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Circulating tumor cells (CTCs) play an important role in metastasis and recurrence. However, which cells comprise the complex tumor lineages in recurrence and are key in metastasis are unknown in colorectal cancer (CRC). CRC with high expression of POU5F1 has a poor prognosis with a high incidence of liver metastatic recurrence. We aim to reveal the key cells promoting metastasis and identify treatment-resistant lineages with established EGFP-expressing organoids in two-dimensional culture (2DOs) under the POU5F1 promotor. POU5F1-expressing cells are highly present in relapsed clinical patients' blood as CTCs. Sorted POU5F1-expressing cells from 2DOs have cancer stem cell abilities and abundantly form liver metastases in vivo. Single-cell RNA sequencing of 2DOs identifies heterogeneous populations derived from POU5F1-expressing cells and the Wnt signaling pathway is enriched in POU5F1-expressing cells. Characteristic high expression of CTLA4 is observed in POU5F1-expressing cells and immunocytochemistry confirms the co-expression of POU5F1 and CTLA4. Demethylation in some CpG islands at the transcriptional start sites of POU5F1 and CTLA4 is observed. The Wnt/β-catenin pathway inhibitor, XAV939, prevents the adhesion and survival of POU5F1-expressing cells in vitro. Early administration of XAV939 also completely inhibits liver metastasis induced by POU5F1-positive cells., (© 2023. The Author(s).)

Approximately 10% of patients with colorectal cancer with submucosal invasion have lymph node metastasis. Pathological risk factors for lymph node metastasis have varying sensitivities and specificities. To predict the risk of lymph node metastasis, the identification of new risk factors is vital. Tumor-infiltrating T cells have been reported to improve the prognosis of many solid tumors. Therefore, the purpose of this study was to examine the relationship between lymph node metastasis and tumor-infiltrating T cells in patients with colorectal cancer with submucosal invasion. We examined CD8 + tumor-infiltrating T cells level as a risk factor for lymph node metastasis in patients with colorectal cancer with submucosal invasion. Using immunohistochemical staining, we identified CD8 + T cells in surgically resected specimens from 98 patients with SM-CRC. We showed that low CD8 + tumor-infiltrating T cells levels are positively correlated with lymph node metastasis. Furthermore, by combining the number of CD8 + tumor-infiltrating T cell and the number of CD103 + tumor-infiltrating T cells, the results showed a high positive predictive value for lymph node metastasis in cases with low numbers of both types of tumor-infiltrating T cells and a high negative predictive value in cases with high numbers of both types of tumor-infiltrating T cells., (© 2023. Crown.)

Background/aim: Fibroblast activation protein (FAP) is known to have prognostic significance in colorectal cancer (CRC). However, FAP and tertiary lymphoid structures (TLSs) have not been associated with each other in predicting the prognosis of CRC recurrence., Patients and Methods: FAP expression was evaluated by real-time reverse transcription polymerase chain reaction in 195 CRC patients at Osaka International Cancer Institute (first data set). Immunohistochemistry (IHC) was then performed to stain FAP at the invasive margin (IM) and in the central tumour (CT) in 159 CRC patients at Osaka University Hospital (second data set). Consecutive slides were used to evaluate the presence of TLSs in 159 CRC patients from Osaka University Hospital., Results: The high FAP mRNA expression group (n=82) was associated with poor recurrence-free survival (RFS) compared with the low FAP expression group (n=83) (p=0.004). In the second data set, patients with high FAP expression in CT and TLS absence (n=49) showed significantly poorer RFS compared with those with low expression of FAP in CT and presence of TLSs (n=101) (p=0.002)., Conclusion: FAP in the CT combined with TLSs was shown to have significant prognostic value in predicting CRC recurrence after curative resection., (Copyright © 2022 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Colorectal cancer (CRC) is a major cause of cancer-related deaths. Metastasis is enhanced through epithelial-mesenchymal transition (EMT), a process primarily induced by the transforming growth factor beta (TGF-β)-mediated canonical Smad pathway. This study focused on plexin D1 (PLXND1), a chemoreceptor for the ligand SEMA3E to mechanosensory, showing that PLXND1 induces EMT via activation of the PI3K/AKT pathway in CRC cells. The findings showed that PLXND1-knockdown decreases cell migration and invasion significantly, and that the binding of p61-SEMA3E to the PLXND1 enhances the invasiveness and migration through EMT. Furin inhibitor suppresses EMT, decreasing cell migration and invasion. Furin cleaves full-length SEMA3E and converts it to p61-SEMA3E, suggesting that furin inhibitors block PLXND1 and p61-SEMA3E binding. Furin is a potential therapeutic target for the purpose of suppressing EMT by inhibiting the binding of p61-SEMA3E to PLXND1. In vivo experiments have shown that PLXND1-knockdown suppresses EMT. Mesenchymal cells labeled with ZEB1 showed heterogeneity depending on PLXND1 expression status. The high-expression group of PLXND1 in 182 CRC samples was significantly associated with poor overall survival compared with the low-expression group (P = 0.0352, median follow-up period of 60.7 months) using quantitative real-time polymerase chain reaction analysis. Further research is needed to determine whether cell fractions with a different expression of PLXND1 have different functions., (© 2022. Society of Surgical Oncology.)

Background/aim: Previous studies have shown that postoperative adjuvant chemotherapy improves overall survival in patients with stage III colorectal cancer (CRC). However, adjuvant chemotherapy may not be necessary for some patients. This study aimed to develop a new nutritional-inflammation score, which would be useful in identifying a favorable prognosis group among stage III CRC patients., Patients and Methods: This retrospective study included 262 patients with stage III CRC who underwent curative surgery and were divided into two groups: a training set (TS) of 162 patients and a validation set (VS) of 100 patients. In the TS, clinicopathological factors were tested using a Cox regression model, and a new prognostic model was developed., Results: Multivariate analyses in TS revealed that lymph node metastasis (N2) (p=0.002), low albumin (p=0.017), high monocyte counts (p=0.008), and low platelet counts (p=0.018) were independent risk factors for disease free survival (DFS). The Kansai prognostic score (KPS) was assessed by 1 point each for <3.5 g/dl albumin level, >450 monocyte counts, and <1.65×10 5 platelet counts. Using KPS, DFS and overall survival (OS) were validated in VS. The C-indices of KPS to predict DFS and OS in TS were 0.707 and 0.772. It was validated in VS that the C-indices of KPS to predict DFS and OS were 0.618 and 0.708, respectively. A high KPS was a significant predictor of DFS and OS., Conclusion: KPS serves as a new model for the prognosis of patients with stage III CRC., (Copyright © 2022 International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background: Anticancer drugs generate excessive reactive oxygen species (ROS), which can cause cell death. Cancer cells can resist this oxidative stress, but the mechanism of resistance and associations with chemoresistance are unclear. Here, we focused on Sirtuin 3 (SIRT3), a deacetylating mitochondrial enzyme, in oxidative stress resistance in colorectal cancer (CRC)., Methods: To evaluate SIRT3-related changes in mitochondrial function, ROS (mtROS) induction, and apoptosis, we used the human CRC cell lines HT29 and HCT116 transfected with short-hairpin RNA targeting SIRT3 and small interfering RNAs targeting superoxide dismutase 2 mitochondrial (SOD2) and peroxisome proliferator-activated receptor γ coactivator-1 (PGC-1α). In 142 clinical specimens from patients with CRC, we also assessed the association of SIRT3 protein levels (high/low) and prognosis., Results: SIRT3 expression correlated with mtROS generation and apoptosis induction in cells treated with anticancer agents. Suppressing SIRT3 increased mtROS levels and cell sensitivity to anticancer agents. SIRT3 knockdown decreased SOD2 expression and activity, and suppressing SOD2 also improved sensitivity to anticancer drugs. In addition, SIRT3 was recruited with PGC-1α under oxidative stress, and suppressing SIRT3 decreased PGC-1α expression and mitochondrial function. PGC-1α knockdown decreased mitochondrial activity and increased apoptosis in cells treated with anticancer drugs. In resected CRC specimens, high vs low SIRT3 protein levels were associated with significantly reduced cancer-specific survival., Conclusions: SIRT3 expression affected CRC cell chemoresistance through SOD2 and PGC-1α regulation and was an independent prognostic factor in CRC. SIRT3 may be a novel target for CRC therapies and a predictive marker of sensitivity to chemotherapy.

The BRAF V600E mutation occurs in approximately 10% of patients with metastatic colorectal cancer (CRC) and constitutes a distinct subtype of the disease with extremely poor prognosis. To address this refractory disease, we investigated the unique metabolic gene profile of BRAF V600E-mutated tumors via in silico analysis using a large-scale clinical database. We found that BRAF V600E-mutated tumors exhibited a specific metabolic gene expression signature, including some genes that are associated with poor prognosis in CRC. We discovered that BRAF V600E-mutated tumors expressed high levels of glycolytic enzyme enolase 2 (ENO2), which is mainly expressed in neuronal tissues under physiological conditions. In vitro experiments using CRC cells demonstrated that BRAF V600E-mutated cells exhibited enhanced dependency on ENO2 compared to BRAF wild-type cancer cells and that knockdown of ENO2 led to the inhibition of proliferation and migration of BRAF V600E-mutated cancer cells. Moreover, inhibition of ENO2 resulted in enhanced sensitivity to vemurafenib, a selective inhibitor of BRAF V600E. We identified AP-1 transcription factor subunit (FOSL1) as being involved in the transcription of ENO2 in CRC cells. In addition, both MAPK and PI3K/Akt signaling were suppressed upon inhibition of ENO2, implying an additional oncogenic role of ENO2. These results suggest the crucial role of ENO2 in the progression of BRAF V600E-mutated CRC and indicate the therapeutic implications of targeting this gene., (© 2021 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.)

Epithelial-mesenchymal transition (EMT) is a drastic phenotypic change during cancer metastasis and is one of the most important hallmarks of aggressive cancer. Although the overexpression of some specific transcription factors explains the functional alteration of EMT-induced cells, a complete picture of this biological process is yet to be elucidated. To comprehensively profile EMT-related genes in colorectal cancer, we quantified the EMT induction ability of each gene according to its similarity to the cancer stromal gene signature and termed it "mesenchymal score." This bioinformatic approach successfully identified 90 candidate EMT mediators, which are strongly predictive of survival in clinical samples. Among these candidates, we discovered that the neuronal gene ARC, possibly originating from the retrotransposon, unexpectedly plays a crucial role in EMT induction. Profiling of novel EMT mediators we demonstrated here may help understand the complexity of the EMT program and open up new avenues for therapeutic intervention in colorectal cancer.

POU5F1-expressing cells can self-renew and differentiate, contributing to metastasis formation in colorectal cancer (CRC), but it plays an important role in normal pluripotent stem cells. Here, we identified the CRC-specific gene, HNF1A, which is the downstream of POU5F1. HNF1A associates with fatty acid and glucose metabolism, and CRC cells highly expressed it. In 198 CRC patients, high HNF1A expression was an independent predictor of disease-free (P = 0.031) and overall (P = 0.007) survival. HNF1A-knockdown showed significantly reduced cell growth, increased apoptosis, and improved anticancer drug sensitivity. We revealed that HNF1A regulated controlled GLUT1 expression via HIF1A and multidrug resistance protein function to suppress SRI. HNF1A expression was elevated in persister cells after exposure to anticancer drugs, and anticancer drug sensitivity was also improved in persister cells via the inhibition of HNF1A. In conclusion, HNF1A expression can reflect resistance to anticancer drug treatment, and its suppression improves anticancer drug sensitivity as a new therapeutic target.

Recently developed molecularly targeted therapies such as EGFR inhibitors have notably improved the prognosis of patients with cancer. However, patients with KRAS and BRAF mutations do not currently benefit from these therapies. Here, we aimed to examine potential effects of crenolanib as a new molecularly targeted therapy in colorectal cancer. We used multiple colorectal cancer cell lines to investigate the growth-inhibitory effect of crenolanib and its effect in combination with other cytotoxic agents. Primary cultures of patient-derived organoids (PDO), a model that reflects the heterogeneity of clinical colorectal cancer, were used to further validate the effects of crenolanib. Unlike cetuximab, crenolanib remarkably suppressed ERK and AKT/mTOR pathways in HT29 cells with BRAF mutation and in HCT116 cells with KRAS mutation with corresponding growth-suppressing effects. Additive or synergistic effects were observed in treatments with combination of crenolanib and other cytotoxic drugs. Moreover, crenolanib suppressed the expression of stem cell markers, such as OCT4, NANOG, and SOX2. These observations were substantiated in seven PDOs with KRAS mutation and two PDOs without KRAS/BRAF mutations, with crenolanib suppressing the growth of all PDOs regardless of their KRAS mutation status. Furthermore, crenolanib abrogated PDGF- and TGFβ-induced increase of OCT4-positive cells in PDOs. Together, these findings suggest that crenolanib may have clinical utility for patients with colorectal cancer, especially patients with KRAS/BRAF mutations. IMPLICATIONS: These findings indicate that crenolanib can be a useful target agent for patients with colorectal cancer, especially patients with KRAS/BRAF mutations., (©2021 American Association for Cancer Research.)

Chromosome instability is one of the hallmarks of cancer. Stromal antigen (STAG) 3 is a core component of the meiosis-specific cohesin complex, which regulates sister chromatid cohesion. Although aberrantly activated genes encoding the cohesin complex have been identified in cancers, little is known about the role of STAG3 in colorectal cancer (CRC). Here, we evaluated the prognostic impact and role of STAG3 in CRC. Analysis of 172 CRC surgical specimens revealed that high STAG3 expression was associated with poor prognosis. STAG3 knockdown inhibited cell migration and increased drug sensitivity to oxaliplatin, 5-fluorouracil, irinotecan hydrochloride hydrate, and BRAF inhibitor in CRC cell lines. The enhanced drug sensitivity was also confirmed in a human organoid established from a CRC specimen. Moreover, suppression of STAG3 increased γH2AX foci. Particularly, in BRAF-mutant CRC cells, STAG3 silencing suppressed the expression of snail family transcriptional repressor 1 and phosphorylation of extracellular signal-regulated kinase via upregulation of dual-specificity phosphatase 6. Our findings suggest that STAG3 is related to poor clinical outcomes and promotes metastasis and chemotherapeutic resistance in CRC. STAG3 may be a novel prognostic marker and potential therapeutic target for CRC., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Histological examination of the lymph nodes (LNs) is crucial to determine the colorectal cancer (CRC) stage. We previously reported a new fat-dissociation method (FM) to detect LNs from surgically resected mesentery. This study aimed to examine the effectiveness of FM compared with that of conventional palpation method (PM) in CRC. This single-center, open-label, randomized controlled study was performed at Osaka International Cancer Institute in Japan in 2014. Randomization was performed using a computer-generated permuted-block sequence. Patients were stratified by surgical procedures and the LN dissection area. The primary endpoint was the time required for LN identification. The secondary endpoint was the number of LNs and 5-year cancer-specific survival. The 130 enrolled patients were randomly assigned in a 1:1 ratio to the FM and the PM groups. LN identification times were 45 (range 15-80) and 15 (range 7-30) minutes in the PM and the FM groups, respectively (P < 0.001). In the PM group, body mass index and identification time were correlated (P = 0.047). The number of LN which could be examined pathologically was 16 (range 2-48) and 18 (range 4-95) in the PM and FM groups, respectively (P = 0.546). In right-sided CRC, the number of LNs was higher in the FM group than in the PM group (P = 0.031). Relapse-free survival rates and cancer-specific survival rates did not differ between the groups. In conclusion, FM reduced the time required for LN detection without reducing the number of detected LNs, making it is a useful method to detect LNs in surgical specimens.

Background: In recent years, systemic chemotherapy has significantly improved the prognosis of metastatic colorectal cancer (CRC); however, different patients have different responses to chemotherapeutics., Methods: Dipeptidyl peptidase 9 (DPP9) is an enzyme in the dipeptidyl peptidase IV family that has been reported to increase drug sensitivity in acute myeloid leukemia. In this study, we examined the relationship between DPP9 expression and the prognosis of patients with CRC, as well as the role of DPP9 in anticancer drug resistance. Moreover, the effects of the DPP9 inhibitors talabostat and vildagliptin in CRC cell lines and primary cultured cells were assessed., Results: High expression of DPP9 was associated with worse prognosis in 196 patients with CRC. Cell viability was markedly inhibited in CRC cell lines transfected with DPP9 small interfering RNA or small hairpin RNA. Talabostat suppressed proliferation in CRC cell lines and primary cultured cells, and increased their sensitivity to chemotherapy. Vildagliptin, a DPP family inhibitor currently administered for diabetes, also increased the sensitivity of CRC cells to anticancer drugs., Conclusion: DPP9 was a poor prognostic factor for CRC and could be a new therapeutic target, while vildagliptin could be used as a repositioned drug for CRC treatment.

Malnutrition has been considered to be associated with the prognosis of cancer. The Geriatric Nutritional Risk Index (GNRI), based on serum albumin levels, present body weight, and ideal body weight, is a simple screening tool to predict the risk of nutrition-related morbidity and mortality in elderly patients. We aimed to evaluate whether preoperative GNRI was associated with postoperative complications and prognosis in elderly patients with colorectal cancer (CRC). We retrospectively enrolled 313 CRC patients aged ≥65 years after curative surgery and classified them into an all-risk GNRI (≤98) group and a no-risk GNRI (>98) group. Kaplan-Meier analysis showed overall survival was significantly worse in the all-risk GNRI group than in the no-risk GNRI group (P = 0.009). Multivariable analyses showed low GNRI (≤98) was an independent risk factor for postoperative complications (P = 0.048) and overall survival (P = 0.001) in the patients. Among the complications, the incidence of surgical site infection, in particular, was significantly higher in the all-risk GNRI group (P = 0.008). In conclusion, low preoperative GNRI (≤98) was associated with increased postoperative complications and poor prognosis. Preoperative GNRI can be used as an identifier for potential high-risk group of morbidity and mortality in elderly CRC patients.

Innate lymphoid cells (ILC) are responsible for mucosal tissue homeostasis and are involved in the progression and suppression of several types of cancer. However, the effects of ILCs on colorectal cancer are poorly understood. We characterized human ILCs in normal colon and colorectal cancer tissue, investigating their role in the tumor immune microenvironment. Normal mucosa and tumor tissues were obtained from patients with colorectal cancer, and the cells were isolated by enzymatic digestion. NKp44 + ILC3s with high expression of tertiary lymphoid structure (TLS) formation-related genes, including LTA, LTB , and TNF , accumulated in the normal colonic mucosa and T1/T2 tumors. However, the number of NKp44 + ILC3s was significantly reduced in T3/T4 tumors compared with normal colonic mucosa and T1/T2 tumors. NKp44 + ILC3s present in T3/T4 tumors had decreased expression of TLS formation-related genes, whereas stromal cells had decreased expression of CXCL13, CCL19 , and CCL21 The decreasing number of NKp44 + ILC3s during tumor progression correlated with the TLS density in tumors. Thus, our results indicate that NKp44 + ILC3s infiltrate colorectal cancer tissue, but the number of cells decreases in T3/T4 tumors with associated decreases in TLS induction., (©2020 American Association for Cancer Research.)

Purpose: Inflammation and the nutritional and immunologic status are known to be associated with the prognosis of malignant tumors. We aimed to examine inflammation-nutrition scores and predict the prognosis of colorectal cancer (CRC) patients by integrating nutritional and immunologic factors and tumor stage., Methods: This study investigated 511 patients with CRC from 2007 to 2013: 380 in a training set (TS) and 131 in a validation set (VS). The Osaka Prognostic Score (OPS) used comprised 1 point each for C-reactive protein > 1.0 mg/dL, albumin (< 3.5 g/dL), and lymphocyte count < 1600. Patients were classified according to the total points. The modified Glasgow Prognostic Score and the Prognostic Nutritional Index were also examined. A nomogram for predicting the disease-free survival (DFS) and overall survival (OS) was constructed based on the OPS and TNM stage., Results: In the TS, a high OPS and high TNM stage were significant predictors of the DFS and OS. The C-indexes of the OPS for the DFS and OS were higher than those of other reported scoring systems. The C-index of the nomogram for the DFS was 0.762 in the TS and 0.675 in the VS. The C-index of the nomogram for the OS was 0.805 in the TS and 0.743 in the VS., Conclusion: Integrating the TNM stage and OPS accurately predicted the prognosis of patients with CRC.

Unlike cancer cell lines, tumors and primary cultured cells exhibit phenotypic heterogeneity. Although methods for establishing organoids within three-dimensional (3D) gels are well-known, the growth is slower than that of two-dimensional (2D) cultured cells and many niche factors need to be added. In this study, we established primary cultured organoid in 2D culture (2D organoid; 2DO) in a reproducible manner and with clinical phenotypic heterogeneity. The 2DO contained cancer stem cells (CSCs) expressing CD44 and CD133. The addition of basic fibroblast growth factor and transforming growth factor-β as niche factors was necessary to establish the 2DO and maintain the CSC population. The established 2DO showed sufficient proliferation, and the culture could be transferred to the 3D culture. Morphological analysis of the xenograft induced by 2DO reflected parental tumor differentiation, and gene expression in the 2DO was similar to that in the parental tumor. In vitro drug sensitivity analysis using the 2DO reflected individual clinical courses. The 2DO is an in vitro personal cancer model, and the results of the drug sensitivity assessment may be useful for introducing clinical chemotherapy agents in personalized medicine., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Purpose: The POU5F1 gene, which encodes the POU domain, class 5, transcription factor 1 (also known as Oct-4), is expressed in embryonic stem cells where it regulates pluripotency and proliferation. Few studies have examined the expression and significance of POU5F1 in cancer tissues. The aim of this study was to clarify its significance in colorectal cancer (CRC)., Methods: The study included 95 patients who underwent surgery for CRC from 2009 to 2011. The correlations between the POU5F1 gene expression and the clinical parameters were assessed in these patients. The serum TP53 expression levels were also examined by an enzyme-linked immunosorbent assay., Results: Patients with a high POU5F1 expression were significantly more likely to have a poor prognosis than those with a low expression. In contrast, patients with a low POU5F1 expression had a better disease-free survival after curative surgical resection than those with a high expression (P = 0.007). Multivariate analyses showed that the POU5F1 expression (P = 0.003) and lymph node metastasis (P < 0.001) were significantly correlated with the disease-free survival. The prognosis was significantly related to the serum TP53 levels, according to the POU5F1 expression., Conclusion: The POU5F1 expression was suggested to be a prognostic factor in patients with CRC.

Platelet‑derived growth factor receptor‑β (PDGFR‑β) in epithelial tumors is mainly expressed by stromal cells. High expression of PDGFR‑β has been related to poor prognosis in several cancers, however its significance in colorectal cancer (CRC) remains unknown. The present study aimed to clarify the prognostic impact of PDGFR‑β in CRC patients. The study included 194 patients who underwent surgery for CRC. PDGFR‑β expression was examined by real‑time reverse transcription‑polymerase chain reaction and immunohistochemistry and the expression levels were correlated with various clinical parameters. The biological significance was evaluated by knockdown experiments in CRC cell lines and the specific PDGFR inhibitor, crenolanib. PDGFR‑β mRNA and protein expression levels were positively correlated with each other. Low PDGFR‑β expression was associated with significantly better disease‑free survival after curative surgical resection, than high PDGFR‑β expression, according to univariate and multivariate analyses. The assessment of PDGFR‑β knockdown in two cell lines revealed that small interfering RNA (siRNA) inhibition resulted in statistically significant reductions in cell growth and invasion. PDGFR inhibitor suppressed CRC cell proliferation in vitro in a dose‑dependent manner. In conclusion, PDGFR‑β expression was a risk factor for recurrence in patients with CRC and PDGFR inhibitor may be a useful therapeutic agent for CRC.

We developed a reliable prediction model for colorectal cancer(CRC)patients after surgically curative resection. Using clinicopathological factors, prediction models were constructed for liver metastasis-free survival(LMFS). Between January 2004 and December 2010, 528 CRC patients were investigated. On univariate analysis of clinicopathological factors, the following factors associated with LMFS: pathological tumor invasion, lymph node metastasis, lymphatic invasion, venous invasion, and preoperative serum CEA. Using these factors, a prediction model was constructed using a Cox regression model with a concordance index of 0.824 for LMFS. These individualized prediction models could help clinicians in the treatment of postoperative CRC patients.

To evaluate the risk factors associated with lymph node(LN)metastases described in the Japanese Society for Cancer of Colon and Rectum (JSCCR) guidelines, we retrospectively analyzed 40 patients with submucosal invasive colorectal cancer who underwent surgical resection after endoscopic resection at Osaka Medical Center for Cancer and Cardiovascular Diseases between 2006 and 2008. We examined clinicopathological factors such as sex, age, tumor diameter, morphology, histological grade, submucosal invasion, lymphatic invasion, venous invasion, and LN metastasis and 5-year disease-free survival(DFS) and overall survival (OS). All patients had tubular adenocarcinoma. Ten patients had LN metastasis. Histological grade, tub2, and a positive vertical margin were significant risk factors. Submucosal invasion was greater than 1,000 µm in patients with LN metastasis. There was no difference in clinicopathological factors between patients with colon cancer and those with rectal cancer, but LN metastasis occurred in 18.7% and 50.0% of colon cancer and rectal cancer patients, respectively. There were no recurrences or cancer-related deaths, although one patient died of other causes. In conclusion, patients who were treated according to the JSCCR guidelines had a favorable prognosis.

Pathologic staging is a key factor in the treatment and outcome of cancer patients, and lymph node status plays a pivotal role in this staging process. Several methods of lymph node assessment, such as the fat clearance, Schwartz solution and GEWF solution, are unpopular as they require a significant amount of time (1‑9 days) to clear the fat of the resected mesentery and to visualize the lymph nodes. In the present study, we discussed a more simple and effective method, called the fat‑dissociation method, which clears the fat using enzymes and allows for easy identification of lymph nodes around vessels. This new procedure facilitates precise staging of cancer which directs the post-operative treatment plan.