PNET.

Results

The prevalence of neural invasion in the cohort was 10.1% (n = 20). The prevalence of lymph node metastasis, organ invasion, and vascular invasion in PNET patients with neural invasion was higher than those in patients without neural invasion (p < 0.05). Neural invasion was more common in grade 3 (G3) tumors than G1/G2 (p < 0.01). Tumor size, tumor grade, and neural invasion were independent associated factors of aggressive behavior (p < 0.05) after adjusting for possible cofounders in total tumors and G1/G2 tumors. Two nomograms were developed to predict the aggressive behavior. The area under the ROC curve was 0.84 (95% confidence interval (CI): 0.77–0.90) for total population and was 0.84 (95% CI: 0.78–0.89) for patients with G1/G2 PNET respectively.

Conclusions

Neural invasion is associated with aggressive behavior in PNET. Nomograms based on tumor size, grade and neural invasion show acceptable performances in predicting aggressive behavior in PNET.

Construction of differential expression plasmids of NGF to detect its influence on PC12 cell neuronal differentiation

Alongside angiogenesis and lymphangiogenesis, neurogenesis also occurs within the cancer microenvironment. Neurogenesis is a complex process involving multiple factors, among which nerve growth factor (NGF) possesses the dual biological roles of neuron nutrition and axon growth promotion. Thus, NGF might be a key molecule involved in regulating cancer-related neurogenesis, which could play a crucial role in the signal transmission system that controls nerve growth in tumors, and enhances the abilities of migration, invasion and metastasis of tumor cells. The present study aimed to construct differential expression plasmids of NGF, in order to detect whether NGF has a vital role in neurogenesis in breast cancer cells. In the present study, 92 clinical cases of breast cancer were collected and immunohistochemical analysis was performed to verify the existence of neurons in the breast cancer microenvironment. Furthermore, recombinant NGF lentiviral overexpression, knockout and silencing plasmids were constructed, and whether NGF has an effect on neuron growth was preliminarily confirmed, indicating that the successfully constructed plasmids could be used to verify the roles of NGF in cancer-associated neurogenesis.

Eukaryotic elongation factor-2 kinase (eEF2K) signaling in tumor and microenvironment as a novel molecular target

Eukaryotic elongation factor-2 kinase (eEF2K), an atypical member of alpha-kinase family, is highly overexpressed in breast, pancreatic, brain, and lung cancers, and associated with poor survival in patients. eEF2K promotes cell proliferation, survival, and aggressive tumor characteristics, leading to tumor growth and progression. While initial studies indicated that eEF2K acts as a negative regulator of protein synthesis by suppressing peptide elongation phase, later studies demonstrated that it has multiple functions and promotes cell cycle, angiogenesis, migration, and invasion as well as induction of epithelial-mesenchymal transition through induction of integrin β1, SRC/FAK, PI3K/AKT, cyclin D1, VEGF, ZEB1, Snail, and MMP-2. Under stress conditions such as hypoxia and metabolic distress, eEF2K is activated by several signaling pathways and slows down protein synthesis and helping cells to save energy and survive. In vivo therapeutic targeting of eEF2K by genetic methods inhibits tumor growth in various tumor models, validating it as a potential molecular target. Recent studies suggest that eEF2K plays a role in tumor microenvironment cells by monocyte chemoattractant protein-1 (MCP-1) and accumulation of tumor-associated macrophages. Due to its clinical significance and the pivotal role in tumorigenesis and progression, eEF2K is considered as an important therapeutic target in solid tumors. However, currently, there is no specific and potent inhibitor for translation into clinical studies. Here, we aim to systematically review current knowledge regarding eEF2K in tumor biology, microenvironment, and development of eEF2K targeted inhibitors and therapeutics.

How Much Was the Elective Lymph Node Region Covered in Involved-Field Radiation Therapy for Locally Advanced Pancreatic Cancer? Evaluation of Overlap Between Gross Target Volume and Celiac Artery-Superior Mesenteric Artery Lymph Node Regions

Purpose

The purpose of this study was to investigate the overlaps between gross target volume (GTV) and the celiac artery (CA) and superior mesenteric artery (SMA) lymph node regions and to examine the dose incidentally irradiated to the CA and SMA lymph node regions by involved-field radiation therapy (IFRT) for locally advanced pancreatic cancer (LAPC).

Methods and Materials

Fifty-nine patients who had LAPC without distant metastasis were included. They received IFRT at 50.4 Gy in 28 fractions with 3-dimensional conformal radiation therapy. We calculated the percentages of overlap of GTV in the CA and SMA lymph node regions and examined what cases tend to have an overlap. We also investigated the dose metrics of CA and SMA lymph node regions by IFRT and the frequency of CA or SMA lymph node metastasis after IFRT.

Results

The median GTV volume was 52.2 mL. Median overlap percentages in the CA and SMA lymph node regions were 39.2% and 28.6%, respectively. There was a significant correlation between GTV volume and SMA overlap percentage (P < .001). Although the SMA overlap percentage was higher in the pancreas head (P = .028), the CA overlap percentage was higher in the pancreas body or tail (P = .002). Median mean dose, D95, and minimum dose in the CA lymph node region were 50.1 Gy, 48.7 Gy, and 45.9 Gy, respectively, and those in the SMA lymph node region 49.9 Gy, 47.3 Gy, and 39.2 Gy, respectively. CA lymph node metastases after IFRT were detected in 4 patients (6.8%).

Conclusions

An overlap between GTV and CA-SMA lymph node regions was detected in many patients, and the CA and SMA lymph node regions were irradiated incidentally even by IFRT. Prophylactic lymph node regions might not be necessary in radiation therapy planning of LAPC.

Extrapancreatic Neuropathy Correlates with Early Liver Metastasis in Pancreatic Head Adenocarcinoma

Background

Pancreatic ductal adenocarcinoma has a devastatingly poor prognosis, and most prognostic factors reflected the tumor stage more than the tumors' biology. The peripheral nerve plexus is densely distributed in the tumor micro-environment, and there are interactions between tumor cells and these nerves. Perineural invasion is an important risk factor for tumor recurrence and metastasis in pancreatic head adenocarcinoma, but the concrete types of extrapancreatic neuropathy and its role in predicting prognosis are still not clear.

Objective

To clarify the role of extrapancreatic neuropathy in the early postoperative liver metastasis and tumor-related mortality in pancreatic head adenocarcinoma and to study the mechanism of tumor recurrence and liver metastasis in pancreatic head adenocarcinoma.

Methods

We reported a retrospective study of 60 patients with resectable pancreatic head adenocarcinoma, all of whom accepted radical pancreaticoduodenectomy. Plexus pancreaticus capitalis II (PLX-II) was the representation of extrapancreatic plexus in our study, and all of these plexus had immunohistochemical staining. We defined the postoperative tumor recurrence and tumor-related mortality within 6 months as the early prognostic indicators and analyzed the pathological alterations in PLX-II among different prognosis groups.

Results

There were 18 patients suffering early postoperative liver metastasis; these two groups differed significantly in the average number of nerve trunks (P<0.001), the proportion of neuritis (P=0.003), the content of sympathetic nerve fibers (P=0.004) and parasympathetic nerve fibers (P<0.001) per unit area of PLX-II. There were 15 patients suffering early postoperative mortality, and there were significant differences between these two groups in the average number of nerve trunks (P<0.001), the proportion of neuritis (P=0.009), the content of sympathetic nerve fibers (P=0.023) and parasympathetic nerve fibers (P<0.001) per unit area of PLX-II.

Conclusion

The patterns of extrapancreatic neuropathy could reflect the biological behavior of resectable pancreatic head adenocarcinoma, and the pathological features of PLX-II were closely related to early liver metastasis and mortality.

Nerves and Pancreatic Cancer: New Insights into a Dangerous Relationship

Perineural invasion (PNI) is defined as the presence of neoplastic cells along nerves and/or within the different layers of nervous fibers: epineural, perineural and endoneural spaces. In pancreatic cancer-particularly in pancreatic ductal adenocarcinoma (PDAC)-PNI has a prevalence between 70 and 100%, surpassing any other solid tumor. PNI has been detected in the early stages of pancreatic cancer and has been associated with pain, increased tumor recurrence and diminished overall survival. Such an early, invasive and recurrent phenomenon is probably crucial for tumor growth and metastasis. PNI is a still not a uniformly characterized event; usually it is described only dichotomously ("present" or "absent"). Recently, a more detailed scoring system for PNI has been proposed, though not specific for pancreatic cancer. Previous studies have implicated several molecules and pathways in PNI, among which are secreted neurotrophins, chemokines and inflammatory cells. However, the mechanisms underlying PNI are poorly understood and several aspects are actively being investigated. In this review, we will discuss the main molecules and signaling pathways implicated in PNI and their roles in the PDAC.

Distinct chemotherapy-associated anti-cancer immunity by myeloid cells inhibition in murine pancreatic cancer models

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy associated with an extremely poor prognosis. Chemotherapy, such as gemcitabine (GEM), is the only treatment for PDAC patients who are not suitable for radical surgical treatment; however, its anti-tumor efficacy is limited. In this study, we investigated the host immune system response in murine PDAC models undergoing GEM treatment. We found that PDAC tumor tissues were infiltrated with a substantial number of Gr-1+ myeloid cells and had relatively small numbers of CD4+ and CD8+ cells. In addition, there were increased numbers of myeloid cells expressing CD11b+ and Gr-1+ in peripheral blood. When mice with PDAC tumors in the intraperitoneal cavity or liver were treated with GEM, numbers of myeloid cells in tumor tissues and in peripheral blood decreased. In contrast, numbers of CD4+ or CD8+ cells increased. In peripheral blood, the numbers of CD8+ cells expressing interferon-gamma (IFN-γ) were higher in GEM-treated mice than in untreated mice. In addition, GEM treatment in combination with myeloid cell depletion further prolonged the survival of PDAC mice. The gene expression profile of peripheral blood in myeloid cell-depleted PDAC mice treated with GEM showed biological processes related to anti-cancer immunity, such as natural killer cell-mediated cytotoxicity, type I IFN signaling, and co-stimulatory signaling for T cell activation. Thus, in PDAC murine models, GEM treatment was associated with an immune response consistent with an anti-cancer effect, and depletion of myeloid-lineage cells played an important role in enhancing anti-cancer immunity associated with GEM treatment.

Expression and significance of autonomic nerves and α9 nicotinic acetylcholine receptor in colorectal cancer

The present study evaluated the distribution of sympathetic and parasympathetic nerves and the expression of the α9 nicotinic acetylcholine receptor (α9nAChR) and investigated their potential association with colorectal cancer (CRC) development. The distribution of autonomic nerves and α9nAChR in CRC was detected by immunohistochemistry, which was then used to analyze their association with clinicopathological parameters and prognosis. Sympathetic fibers were primarily observed in the stroma adjacent to cancer cells, whereas parasympathetic fibers were primarily observed in the stroma away from cancer cells. Patients with samples positive for sympathetic nerve fibers had less lymph node invasion and a better prognosis compared with patients with samples negative for sympathetic nerve fibers. The expression of parasympathetic nerves in patients >60 years old was increased compared with patients ≤60 years old. The expression of parasympathetic nerves in patients with lymph node invasion was increased compared with patients without lymph node invasion. The detection of parasympathetic nerves gradually increased as CRC (T stage) advanced. Patients with parasympathetic negative samples had better prognoses compared with patients with parasympathetic positive samples. The expression of α9nAChR was principally localized in cellular membranes and the cytoplasm of CRC tissues and it was revealed to have a positive association with the number of parasympathetic nerves. Increased α9nAChR expression was observed in patients >60 years old compared with patients <60 years old. The detection rate of α9nAChR in tissues from patients with lymph node invasion was increased compared with patients without lymph node invasion. The detection of α9nAChR gradually increased as the CRC stage advanced. The prognoses for patients with α9nAChR negative tissue were improved compared with the prognoses for patients with α9nAChR positive tissue. Sympathetic nerves were primarily detected in the early phases of CRC and indicated a good prognosis. Parasympathetic nerves and α9nAChR were principally observed in the late phases of cancer and indicated a poor prognosis. The present study revealed that parasympathetic nerves may promote the progression of CRC through α9nAChR.

Significance and Prevalence of Haziness Surrounding the Hepatic Artery and Celiac Axis on Computed Tomographic Imaging After Pancreaticoduodenectomy

PURPOSE

This study was conducted to assess the prevalence and significance of "haziness" around the hepatic artery and celiac axis in patients after pancreaticoduodenectomy.

METHODS

This retrospective study was conducted on 116 patients who underwent pancreaticoduodenectomy or a similar procedure and had no clinical evidence of tumor recurrence or malignancy within 2 years from the date of surgery.

RESULTS

Most images exhibited at least mild to moderate haziness around the hepatic artery and celiac axis. Patients with benign vs malignant results on formal pathology had no significant difference in severity of findings. Haziness remained in the mild to moderate range 2 years after surgery.

CONCLUSIONS

Mild to moderate soft tissue stranding with increased attenuation around the hepatic artery and celiac axis is a common finding after pancreaticoduodenectomy that may persist for years after surgery. Such haziness alone has low specificity for tumor recurrence and should not be regarded as an indicator of malignancy.

Tumor progression: the neuronal input

One of the challenges of cancer is its heterogeneity and rapid capacity to adapt. Notwithstanding significant progress in the last decades in genomics and precision medicine, new molecular targets and therapies appear highly necessary. One way to approach this complex problem is to consider cancer in the context of its cellular and molecular microenvironment, which includes nerves. The peripheral nerves, the topic of this review, modulate the biological behavior of the cancer cells and influence tumor progression, including the events related to the metastatic spread of the disease. This mechanism involves the release of neurotransmitters directly into the microenvironment and the activation of the corresponding membrane receptors. While this fact appears to complicate further the molecular landscape of cancer, the neurotransmitters are highly investigated molecules, and often are already targeted by well-developed drugs, a fact that can help finding new therapies at a fraction of the cost and time needed for new medicines (through the so-called drug repurposing). Moreover, the modulation of tumor progression by neurotransmitters can probably explain the long-recognized effects of psychological factors on the burden of cancer. We begin with an introduction on the tumor-nervous-connections and a description of the perineural invasion and neoneurogenesis, the two most important interaction patterns of cancer and nerves. Next, we discuss the most recent data that unequivocally demonstrate the necessity of the nervous system for tumor onset and growth. We introduce the molecular players of the tumor-nervous-connections by citing the role of three main families: neurotropic factors, axon guidance molecules, and neurotransmitters. Finally, we review the role the most important neurotransmitters in tumor biology and we conclude by analyzing the significance of the presented data for cancer therapy, with all the potential advantages and caveats.

Prospective Evaluation of Associations between Cancer-Related Pain and Perineural Invasion in Patients with Resectable Pancreatic Adenocarcinoma

INTRODUCTION

Perineural invasion is a unique characteristic of pancreatic adenocarcinoma biology and is present in the majority of resected pathologic specimens. The purpose of this study was to understand the relationships between preoperative pain and perineural invasion in patients with pancreatic adenocarcinoma.

METHODS

Fifty-two chemotherapy naive patients undergoing resection for pancreatic adenocarcinoma from 2012 to 2014 completed a previously validated Brief Pain Inventory survey for preoperative clinical pain scoring. Preoperative pain was correlated with multiple clinicopathologic features.

RESULTS

Preoperative pain was not associated with pathologic cancer stage, lymph node status, lymph node positivity ratio, resection margin status, or tumor location within the pancreas. In the subgroup of pancreatic head cancers, pain interference with affect was associated with the absence of perineural invasion (p = 0.02). Patients with stage I cancer had higher pain interference scores than those with stage II cancer (p = 0.02).

CONCLUSIONS

Preoperative pain does not predict the presence of perineural invasion or other pathologic prognostic factors in patients with resectable pancreatic adenocarcinoma. Higher pain scores in pancreatic head cancers correlated with absence of perineural invasion and early cancer stage. The effects of preoperative pain on quality and interference of daily life deserve further investigation in larger prospective studies involving patients with pancreatic cancer.

Pleiotrophin and N-syndecan promote perineural invasion and tumor progression in an orthotopic mouse model of pancreatic cancer

AIM

To detect the expression of pleiotrophin (PTN) and N-syndecan in pancreatic cancer and analyze their association with tumor progression and perineural invasion (PNI).

METHODS

An orthotopic mouse model of pancreatic cancer was created by injecting tumor cells subcapsularly in a root region of the pancreas beneath the spleen. Pancreatic cancer tissues were taken from 36 mice that survived for more than 90 d. PTN and N-syndecan proteins were detected by immunohistochemistry and analyzed for their correlation with pathological features, PNI, and prognosis.

RESULTS

The expression rates of PTN and N-syndecan proteins were 66.7% and 61.1%, respectively, in cancer tissue. PTN and N-syndecan expression was associated with PNI (P = 0.019 and P = 0.032, respectively). High PTN expression was closely associated with large bloody ascites (P = 0.009), liver metastasis (P = 0.035), and decreased survival time (P = 0.022). N-syndecan expression was significantly associated with tumor size (P = 0.025), but not with survival time (P = 0.539).

CONCLUSION

High PTN and N-syndecan expression was closely associated with metastasis and poor prognosis, suggesting that they may promote tumor progression and PNI in the orthotopic mouse model of pancreatic cancer.

Revisiting Seed and Soil: Examining the Primary Tumor and Cancer Cell Foraging in Metastasis

Metastasis is the consequence of a cancer cell that disperses from the primary tumor, travels throughout the body, and invades and colonizes a distant site. On the basis of Paget's 1889 hypothesis, the majority of modern metastasis research focuses on the properties of the metastatic "seed and soil," but the implications of the primary tumor "soil" have been largely neglected. The rare lethal metastatic "seed" arises as a result of the selective pressures in the primary tumor. Optimal foraging theory describes how cancer cells adopt a mobile foraging strategy to balance predation risk and resource reward. Further selection in the dispersal corridors leading out of the primary tumor enhances the adaptive profile of the potentially metastatic cell. This review focuses on the selective pressures of the primary tumor "soil" that generate lethal metastatic "seeds" which is essential to understanding this critical component of prostate cancer metastasis.Implication: Elucidating the selective pressures of the primary tumor "soil" that generate lethal metastatic "seeds" is essential to understand how and why metastasis occurs in prostate cancer. Mol Cancer Res; 15(4); 361-70. ©2017 AACR.

The influence of neural invasion on survival and tumor recurrence in pancreatic ductal adenocarcinoma - A systematic review and meta-analysis

OBJECTIVES

To assess the impact of neural invasion/NI on overall survival/OS and tumor recurrence in pancreatic ductal adenocarcinoma/PDAC.

SUMMARY BACKGROUND DATA

NI is a histopathological hallmark of PDAC. Although some studies suggested an important role for NI on OS, disease-free/DFS and progression-free survival/PFS in PDAC, there is still no consensus on the actual role of NI on survival and local recurrence in PDAC.

METHODS

Pubmed, Cochrane library, Ovid and Google Scholar were screened for the terms "pancreatic ductal adenocarcinoma", "pancreatic cancer", "survival", "tumor recurrence" and "perineural invasion". The Preferred-Reporting-Items-for-Systematic-review-and-Meta-Analysis/PRISMA-guidelines were used for systematic review and meta-analysis. Articles meeting predefined criteria were critically analysed on relevance, and meta-analyses were performed by pooling univariate and multivariate hazard ratios/HR.

RESULTS

A total number of 25 studies on the influence of NI on tumor recurrence, and 121 studies analysing the influence of NI on survival were identified by systematic review. The HR of the univariate (HR 1.88; 95%-CI 1.71-2.07; p < 0.00001) and multivariate meta-analysis (HR 1.68; 95%-CI 1.47-1.92; p < 0.00001) showed a major impact of NI on OS. Likewise, NI was associated with decreased DFS (HR 2.53; 95%-CI: 1.67-3.83; p = 0.0001) and PFS (HR 2.41; 95%-CI: 1.73-3.37: p < 0.00001) multivariate meta-analysis.

CONCLUSIONS

Although the power of this study is limited by missing pathological procedures to assess the true incidence of NI, NI appears to be an independent prognostic factor for OS, DFS and PFS in PDAC. Therefore, NI should be increasingly considered in patient stratification and in the development of novel therapeutic algorithms.

Significance of pathological positive superior mesenteric/portal venous invasion in pancreatic cancer

BACKGROUND

Pancreaticoduodenectomy with superior mesenteric/portal venous resection for pancreatic ductal adenocarcinoma (PDAC) is frequently performed with no added morbidity or mortality in case of tumor abutment to the superior mesenteric or portal vein so as to obtain a margin negative resection. True histopathological portal vein invasion is found only in a small subset of such patients. The aim of this review aimed to discuss the significance of histopathological venous invasion in PDAC.

DATA SOURCES

For this review available data was searched from PubMed and analyzed. No randomized trials have been published on this topic.

RESULTS

Existing data on prognostic factors in histopathological venous invasion by PDAC are limited and recent studies indicate worse survival in this subgroup of patients. In addition, venous invasion in PDAC has been associated with large tumors, involved lymph nodes, perineural invasion and R1 resection. The survival of patients with portal venous resection but without histologic venous invasion is reportedly better than those with histopathological venous invasion; though conflicting studies do exist on the subject. Some studies also relate the depth of venous invasion to prognosis after surgical resection of PDAC.

CONCLUSIONS

Frank/'histopathological' invasion of superior mesenteric/portal venous and R1 resection indicate a very poor survival. Such patients may be given the opportunity of benefit of neoadjuvant treatment.

Blocking Nerve Growth Factor Signaling Reduces the Neural Invasion Potential of Pancreatic Cancer Cells

Perineural invasion (PNI) is thought to be one of the factors responsible for the high rate of tumor recurrence after surgery and the pain generation associated with pancreatic cancer. Signaling via the nerve growth factor (NGF) pathway between pancreatic cancer cells and the surrounding nerves has been implicated in PNI, and increased levels of these proteins have been correlated to poor prognosis. In this study, we examine the molecular mechanism of the NGF signaling pathway in PNI in pancreatic cancer. We show that knocking down NGF or its receptors, TRKA and p75NTR, or treatment with GW441756, a TRKA kinase inhibitor, reduces the proliferation and migration of pancreatic cancer cells in vitro. Furthermore, pancreatic cancer cells migrate towards dorsal root ganglia (DRG) in a co-culture assay, indicating a paracrine NGF signaling between the DRGs and pancreatic cancer cells. Knocking down the expression of NGF pathway proteins or inhibiting the activity of TRKA by GW441756 reduced the migratory ability of Mia PaCa2 towards the DRGs. Finally, blocking NGF signaling by NGF neutralizing antibodies or GW441756 inhibited the neurite formation in PC-12 cells in response to conditioned media from pancreatic cancer cells, indicating a reciprocal signaling pathway between the pancreatic cancer cells and nerves. Our results indicate that NGF signaling pathway provides a potential target for developing molecularly targeted therapies to decrease PNI and reduce pain generation. Since there are several TRKA antagonists currently in early clinical trials they could now be tested in the clinical situation of pancreatic cancer induced pain.

Nerve growth factor regulates CD133 function to promote tumor cell migration and invasion via activating ERK1/2 signaling in pancreatic cancer

BACKGROUND

Perineural invasion (PNI) is extremely high frequency among the various metastatic routes in pancreatic cancer. Nerve growth factor, secreted by astroglial cells, exerts effects on tumor invasion in some cancer cells, but its function on migration and invasion in pancreatic cancer is still unclear. In the present study, we determined the effects of NGF on modulating tumor cell metastatic potential and invasion activity and explored its mechanisms in pancreatic cancer.

METHODS

NGF and CD133 expression were detected in tumor tissues using immunohistochemical analysis and Western blotting analysis. The effects of NGF on the regulation of CD133 expression and the promotion of cancer migration and invasion were investigated using wound healing and matrigel transwell assay. A related mechanism that NGF regulates CD133's function via activating ERK1/2 signaling also was observed.

RESULTS

NGF/CD133 is overexpressed in human pancreatic cancer and promotes the migration and invasion of human pancreatic cancer cells through the activation of the ERK/CD133 signaling cascade. NGF/ERK signaling modulates the cancer cell EMT process, migration and invasion through the regulation of CD133 expression and its subcellular localization.

CONCLUSIONS

NGF/CD133 signaling initiated the migration and invasion of pancreatic cancer cells. NGF/CD133 might be an effective and potent therapeutic target for pancreatic cancer metastasis, particularly in PNI.

Pancreatic Cancer: a Challenge to Cure

Pancreatic ductal adenocarcinoma (PDA) is a challenging disease, as overall survival has not improved over the last several decades. The disease is characterized by late diagnosis, difficult major surgery in resectable patients, and a biologically chemoresistant tumor. Intense research in the field is ongoing to develop biomarkers for early detection and prognostication. Surgery is presently the crux of the management of PDA and has been standardized over the years with high-volume centers reporting <5 % operative mortality. The biggest problem is to overcome the inherent chemoresistance of the tumor that is densely fibrotic and hypoxic and has a tendency to invade surrounding neuronal plexuses. This review attempts to summarize in brief the reasons why PDA is difficult to treat, and provides a glimpse of the ongoing research in the field.

An Increased Number of Perineural Invasions Is Independently Associated With Poor Survival of Patients With Resectable Pancreatic Ductal Adenocarcinoma

OBJECTIVES

The aim of this study was to investigate the impact of the number of perineural invasions (PNIs) in resected specimens on the survival of patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

A retrospective cohort study of 209 patients underwent surgical resection for PDAC between 1999 and 2013 was performed. The severity of PNI was evaluated by counting the number of PNIs in all sections with PDAC. The relationships of the number of PNIs with disease-free survival (DFS) and overall survival (OS) were analyzed.

RESULTS

At least 1 PNI was observed in 197 (94%) of 209 patients. Significant differences in DFS and OS were found between groups when analyzed by the median number of PNIs (≥25 vs <25) (DFS: P < 0.0001; OS: P < 0.0001) and among tertiles greater than 40 versus 40 to 14 versus less than 14 (DFS: P < 0.0001, OS: P < 0.0001). By multivariate analysis, an increased number of PNIs (>40 vs 40-14 vs <14) was identified as an independent risk factor for poor DFS (P < 0.0001) and OS (P < 0.0001).

CONCLUSIONS

The severity of PNI evaluated by counting the number of PNIs in resected specimens was useful for predicting the prognosis of patients with resectable PDAC.

Perineural spread of pelvic malignancies to the lumbosacral plexus and beyond: clinical and imaging patterns

OBJECT

Perineural spread along pelvic autonomie nerves has emerged as a logical, anatomical explanation for selected cases of neoplastic lumbosacral plexopathy (LSP) in patients with prostate, bladder, rectal, and cervical cancer. The authors wondered whether common radiological and clinical patterns shared by various types of pelvic cancer exist.

METHODS

The authors retrospectively reviewed their institutional series of 17 cases concluded as perineural tumor spread. All available history, physical examination, electrodiagnostic studies, biopsy data and imaging studies, evidence of other metastatic disease, and follow-up were recorded in detail. The series was divided into 2 groups: cases with neoplastic lumbosacral plexopathy confirmed by biopsy (Group A) and cases included based on imaging characteristics despite the lack of biopsy or negative biopsy results (Group B).

RESULTS

Group A comprised 10 patients (mean age 69 years); 9 patients were symptomatic and 1 was asymptomatic. The L5–S1 spinal nerves and sciatic nerve were most frequently involved. Three patients had intradural extension. Seven patients were alive at last follow-up. Group B consisted of 7 patients (mean age 64 years); 4 patients were symptomatic, 2 were asymptomatic, and 1 had only imaging available. The L5–S1 spinal nerves and the sciatic nerve were most frequently involved. No patients had intradural extension. Four patients were alive at last follow-up.

CONCLUSIONS

The authors provide a unifying theory to explain lumbosacral plexopathy in select cases of various pelvic neoplasms. The tumor cells can use splanchnic nerves as conduits and spread from the end organ to the lumbosacral plexus. Tumor can continue to spread along osseous and muscle nerve branches, resulting in muscle and bone “metastases.” Radiological studies show a reproducible, although nonspecific pattern, and the same applies to clinical presentation.

Prognostic value of perineural invasion in colorectal cancer: a meta-analysis

BACKGROUND

The prognostic value of perineural invasion (PNI) in colorectal cancer (CRC) does not reach a consensus.

METHODS

A comprehensive literature search for relevant reports published up to October 2014 was performed using the electronic databases: PubMed, Embase, and Web of Science. The pooled hazard ratio (HR) with 95 % confidence intervals (CI) was used to estimate the prognostic effects.

RESULT

Thirty-eight studies comprising 12,661 CRC patients were analyzed. Our results showed that PNI is significantly associated with poor prognosis in OS (overall survival) (HR = 2.07, 95 % CI = 1.87-2.29, P < 0.01) and DFS (disease-free survival) (HR = 2.23, 95 % CI = 1.79-2.78, P < 0.01). There was no significant prognostic difference in DFS between stage II CRC patients with PNI(+) and stage III patients (HR = 1.67, 95 % CI = 0.53-5.25, P = 0.38). Further subgroup analysis revealed that the significance of the association between PNI and worse prognosis in CRC patients is not affected by many factors, including geographic setting, PNI positive rate, treatment, TNM stage, tumor site, and quality of the study.

CONCLUSIONS

The meta-analysis indicates that PNI is a poor prognostic factor in CRC patients. The postoperative survival of stage II CRC patients with PNI(+) is probably more similar to that of stage III patients. Currently available adjuvant therapy should be considered in stage II CRC patients with PNI(+).

Preoperative gemcitabine-based chemoradiation therapy for pancreatic ductal adenocarcinoma of the body and tail: impact of splenic vessels involvement on operative outcome and pattern of recurrence

BACKGROUND

Among the various multimodal treatment strategies for pancreatic ductal adenocarcinoma (PDA), preoperative chemoradiation therapy (CRT) and subsequent operation is a promising strategy. The aim of this study is to evaluate the outcome of preoperative gemcitabine-based CRT for PDA of the body and tail, focusing on the associations among splenic vessel involvement, surgical outcomes, and pattern of recurrence.

METHODS

A total of 99 patients with PDA of the body and tail received preoperative CRT. The status of tumor involvement of the splenic artery (SA) and vein (SV) were evaluated based on radiographical findings obtained before the initiation of preoperative CRT. We assessed the following in association with the status of SA and SV involvement: (1) resection rate, (2) survival, and (3) pattern of recurrence.

RESULTS

The resection rate of SA-positive cases (71%) was significantly lesser than that of SA-negative cases (94%; P = .004), whereas SV involvement was not associated with the resection rate. The 5-year survival rates of the resected SA-negative and SA-positive cases were 76% and 20%, respectively (P < .001). The 5-year cumulative incidence of distant recurrence was significantly higher in the SA-positive patients than in the SA-negative patients (74% vs. 17%; P < .001).

CONCLUSION

In preoperative CRT for PDA of the body and tail, positive SA involvement was associated with a lesser resection rate, and the survival rate for the patients with SA-positive tumors was lesser than that for patients with SA-negative tumors because of the greater incidence of distant recurrence in SA-positive patients.

Stromal SLIT2 impacts on pancreatic cancer-associated neural remodeling

Pancreatic ductal adenocarcinoma (PDA) is a critical health issue in the field of cancer, with few therapeutic options. Evidence supports an implication of the intratumoral microenvironment (stroma) on PDA progression. However, its contribution to the role of neuroplastic changes within the pathophysiology and clinical course of PDA, through tumor recurrence and neuropathic pain, remains unknown, neglecting a putative, therapeutic window. Here, we report that the intratumoral microenvironment is a mediator of PDA-associated neural remodeling (PANR), and we highlight factors such as 'SLIT2' (an axon guidance molecule), which is expressed by cancer-associated fibroblasts (CAFs), that impact on neuroplastic changes in human PDA. We showed that 'CAF-secreted SLIT2' increases neurite outgrowth from dorsal root ganglia neurons as well as from Schwann cell migration/proliferation by modulating N-cadherin/β-catenin signaling. Importantly, SLIT2/ROBO signaling inhibition disrupts this stromal/neural connection. Finally, we revealed that SLIT2 expression and CAFs are correlated with neural remodeling within human and mouse PDA. All together, our data demonstrate the implication of CAFs, through the secretion of axon guidance molecule, in PANR. Furthermore, it provides rationale to investigate the disruption of the stromal/neural compartment connection with SLIT2/ROBO inhibitors for the treatment of pancreatic cancer recurrence and pain.

Structural similarities and differences between the human and the mouse pancreas

Mice remain the most studied animal model in pancreas research. Since the findings of this research are typically extrapolated to humans, it is important to understand both similarities and differences between the 2 species. Beside the apparent difference in size and macroscopic organization of the organ in the 2 species, there are a number of less evident and only recently described differences in organization of the acinar and ductal exocrine tissue, as well as in the distribution, composition, and architecture of the endocrine islets of Langerhans. Furthermore, the differences in arterial, venous, and lymphatic vessels, as well as innervation are potentially important. In this article, the structure of the human and the mouse pancreas, together with the similarities and differences between them are reviewed in detail in the light of conceivable repercussions for basic research and clinical application.

Influence of perineural invasion on survival and recurrence in patients with resected pancreatic cancer

BACKGROUND

Perineural invasion (PNI) has been reported as one of the sources of locoregional recurrence in resected pancreatic cancer (PC). However the impact of PNI in resected pancreatic cancer remains controversial. The purpose of this study was to determine the association between PNI status and clinical outcomes.

METHODS

Publications were identified which assessed prognostic significance of PNI status in resected pancreatic cancer up to February 2013. A meta-analysis was performed to clarify the association between PNI status and clinical outcomes.

RESULTS

A total of 21 studies met the inclusion criteria, covering 4,459 cases. Analysis of these data showed that intrapancreatic PNI was correlated with reduced overall survival only in resected pancreatic ductal adenocarcinoma (PDAC) patients (HR=1.982, 95%CI: 1.526-2.574, p=0.000). Extrapancreatic PNI was correlated with reduced overall survival in all resected pancreatic cancer patients (HR=1.748, 95%CI: 1.372- 2.228, p=0.000). Moreover, intrapancreatic PNI status may be associated with tumor recurrence in all resected pancreatic cancer patients (HR=2.714, 95%CI: 1.885-3.906, p=0.000).

CONCLUSION

PNI was an independent and poor prognostic factor in resected PDAC patients. Moreover, intrapancreatic PNI status may be associated with tumor recurrence.

The outcome of cryoablation in treating advanced pancreatic cancer: a comparison with palliative bypass surgery alone

OBJECTIVE

This study aimed to investigate the efficacy and safety of palliative bypass surgery combined with cryoablation in treating patients with advanced pancreatic cancer and compare this combination therapy with palliative bypass surgery alone.

METHODS

Medical records of 118 patients with advanced pancreatic cancer who received palliative bypass surgery combined with cryoablation (the combination treatment group) or bypass surgery alone (the bypass surgery alone group) at the Department of Pancreatic Cancer, Tianjin Medical University Cancer Institute and Hospital (Tianjin, China) were retrospectively reviewed. Their baseline and peri-operative parameters were collected and compared.

RESULTS

In both groups abdominal distension and pain was significantly ameliorated after treatment. Preoperative jaundice was more common in the bypass surgery group while backache was more frequent in the combination treatment group, which were both relieved by treatment. The pre-operative serum bilirubin level was higher in the bypass surgery group and was decreased significantly after treatment. However, a significant reduction in tumor size and serum carbohydrate antigen 19-9 level was found only in the combination treatment group. There was no significant difference in the incidence of postoperative complications and prognosis between the two groups.

CONCLUSIONS

Cryoablation can reduce tumor size and relieve the patients' symptoms and signs such as abdominal discomfort and backache, although it could not improve the patients' prognosis significantly. It is a safe and efficient modality when combined with bypass surgery for patients with advanced pancreatic cancer.