Introduction

Although the prognostic significance of cellular components of the immune system has been investigated in several solid neoplasms and is well established, the role of plasma cells in the tumor microenvironment has been neglected and only recently these cells are increasingly being appreciated as key players in the tumor microenvironment.

Aims & Methods

The purpose of our study is to explore the contribution of plasma cells to the immune microenvironment of colorectal adenocarcinomas and describe their correlation with prognosis.
In our study, a total of 108 patients with colorectal adenocarcinoma were included [68 men/40 women, median age (IQR): 70 (64-76) years, I-IV stage (AJCC/TNM 8^th edition)] who underwent surgical resection between January 2004 to May 2008. Histological slides and paraffin blocks were retrieved from the archives of the Department of Pathology, Attikon University Hospital. Tissue microarrays (TMAs) of 2 mm diameter were constructed with representative areas from the center and periphery of the tumor. Immunohistochemical stains were performed on TMAs to detect the presence of plasma cells (CD138) and cells of adaptive immunity (CD3, CD4, CD8, CD20). Tertiary lymphoid structures (TLS) were assessed on hematoxylin-eosin-stained slides. Depending on the number of plasma cells, the cases were classified into the following categories: absence of plasma cells or presence of rare single cells, presence of rare small aggregates (>5 cells/aggregation), presence of frequent aggregates, presence of large aggregates or sheets of plasma cells. Clinical and pathologic information was acquired from hospital medical records including patient’s outcome and survival.

Results

Ιncreased number of plasma cells (presence of frequent aggregates, presence of large aggregates or sheets of plasma cells) was observed in 70 cases (65%), while absence or rare aggregates of plasma cells was demonstrated 38 cases (35 %). The presence of large aggregates or sheets of plasma cells in the tumor was significantly associated with the presence of TLS (p=0.004) and tumor infiltration by increased numbers of CD3⁺, CD8⁺ T, and CD20⁺ B lymphocytes compared with the absence of plasma cells or the presence of rare single plasma cells (p=0.025, p=0.012, p=0.001, respectively). Moreover, it was reported that the presence of an increased number of plasma cells compared with the absence of plasma cells in the center of the tumor is significantly correlated to a more favorable prognosis (77 vs 47 months; p=0.047; p<0.05).

Conclusion

In patients with colorectal adenocarcinoma, the presence of high densities of plasma cells in the tumor bed may be associated with increased adaptive immune cell populations in the tumor environment, as well as with longer patient’s survival. Consequently, a careful evaluation of plasma cells and a better understanding of their role in the tumor microenvironment of colorectal cancer seems to be crucial in order to design efficient immunotherapeutic strategies.

References

1.Galon et al. Tumor immunology and tumor evolution: intertwined hisories. Immunity. 2020 Jan 14;52(1):55-81.
2.Hegde et al. Top 10 Challenges in Cancer Immunotherapy. Immunity. 2020 Jan 14;52(1):17-35.

Introduction

The MYC oncogene plays a pivotal role in variable cellular functions including proliferation, differentiation, metabolism, protein synthesis, survival and apoptosis, while it is also considered a crucial regulator of tumor immune microenvironment.

Aims & Methods

The purpose of our research is the evaluation of the immunohistochemical expression of MYC protein in primary colorectal adenocarcinomas and its correlation with prognosis, as well as with the qualitative and quantitative characteristics of the immune microenvironment.
In our study, a total of 94 patients with colorectal adenocarcinoma were included [59 men/35 women, median age (IQR): 71 (44-88) years, I-IV stage (AJCC/TNM 8^th edition)] who underwent surgical resection between January 2004 to May 2008. Histological slides and paraffin blocks were retrieved from the archives of the Department of Pathology, Attikon University Hospital. Tissue microarrays (TMAs) of 2 mm diameter were constructed with representative areas from the center and the periphery of the tumor. Immunohistochemical stains were performed on TMAs to detect the expression of MYC and Ki67 (proliferation index) by neoplastic cells and the presence of adaptive immunity (CD3, CD4, CD8, CD20) cells. MYC immunostaining in >20% of neoplastic cells was scored as positive (over-expressed). Clinical and pathologic information was acquired from hospital medical records including patient’s outcome and survival.

Results

MYC over-expression (>20%) in the center and periphery of the tumor was observed in 59 patients (63%) and is significantly associated with tumor infiltration by increased number of CD3+, CD4+, CD8+ T and CD20+ B lymphocytes as well as with an increased index of cell proliferation Ki-67 (p<0.001). In addition, positive MYC expression in the tumor periphery is significantly correlated with longer overall survival compared to cases with weak MYC expression (70 vs 48,5 months; p=0.046; p<0.05).

Conclusion

In patients with colorectal adenocarcinoma, increased MYC expression by neoplastic cells is associated with increased densities of adaptive immune cells in the tumor microenvironment. In addition, it is associated with a favorable prognosis, possibly through a more effective antitumor immune response. Consequently, the expression of MYC might be a useful predicting indicator of anti-tumor immunity status and patient’s prognosis.

References

1. Dhanasekaran et al. The MYC oncogene - the grand orchestrator of cancer growth and immune evasion. Nat Rev Clin Oncol. 2022 Jan;19(1):23-36.
2. Lee et al. Favorable prognosis in colorectal cancer patients with co-expression of c-MYC and ß-catenin. BMC Cancer. 2016 2016 Sep 13;16(1):730.

Introduction

The global incidence of early-onset colorectal cancer is rising at an alarming rate, underscoring the urgent need for effective preventive and therapeutic strategies. While age-associated molecular and pathological alterations have been reported, the immunological landscape—particularly the roles of distinct T cell subtypes in anti-tumor immunity—remains poorly characterized in early-onset colorectal tumor, especially in endoscopically resected colorectal tumors.
In this study, we investigated the association between T cell subtype densities—specifically CD3+, CD4+, CD8+, and FOXP3+ T cells—and clinicopathological features, with a particular focus on tumors arising in younger individuals. Early-onset colorectal tumors were defined as those diagnosed before the age of 50, whereas later-onset tumors were defined as those diagnosed at age 50 or older.

Aims & Methods

This study aimed to evaluate the relationship between T cell subtypes and the clinicopathological features of early-onset colorectal tumors. We utilized a molecular pathology database comprising 169 cases of colorectal cancer and adenoma, analyzing a total of 306 colorectal lesions. Among these, 214 lesions were classified as early-onset tumors and had been resected via endoscopic techniques—including cold snare polypectomy, endoscopic mucosal resection, and endoscopic submucosal dissection—at Nippon Medical School Hospital in Japan between February 2017 and January 2020.
Formalin-fixed paraffin-embedded (FFPE) tissue blocks were collected, and immunohistochemical staining for CD3, CD4, CD8, and FOXP3 was conducted. The densities of CD3+, CD4+, CD8+, and FOXP3+ cells were quantified within tumor, stromal, and normal tissue regions. Depending on lesion size, one to five fields of view (median: five) were selected and imaged at 200x magnification using a BZX800 fluorescence microscope (KEYENCE). Automated image analysis was employed to determine the average number of each T cell subtype. Quantification within stromal and normal regions was restricted to specimens with sufficiently large resected tissue to include these areas in addition to tumor tissue. Clinicopathological variables were assessed retrospectively. Statistical analyses included the chi-square test for categorical variables, Spearman’s rank correlation for assessing associations, the Mann–Whitney U test for comparison of continuous variables, and the Kruskal–Wallis test for comparisons across three or more groups.

Results

Tumor locations were distributed as follows: 126 cases (41%) in the proximal colon, 142 cases (47%) in the distal colon, and 37 cases (12%) in the rectum. Compared with later-onset colorectal tumors, early-onset tumors had significantly lower numbers of CD3+, CD4+, and CD8+ T cells (all P <0.001). In contrast, no significant difference was observed in the number of FOXP3+ T cells between the two groups.
Additionally, the densities of CD3+, CD4+, and CD8+ T cells decreased with increasing tumor diameter (all P <0.001). The distributions of CD3+, CD8+, and FOXP3+ T cells also differed significantly by tumor location (P = 0.040, 0.006, and 0.013, respectively).

Conclusion

Analysis of endoscopically resected specimens suggests that anti-tumor immune responses mediated by T cells may vary depending on age of onset, tumor size, and tumor location. These findings highlight the need for further research to identify subsets of early-onset colorectal tumors that may require more intensive surveillance following endoscopic resection, based on their immunological profiles.

Introduction

Metastasis is the major cause of mortality among colorectal cancer (CRC) patients and represents a crucial cancer research challenge. Metastasis is the results of an intimate crosstalk between cancer cells and the surrounding tumor microenvironment, where neoplastic cells exploit the inefficient and leaky tumor vessels to disseminate to secondary organs¹. In this context, the extracellular matrix protein Multimerin-2, specifically deposited by endothelial cells (EC), is instrumental for the maintenance of vascular homeostasis, ensuring the proper formation of cell-cell junctions via the VEGFR2 signaling².

Aims & Methods

We observed that Multimerin-2 is down modulated in tumors both at transcriptional and post-translational levels. Thus we hypothesized that Multimerin-2-devoid vessels may enhance cancer cell dissemination, being characterized by a compromised endothelial barrier.
Multimerin-2 expression was analyzed in human CRC samples through IHC, ELISA and in silico by the tnmplot.com tool. The effects of Multimerin-2 loss were assessed in vitro through transmigration assays upon Multimerin-2 down-regulation in EC cells and the molecular mechanism verified by WB and qRT-PCR. The putative Multimerin-2-affected metastatic dissemination was assessed through intravenous injection of MC38 colon cancer cells in wt and Multimerin-2^-/-mice.

Results

Multimerin-2 expression is significantly reduced within the tumor tissue respect to the normal counterpart among CRC patients, despite at variable degree. Importantly, in vitro, we found an increased number of CRC cells transmigrating through a Multimerin-2-depleted endothelium. This phenomenon was not VEGFR2-dependent since the use of a VEGFA blocking agents did not affect the extravasation of tumor cells. Indeed, under tumor-mimicking conditions, the knock-down of Multimerin-2 in ECs induces the upregulation of the vascular adhesion molecule VCAM1, a molecule exploited also by cancer cells to transpass the endothelium³. Accordingly, the intravenous injection of B16F10 syngeneic melanoma cells, as well as MC38 colon cancer cells, in Multimerin-2^-/-mice led to the formation of a higher number of metastatic lesions in the lungs.

Conclusion

Overall, these data indicate that Multimerin-2 expression is required to maintain vascular stability and halt the escape of cancer cells, suggesting that the Multimerin-2-devoid tumor vessels may represent a preferential route for metastatic dissemination, during CRC progression.

References

¹ Lugano R. et al, Tumor angiogenesis: causes, consequences, challenges and opportunities, Cell Mol Life Sci., 2020
² Pellicani R. et al, Multimerin-2 Maintains Vascular Stability and Permeability, Matrix Biol., 2020
³ Wieland E. et al, Endothelial Notch1 Activity Facilitates Metastasis, Cancer Cell 2017