Enhancement of radiation therapy by indoleamine 2,3 dioxygenase 1 inhibition through multimodal mechanisms.

BACKGROUND: Indoleamine 2,3-dioxygenase 1 (IDO1) is an enzyme that converts tryptophan to kynurenine. IDO1 expression is found not only in tumor cells but also in immune cells and is associated with tumor proliferation and immune responses. IDO1 inhibitors and radiation may cooperatively suppress tumor proliferation through the alterations in the Wnt/ß-catenin pathway, cell cycle, and immune response. We investigated the antitumor effects of combination therapy of an IDO1 inhibitor, 1-methyl tryptophan (1-MT), and radiation on colorectal cancer. METHODS: In vitro experiments were conducted using human and murine colon cancer cell lines (HCT116, HT-29, and Colon26). Cell growth inhibition was assessed using a MTS assay and Clonogenic assay. Cells were cultured for 48 h with or without 500 µM 1-MT after exposure to radiation (4 Gy). Cell cycle effects and modulation of Wnt/ß-catenin pathway were evaluated using western blot analysis, flow cytometry, RT-PCR. Subcutaneous Colon26 tumors in BALB/c mice were treated by oral 1-MT (6 mg/mL) for 2 weeks and/or local radiation (10 Gy/10 fr). Bromodeoxyuridine (BrdU) incorporation in tumor cells and expression of differentiation markers of immune cells were evaluated using immunohistochemistry. RESULTS: 1-MT and a small interfering RNA against IDO1 suppressed proliferation of all cell lines, which was rescued by kynurenine. Clonogenic assay showed that administration of 1-MT improved radiosensitivity by suppressing the Wnt/ß-catenin pathway activated by radiation and enhancing cell cycle arrest induced by radiation. Combination therapy showed a further reduction in tumor burden compared with monotherapies or untreated control, inducing the highest numbers of intratumoral CD3 + and CD8 + T cells and the lowest numbers of Foxp3 + and BrdU-positive tumor cells. CONCLUSIONS: The combination of 1-MT and radiation suppressed colon cancer cells in vitro and in vivo via multiple mechanisms.

Prognoses in Pathologically Confirmed T1 Lower Rectal Cancer Patients with or without Preoperative Therapy: An Analysis Using the Surveillance, Epidemiology, and End Results Database.

INTRODUCTION: Preoperative chemoradiotherapy (CRT) is the standard therapy for downstaging in locally advanced lower rectal cancer. However, it remains unclear whether rectal cancers downstaged by preoperative therapy show similar prognoses to those of the same stage without preoperative therapy. We previously demonstrated that preoperative CRT did not affect prognosis of rectal cancer with pathological T1N0 (pT1N0) stage in a single institute. Here, using a larger dataset, we compared prognoses of (y)pT1 rectal cancer stratified by the use of preoperative therapy and analyzed prognostic factors. METHODS: Cases of pT1N0 rectal cancer, registered between 2004 and 2016, were extracted from the Surveillance, Epidemiology, and End Results database. Patients were categorized as the "ypT1 group" if they had undergone preoperative therapy before surgery or as the "pT1 group" if they had undergone surgery alone. Overall survival (OS) and cancer-specific survival (CSS) between these groups of patients were compared. Factors associated with CSS and OS were identified by univariate and multivariate analyses. RESULTS: Among 3,757 eligible patients, ypT1 and pT1 groups comprised 720 and 3,037 patients, respectively. While ypT1 patients showed poorer CSS than ypT1 patients, there was no significant difference in OS. Preoperative therapy was not an independent prognostic factor for CSS or OS. Multivariate analysis identified age and histological type as significant factors associated with CSS. Sex, age, race, and number of lymph nodes dissected were identified as significant factors associated with OS. CONCLUSIONS: Prognosis among patients with (y)p T1N0 rectal cancer was similar irrespective of whether they underwent preoperative therapy, which is consistent with our previous observations.

Negative impact of sarcopenia on survival in elderly patients with colorectal cancer receiving surgery: A propensity­score matched analysis.

Sarcopenia is a prognostic factor for patients with colorectal cancer and is commonly seen in elderly patients. The purpose of the present study was to demonstrate the impact of preoperative sarcopenia on the short- and long-term outcomes of curative surgery for treating colorectal cancer in elderly patients. Between 2016 and 2020, patients aged ≥80 years with colorectal cancer were investigated. The total muscle cross-sectional area was calculated using computed tomography imaging at the mid-3rd lumbar vertebra. Elder sarcopenia was identified using sex-specific cut-offs. Out of 106 elderly colorectal cancer patients, 27 patients were diagnosed with elder sarcopenia. Patients with elder sarcopenia had a reduced body mass index (19.7±2.5 vs. 22.5±2.9 kg/m2; P<0.01), an advanced pN stage (P<0.01) and an advanced stage (stage 3) (P=0.029). Elder sarcopenia had a negative impact on relapse-free survival (3-year, 78.4 vs. 91.1%; P=0.049) and overall survival (3-year, 73.0 vs. 93.9%; P=0.022). Propensity score-matched analysis was performed, matching 27 patients in each group to remove selection bias, which demonstrated elder sarcopenia had a negative impact on overall survival (3-year, 73.0 vs. 100%; P<0.01). Overall, elder sarcopenia was prevalent in 25% of elderly patients with colorectal cancer that received curative surgery, and it was a poor prognostic indicator in this patient population.

Risk of extracolonic malignancies and metachronous rectal cancer after colectomy and ileorectal anastomosis in familial adenomatous polyposis.

BACKGROUND: Analysis of long-term clinical outcomes of patients with familial adenomatous polyposis is critical in reducing or preventing the incidence of extracolonic malignancies after initial surgery. The aim of the present study was to clarify the long-term outcomes, and establish a surveillance strategy for surgically treated familial adenomatous polyposis patients. METHODS: Between January 1967 and March 2020, retrospective data were collected from 37 patients with familial adenomatous polyposis treated or monitored in our department. Occurrence of metachronous cancers, including rectal cancers and extracolonic malignancies, and other diseases was analyzed. RESULTS: The median follow-up duration after the first surgery was 13.8 years. Initially, 16 patients underwent total proctocolectomy with ileal pouch-anal anastomosis, 18 underwent total colectomy with ileorectal anastomosis, and three underwent other procedures. A secondary proctectomy was performed for 9 of the 18 patients who underwent ileorectal anastomosis. Rectal cancer was diagnosed in 6 patients who underwent ileorectal anastomosis. In addition, 5 gastric cancer, 2 duodenal cancer, 1 gallbladder cancer, and 1 thyroid cancer cases were diagnosed. The age at which the extracolonic malignancies were diagnosed was >50 years. 4 patients died due to metachronous rectal cancer, gastric cancer, or gallbladder cancer. CONCLUSION: Careful consideration should be paid before choosing ileorectal anastomosis as the treatment procedure for familial adenomatous polyposis patients because completion proctectomy was eventually necessary for half of the patients. Long-term surveillance, with more frequent gastric surveillance for patients over 50 years, is important for the prevention and treatment of extracolonic malignancies in familial adenomatous polyposis patients.

Establishing a novel method for assessing elasticity of internal anal sphincter using ultrasonic real-time tissue elastography.

BACKGROUND: Evaluating anorectal function using real-time tissue elastography (RTE) has not been reported. A previous study reported that in the internal anal sphincter (IAS) of surgical specimens of patients with rectal cancer who underwent abdominoperineal resection, there was an increased fibrosis trend in those who underwent pre-operative chemoradiotherapy (CRT) compared with non-CRT. We speculated that CRT might have induced sclerosis of the IAS because of fibrosis. Therefore, we aimed to establish a method of quantitating the degree of IAS hardness using RTE on endoanal ultrasonography. METHODS: RTE was performed with freehand manual compression under a defined pressure at the middle anal canal. Using the most compressive point in the strain graph, we traced the region of interest in the IAS. The strain histogram showed a frequency distribution of colours according to the degree of strain (numeric scan ranging from 0 to 255; smaller number indicated harder tissue). We defined the mean of the strain histogram as 'elasticity'. Ten patients with locally advanced rectal cancer who underwent pre-operative CRT were prospectively enrolled. We statistically evaluated the correlation between IAS elasticity and maximum resting pressure (MRP) values both at pre- and post-CRT. MRP was examined concurrently with the examination of IAS elasticity. RESULTS: Representativity of elasticity measurements was demonstrated. It revealed a trend: IAS elasticity had a moderate inverse correlation with MRP (r = 0.41, P = 0.07), regardless of whether measurements were made before or after CRT. CONCLUSION: We established a completely novel method for the assessment of elasticity of the IAS, using RTE on endoanal ultrasonography.

Oncological Outcomes of Pathological T1 Lower Rectal Cancer Patients With or Without Preoperative Chemoradiotherapy.

BACKGROUND/AIM: It remains unclear whether rectal cancers down-staged by preoperative chemoradiotherapy (CRT) have similar prognoses to those of the same stage without preoperative CRT. We compared prognoses of pT1 rectal cancer patients stratified by preoperative CRT. PATIENTS AND METHODS: We retrieved data of patients with pathological T1 rectal cancer between 2003 and 2020. Patients were divided into the "ypT1 group" who received preoperative CRT following surgery and the "pT1 group" who underwent surgery alone. Factors associated with relapse-free survival (RFS) were investigated. RESULTS: Among 86 patients, ypT1 and pT1 groups comprised 18 and 68 patients, respectively. There was no significant difference in RFS between the groups (p=0.19). Tumor location within 5 cm from the anal verge was associated with recurrence (hazard ratio: 0.13, p=0.034). CONCLUSION: The prognosis of patients with ypT1 rectal cancer was similar to that of patients with pT1. Low tumor location was a poor prognostic factor.

A cross sectional study to investigate internal hernia post left-sided colectomy preserving superior rectal artery.

BACKGROUND: and Purpose: Intestinal obstruction caused by an internal hernia projecting through a mesenteric defect is a rare sequela of laparoscopic colectomy, as surgeons usually leave such defects open. In this study, we investigated cases of internal hernia after laparoscopic left-sided colectomy. METHODS: Data of 308 patients who underwent laparoscopic left hemicolectomy or sigmoidectomy at our institute between 2013 and 2018 were retrospectively reviewed. Patient characteristics and surgical variables were analyzed. The distance between the superior rectal artery (SRA) and abdominal aorta at the level of aortic bifurcation was measured using postoperative computed tomography in patients who underwent SRA-preserving colectomy. RESULTS: In all, 3 patients (0.97%), all of whom had undergone colostomy without anastomosis and with SRA preservation, developed internal hernia passing between the SRA and the aorta. The distance between the SRA and abdominal aorta in patients who underwent ostomy was significantly more than that in patients who underwent non-ostomy (10.6 mm vs. 4.7 mm, respectively, p < 0.001). CONCLUSIONS: SRA preservation and stoma construction are potential risk factors for internal hernia after laparoscopic left-sided colectomy. Lifting of the SRA due to stoma construction possibly enlarges the space between the SRA and aorta. When colostomy is created, it is important to evaluate the space behind the SRA.

Primary gastrointestinal stromal tumor of the liver: a case report and review of the literature.

BACKGROUND: Recently, gastrointestinal stromal tumors that have developed outside of the digestive tract have been reported. These tumors are collectively termed extra-gastrointestinal stromal tumors. Extra-gastrointestinal stromal tumors can also develop in the liver. Only eight case reports involving primary GIST of the liver have been published. We report a case and review the literature regarding this disease. CASE PRESENTATION: A 70-year-old woman with a past history of gastric cancer visited our hospital for regular inspection. With extensive radiological imaging, a computed tomography scan revealed a mass with a size of 6.8 cm in the lateral segment of the liver. (18)F-Fluoro-2-deoxyglucose positron emission tomography revealed no other malignancies except for the liver tumor. Because the lesion was suspected of being a primary malignant hepatic tumor, lateral segmentectomy was performed. The immunohistochemical analysis supported the diagnosis of gastrointestinal stromal tumors in the liver. The patient has had no evidence of recurrence during the 10-month follow-up period; imatinib chemotherapy was not administered. CONCLUSIONS: Primary hepatic gastrointestinal stromal tumors had no characteristics that distinguished them from ordinary tumors in imaging examinations. Primary gastrointestinal stromal tumors might have developed from interstitial Cajal-like cells.

Giant insulinoma: report of a case and review of published reports.

BACKGROUND: Larger insulinomas are reportedly more likely to be malignant; however, their biological behavior has not been clearly elucidated. We here report the characteristics and treatment of a giant insulinoma with local invasion and lymph node metastasis. We also review published reports concerning the clinical features of giant insulinomas and comparing their grading with that of pancreatic neuroendocrine tumors. CASE PRESENTATION: A 71-year-old man was referred to our hospital for investigation of persistent hypoglycemia. On the current presentation, laboratory tests showed serum glucose, immunoreactive insulin, and C peptide concentrations of 45 mg/dL, 17.2 µIU/mL and 4.1 ng/mL, respectively. Dynamic magnetic resonance imaging showed a hypervascular tumor measuring 13.5 cm in the head of the pancreas. Computed tomography scanning demonstrated local invasion and lymph node involvement. He thus had Whipple's triad, which is associated with malignant insulinoma. No distant metastases having been identified, pancreaticoduodenectomy was performed. Intraoperatively, three separate tumors were identified in the pancreatic head. Pathological examination showed all three tumors were pancreatic neuroendocrine tumors; the tumor cells in the largest mass were strongly immunoreactive for insulin. The Ki-67 index was 2-5% in most parts of the largest tumor and over 20% in the poorly differentiated areas. This tumor was classified as neuroendocrine carcinoma in accordance with the 2010 World Health Organization classification of pancreatic endocrine neoplasms. He remains free of evidence of recurrence 2 years postsurgery. A review of published reports indicated that giant insulinomas are more malignant than smaller ones, and metastatic disease is found on presentation in 56% of patients with giant insulinomas; however, we were unable to identify any correlation between grade of pancreatic neuroendocrine tumor and biological behavior of giant insulinomas. CONCLUSIONS: Giant insulinomas more frequently exhibit malignant behavior, such as local invasion, lymph node involvement, and liver metastasis, than smaller ones. However, there was no relationship between grade and rate of metastases or survival in this small case series. Identification of useful biological markers is necessary.

Protocadherin-9 involvement in retinal development in Xenopus laevis.

Biological roles of most protocadherins (Pcdhs) are a largely unsolved problem. Therefore, we cloned cDNA for Xenopus laevis protocadherin-9 and characterized its properties to elucidate the role. The deduced amino acid sequence was highly homologous to those of mammalian protocadherin-9 s. X. laevis protocadherin-9 expressed from the cDNA in L cells showed basic properties similar to those of mammalian Pcdhs. Expression of X. laevis protocadherin-9 was first detected in stage-31 embryos and increased as the development proceeded. In the later stage embryos and the adults, the retina strongly expressed protocadherin-9, which was mainly localized at the plexiform layers. Injection of morpholino anti-sense oligonucleotide against protocadherin-9 into the fertilized eggs inhibited eye development; and eye growth and formation of the retinal laminar structure were hindered. Moreover, affected retina showed abnormal extension of neurites into the ganglion cell layer. Co-injection of protocadherin-9 mRNA with the morpholino anti-sense oligonucleotide rescued the embryos from the defects. These results suggest that X. laevis protocadherin-9 was involved in the development of retina structure possibly through survival of neurons, formation of the lamina structure and neurite localization.