The different role of intratumoral and peritumoral lymphangiogenesis in gastric cancer progression and prognosis

Lymphangiogenesis in gastric cancer: function and mechanism

Increased lymphangiogenesis and lymph node (LN) metastasis are thought to be important steps in cancer metastasis, and are associated with patient's poor prognosis. There is increasing evidence that the lymphatic system may play a crucial role in regulating tumor immune response and limiting tumor metastasis, since tumor lymphangiogenesis is more prominent in tumor metastasis and diffusion. Lymphangiogenesis takes place in embryonic development, wound healing, and a variety of pathological conditions, including tumors. Tumor cells and tumor microenvironment cells generate growth factors (such as lymphangiogenesis factor VEGF-C/D), which can promote lymphangiogenesis, thereby inducing the metastasis and diffusion of tumor cells. Nevertheless, the current research on lymphangiogenesis in gastric cancer is relatively scattered and lacks a comprehensive understanding. Therefore, in this review, we aim to provide a detailed perspective on molecules and signal transduction pathways that regulate gastric cancer lymphogenesis, which may provide new insights for the diagnosis and treatment of cancer.

Evaluation of Lymphovascular Invasion by CD31 Expression in Gastric Adenocarcinoma

Background & Objective

Lymphovascular tumoral invasion is a typical histopathological feature of gastric carcinomas and supports the recognition of high-risk patients for the recurrence. We aimed to study CD31 expression in diverse subtypes of gastric carcinomas and to show its association with the histopathologic findings of the carcinoma to assess the prognosis.

Methods

This cross-sectional study was conducted on 40 established patients with gastric adenocarcinoma from radical gastrectomy. The patients were classified according to the pathology assessments. Tumoral tissues were assessed by immunohistochemical staining for CD31 expression. Malignant behavior was estimated by histopathological evaluations.

Results

CD31 positivity was described in 23 (57.5%) of all evaluated patients. In assessment of CD31 expression and tumor features presented, no significant association between the CD31 expression and patients' age, sex, tumor site, size, grade and stage, subtypes of carcinoma, perineural invasion, and also lymphovascular invasion was found. (P>0.05).

Conclusion

Lymphovascular invasion may make valuable additional evidence and may be useful to detect gastric carcinoma patients at high risk for recurrence, who could be candidates for more supplementary therapies. However, in our study, CD31 expression did not show any association with the aggressive histopathologic features of this tumor.

The significance of the microlymphangiogenesis, microangiogenesis, and combined detection of programmed cell death-1 protein (PD-1)/ki67 in gastric cancer tissues

PURPOSE

To investigate the relationship between the microlymphangiogenesis, microangiogenesis, and combined detection of the programmed cell death-1 protein (PD-1)/ki67 in patients with gastric cancer as well as the disease prognosis.

METHODS

Immunohistochemistry was used to detect the microlymphatic density (MLD) and microvessel density (MVD) in the central and peripheral zones in 92 cases of gastric cancer, along with the number of PD-1- and ki67-positive tumor cells.

RESULTS

The central zone of the gastric cancer tissue contained fewer atretic cord-like lymphatic vessels than the peripheral zone, while the peripheral zone contained an increased number of lymphatic vessels compared with the central zone. In most cases, the lumen was also dilated. Compared with the MLD in the peripheral zone, the MLD in central zone was significantly decreased. Compared with the number of PD-1-positive cells in the peripheral zone, the number of PD-1-positive cells in the central zone was significantly decreased, and compared with the number of ki67-positive cells in the peripheral zone. The differences in the microlymphangiogenesis, microangiogenesis, and the number of PD-1- and ki67-positive cells among the different histological types were not statistically significant. The microlymphangiogenesis, microangiogenesis, and PD-1- and ki67-positive cells were significantly decreased in the gastric cancer tissues from the patients in stages T1 and T2 compared with the gastric cancer tissues from the patients in stages T3 and T4.

CONCLUSIONS

The detection of the MLD and MVD as well as the positive expression of PD-1 and ki67 in gastric cancer tissue are important reference indicators for judging the prognosis of gastric cancer.

Evaluation of Fourier transform infrared (FTIR) spectroscopy with multivariate analysis as a novel diagnostic tool for lymph node metastasis in gastric cancer

Fourier transform infrared (FTIR) spectroscopy is a vibration spectroscopy that uses infrared radiation to vibrate to absorb the molecular bonds in its absorbed sample. The main purpose of this study was to evaluate FTIR spectroscopy as a novel diagnostic tool for lymph node metastasis (LNM) of gastric cancer. We collected 160 fresh non-metastatic and metastatic lymph nodes (80 each) from 60 patients with gastric cancer for spectral analysis. FTIR spectra of lymph node (LN) samples were obtained in the wavenumber range of 4000 cm^-1 to 900 cm^-1. We calculated the changes in the ratio of spectral intensity (/ I1460). Principal component analysis (PCA) and Fisher's discriminant analysis (FDA) were used to distinguish malignant from normal LN. Four significant bands at 1080 cm^-1, 1640 cm^-1, 1740 cm^-1 and 3260 cm^-1 separated metastatic and non-metastatic LN spectra into two distinct groups by PCA.T-tests showed that, along with the relative intensity ratios (I₁₀₈₀/I₁₄₆₀, I₁₆₄₀/I₁₄₆₀, I₃₂₆₀/I₁₄₆₀, I₁₇₄₀/I₁₄₆₀), these band ratios were also able to differentiate between malignant and benign LN spectra. Six parameters (P1080 cm^-1, P1300 cm^-1, I₁₀₈₀/I₁₄₆₀, I₁₆₄₀/I₁₄₆₀, I₃₂₆₀/I₁₄₆₀, I₁₇₄₀/I₁₄₆₀) were selected as independent factors to set up discriminant functions. The sensitivity of FTIR spectroscopy in diagnosing LNM was 95 % by discriminant analysis. Our study suggested that FTIR spectroscopy can be a useful tool to examine LNM with high sensitivity and specificity for LNM diagnosis. Therefore it can be used in clinical practice as a non-invasive method.

A Bounding Box-Based Radiomics Model for Detecting Occult Peritoneal Metastasis in Advanced Gastric Cancer: A Multicenter Study

Purpose

To develop a bounding box (BBOX)-based radiomics model for the preoperative diagnosis of occult peritoneal metastasis (OPM) in advanced gastric cancer (AGC) patients.

Materials and Methods

599 AGC patients from 3 centers were retrospectively enrolled and were divided into training, validation, and testing cohorts. The minimum circumscribed rectangle of the ROIs for the largest tumor area (R_BBOX), the nonoverlapping area between the tumor and R_BBOX (peritumoral area; PERI) and the smallest rectangle that could completely contain the tumor determined by a radiologist (M_BBOX) were used as inputs to extract radiomic features. Multivariate logistic regression was used to construct a radiomics model to estimate the preoperative probability of OPM in AGC patients.

Results

The M_BBOX model was not significantly different from R_BBOX in the validation cohort [AUC: M_BBOX model 0.871 (95% CI, 0.814–0.940) vs. R_BBOX model 0.873 (95% CI, 0.820–0.940); p = 0.937]. M_BBOX was selected as the final radiomics model because of its extremely low annotation cost and superior OPM discrimination performance (sensitivity of 85.7% and specificity of 82.8%) over the clinical model, and this radiomics model showed comparable diagnostic efficacy in the testing cohort.

Conclusions

The BBOX-based radiomics could serve as a simpler reliable and powerful tool for the preoperative diagnosis of OPM in AGC patients. And M_BBOX-based radiomics is simpler and less time consuming.

Comprehensive bioinformatics analyses identified Homeobox B9 as a potential prognostic biomarker and therapeutic target for gastric cancer

Background

The Homeobox B (HOXB) family promotes tumor progression, but the mechanism of its action in gastric cancer (GC) is unclear. We sought to identify the HOXB family members that are critical to the prognosis of GC patients.

Methods

The Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), cBioPortal, UALCAN, Kaplan-Meier plotter, and the GeneMANIA databases were used to analyze the messenger RNA (mRNA) expression levels, prognostic value, and gene-gene interaction network of the HOXB9 family members in GC. The expression of HOXB9 in GC and its relationship with various clinicopathological parameters and the prognosis of patients were verified by immunohistochemistry.

Results

The expression of HOXB3, HOXB5, HOXB6, HOXB7, HOXB9, and HOXB13 mRNA was significantly upregulated in GC. There was a significant correlation between the upregulation of HOXB3, HOXB5, and HOXB9 mRNA and a low overall survival (OS) rate. The high expression of HOXB7, HOXB9, and HOXB13 mRNA was closely correlated to tumor grade and stage. HOXB9 was the HOXB family member most closely related to the occurrence and development of GC. A further analysis showed that HOXB9 might be involved in deoxyribonucleic acid repair and division regulation. A validation study showed that the advanced cancer group had a higher level of HOXB9 expression than the early cancer group. The high expression of HOXB9 in gastric tissue plays an important role in the survival and prognosis of GC patients.

Conclusions

HOXB family members have different degrees of abnormal expression in GC. High HOXB9 expression in GC tissues was significantly correlated with a worse prognosis. Thus, HOXB9 is a potential novel biomarker and therapeutic target for GC.

CT-Based Peritumoral and Intratumoral Radiomics as Pretreatment Predictors of Atypical Responses to Immune Checkpoint Inhibitor Across Tumor Types: A Preliminary Multicenter Study

OBJECTIVE

To develop and validate a new strategy based on radiomics features extracted from intra- and peritumoral regions on CT images for the prediction of atypical responses to the immune checkpoint inhibitor (ICI) in cancer patients.

METHODS

In total, 135 patients derived from five hospitals with pathologically confirmed malignancies receiving ICI were included in this retrospective study. Atypical responses including pseudoprogression (PsP) and hyperprogression disease (HPD) were identified as their definitions. A subgroup of standard progression disease (sPD) in 2018 was also involved in this study. Based on pretreatment CT imaging, a total of 107 features were extracted from intra- and peri-tumoral regions, respectively. The least absolute shrinkage and selection operator (Lasso) algorithm was used for feature selection, and multivariate logistic analysis was used to develop radiomics signature (RS). Finally, a total of nine RSs, derived from intra-tumoral, peri-tumoral, and combination of both regions, were built respectively to distinguish PsP vs. HPD, PsP vs. sPD, and HPD vs. sPD. The performance of the RSs was evaluated with discrimination, calibration, and clinical usefulness.

RESULTS

No significant difference was found when compared in terms of clinical characteristics of PsP, HPD, and sPD. RS based on combined regions outperformed those from either intra-tumoral or peri-tumoral alone, yielding an AUC (accuracy) of 0.834 (0.827) for PsP vs. HPD, 0.923 (0.868) for PsP vs. sPD, and 0.959 (0.894) for HPD vs. sPD in the training datasets, and 0.835 (0.794) for PsP vs. HPD, 0.919 (0.867) for PsP vs. sPD, and 0.933 (0.842) for HPD vs. sPD in the testing datasets. The combined RS showed good fitness (Hosmer-Lemeshow test p > 0.05) and provided more net benefit than the treat-none or treat-all scheme by decision curve analysis in both training and testing datasets.

CONCLUSION

Pretreatment radiomics are helpful to predict atypical responses to ICI across tumor types. The combined RS outperformed those from either intra- or peri-tumoral alone which may provide a more comprehensive characterization of atypical responses to ICI.

The relationship of the tertiary lymphoid structures with the tumor-infiltrating lymphocytes and its prognostic value in gastric cancer

Introduction

To explore the relationship between the tertiary lymphoid structures (TLSs) and tumor-infiltrating lymphocytes (TILs), and their distribution characteristics as well as the prognostic value in gastric cancer (GC).

Material and methods

The TLSs and four subtypes of TILs were assessed by immunohistochemical (IHC) staining. The presence of MECA-79 positive high endothelial venules (HEVs) identified among the ectopic lymphocyte aggregation area in the GC tissue was defined as valid TLSs. The number of labeled TILs was observed in 5 fields of the most positive cells in the tumor center, invasive edge and within the TLSs, at a field of vision ×40.

Results

The TLS distribution was significantly higher in the tumor invasive edge than the tumor center (p < 0.001). Similarly, the infiltrating density of CD8+ T cells and GrB+ T cells was statistically significantly higher in the tumor infiltrating edge than the tumor center. The total number of TILs and FOXP3+ T cells showed a contrary distribution. There was a positive correlation of the density of TLSs and TILs with both the location and the immune phenotype. A higher frequency of TILs and TLSs is often associated with favorable clinicopathologic parameters. Higher numbers of peri-TLSs (p = 0.007), peri-CD8+ (p = 0.019) and peri-GrB+TILs (p = 0.032) were significantly correlated with the favorable overall survival. Multivariate analysis revealed that the densities of TILs (p = 0.019) and TLSs (p = 0.037) were independent prognostic predictor for GC patients.

Conclusions

We provide evidence that TLSs were positively associated with lymphocyte infiltration in GC. Thus, the formation of TLSs predicts advantageous immune system function and can be considered as a novel biomarker to stratify the overall survival risk of untreated GC patients.

Tumor exposed-lymphatic endothelial cells promote primary tumor growth via IL6

Solid tumors are composed of tumor cells and stromal cells including lymphatic endothelial cells (LEC), which are mainly viewed as cells forming lymphatic vessels involved in the transport of metastatic and immune cells. We here reveal a new mechanism by which tumor exposed-LEC (teLEC) exert mitogenic effects on tumor cells. Our conclusions are supported by morphological and molecular changes induced in teLEC that in turn enhance cancer cell invasion in 3D cultures and tumor cell proliferation in vivo. The characterization of teLEC secretome by RNA-Sequencing and cytokine array revealed that interleukine-6 (IL6) is one of the most modulated molecules in teLEC, whose production was negligible in unexposed LEC. Notably, neutralizing anti-human IL6 antibody abrogated teLEC-mediated mitogenic effects in vivo, when LEC were mixed with tumor cells in the ear sponge assay. We here assign a novel function to teLEC that is beyond their role of lymphatic vessel formation. This work highlights a new paradigm, in which teLEC exert “fibroblast-like properties”, contribute in a paracrine manner to the control of tumor cell properties and are worth considering as key stromal determinant in future studies.

•

teLEC, but not normal LEC, produce huge amount of IL6.

•

IL6-derived teLEC exert mitogenic effect on tumor cells, in the primary tumor.

•

teLEC act as fibroblast-like cells in the tumor microenvironment.

•

It warrants to revisit the “vascular-centric view” of LECs.

Detection and prognostic value of intratumoral and peritumoral lymphangiogenesis in colorectal cancer

Background

Colorectal cancer (CRC) with lymphatic invasion is one of the critical prognostic factors in lymph node metastasis. Lymphangiogenesis has a significant effect on lymphatic metastasis and tumor progression. However, the significance of intratumoral and peritumoral lymphangiogenesis has been controversial in CRC. The aim of this study is to investigate the different role of introtumoral and peritumoral lymphangiogenesis in CRC progression and prognosis.

Methods

Lymphangiogenesis of 120 CRC specimens, as measured by lymphatic vessel density (LVD), was examined by immunostaining for podoplanin, a lymphatic vessel-specific marker. The mean number of lymphatic vessels of three hotspots was measured in intratumoral and peritumoral areas as intratumoral LVD (LVDit) and peritumoral LVD (LVDpt), respectively. The association of LVDit and LVDpt with the clinicopathological findings and prognosis was investigated.

Results

Compared to the peritumoral lymphatics, the intratumoral lymphatics were small, collapsed and irregular. The mean LVDpt was higher than the mean LVDit (P<0.001). LVDit was positively correlated with tumor size (P=0.009), tumor histologic grade (P=0.023), and overall survival (P=0.036). LVDpt was correlated with lymph node metastasis (P<0.001), tumor stage (P=0.004), and overall survival (P=0.016).

Conclusions

LVDpt plays a prominent role in lymph node metastasis, whereas LVDit is more closely correlated with tumor growth and histopathological differentiation. Both LVDpt and LVDit contribute to CRC progression and prognosis.

Drug formulation and nanomedicine approaches to targeting lymphatic cancer metastases

Lymphatic metastasis plays an important role in cancer progression and prognosis. However, conventional small-molecule chemotherapy drugs inefficiently access the lymphatic system, making the effective eradication of lymphatic metastases difficult without dose-limiting toxicity. Various formulation and nanomedicine-based approaches can be used to significantly enhance the trafficking of small-molecule, peptide and protein drugs toward the lymphatic system to enhance drug exposure at sites of lymphatic cancer growth. However, a number of obstacles exist in translating improved lymphatic exposure into improved chemotherapeutic outcomes. This review highlights the opportunities and challenges inherent in employing formulation and nanomedicinal approaches to improve chemotherapeutic drug activity within the lymphatic system and, importantly, at sites of lymphatic cancer metastasis.

Experimental and clinicopathological analysis of HOXB9 in gastric cancer

The association between homeobox (HOX)B9 expression and tumor malignancy was identified recently. It was reported that HOXB9 induced tumor angiogenesis, and associated with poor prognosis in patients with breast and colon cancer. On the other hand, regional lymph nodes are the most common site of tumor spread, and lymph node metastasis is a major prognostic factor in gastric cancer. It was hypothesized that HOXB9 promotes tumor lymphangiogenesis and induces tumor progression, invasion and metastasis in gastric cancer. The aim of the present study was to evaluate the correlation between HOXB9 expression, prognosis and clinicopathologic factors in patients with gastric cancer, and to assess the contribution of HOXB9 expression to tumor cell lymphangiogenesis in vitro. HOXB9 expression was evaluated by immunohistochemistry in resected tumor tissues from 58 patients with gastric cancer, and the association between prognosis and clinicopathologic factors was determined. HOXB9 gene was overexpressed in human gastric cancer TMK-1 cells and the effect of HOXB9 overexpression on the expression of vascular endothelial growth factor (VEGF)-C, VEGF-D and VEGF receptor (R)-3 was determined. It was demonstrated that the depth of tumor invasion, the number of node metastases, lymphatic invasion and vascular invasion were significantly associated with HOXB9 expression. Overall survival was decreased in patients with HOXB9 expression. The mRNA expression of VEGF-D but not of VEGF-C and VEGFR-3 was increased in HOXB9-overexpressing TMK-1 cells compared with control cells. In conclusion, HOXB9 expression was positively correlated with gastric cancer progression and lymphangiogenesis marker expression. HOXB9 may be associated with lymphogenic metastasis.

Heterogeneity of tumor lymphangiogenesis: Progress and prospects

Lymphangiogenesis and increased expression of lymphangiogenic growth factors are associated with high rates of lymph node (LN) metastasis and with poor prognosis in some, but not all, solid tumors. In addition to its involvement in metastasis, lymphangiogenesis has been shown to have other roles in tumor pathogenesis, such as the niche function of tumor stem cells and regulatory functions of antitumor immune responses. In contrast, evidence has accumulated that tumor-induced lymphangiogenesis displays the heterogeneity in gene signature, structure, cellular origins and functional plasticity. This review summarizes the advances in the research on the heterogeneity of tumor lymphangiogenesis and discusses how it may contribute to functional complexity and multiplicity of lymphangiogenesis in tumor progression.

Somatic mutations and increased lymphangiogenesis observed in a rare case of intramucosal gastric carcinoma with lymph node metastasis

BACKGROUND AND AIM

Intramucosal gastric adenocarcinoma of the well-moderately differentiated type only exhibits lymph node metastasis in extremely rare cases. We encountered such case and investigated both the lymphangiogenic properties and somatic mutations in the cancer to understand the prometastatic features of early-stage gastric cancer.

METHODS

We quantitatively measured the density of lymphatic vessels and identified mutations in 412 cancer-associated genes through next-generation target resequencing of DNA extracted from tumor cells in a formalin-fixed and paraffin-embedded tissue. Functional consequence of the identified mutation was examined in vitro by means of gene transfection, immunoblot, and the quantitative real-time polymerase chain reaction assay.

RESULTS

The intramucosal carcinoma was accompanied by abundant lymphatic vessels. The metastatic tumor harbored somatic mutations in NBN, p.P6S, and PAX8, p.R49H. The PAX8R49H showed significantly higher transactivation activity toward E2F1 than the wild-type PAX8 (P< 0.001).

CONCLUSIONS

Our data suggest that increased lymphangiogenesis and somatic mutations of NBN and/or PAX8 could facilitate lymph node metastasis from an intramucosal gastric carcinoma. These findings may potentially inform evaluations of the risk of developing lymph node metastasis in patients with intramucosal gastric cancer.

A meta-analysis of the lymphatic microvessel density and survival in gastric cancer with 1809 cases

Lymph node metastasis commonly occurs in gastric cancer. Previous studies have demonstrated that the overexpression of lymphatic microvessel density (LVD) is correlated with various malignancies. To evaluate the potential role of LVD in various malignancies, we conducted a systematic review and meta-analysis to thoroughly investigate the association of LVD expression with tumor progression and survival in gastric cancer. We performed a comprehensive search of common databases and selected studies demonstrating the relationship between LVD expression and gastric cancer prognosis. Hazard ratios (HR) were used to determine the value of LVD for predicting gastric cancer metastasis and prognosis. The data were extracted from the included studies and pooled with the appropriate effects model using STATA 12.0. The results showed that high LVD expression obviously impacted the prognosis of gastric cancer, based on an overall survival (OS) HR of 2.58 (95% CI: 1.91–3.48, P < 0.001) and a disease-free survival (DFS) HR of 2.51 (95% CI: 1.35–4.68, P = 0.004) in the univariate analysis. In addition, the results of the multivariate analysis indicated a remarkable relationship between high LVD expression and gastric neoplasm prognosis. The pooled OS HR was 4.12 (95% CI: 3.45–4.91, P < 0.001). The current meta-analysis shows that high LVD is closely related to tumor metastasis and poor prognosis in gastric malignancy. LVD could be a key factor in tumor lymphatic metastasis. Moreover, LVD is likely a potential index and an effective biomarker for the prediction of patient prognosis.

Auxiliary diagnosis of lymph node metastasis in early gastric cancer using quantitative evaluation of sentinel node radioactivity

BACKGROUND

Sentinel node (SN) mapping using dye and radioisotope (RI) tracer has been reported to be feasible in cases of early gastric cancer. Because accurate diagnosis of micrometastasis is sometimes difficult in the limited time available during surgery, a faster and simpler method of improving the intraoperative diagnostic precision of lymph node metastasis is needed. The amount of tracer deposited in an SN can be determined from its radioactivity; however, the significance of the RI count has not been fully discussed. We investigated the clinical impact of the RI count when used as an adjunct to conventional lymph node dissection when diagnosing lymphatic metastasis in cases of early gastric cancer.

METHODS

From 2008 to 2009, patients with clinically diagnosed T1N0M0 gastric cancers who underwent gastrectomy and SN mapping were enrolled. SNs were examined by intraoperative and postoperative pathology. The RI count was measured for each SN with a handheld gamma probe; the correlation between nodal metastasis and the RI count was assessed.

RESULTS

A total of 308 SNs were harvested from 72 patients. Patients with SN metastasis had significantly higher total RI counts than those without SN metastasis (p = 0.007). Among cases with SN metastasis, RI counts were also significantly elevated in metastasis-positive nodes, stations, and basins. In these cases, the most of SNs having the highest RI count in each case had metastasis including isolated tumor cells.

CONCLUSION

In early gastric cancer patients, a high RI count from an SN was correlated with lymph node metastasis. Therefore, RI counting may aid efficient pathological diagnosis and focused lymph node dissection.