Low-Dose Alcohol-Induced Inhibition of Mouse Orthotopically Transplanted Tumors Is Associated with T-Cell Response.

INTRODUCTION: The effects of low-dose alcohol consumption on colorectal cancer development are not well understood. Epidemiological studies have reported that people who consume small amounts of alcohol have lower mortality rates than both nondrinkers and heavy drinkers. This phenomenon has been labeled the "J-curve effect" of alcohol. This study examined the effects of low-dose alcohol (0.5%, 1%, and 2%) on tumor growth in a transplant colon cancer model. METHODS: BALB/c and BALB/c nude mice were used to analyze T-cell immunity. Syngeneic CT26 murine colon cancer cells were implanted into the cecal wall, and the resulting T-cell immune effects were monitored. RESULTS: The growth of orthotopic tumors was markedly inhibited upon ingestion of low-dose (0.5%) alcohol compared with that in the control mice. In contrast, cells from the same line were injected into the cecal wall of nude mice, and tumor growth inhibition was not observed. Histopathological and RNA sequence analyses were performed to elucidate the mechanisms underlying tumor growth inhibition. An increase in tumor CD8+ T lymphocytes and changes in cytokine levels were observed. Microbiome analysis using 16S rRNA gene sequencing of cecal contents was performed and revealed Mucispirillum schaedleri and Clostridium cocleatum showed decreased and increased abundance, respectively, in the alcohol group. DISCUSSION/CONCLUSION: Ingesting a threshold amount of alcohol results in the infiltration of T lymphocytes, which may enhance immune responsiveness in mouse colorectal cancer models.

Investigation of endoscopic findings in nine cases of Helicobacter suis-infected gastritis complicated by gastric mucosa-associated lymphoid tissue lymphoma.

BACKGROUND: We have previously reported that eradication therapy was more effective against Helicobacter pylori (Hp)-negative gastric mucosa-associated lymphoid tissue (MALT) lymphoma in non-Helicobacter pylori Helicobacter (NHPH)-positive cases than in NHPH-negative cases and that the infection status of NHPH could be a predictive marker for the efficacy of eradication therapy for H. pylori negative gastric MALT lymphoma. However, a diagnostic test for NHPH infection has not yet been clinically established. In this study, we investigated the endoscopic findings in cases of H. suis-infected gastritis associated with gastric MALT lymphoma reported at our institution. MATERIALS AND METHODS: Participants were selected from cases of gastric MALT lymphoma who underwent esophagogastroduodenoscopy at Hiroshima University Hospital, who were negative for the API2-MALT1 gene, and who received eradication therapy as a first-line treatment. We examined the endoscopic findings in nine cases from this group in which H. suis infection was confirmed by polymerase chain reaction. RESULTS: Endoscopic findings, such as cracked mucosa, spotty redness, nodular gastritis-like appearance, and white marbled appearance, which have been reported as characteristics of NHPH gastritis, were observed in multiple cases. The most common endoscopic findings in this study were cracked mucosa (7/9 cases), followed by spotty redness (6/9 cases), nodular gastritis-like appearance (5/9 cases), and white marbled appearance (2/9 cases). CONCLUSIONS: Our study may serve as a reference for re-evaluation of the diagnostic criteria for H. suis infection and indications for eradication therapy, particularly for cases of H. pylori negative gastric MALT lymphoma, where endoscopic findings such as those seen in this study were observed in the background mucosa.

Role of tumor-associated macrophages at the invasive front in human colorectal cancer progression.

Macrophages are an essential component of antitumor activity; however, the role of tumor-associated macrophages (TAMs) in colorectal cancer (CRC) remains controversial. Here, we elucidated the role of TAMs in CRC progression, especially at the early stage. We assessed the TAM number, phenotype, and distribution in 53 patients with colorectal neoplasia, including intramucosal neoplasia, submucosal invasive colorectal cancer (SM-CRC), and advanced cancer, using double immunofluorescence for CD68 and CD163. Next, we focused on the invasive front in SM-CRC and association between TAMs and clinicopathological features including lymph node metastasis, which were evaluated in 87 SM-CRC clinical specimens. The number of M2 macrophages increased with tumor progression and dynamic changes were observed with respect to the number and phenotype of TAMs at the invasive front, especially at the stage of submucosal invasion. A high M2 macrophage count at the invasive front was correlated with lymphovascular invasion, low histological differentiation, and lymph node metastasis; a low M1 macrophage count at the invasive front was correlated with lymph node metastasis. Furthermore, receiver operating characteristic curve analysis revealed that the M2/M1 ratio was a better predictor of the risk of lymph node metastasis than the pan-, M1, or M2 macrophage counts at the invasive front. These results suggested that TAMs at the invasive front might play a role in CRC progression, especially at the early stages. Therefore, evaluating the TAM phenotype, number, and distribution may be a potential predictor of metastasis, including lymph node metastasis, and TAMs may be a potential CRC therapeutic target.

Long-term prognosis after endoscopic submucosal dissection for colorectal tumors in patients aged over 80 years.

BACKGROUND: In Japan, endoscopic submucosal dissection (ESD) is standardized for large colorectal tumors. However, its validity in the elderly population is unclear. We aimed to evaluate the safety and efficacy of ESD for colorectal tumors in elderly patients aged over 80 years. METHODS: ESD was performed on 178 tumors in 165 consecutive patients aged over 80 years between December 2008 and December 2018. We retrospectively evaluated the clinicopathological characteristics and clinical outcomes of ESD. We also assessed the prognosis of 160 patients followed up for more than 12 months. RESULTS: The mean patient age was 83.7 ± 3.1 years. The number of patients with comorbidities was 100 (62.5%). Among all patients, 106 (64.2%) were categorized as class 1 or 2 according to the American Society of Anesthesiologists classification of physical status (ASA-PS), and 59 (35.8%) were classified as class 3. The mean procedure time was 97.7 ± 79.3 min. The rate of histological en bloc resection was 93.8% (167/178). Delayed bleeding in 11 cases (6.2%) and perforation in 7 cases (3.9%) were treated conservatively. The 5-year survival rate was 89.9%. No deaths from primary disease (mean follow-up time: 35.3 ± 27.5 months) were observed. Overall survival rates were significantly lower in the non-curative resection group that did not undergo additional surgery than in the curative resection group (P = 0.0152) and non-curative group that underwent additional surgery (P = 0.0259). Overall survival rates were higher for ASA-PS class 1 or 2 patients than class 3 patients (P = 0.0105). Metachronous tumors (> 5 mm) developed in 9.4% of patients. CONCLUSIONS: ESD for colorectal tumors in patients aged over 80 years is safe. Colorectal cancer-associated deaths were prevented although comorbidities pose a high risk of poor prognosis.

Effect of educational lecture on the diagnostic accuracy of Japan NBI Expert Team classification for colorectal lesions.

BACKGROUND: An educational and training program is required for generalization of Japan NBI Expert Team (JNET) classification. However, there is no detailed report on the learning curve of the diagnostic accuracy of endoscopists using JNET classification. We examined the effect of an educational lecture on beginners and less experienced endoscopists for improving their diagnostic accuracy of colorectal lesions by JNET classification. METHODS: Seven beginners with no endoscopy experience (NEE group), 7 less experienced endoscopists (LEE group), and 3 highly experienced endoscopists (HEE group) performed diagnosis using JNET classification for randomized NBI images of colorectal lesions from 180 cases (Type 1: 22 cases, Type 2A: 105 cases, Type 2B: 33 cases, and Type 3: 20 cases). Next, the NEE and LEE groups received a lecture on JNET classification, and all 3 groups repeated the diagnostic process. We compared the correct diagnosis rate and interobserver agreement before and after the lecture comprehensively and for each JNET type. RESULTS: In the HEE group, the correct diagnosis rate was more than 90% with good interobserver agreements (kappa value: 0.78-0.85). In the NEE and LEE groups, the correct diagnosis rate (NEE: 60.2 → 68.0%, P < 0.01; LEE: 66.4 → 86.7%, P < 0.01), high-confidence correct diagnosis rate (NEE: 19.6 → 37.2%, P < 0.01; LEE: 43.6 → 61.1%, P < 0.01), and interobserver agreement (kappa value, NEE: 0.32 → 0.43; LEE: 0.39 → 0.75) improved after the lecture. In the examination by each JNET type, the specificity and positive predictive value in the NEE and LEE groups generally improved after the lecture. CONCLUSION: After conducting an appropriate lecture, the diagnostic ability using JNET classification was improved in beginners or endoscopists with less experience in NBI magnifying endoscopy.

Involvement of non-Helicobacter pylori helicobacter infections in Helicobacter pylori-negative gastric MALT lymphoma pathogenesis and efficacy of eradication therapy.

BACKGROUND: Eradication therapy is known to be effective against Helicobacter pylori-positive gastric MALT lymphoma but predicting the efficacy of eradication therapy against Helicobacter pylori-negative gastric MALT lymphoma is difficult. Recent reports have shown that non-Helicobacter pylori helicobacter infections induce gastric MALT lymphoma, and we aimed to clarify whether non-Helicobacter pylori helicobacter infections are associated with the efficacy of eradication therapy. METHODS: We analyzed eradication therapy as a first-line treatment for 182 cases of gastric MALT lymphoma, classified according to Helicobacter pylori infection and API2-MALT1 mutation status. We also evaluated the non-Helicobacter pylori helicobacter infection status in 29 Helicobacter pylori-negative cases via PCR with DNA extracted from paraffin-embedded biopsy tissues. Finally, we analyzed the relationship between non-Helicobacter pylori helicobacter infection status and eradication therapy outcome. RESULTS: The API2-MALT1 mutation was observed in 13/182 patients (7.1%), none of whom were cured by eradication therapy. Helicobacter pylori-negative cases had a significantly higher non-Helicobacter pylori helicobacter infection rate than Helicobacter pylori-positive cases (16/29, 55% vs. 3/29, 10%; P < 0.05). Among the Helicobacter pylori-negative cases, non-Helicobacter pylori helicobacter-positive cases had a significantly higher complete response rate than non-Helicobacter pylori helicobacter-negative cases (12/16, 75% vs. 3/13, 23%; P < 0.05). CONCLUSION: Helicobacter pylori-negative and API2-MALT1-negative gastric MALT lymphoma cases exhibited a high rate of non-Helicobacter pylori helicobacter infections, which may have contributed to the success of eradication therapy. Therefore, we recommend eradication therapy as a first-line treatment for non-Helicobacter pylori helicobacter-positive gastric MALT lymphoma.

Clinical usefulness of linked color imaging for evaluation of endoscopic activity and prediction of relapse in ulcerative colitis.

PURPOSE: In the treatment of ulcerative colitis (UC), accurate evaluation of UC activity is important to achieve mucosal healing. We sought to investigate the clinical utility of linked color imaging (LCI) for the evaluation of endoscopic activity and prediction of relapse in UC patients. METHODS: We enrolled 72 consecutive UC patients in remission who underwent colonoscopy at our institution between September 2016 and October 2018. The relationship between the presence of redness in white light imaging (WLI) and LCI and histopathological inflammation (Geboes score: GS) at 238 biopsy sites was examined. We also assessed the presence or absence of planar redness in the entire rectum as ± and classified the patients into three groups according to the combination of WLI/LCI: A: WLI-/LCI-, B: WLI-/LCI+, and C: WLI+/LCI+. The relationship between WLI/LCI classification and relapse in 64 patients followed up for more than 12 months from initial colonoscopy was assessed and compared to the Mayo endoscopic subscore (MES). RESULTS: A GS of 0 or 1 accounted for 89% of WLI/LCI non-redness sites, while a GS of 2 or 3 accounted for 42% of WLI non-redness/LCI redness sites. LCI findings were significantly correlated with GS. During follow-up, 10 patients in group C and four patients in group B relapsed, but none in group A. Non-relapse rates were significantly correlated with WLI/LCI classification, but not with MES. CONCLUSION: LCI is a useful modality for accurate assessment of endoscopic activity and prediction of relapse in UC by detecting mild inflammation unrecognizable by WLI.

Clinical significance of immunohistochemical lymphovascular evaluation to determine additional surgery after endoscopic submucosal dissection for colorectal T1 carcinoma.

PURPOSE: The Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines indicate lymphovascular invasion-evaluated by hematoxylin and eosin (HE) staining-as a surgical requirement after endoscopic submucosal dissection (ESD) in T1 colorectal carcinoma (CRC) patients; however, immunohistochemical evaluation may be superior. This study aimed to clarify the significance of immunohistochemical lymphovascular evaluation as an indicator for additional surgery of T1 CRC after ESD, and assessed the guidelines' adequacy, even when evaluating through immunostaining. METHODS: Patients with T1 CRC who underwent ESD were enrolled across three institutions between January 2012 and December 2017. Immunohistochemical lymphovascular evaluation was performed. Clinicopathological features, pathological evaluations, and surgery indications were recorded. Univariate and multivariate logistic regression identified risk factors for lymph node (LN) metastasis of T1 CRC after ESD. RESULTS: Among 370 patients with T1 CRC, recurrence, 5-year overall survival, and 5-year disease specific survival rates were 1.6%, 94.6%, and 99.5%, respectively. Six patients (1.6%) experienced recurrence, five of whom underwent additional surgery. Those with no risk factors did not exhibit recurrence. A total of 215 (58.1%) patients underwent additional surgery after ESD, 21 (9.7%) of whom exhibited LN metastasis. Among 16 patients who underwent additional surgery due to lymphovascular invasion, three (18.8%) had LN metastasis. Multivariate logistic regression analysis identified lymphatic invasion as a significant risk factor for LN metastasis (odds ratio 3.9, 95% confidence interval 1.0-14.6, P = 0.0421). CONCLUSIONS: The JSCCR guidelines have clinical validity, and immunohistochemical lymphatic evaluation findings potentially predict LN metastasis for T1 CRC after ESD.

Fatty change of the liver microenvironment influences the metastatic potential of colorectal cancer.

Fatty liver is the most common cause of liver disease, and its prevalence has been increasing globally. Colorectal cancer (CRC) accounts for approximately 10% of all cancers and metastasizes most commonly to the liver. Paget's 'Seed and Soil' theory of metastasis proposed that the secondary growth of cancer cells is dependent on the distal organ microenvironment. This implies that the risk of metastasis may change due to changes in the microenvironment of target organs. However, the association between steatosis, fatty change in the liver microenvironment, and liver metastasis has not been clarified. Here, we induced fatty liver conditions in BALB/c mice using a choline-deficient high-fat diet with 0.1% methionine (CDAHFD) and then injected the CT26 cells to produce experimental metastasis. The number of metastatic tumours was significantly increased in mice with severe fatty liver as compared to control mice. The average size of metastatic tumours was smaller in mice with moderate fatty liver than in control mice. The stromal components, including cancer-associated fibroblasts, tumour-associated macrophages and tumour-infiltrating lymphocytes, were also examined. Metastatic tumours in fatty liver showed invasive growth patterns without a fibrotic capsule. Compared to control groups, the polarization of macrophages and subtypes of tumour-infiltrating lymphocytes differed depending on the extent of fatty liver progression. These results indicated that fatty changes in the liver influenced liver metastasis of CRC. Although moderate fatty changes suppress the growth of metastatic tumours in the liver, a severe fatty microenvironment may promote invasion and metastasis through alteration of the tumour microenvironment (TME).

Potential of Helicobacter pylori-uninfected signet ring cell carcinoma to invade the submucosal layer.

BACKGROUND AND AIM: The typical histology of Helicobacter pylori-uninfected gastric cancer is signet ring cell carcinoma (SRCC) localized in the mucosal layer, but the potential of these SRCCs to invade the submucosal layer is unclear. This study aimed to investigate the clinicopathological characteristics of SRCC in H. pylori-uninfected patient and its prevalence in diffuse-type gastric cancer (DGC) within Japan. METHODS: We enrolled consecutive pure DGC patients diagnosed with the disease either localized in the mucosal layer or with submucosal invasion. H. pylori infection was investigated, and the patients were divided into three groups according to histological types: pure SRCC, SRCC with poorly differentiated adenocarcinoma (PDA), and pure PDA. RESULTS: Of the 345 pure DGC patients, 132 (38%), 127 (37%), and 86 (25%) had pure SRCC, SRCC with PDA, and pure PDA histologies, respectively. The prevalence of H. pylori infection and the SM ratio were significantly lower in the pure SRCC group than other groups (P < 0.01). Twenty-two (6.4%) patients, including two with submucosal invasion, were negative for H. pylori and had mucosal SRCC component in the cancer lesions. Of the 259 SRCC cases (pure SRCC or SRCC + PDA), H. pylori-uninfected cases had different clinicopathological characteristics compared with H. pylori-positive cases. Particularly, the ratio of patients with submucosal invasive SRCC was significantly lower in the H. pylori-uninfected gastric cancer group than in those with H. pylori infection. CONCLUSION: Helicobacter pylori-uninfected gastric cancer is not rare among pure DGC patients in Japan. SRCC in patients without H. pylori infection is less likely to be invasive.

Expression of cytosolic malic enzyme (ME1) is associated with disease progression in human oral squamous cell carcinoma.

Malic enzyme 1 (ME1) is a multifunctional protein involved in glycolysis, the citric acid cycle, NADPH production, glutamine metabolism, and lipogenesis. It is overexpressed in various cancers. We examined the expression of ME1 in 119 oral squamous cell carcinomas (OSCCs) using immunohistochemistry. Malic enzyme 1 expression was moderate to strong in 57 (48%) OSCCs and correlated with pT, pN, clinical stage, and histological grade. In 37 cases with prognostic evaluation, moderate to strong ME1 expression indicated a worse prognosis than did weak ME1 expression. Malic enzyme 1 knockdown or inactivation by lanthanide inhibited cell proliferation and motility and suppressed the epithelial-mesenchymal transition in HSC3 human OSCC cells. Knockdown of ME1 also shifted energy metabolism from aerobic glycolysis and lactate fermentation to mitochondrial oxidative phosphorylation, and the redox status from reductive to oxidative. In a mouse tumor model, lanthanide suppressed tumor growth and increased survival time. These findings reveal that ME1 is a valid target for molecular therapy in OSCC.

Anti-Helicobacter pylori therapy in localized gastric mucosa-associated lymphoid tissue lymphoma: A prospective, nationwide, multicenter study in Japan.

BACKGROUND: Helicobacter pylori eradication therapy was approved in Japan for the first-line, standard treatment of H. pylori-positive gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Although several retrospective studies or small-scale single-center studies have been reported, a prospective, large-scale, nationwide, multicenter study has not been reported from Japan. MATERIALS AND METHODS: We conducted a prospective, nationwide, multicenter study to evaluate the clinical efficacy of rabeprazole-based triple H. pylori eradication therapy for patients with localized gastric MALT lymphoma in practice-based clinical trial. A total of 108 H. pylori-positive patients with stage I/II1 gastric MALT lymphoma underwent H. pylori eradication therapy. The primary endpoints were complete remission (CR) rate and the rate of transfer to secondary treatment. The secondary endpoints were CR maintenance duration and overall survival (OS). RESULTS: CR of lymphoma was achieved in 84 of 97 patients (86.6%), during the period 2.0-44.7 months (median, 5.3 months) after starting H. pylori eradication treatment. CR was maintained in 77 of 81 patients (95.1%) for 0.4-53.2 months (median, 33.1 months). Secondary treatments (radiotherapy, rituximab, or gastrectomy) for gastric MALT lymphoma were needed in 10 of the 97 patients (10.31%). During follow-up, OS rate was 96.9% (94/97) and the causes of 3 deaths were not related to lymphoma. CONCLUSIONS: Rabeprazole-based H. pylori eradication therapy demonstrated a high CR rate, long CR maintenance, and a good OS for patients with localized gastric MALT lymphoma in this prospective, practice-based, multicenter study.

Watch-and-wait policy versus rituximab-combined chemotherapy in Japanese patients with intestinal follicular lymphoma.

BACKGROUND AND AIM: Few reports have demonstrated the effectiveness of treatments for intestinal follicular lymphoma (FL) because of the limited number of patients who undergo comprehensive small intestinal examinations. This study compared the efficacy of rituximab-combined chemotherapy in patients with asymptomatic and low tumor burden (LTB) intestinal FL, according to the criteria of the Groupe d'Etude des Lymphomes Folliculaires, with that of a "watch and wait" (W&W) approach. METHODS: The endoscopic examination for entire gastrointestinal tracts was performed in 29 Japanese patients with intestinal FL. These patients had CD21-positive follicular dendritic cells arranged in a duodenal pattern. In a prospective, two-center, open-label trial, this study evaluated the efficacy of rituximab-combined chemotherapy ([cyclophosphamide, doxorubicin, vincristine, and prednisone] or [cyclophosphamide, vincristine, and prednisone]) and prolonged treatment with rituximab (R-Chemo+prolongedR) in 14 patients and compared their outcomes with those of 15 patients managed with a W&W approach. RESULTS: Four patients managed with the W&W plan showed worsening macroscopic findings, lesion area enlargement, or clinical stage progression but stayed on this plan because they had LTB and experienced no changes in bowel function. In the R-Chemo+prolongedR group, all patients achieved complete remission; recurrence occurred in one patient, who was subsequently managed with the W&W plan because of LTB. There were no significant differences in progression-free survival between the two groups (P = 0.1045). Overall survival was 100% in both groups. CONCLUSIONS: The prognoses of patients with asymptomatic intestinal FL and LTB who were managed with a W&W strategy were comparable with those of patients receiving R-Chemo+prolongedR.

Clinicopathologic and endoscopic features of early-stage colorectal serrated adenocarcinoma.

BACKGROUND: Serrated adenocarcinoma (SAC) is a distinct colorectal carcinoma variant that accounts for approximately 7.5% of all advanced colorectal carcinomas. While its prognosis is worse than conventional carcinoma, its early-stage clinicopathologic features are unclear. We therefore aimed to clarify the clinicopathologic and endoscopic characteristics of early-stage SACs. METHODS: Forty consecutive early-stage SAC patients at Hiroshima University Hospital were enrolled; SACs were classified into epithelial serration (Group A, n = 17) and non-epithelial serration (Group B, n = 23) groups. Additionally, we classified serrated adenoma into 4 types: sessile serrated adenoma (SSA), traditional serrated adenoma (TSA), unclassified, and non-serrated adenoma type. RESULTS: There were significant differences between Groups A and B in terms of tumor size (27.6 vs. 43.1 mm), incidences of T1 carcinoma (71% vs. 13%), and having the same color as normal mucosa (47% vs. 17%), respectively (p <0.01). In SACs >20 mm, the incidence of T1 carcinoma in Group A (70%) was significantly greater than that in Group B (13%) (p <0.05). There were significant differences in 'Japan NBI Expert Team' type 3 and type V pit pattern classifications between the 2 groups. The average TSA-type tumor size (42.6 mm) was significantly larger than that of the SSA (17.2 mm) and non-serrated component types (18.3 mm). The incidences of submucosal invasion in SSA- (80%), unclassified- (100%), and non-serrated-type (100%) tumors were significantly higher than that in the TSA type (11%). CONCLUSIONS: Epithelial serration in the cancerous area and a non-TSA background indicated aggressive behavior in early-stage SACs.

Multikinase inhibitor regorafenib inhibits the growth and metastasis of colon cancer with abundant stroma.

Interaction between tumor cells and stromal cells plays an important role in the growth and metastasis of colon cancer. We previously found that carcinoma-associated fibroblasts (CAFs) expressed platelet-derived growth factor receptor-ß (PDGFR-ß) and that PDGFR targeted therapy using imatinib or nilotinib inhibited stromal reaction. Bone marrow-derived mesenchymal stem cells (MSCs) migrate to tumor stroma and differentiate into CAFs. A novel oral multikinase inhibitor regorafenib inhibits receptor tyrosine kinases expressed on stromal cells (vascular endothelial growth factor receptor 1-3, TIE2, PDGFR-ß, and fibroblast growth factors) and tumor cells (c-KIT, RET, and BRAF). These molecules are involved in tumor growth, angiogenesis, lymphangiogenesis, and stromal activation. Therefore, we examined whether regorafenib impaired the tumor-promoting effect of CAFs/MSCs. KM12SM human colon cancer cells alone or KM12SM cells with MSCs were transplanted into the cecal wall of nude mice. Co-implantation of KM12SM cells with MSCs into the cecal wall of nude mice produced tumors with abundant stromal component and promoted tumor growth and lymph node metastasis. Single treatment with regorafenib inhibited tumor growth and metastasis by inhibiting both tumor cells and stromal reaction. This tumor-inhibitory effect of regorafenib was more obvious in tumors developed by co-implanting KM12SM cells with MSCs. Our data suggested that targeting of the tumor microenvironment with regorafenib affected tumor cell-MSC interaction, which in turn inhibited the growth and metastasis of colon cancer.

mTOR and PDGF pathway blockade inhibits liver metastasis of colorectal cancer by modulating the tumor microenvironment.

Tumor growth and metastasis are not determined by cancer cells alone but also by a variety of stromal cells, and platelet-derived growth factor receptors (PDGF-Rs) are overexpressed by various stromal cell populations. Activation of PI3K-AKT-mTOR signaling is frequently observed in many cancer types. We investigated whether the mTOR inhibitor everolimus, alone or in combination with the PDGF-R tyrosine kinase inhibitor nilotinib, can inhibit growth and metastasis of human colon cancer. The effects of nilotinib and everolimus on tumor growth and metastasis were examined in an orthotopic mouse model of human colon cancer and a model of liver metastasis. After treatment with nilotinib (versus distilled water), the stromal reaction of xenografts growing in the cecal wall and liver was significantly decreased. After treatment with everolimus, the stromal reaction did not decrease, but tumor cell proliferation and microvessel density decreased. With the two drugs in combination, both stromal reaction and tumor cell proliferation decreased and apoptosis of tumor cells increased, resulting in remarkable inhibition of tumor growth at both the orthotopic and the metastatic site. Concurrent inhibition of tumor cells and activated stromal cells by a PDGF-R tyrosine kinase inhibitor and an mTOR inhibitor used in combination may represent a novel therapeutic approach for colorectal cancer.

Stroma-directed imatinib therapy impairs the tumor-promoting effect of bone marrow-derived mesenchymal stem cells in an orthotopic transplantation model of colon cancer.

Bone marrow-derived mesenchymal stem cells (MSCs) are reported to contribute to formation of tumor-promoting stromal cells. We reported recently that, in an orthotopic nude mice model of colon cancer, MSCs traveled to tumor stroma, where they differentiated into carcinoma-associated fibroblast (CAF)-like cells. We also found that CAFs express platelet-derived growth factor receptor (PDGFR) at a high level and that imatinib therapy targeting PDGFR in CAFs inhibits growth and metastasis of human colon cancer. These findings led us to examine whether the tumor-promoting effect of MSCs is impaired by blockade of PDGFR signaling achieved with imatinib. Orthotopic transplantation and splenic injection of human MSCs along with KM12SM human colon cancer cells, in comparison with transplantation of KM12SM cells alone, resulted in significantly greater promotion of tumor growth and liver metastasis. The KM12SM + MSC xenograft enhanced cell proliferation and angiogenesis and inhibited tumor cell apoptosis. When tumor-bearing animals were treated with imatinib, there was no significant increase in primary tumor volume or total volume of liver metastases, despite the KM12SM+MSC xenograft, and survival in the mixed-cell group was prolonged by imatinib treatment. Moreover, the ability of MSCs to migrate to tumor stroma was impaired, and the number of MSCs surviving in the tumor microenvironment was significantly decreased. In in vitro experiments, treatment with imatinib inhibited migration of MSCs. Our data suggest that blockade of PDGF signaling pathways influences the interaction between bone marrow-derived MSCs and tumor cells in the tumor microenvironment and, hence, inhibits the progressive growth of colon cancer.

MicroRNA-155 is a predictive marker for survival in patients with clear cell renal cell carcinoma.

OBJECTIVES: To investigate the clinical significance of micro-ribonucleic acid-155 in clear cell renal cell carcinoma, in particular focusing on the association of expression levels of micro-ribonucleic acid-155 with clinicopathological factors, cancer-specific survival and therapeutic outcomes in clear cell renal cell carcinoma patients. METHODS: Quantitative reverse transcription polymerase chain reaction of micro-ribonucleic acid-155 was carried out on 137 clear cell renal cell carcinoma cases, containing 77 matched pairs of clear cell renal cell carcinoma and normal adjacent kidney tissues from the same patients. RESULTS: Significant overexpression of micro-ribonucleic acid-155 was found in clear cell renal cell carcinoma compared with normal kidney tissue. Expression of micro-ribonucleic acid-155 was not associated with prognosis in all stage groups. However, in 43 patients with stage III and IV clear cell renal cell carcinoma, low expression levels of micro-ribonucleic acid-155 correlated with a poor prognosis. Regarding cancer-free survival of 26 patients with stage III and IV clear cell renal cell carcinoma who received curative resection and cancer-specific survival of 31 patients who received postoperative therapy with interferon-α after radical nephrectomy, low expression levels of micro-ribonucleic acid-155 correlated with poor clinical outcomes in these two groups. CONCLUSIONS: Low expression of micro-ribonucleic acid-155 represents a valuable marker of poor clinical outcomes in patients with stage III and IV clear cell renal cell carcinoma.

Long-term clinical outcome of gastric MALT lymphoma after eradication of Helicobacter pylori: a multicentre cohort follow-up study of 420 patients in Japan.

OBJECTIVE: A multicentre cohort follow-up study of a large number of patients with gastric mucosa-associated lymphoid tissue (MALT) lymphoma was conducted to elucidate the long-term outcome of the disease after Helicobacter pylori eradication. METHODS: 420 patients with gastric low-grade MALT lymphoma who had undergone successful H pylori eradication and been followed up for at least 3 years were registered from 21 participating institutes. Responders to treatment were defined as patients whose post-treatment biopsies showed complete histological response (ChR) or probable minimal residual disease (pMRD). Treatment failure was defined as the status of progressive disease or lymphoma relapse after ChR/pMRD. RESULTS: 323 patients (77%) responded to H pylori eradication. A logistic regression analysis showed that absence of H pylori, submucosal invasion determined by endoscopic ultrasonography and t(11;18)/API2-MALT1 were independent predictors of resistance to H pylori eradication. During the follow-up periods ranging from 3.0 to 14.6 years (mean 6.5 years, median 6.04 years), the disease relapsed in 10 of 323 responders (3.1%) while progressive disease was found in 27 of 97 non-responders (27%). Thus, 37 of 420 patients (8.8%) were regarded as treatment failures. Of these 37 patients, transformation into diffuse large B cell lymphoma occurred in nine patients. Among the non-responders and relapsed patients, 17 patients were subjected to a 'watch and wait' strategy while 90 patients underwent second-line treatments including radiotherapy (n=49), chemotherapy (n=26), surgical resection (n=6), chemoradiotherapy (n=5), antibiotic treatment (n=2), rituximab monotherapy (n=1) or endoscopic resection (n=1). Probabilities of freedom from treatment failure, overall survival and event-free survival after 10 years were 90%, 95% and 86%, respectively. Cox multivariate analysis revealed endoscopic non-superficial type to be an independent prognostic factor for adverse freedom from treatment failure, overall survival and event-free survival. CONCLUSIONS: The excellent long-term outcome of gastric MALT lymphoma after H pylori eradication was confirmed by this large-scale follow-up study.

Investigating the Role of Tumor-Infiltrating Lymphocytes as Predictors of Lymph Node Metastasis in Deep Submucosal Invasive Colorectal Cancer: A Retrospective Cross-Sectional Study.

The role of tumor-infiltrating T cells (TILs) in colorectal cancer (CRC) and their significance in early-stage CRC remain unknown. We investigated the role of TILs in early-stage CRC, particularly in deep submucosal invasive (T1b) CRC. Sixty patients with CRC (20 each with intramucosal [IM group], submucosal invasive [SM group], and advanced cancer [AD group]) were randomly selected. We examined changes in TILs with tumor invasion and the relationship between TILs and LN metastasis risk. Eighty-four patients with T1b CRC who underwent initial surgical resection with LN dissection or additional surgical resection with LN dissection after endoscopic resection were then selected. TIL phenotype and number were evaluated using triple immunofluorescence for CD4, CD8, and Foxp3. All subtypes were more numerous according to the degree of CRC invasion and more abundant at the invasive front of the tumor (IF) than in the center of the tumor (CT) in the SM and AD groups. The increased Foxp3 cells at the IF and high ratios of Foxp3/CD4 and Foxp3/CD8 positively correlated with LN metastasis. In conclusion, tumor invasion positively correlated with the number of TILs in CRC. The number and ratio of Foxp3 cells at the IF may predict LN metastasis in T1b CRC.