CD8-positive T Cell Infiltration With Human Leukocyte Antigen Class 1 Expression Predicts Patients With Stage IV Colorectal Cancer Survival.

BACKGROUND/AIM: The immune microenvironment in cancer correlates with cancer progression and patient prognosis. Cancer immune microenvironment evaluation, based on CD3+ and CD8+ T cell infiltration at the center and invasive margin of the tumor, is defined as the immunoscore. An international multicenter analysis revealed that the immunoscore can accurately predict the prognosis of patients with colorectal cancer (CRC) (stage I, II, and III). However, no markers are currently available to predict the prognosis in patients with stage IV CRC. We thus aimed to analyze the immune microenvironment in patients with stage IV CRC in this study. PATIENTS AND METHODS: We analyzed the immune microenvironment of patients with stage IV CRC using immunohistochemical (IHC) staining. We evaluated the expressions of CD8 and the cases were divided into CD8 high (CD8Hi) and CD8 low (CD8Low) groups according to median CD8 expression. HLA class 1 (HLA1) expression was also evaluated using IHC staining and the cases were divided into HLA1Hi group and HLA1Low group according to 50% of HLA1 expression rate. CD8×HLA1 score was defined by the combination of CD8 and HLA1 expressions. RESULTS: CD8Hi and HLA1Hi cases were associated with better prognosis compared with CD8Low and HLA1Low cases according to a log-rank test, respectively. We defined a novel biomarker by combining CD8+ T-cell infiltration and HLA1 expression, referred to as the CD8×HLA1 score. We found that CD8×HLA1Hi cases predicted patient prognosis better than CD8×HLA1Int and CD8×HLA1Low according to a log-rank test. CONCLUSION: The combination of CD8+ T cell infiltration and HLA1 expression is crucial for cancer immune microenvironment evaluation in CRCs.

Snapshots of lymphatic pathways in colorectal cancer surgery using near-infrared fluorescence, in vivo and ex vivo.

INTRODUCTION: Indocyanine green (ICG) fluorescence imaging has been used for blood flow assessment in anastomoses in the field of colorectal cancer surgery. However, whether ICG fluorescence is related to the presence of cancer cells in the lymph nodes is unclear. We explored the utilization of ICG fluorescence in colorectal cancer surgery. MATERIALS AND METHODS: ICG was injected into the submucosa around the tumor before radical resection in colorectal cancer patients. Intraoperatively, near-infrared (NIR) fluorescence was used for lymphatic flow visualization. After specimen removal, harvested lymph nodes were classified as positive or negative based on the detection of fluorescence, followed by pathological examination. ICG distribution on a section of each lymph node was examined by fluorescence microscopy. RESULTS: Overall, 155 patients underwent real-time NIR fluorescence imaging-guided surgery. Altogether, 1,017 lymph nodes were retrieved from these patients. Metastatic lymph nodes were present in 36 (5.8%) of 622 fluorescence-negative lymph nodes, which was significantly higher than 11 (2.8%) of 395 fluorescence-positive lymph nodes (odds ratio: 2.15, P = 0.03). Fluorescence microscopy of metastatic lymph nodes showed that ICG fluorescence was present in the normal structural region but not in the cancerous region of the lymph nodes. Furthermore, ICG fluorescence was observed in all metastatic lymph nodes, except those with cancer cells occupying >90% of the total area. CONCLUSIONS: ICG fluorescence detected only the normal parts of the lymph node draining from the peritumoral area and not the cancer tissues. This finding is important for developing appropriate strategies for navigation surgery using NIR fluorescence.

Timing of indocyanine green injection prior to laparoscopic colorectal surgery for tumor localization: a prospective case series.

BACKGROUND: Accurate identification of tumor sites during laparoscopic colorectal surgery helps to optimize oncological clearance. We aimed to assess the timing of the local injection preoperatively and clarify the usefulness and limitation of tumor site marking using indocyanine green (ICG) fluorescence imaging. METHODS: Consecutive patients who underwent primary colorectal cancer surgery from September 2017 to January 2019 were included. Preoperatively, lower endoscopy was used to inject the ICG solution into the submucosal layer near the tumor. During laparoscopic surgery, ICG fluorescence marking as the tumor site marking was detected using a laparoscopic near-infrared camera system. The detection rate and factors associated with successful intraoperative ICG fluorescence visualization including the interval between local injection and surgery were evaluated. RESULTS: One hundred sixty-five patients were enrolled. Using the laparoscopic near-infrared system, the intraoperative detection rates of ICG marking were 100% for ICG injection within 6 days preoperatively, 60% for injection between 7 and 9 days preoperatively, and 0% for injection earlier than 10 days preoperatively. There were no complications associated with ICG marking. Additionally, this method did not disturb the progress of the surgical procedure because injected ICG in the submucosal layer did not cause any tissue inflammation, and if ICG spilled into the serosa, it was invisible by white light. CONCLUSION: Advantages of ICG fluorescence tumor site marking were high visibility of infrared imaging during laparoscopic colorectal surgery and minimal adverse events of surgery. One of the most important findings regarding practical use was a rapid decrease in fluorescence marking visibility if one week passed from the time of ICG local injection.

Distribution of Regulatory T-Cells and Other Phenotypes of T-Cells in Tumors and Regional Lymph Nodes of Colorectal Cancer Patients.

BACKGROUND/AIM: Tumor microenvironments consist of many types of immune cells, in which regulatory T-cells (Tregs) are supposed to play important roles to suppress anti-tumor immunity. Regional lymph nodes are essential for antitumor immunity in colorectal cancer (CRC). In this study, we compared the diversity of phenotypes of T-cells in normal tissue and regional lymph nodes in order to determine the immunosuppressive mechanism of lymph node metastasis of CRC. PATIENTS AND METHODS: Fifty patients were enrolled in this study, and paired samples (tumor tissue, normal tissue, and three regional lymph node samples and as well as non-regional lymph node samples) were obtained from each patient. In each paired-sample set, the proportions of different immune cell types and T-cells expressing immune checkpoint molecules were compared using flow cytometry. RESULTS: Higher proportions of Tregs [7.58% (4.94%-13.87%) vs. 1.79% (0.03%-5.36%), p<0.001] and lower proportions of INFγ-producing CD4-positive T (iCD4+) cells [21.49% (12.08%-27.35%) vs. 26.55% (15.65%-37.63%), p<0.001] were observed in tumor tissue than in normal mucosa. Parts of regional lymph nodes nearest the tumor had a greater proportion of Tregs [5.86% (4.18%-7.69%)] and lower proportions of iCD4+ [5.94% (3.51%-9.04%)] and INFγ-producing CD8-positive T (iCD8+) cells [21.93% (14.92%-35.90%)] than distant parts of regional lymph nodes and non-regional lymph nodes. Both immune-suppressing molecules (CTLA-4 and PD-1) and immune-promoting molecules (OX-40 and ICOS) tended to be highly expressed in tumor tissue and local lymph nodes. CONCLUSION: In patients with CRC, regional lymph nodes, especially the parts nearest the tumor, had a higher proportion of Tregs and other suppressive immunophenotypes of T-cells than those located more distantly.

Efficacy of indocyanine green fluorescence angiography in preventing anastomotic leakage after laparoscopic colorectal cancer surgery.

PURPOSE: Some recent studies have suggested that fluorescence angiography with indocyanine green (ICG) might be useful for preventing anastomotic leakage (AL) after laparoscopic colorectal surgery. However, its efficacy has not been proven. We evaluated whether intraoperative ICG fluorescence angiography could decrease the AL rate with laparoscopic colorectal cancer surgery. METHODS: This retrospective study included patients with colorectal cancer who underwent laparoscopic surgery at our institution between March 2014 and December 2018. Patients were divided into two groups: with or without ICG fluorescence angiography. The primary outcome was the rate of AL. RESULTS: A total of 488 patients were included: 223 patients in the ICG group and 265 patients in the no-ICG group. In the ICG group, the transection line was changed to a more proximal location in seven patients (3.1%), including one patient with transverse colon surgery and six with rectal surgery. None of these seven patients developed AL. There were 18 ALs (3.7%) overall. The AL rate was 1.8% in the ICG group and 5.3% in the no-ICG group. For colon cancer, there were no significant differences in the AL rate between the groups (p = 0.278). In rectal cancer, the AL rate was significantly lower in the ICG group than in the no-ICG group (3.5% vs. 10.5%, p = 0.041). After propensity score matching, the AL rate was also significantly lower in the ICG group for rectal cancer (p = 0.044). CONCLUSION: ICG fluorescence angiography can potentially reduce the AL rate with laparoscopic rectal cancer surgery.

Validation of the Japanese Version of the Low Anterior Resection Syndrome Score.

BACKGROUND: The low anterior resection syndrome (LARS) score is a patient-reported outcome measure to evaluate the severity of bowel dysfunction after rectal cancer surgery by scoring the major symptoms of LARS. The aim of this study was to translate the English version of the LARS score into Japanese and to investigate the validity and reliability of the LARS score. METHODS: The LARS score was translated in Japanese following current international recommendations. A total of 149 rectal cancer patients completed the LARS score questionnaire and were also asked a single question assessing the impact of bowel function on quality of life (QoL). A total of 136 patients answered the LARS score questionnaire twice. RESULTS: The Japanese LARS score showed high convergent validity, based on its good correlation between the LARS score and QoL (p < 0.001). The LARS score was able to discriminate between patients according to the tumor distance to anal verge (p < 0.001), type of surgery (p < 0.001), and time since surgery (p = 0.001). Patients after ultra-low anterior resection and intersphincteric resection showed especially high scores. The score also had high test-retest reliability (intraclass correlation coefficient: 0.87). CONCLUSION: The Japanese LARS score is a valid and reliable tool for measuring LARS. The LARS score is appropriate for assessments in postoperative bowel function and international comparison. Using this score, patient-reported outcome measures of LARS in Japanese patients can be shared internationally. Additional validation reports from non-English speaking countries can support the LARS score as a worldwide assessment tool for postoperative bowel dysfunction.

ST6GALNAC1 plays important roles in enhancing cancer stem phenotypes of colorectal cancer via the Akt pathway.

Colorectal cancer (CRC) is a mortal disease due to treatment resistance, recurrence and distant metastasis. Emerging evidence has revealed that a small sub-population of cancer cells termed cancer stem cells (CSCs)/ cancer-initiating cells (CICs) is endowed with high levels of tumor-initiating ability, self-renewal ability and differentiation ability and is responsible for treatment resistance, recurrence and distant metastasis. Eradication of CSCs/CICs is essential to improve current treatments. However, the molecular mechanisms by which CSCs/CICs are maintained are still elusive. In this study, we aimed to determine the molecular mechanisms by which colorectal (CR)-CSCs/CICs in are maintained human primary CRC cells. CR-CSCs/CICs were isolated by sphere-culture and the ALDEFLUOR assay, and transcriptome analysis revealed that the gene ST6 N-Acetylgalactosaminide Alpha-2,6-Sialyltransferase 1 (ST6GALNAC1) was expressed at high levels in CR-CSCs/CICs. Overexpression of ST6GALNAC1 enhanced the expression of sialyl-Tn (STn) antigen, which is carried by the CSC marker CD44, and increased the sphere-forming ability and resistance to a chemotherapeutic reagent. The opposite phenomena were observed by gene knockdown using siRNA. Furthermore, the Akt pathway was activated in ST6GANAC1-overexpressed cells, and activation of the pathway was cancelled by gene knockdown of galectin-3. The results indicate that ST6GALNAC1 has a role in the maintenance of CR-CSCs/CICs by activating the Akt pathway in cooperation with galectin-3 and that ST6GalNAC1 (or STn antigen) might be a reasonable molecule for CSC/CIC-targeting therapy.

[Safety and Feasibility of Pancreatic Surgery for Pancreatic Cancer in Elderly Patients].

PURPOSE: This study aimed to evaluate the safety and feasibility of pancreatic surgery for pancreatic cancer in elderly patients. PATIENTS AND METHODS: In total, 9 patients underwent pancreatic surgery for pancreatic cancer between April 2005 and March 2014. The surgical complications were evaluated by Clavien-Dindo classification. RESULTS: The median operating time was 420(range: 354-503)min and the median blood loss was 640(range: 350-1,170)mL. Grade 2 or higher complications were observed in 3 patients. Pancreatic fistula(Grade 3b)was observed in 1 patient, delirium was observed(Grade 2)in 1 patient, and portal vein thrombosis(Grade 2)was observed in 1 patient. No surgical mortality was observed. DISCUSSION: Our results suggest that pancreatic surgery is a safe and feasible treatment for pancreatic cancer in elderly patients.

[Case of Colon Metastasis from Early Gastric Cancer 4 Years after Laparoscopic Assisted Distal Gastrectomy].

A 69-year-old woman who underwent laparoscopic assisted distal gastrectomy for early gastric cancer(pathological T1bN1M0)in June 2011was admitted to the hospital because of abdominal pain in May 2015.A n abdominal CT scan showed ileus caused by a transverse colon tumor and ascending colon perforation.We performed emergency right hemicolectomy and diverting ileostomy.The postoperative pathological findings revealed poorly differentiated adenocarcinoma and signetring cell carcinoma similar to the gastric cancer resected 4 years ago.Immunohistochemical findings showed that the colon tumor was positive for CK7, but negative for CK20 and expressed a gastric mucin phenotype.From these findings, the colon tumor was diagnosed as a metastasis from early gastric cancer.Colon metastasis from early gastric cancer is rare and the diagnosis is difficult in some cases.We herein report this case and discuss the clinical and pathologic features of colon metastasis from gastric cancer.