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Tumour-Node-Metastasis (TNM) staging of colorectal cancer (CRC) needs further classification for better treatment because of disease heterogeneity. Although molecular classifications which are expensive and laborious are under study, cost and labour efficient subtyping is desirable. We assessed the combinations of preoperative tumour marker (TM) elevation and tumour lymphovascular invasion (LVI) as a solution. We used the pooled data of 7151 colon cancer (CC) patients and 4620 rectal cancer (RC) patients who received curative surgery between 2004 and 2008 in Japan. The best-matched subtyping for predicting relapse-free survival (RFS) was statistically selected using the c-index and Akaike’s information criterion. This subtyping (TM-LVI), which consisted of three categories by TM elevation status and severity of LVI status, was an independent prognostic factor for RFS of CC (stage IIa, IIIb, and IIIc) and RC (stage I, IIa, IIb, IIIa, and IIIb) and also for disease specific survival of CC (stage IIa, IIb, IIIb, and IIIc) and RC (all stage except for IIc). Although TM-LVI classified CRC patients into low and high recurrence risk groups, the application of adjuvant therapy was not accordance with the TM-LVI status. TM-LVI may be a cost and labour efficient subtyping of colorectal cancer for better treatment strategy.

Background/aim The difficulty of early diagnosis of colitis associated colorectal cancer (CACRC) due to colonic mucosal changes in long-standing ulcerative colitis (UC) patients is often experienced in daily clinical practice. Noninvasive objective monitoring for cancer development is advantageous for optimizing treatment strategies in UC patients. We aimed to examine the epigenetic alterations occurring in CACRC, focusing on DNA hypermethylation of CpG islands. Materials and methods The level of DNA methylation in CpG cites was compared between CACRC and the counterpart non-tumorous mucosa using Infinium HumanMethylation 450K BeadChip. Results Our subjects included 3 males and 3 females (median age, 49.5 years). The 450K CpG site DNA methylation microarray revealed that the difference in β value (level of hypermethylation) was the highest for corcicotropin releasing hormone receptor 2 (CRHR2) between CACRC and counterpart non-tumorous mucosa. Conclusion Detection of hypermethylation of CRHR2 may be promising for cancer screening in UC patients.

Introduction It has been considered difficult to achieve en bloc resection in cases of locally advanced rectal cancer with lateral pelvic sidewall invasion. The present study demonstrates a novel surgical procedure for these tumors. Technique There are 3 avascular planes of the retroperitoneum in the pelvic sidewall. Two visceral pelvic fasciae, namely the ureterohypogastric fascia and umbilical prevesical fascia, and the parietal pelvic fascia can be identified. In addition, the key structures of these fasciae, the ureter, umbilical artery, and external iliac vessels, can be identified transperitoneally before any dissection. Thus, these 3 avascular planes can be dissected without resorting to dissection of the retrorectal space. The key steps to this technique are: 1) after dissection from the side opposite to the site of tumor invasion to the dorsal side of the rectum, the avascular planes of the retroperitoneum among the 3 above-mentioned fasciae are dissected; and 2) the retrorectal space and pelvic sidewall space are connected by sharp dissection. Results Recognizing the 3 above-mentioned fasciae enables the dissection of the avascular planes of the pelvic sidewall, which helps to achieve en bloc dissection in cases of locally advanced rectal cancer with lateral pelvic sidewall invasion. Conclusion The pelvic sidewall could be divided into 3 areas based on the visceral pelvic fasciae, which has helped to achieve en bloc dissection in cases of locally advanced rectal cancer with lateral pelvic sidewall invasion.

Circulating microRNAs (miRNAs) are considered promising biomarkers for diagnosis, prognosis, and treatment efficacy of diseases. However, usefulness of circulating miRNAs as biomarkers for hereditary gastrointestinal diseases have not been confirmed yet. We explored circulating miRNAs specific for patients with familial adenomatous polyposis (FAP) as a representative hereditary gastrointestinal disease. Next-generation sequencing (NGS) indicated that plasma miR-143-3p, miR-183-5p, and miR-885-5p were candidate biomarkers for five FAP patients compared to three healthy donors due to moderate copy number and significant difference. MiR-16-5p was considered as an internal control due to minimum difference in expression across FAP patients and healthy donors. Validation studies by real-time PCR showed that mean ratios of maximum expression and minimum expression were 2.2 for miR-143-3p/miR-16-5p, 3.4 for miR-143-3p/miR-103a-3p, 5.1 for miR-183-5p/miR-16-5p, and 4.9 for miR-885-5p/miR-16-5p by using the samples collected at different time points of eight FAP patients. MiR-143-3p/16-5p was further assessed using specimens from 16 FAP patients and 7 healthy donors. MiR-143-3p was upregulated in FAP patients compared to healthy donors (P = 0.04), but not significantly influenced by clinicopathological features. However, miR-143-3p expression in colonic tumors was rare for upregulation, although there was a significant difference by existence of desmoid tumors. MiR-143-3p transfection significantly inhibited colorectal cancer cell proliferation compared to control microRNA transfection. Our data suggested regulation of miR-143-3p expression differed by samples (plasma or colonic tumors) in most FAP patients. Upregulation of plasma miR-143-3p expression may be helpful for diagnosis of FAP, although suppressive effect on tumorigenesis seemed insufficient in FAP patients.

FR901464 (FR) was first described as an anticancer drug and later identified as a modulator of splicing factor 3B subunit 1 (SF3B1). Although the effectiveness of splicing modulators has been investigated in colorectal cancer (CRC) cells, their usefulness in animal experiments has not been confirmed. The association of SF3B1 with CRC progression and the influence of FR on transcriptional activity in CRC has not been fully elucidated. FR showed strong cytotoxicity against CRC cell lines, SF3B1-mutated cancer cell lines, and human fibroblasts with IC50 values less than 1 ng/ml. FR-resistant clones derived from HCT116, DLD1, Lovo, and CT26 cells showed IC50 values greater than 100 ng/ml. SF3B1 sequencing demonstrated low frequencies of SF3B1 mutations in CRC and mutations in codon 1074 of exon 22 in all FR-resistant clones. Unlike hematological malignancies, SF3B1 expression was not associated with CRC progression. Although FR showed significant growth inhibition in a xenograft model of RKO cells, severe toxicity was also induced. These data indicated CRC might be a suitable target of FR unless toxicity occurs. Microarray analysis and real-time quantitative PCR demonstrated downregulation of genes associated with Fanconi anemia (BRCA1 and BRCA2) and 28 driver oncogenes. These data suggested combination treatment of FR with other anticancer drugs whose sensitivity is associated with genes affected by FR treatment. Combination treatment with PARP1 inhibitor olaparib, whose sensitivity was enhanced by BRCA 1/2 deficiency, showed synergistic effects in CRC cells. Our data indicates the potential of FR in combination therapy rather than monotherapy for CRC treatment.

// Tomoki Yamano 1 , Shinichi Yamauchi 2 , Kiyoshi Tsukamoto 1 , Masafumi Noda 1 , Masayoshi Kobayashi 1 , Michiko Hamanaka 1 , Akihito Babaya 1 , Kei Kimura 1 , Chihyon Son 1 , Ayako Imada 1 , Shino Tanaka 1 , Masataka Ikeda 1 , Naohiro Tomita 1 , Kenichi Sugihara 2 and Japanese Study Group for Postoperative Follow-up of Colorectal Cancer 1 Division of Lower GI Surgery, Department of Surgery, Hyogo College of Medicine, Hyogo, Japan 2 Division of Colorectal Surgery, Department of Surgery, Tokyo Medical and Dental University, Tokyo, Japan Correspondence to: Tomoki Yamano, email: yamanot@hyo-med.ac.jp Keywords: colorectal cancer; curative surgery; follow-up; recurrence; survival Received: March 02, 2018 Accepted: April 12, 2018 Published: May 22, 2018 ABSTRACT Background: The follow-up schedule for colorectal cancer patients after curative surgery is inconsistent among the guidelines. Evaluation of time to recurrence (TTR) and survival after recurrence (SAR) may provide evidence for appropriate follow-up. Methods: We assessed 3039 colon cancer (CC) and 1953 rectal cancer (RC) patients who underwent curative surgery between 2007 and 2008. We evaluated the pre- and post-recurrent clinicopathological factors associated with TTR and SAR in each stage of CC and RC. Results: The recurrence rates of stages I, II, and III were 1.2%, 13.1%, and 26.3%, respectively, for CC, and 8.4%, 20.0%, and 30.4%, respectively, for RC. In CC patients, high carcinoembryonic antigen (CEA) level and lymphovascular invasion were independent predictors of short TTR. In RC patients, metastatic factors (liver metastasis in stage III) and venous invasion (stage III) were independent predictors of short TTR. The prognostic factors of SAR were age (stage II CC and stage III RC), female gender (stage III RC), high CEA level (stage II RC), histological type (stage III CRC), nodal status (stage III CC), recurrence within 1 year (stage III RC), M1b recurrence (stage II CRC), local recurrence (stage II CC), and no surgical resection after recurrence (stage II and III CRC). Conclusions: The follow-up schedule for stage I should be different from that for the other stages. We recommend that intensive follow-up is appropriate in stage III CC patients with undifferentiated adenocarcinoma or N2 nodal status, stage II RC patients with high preoperative CEA level, and stage III RC patients.

Inflammatory bowel disease (IBD) increases the risk of colorectal cancer, known as colitis-associated cancer (CAC). It is still unclear what driver mutations are caused by chronic inflammation and lead to CAC development. To get insight into this issue, we investigated somatic alterations in CAC. We performed exome sequencing of 22 fresh CACs and targeted sequencing of 43 genes on 90 archive specimens from Japanese CAC patients, of which 58 were ulcerative colitis (UC) and 32 were Crohn’s disease (CD). Consistently with the previous reports, TP53 was commonly mutated (66%) whereas APC, KRAS and SMAD4 were mutated less frequently (16%, 11% and 11%, respectively). Mucinous CD-CACs in the anus, an Asian-specific subtype of CD-CAC, had less somatic mutations in our target genes. We also found that RNF43, a negative regulator of the Wnt signaling, was somatically mutated in a significant fraction of CACs (10 of 90; 11%). Two lines of evidence indicated that somatic mutations of RNF43 were related to chronic inflammation. First, somatic mutations of RNF43 were significantly associated with longer duration of IBD. Second, clinico-pathological features suggested many of the APC-mutated CACs were actually sporadic colorectal cancer whereas RNF43-mutated CACs did not have this tendency. RNA-Seq analysis showed that RNF43-mutated CACs had elevated expression of c-Myc and its target genes, suggesting that RNF43 is a bona fide driver of CAC development. This study provides evidence that somatic mutation of RNF43 is the driver genetic alteration that links chronic inflammation and cancer development in about 10% of CACs.

Lynch syndrome (LS) and familial adenomatous polyposis (FAP) are major sources of hereditary colorectal cancer (CRC) and are associated with other malignancies. There is some heterogeneity in management strategies in Japan. We undertook a survey of management of hereditary CRC in hospitals that are members of the Japan Society of Colorectal Cancer Research. One hundred and ninety departments responded, of which 127 were from designated cancer care hospitals (DCCHs) according to the Japanese government. There were 25 488 operations for CRC in these departments in 2015. The DCCHs performed better with regard to usage of Japan Society of Colorectal Cancer Research guidelines, referring new CRC patients for LS screening, and having in-house genetic counselors and knowledge of treatment for LS. There were 174 patients diagnosed with LS and 602 undergoing follow-up in 2011-2015, which is fewer than the number expected from CRC operations in 2015. These numbers were not affected by whether the institution was a DCCH. Universal screening for LS was carried out in 8% of the departments. In contrast, 541 patients were diagnosed with FAP and 273 received preventive proctocolectomy/colectomy in 2011-2015. The DCCH departments undertook more surgery than non-DCCH departments, although most of the management, including surgical procedures and use of non-steroidal anti-inflammatory drugs, was similar. Management of desmoid tumor in the abdominal cavity differed according to the number of patients treated. In conclusion, there was heterogeneity in management of LS but not FAP. Most patients with LS may be overlooked and universal screening for LS is not common in Japan.

Data on long-term outcomes of familial adenomatous polyposis (FAP) are unclear in Japan because a nationwide registry system is lacking. We assessed overall survival, incidence of neoplasms, fecal incontinence, and postoperative follow-up status of patients with FAP treated surgically in our hospital. In total, 154 patients with FAP who underwent radical surgery from 1981 to 2017 in our department were available for the questionnaire. Sixty-five patients, 36 of whom were followed at our hospital, were assessed using clinical records and the questionnaire. The median follow-up time was 187 months (interquartile range, 93.5–296 months). The median age at surgery was 36 years (range, 12–69 years). The 5-, 10-, 15-, and 20-year overall survival rate was 100%, 98%, 95%, and 89%, respectively. All five deaths were caused by diseases other than colorectal cancer. FAP-related neoplasms comprised 23 colorectal cancers, five duodenal cancers, three gastric cancers, five thyroid cancers, two ileal pouch cancers, and nine desmoid tumors. The incidence of desmoid tumors was significantly associated with the operation date. The duration from radical surgery to neoplasm onset significantly differed by neoplasm type. Forty-five of 54 patients (excluding those who died or underwent ileostomy) developed fecal incontinence (median Wexner score of 8). Surgical procedures involving hand-sewn sutures with rectal mucosal stripping were significantly associated with fecal incontinence and the Wexner score. Fifty-eight of the 60 surviving patients underwent follow-up examinations. Overall survival was favorable. Fecal incontinence depended on the surgical procedures. Most patients continued to receive follow-up examinations. No. 3112 by Institutional Review Board of Hyogo College of Medicine

The aim of this study was to investigate the influence of chemoradiotherapy (CRT) on nutritional status and the association between changes in nutritional status and clinical outcomes (treatment completion, adverse events, perioperative complications, and relapse-free survival [RFS]) in patients with locally advanced rectal cancer (LARC).In this multicenter, phase II study, 41 patients with LARC underwent CRT for 5 wk, followed by a 6- to 8-wk interval before surgery. Body weight, body mass index (BMI), lean body mass, serum albumin, and prealbumin levels were measured before (pre-), during, and after CRT, and before surgery. Changes in these data and scores on the Malnutrition Universal Screening Tool (MUST) were calculated based on pre-CRT status.Twelve patients (29.3%) experienced body weight loss (BWL) ≥5% (defined as malnutrition) after CRT (P0.001) and before surgery (P = 0.035). Significant changes were seen in serum albumin levels and BMI during and after CRT (P0.001), and in MUST scores after CRT (P = 0.003) and before surgery (P = 0.035). Treatment completion was significantly associated with BWL (P = 0.028), MUST score (P = 0.013), and decreased serum albumin level (P = 0.001) after CRT. Regarding adverse events, MUST score before surgery (P = 0.009) and serum albumin level after CRT (P = 0.002) were significantly associated with diarrhea severity. Serum albumin level during CRT was associated with the onset of neutropenia (P = 0.005). No association was found between BWL and RFS.These findings suggest that malnutrition and changes in nutritional status are not only commonly observed after CRT, but also associated with treatment completion and adverse events.

Purpose This study assessed the incidence of malnutrition caused by preoperative chemoradiotherapy (CRT) in rectal cancer patients, which is seemingly underestimated; however, malnutrition affects treatment tolerability, postoperative complications, including anastomotic leakage (AL), and oncological outcomes. Methods Between January 2008 and December 2014, 54 consecutive patients with T3–4, N0–2, M0–1 resectable rectal cancer received CRT comprising 45 Gy radiotherapy and S-1 alone or with irinotecan for 5 weeks and then underwent curative surgery with diverting or permanent stomas 6–8 weeks after CRT. We assessed malnutrition after completion of CRT (5–6 weeks after CRT start date) and at surgery (11–14 weeks after CRT start date), defining weight loss as ≥5 % of pre-CRT weight; this definition differs from commonly used criteria for adverse events. We evaluated the incidence of malnutrition associated with CRT and influence of malnutrition on treatment tolerability, AL, and disease-free survival (DFS). We also assessed the influence of CRT on the rate of postoperative complications by comparing the study group with 61 patients who had undergone excision with diverting or permanent stomas alone. Results Malnutrition was observed in 51 % of patients after CRT and in 29 % at surgery. Malnutrition after CRT was associated with treatment tolerability, and malnutrition at surgery was significantly associated with AL, which significantly influenced DFS in stage 1–3 patients. Conclusion Malnutrition caused by CRT is common and is associated with treatment tolerability and AL. Nutritional assessment and support seem indispensable for the rectal cancer patients receiving CRT.

The purpose of the present study was to assess the efficacy and toxicity of preoperative chemoradiotherapy using irinotecan against locally advanced lower rectal cancer according to UDP-glucuronosyltransferase 1A1 (UGT1A1) polymorphisms. Between 2009 and 2016, 46 patients with resectable rectal cancer (T3-T4, N0-N2, M0) received preoperative chemoradiotherapy consisting of 80 mg/m2 per day tegafur/gimeracil/oteracil (S-1; days 1-5, 8-12, 22-26, and 29-33), 60 mg/m2 per day irinotecan (days 1, 8, 22, and 29), and 45 Gy radiation (1.8 Gy/day, 5 days per week for 5 weeks). Six to eight weeks after completing chemoradiotherapy, total mesorectal excision was carried out. Patients with UGT1A1 polymorphisms were divided into WT (n = 26), heterozygous (n = 15), and homozygous (n = 5) groups, the latter including double heterozygosities. We evaluated associations between clinical characteristics, including UGT1A1 polymorphisms, and chemoradiotherapy efficacy and toxicity. Incidence rates of grade 3+ neutropenia and diarrhea were 17.0% and 30.4%, respectively. Relative dose intensity was 89.3%. Pathological complete response rate (grade 3) was 26.1%, and the good response (grade 2/3) rate was 84.8%. UGT1A1 polymorphisms were significantly associated with neutropenia and pathological good responses, but not with diarrhea. UGT1A1 polymorphism was the only predictive factor for pathological good responses. Our results indicate that UGT1A1 polymorphism is a predictive factor to determine the clinical efficacy of preoperative chemoradiotherapy and hematological toxicity induced by chemoradiotherapy using irinotecan in locally advanced rectal cancer patients.

Introduction The aim of this study was to compare the short- and long-term outcomes between short-course radiotherapy with delayed surgery (SRT-delay) and a standard conventional chemoradiotherapy (CRT) regimen. Methods Two collaborating institutions adopted different regimens; the SRT-delay regimen was selected by Meiwa Hospital and the CRT regimen was selected by Hyogo College of Medicine. The inclusion criteria were T3 middle and low rectal cancer patients treated with radical surgery after preoperative therapy. The median follow-up period was 44 months (range, 12–85). Results From 2007 to 2013, 104 patients were treated using the SRT-delay regimen and 61 patients were treated using the CRT regimen. The pretreatment characteristics of the 2 groups were not significantly different. The sphincter-preserving rate (93.3%, 85.2%), T downstaging (37.5%, 37.7%), ypN(−) (74.0%, 67.2%), postoperative complications and the bowel, and urinary and sexual functioning of the SRT-delay regimen were noninferior to those of the CRT regimen. The 3-year local recurrence-free survival, recurrence-free survival, and overall survival in the SRT-delay and CRT groups were 90.6% and 90.6% ( P = .764), 83.8% and 78.3% ( P = .687) and 96.0% and 92.8% ( P = .833), respectively. Conclusion The SRT-delay regimen was noninferior in terms of the downstaging effect, and oncologic and functional outcomes compared with the CRT regimen for T3 middle and low rectal cancer.

Adjuvant therapy for colorectal cancer (CRC) in patients aged ≥75 years is supported by inadequate evidence, although such patients are increasing in number worldwide.We assessed the influence of age and comorbidities on the prognosis of CRC in elderly patients using pooled data by the Japanese Study Group for Postoperative Follow-up of Colorectal Cancer. In total, 4598 patients (3304 with colon cancer and 1294 with rectal cancer) who underwent curative surgery from 2004 to 2006 were analysed with respect to age, Charlson comorbidity score (CS), tumour marker positivity, adjuvant therapy and prognosis.The number of patients aged64, 65-74 and75 years was 2007 (44%), 1614 (35%) and 977 (21%), respectively. Tumour location, tumour marker positivity, clinical stage, performance of adjuvant therapy, CS and overall survival (OS) were significantly different among these age groups (P 0.0001). Among patients aged ≥75 years with stage III CRC, 35% with colon cancer and 21% with rectal cancer received adjuvant therapy; these proportions were much lower than those in younger patients. Application of adjuvant therapy was dependent on the CS in patients aged ≤74 years, but not in older patients. Sex, the carcinoembryonic antigen concentration and adjuvant therapy were significantly associated with OS in elderly patients with stage III CRC.Age and comorbidities worsened the OS of patients with CRC who underwent curative surgery. However, patients aged ≥75 years were undertreated regardless of their CS despite the possibility of OS improvement by adjuvant therapy.

819 Background: Preoperative chemoradiotherapy regimen using S-1 plus Irinotecan is still under clinical investigation. The aim of this study was to investigate the significance and the long-term outcomes of this regimen for locally advanced rectal cancer. Methods: Between 2009 and 2016, 81 patients underwent radical surgery after preoperative chemoradiotherapy. Radiotherapy was administered in total 45Gy with 1.8Gy/day for 25 days. S-1 was administered orally in a fixed daily dose of 80mg/m2 on days 1 to 5, 8 to 12, 22 to 26, and 29 to 33. Irinotecan was infused with dose of 80 mg/m2 on days 1, 8, 22, and 29. 6-9 weeks after the completion of the treatment, radical surgery was performed. The median follow-up was 35.3 months. Results: Of the 81 patients, 76 (93.8%) completed treatment of chemoradiotherapy. Relative dose intensity of CPT-11 was 92.8%, S-1 was 90.1%. 79 (97.5%) patients completed the radiotherapy. 18 patients (22.2%) had ≧Grade 3 hematologic toxicity (leukopenia; 15 patients, neutropenia; 16 patients ). 23 patients (28.3%) had ≧Grade 3 nonhematologic toxicity (diarrhea). In terms of the surgical procedure, 73 of 81 patients (90.1%) underwent sphincter-preserving surgery including 42 patients intersphincteric resection, and 8 patients (9.9%) underwent abdominoperineal resection. The tumor regression grade of 1/2/3(pCR) was 30/39/12(14.8%). In terms of long-term survival, 3-year local relapse-free survival rate was 96.7%, the recurrence-free survival rate was 71.6% and 3-year overall survival rate was 94.9%. Conclusions: Preoperative chemoradiotherapy using combined with Irinotecan as secondary drugs may result safe and feasible and accomplished favorable downstaging. This regimen was considered to be effective in patients with locally advanced rectal cancer.

The aim of this study was to compare the pathological response of mesorectal positive nodes between short-course chemoradiotherapy with delayed surgery (SCRT-delay) and long-course chemoradiotherapy (LC-CRT) in patients with rectal cancer. The resected primary tumor specimens following the two different approaches were assessed utilizing the tumor regression grade (TRG 0–4), and each positive lymph node was assessed according to the lymph node regression grade (LRG 1–3), with TRG 4 and LRG 3 indicating total regression. The lymph node sizes were measured to elucidate any correlation with LRG scores. Seventy-four patients with ypN-positive rectal cancer had 220 positive lymph nodes following the SCRT-delay, and 48 patients had 141 positive lymph nodes following the LC-CRT. The distribution of LRG 1/2/3 in the two groups was 123/72/25 and 60/31/50 (p

Background Extramural tumor deposits (TDs) and extracapsular lymph node involvement (ECLNI) are considered to be poor prognostic factors in patients with T3–4, N0–2, M0 colorectal cancer (CRC). Although TDs are known to have multiple origins and pleomorphic features, the prognostic significances of the different type of TDs have not yet been established. Methods We performed a retrospective review of 385 consecutive patients with T3–4, N0–2, M0 CRC who received curative resection at our institution between 2006 and 2012. We classified the TDs into two groups: invasive-type TD (iTD), which is characterized by the presence of lymphatic invasion, vascular invasion, perineural invasion, or undefined cancer cell clusters and nodular-type TD (nTD), which is characterized by a smooth or irregular-shaped tumor nodule other than an iTD. ECLNI was defined as invasion of cancer cells into capsular collagen tissues or adipose tissues beyond the capsular collagen. Multivariate analyses were used to assess the prognostic significance of iTD, ND, and ECLNI for relapse-free survival (RFS), disease-specific survival (DSS), and sites of recurrence. Results In patients without lymph node (LN) metastasis, the incidences of iTD and nTD were both in the range of 2–3 %. Conversely, in patients with LN metastasis, the incidences of iTD, nTD, and ECLNI were 31, 22, and 34 %, respectively. iTD, nTD, and ECLNI were all significant independent adverse factors for RFS in rectal cancer, and were all associated with pT, pN, and LN ratio. iTD was a significant independent adverse prognostic factor for DSS in rectal cancer, metastasis to the liver in colorectal cancer, and distant LN metastasis in colon cancer. ECLNI was a significant independent prognostic factor for RFS in colon cancer. Conclusions Classifying TDs and assessing ECLNI may help establish significant prognostic factors for patients with T3–4, N0–2, M0 CRC.

The purpose of this study was to analyze the influence of variations in clinical practice regarding the timing of surgery with short-course chemoradiotherapy with delayed surgery (SCRT-delay) for lower rectal cancer. A total of 171 patients with T3 N0-2 lower rectal cancer treated with SCRT-delay (25 Gy/10 fractions/5 days (S-1); days 1–10) were retrospectively evaluated. The median waiting period of 30 days was used as a discriminator (group A: waiting period, ≤30 days; group B: waiting period, ≥31 days). Preoperative treatment responses and oncological outcomes were analyzed. The mean waiting periods for groups A and B were 24.4 ± 5.3 and 41.4 ± 12.3 days, respectively. There were no statistically significant differences between the two groups in any of the clinical variables. The clinicopathological outcomes were as follows: T downstaging (43.5 vs 37.2 %; p = 0.400), negative yp N (67.1 vs 75.6 %; p = 0.218), pCR (7.1 vs 1.2 %; p = 0.119). The 5-year local recurrence-free survival (89.3 vs 87.6 %; p = 0.956), the recurrence-free survival (82.2 vs 78.8 %; p = 0.662), and the overall survival (88.5 vs 84.4 %; p = 0.741), all of which were similar between the two groups. The longer waiting period did not increase the tumor downstaging and not improve the oncological outcomes for T3 lower rectal cancer treated with SCRT-delay. In addition, considering that the impaired leukocyte response occurred during the sub-acute period, any time after the sub-acute period (day 12) up to 30 days after radiotherapy would be a suitable waiting period.

Background The response of positive mesorectal lymph nodes to chemoradiotherapy remains largely unstudied in patients with rectal cancer. The aim of this study was to investigate the requirements of the total regression of positive nodes treated with chemoradiotherapy. Methods The response of the primary tumor was evaluated according to the tumor regression grade (TRG 0−4) in resected specimens, and positive lymph nodes were assessed according to the lymph node regression grade (LRG 1−3), with TRG 4 and LRG 3 indicating total regression. We investigated the relationships among TRG, LRG, and the sizes of positive lymph nodes. Results Among 178 patients, 68 (38.2%) had 200 positive lymph nodes. We first investigated the relationship of positive nodes to TRG and LRG and found that the response of the primary tumor to chemoradiotherapy correlated with the response of positive nodes. Next, we investigated the correlation between LRG and the size of positive nodes. At TRG 1 and 2, LRG score was not correlated with the positive node size. In contrast, at TRG 3, LRG score was correlated with the size of positive nodes. Next, our assessment of the relationship between the sizes of positive nodes and complete degeneration to LRG 3 showed that the most accurate cut-off score on receiver-operator-characteristics curve analysis was 6 mm in maximum diameter for TRG 3. Conclusion The requirements of the total regression of positive nodes are 1) degeneration of the primary tumor to TRG 3 and 2) a positive node diameter of

Thymidine phosphorylase (dThdPase) is an enzyme that converts 5'-deoxy-5-fluorouridine (5'DFUR) to the toxic substance 5-fluorouracil (5-FU); it is also known to be a platelet-derived endothelial cell growth factor. In order to investigate the feasibility of suicide gene therapy against colorectal cancer by means of the combination of 5'DFUR and the converting enzyme dThdPase, we transfected the dThdPase gene into the human colon cancer cell line SW480 and analyzed the growth pattern as well as the sensitivity to 5-FU or 5'DFUR of the dThdPase-transfected cells. The 50% inhibition (IC50) values of 5-FU against the SW480 parental cells, control vector-transfected cells SW480/V1, and dThdPase-transfected cells SW480/dThdPase were approximately 4.9, 6.3, and 2.9 microM, respectively. The IC50 of SW480/dThdPase was lower than that of SW480 or SW480/V1, although the differences were not statistically significant. The IC50 values of 5'DFUR for SW480, SW480/V1, and SW480/dThdPase were approximately 300, 330, and 3.2 microM, respectively. The sensitivity to 5'DFUR of SW480/dThdPase was increased by about 100-fold compared with that of SW480 or SW480/V1. With only 10% transfection efficacy, a high enough sensitivity to 5'DFUR was obtained to suppress the cell growth, indicating that a strong bystander effect was induced by this system. The in vivo growth of the s.c. transplanted SW480/dThdPase tumor in nude mice was significantly suppressed by i.p. injection of 5'DFUR compared with that in control mice that received phosphate-buffered saline (PBS) treatment. These results suggest that gene therapy using the combination of 5'DFUR and the dThdPase gene may be a useful approach for treatment of colon cancer.

Background Colorectal metastasis of lobular carcinoma of the breast is a diagnostic challenge. It may macroscopically simulate primary colon cancer or inflammatory bowel disease. In some cases, the interval between the primary breast cancer and metastatic colorectal lesions is so long that the critical records for diagnosis including history might be lost or missed. Case presentation Reported herein is a case of metastatic lobular carcinoma of the breast masquerading as a primary rectal cancer developed in a 62-year-old Japanese woman. The case initially presented as a circumferential rectal lesion, and information on the patient’s history of breast cancer was not noted. As the result of endoscopic biopsy, diagnosis of poorly differentiated rectal adenocarcinoma was made. The lesion was surgically resected after chemo-radiotherapy. Histopathological examination of the resected specimen with hematoxylin and eosin (HE) stain revealed a single-file arrangement of the tumor cells, reminiscent of lobular carcinoma of the breast. Immunohistochemical analysis revealed an immunophenotype consistent with lobular carcinoma of the breast. Because further review of the patient’s history revealed an occurrence of ‘poorly differentiated adenocarcinoma of the breast’, which she had experienced 24 years earlier, the final diagnosis of the lesion was made as rectal metastasis from lobular breast carcinoma. Conclusions Poorly differentiated adenocarcinoma of the colorectum is rarer than that of the stomach. Linitis plastica-type cancer of the colorectum is also rarer than that of the stomach. A lesson from the present case is that before we conclude a linitis plastica-type cancer of poorly differentiated type as a primary colorectal cancer, it is critical to exclude a possibility of metastatic colorectal cancer.

Distinguishing primary ovarian cancer from metastatic colorectal cancer is often difficult by a conventional pathological examination alone. We assessed the usefulness of p53 gene mutation analysis for the differential diagnosis of ovarian adenocarcinoma. A 66-year-old woman suffered multiple organ metastases, including the liver, para-aortic lymph node, and right ovary, following an operation for advanced sigmoid colon cancer. She underwent ovarian resection after effective chemotherapy against the liver and para-aortic lymph node cancer. Histological analysis suggested primary ovarian cancer. Therefore, we applied p53 gene mutation analysis for the differential diagnosis of primary versus metastatic ovarian cancer from sigmoid colon cancer. The direct sequence of the p53 gene demonstrated the same gene mutation in codon 211 (ACT to ATT) in both the sigmoid colon and ovarian cancers. According to the International Agency for Research on Cancer TP53 mutation database, this type of p53 mutation in colorectal cancer and ovarian cancer is 0.13% (5/3,693) and 0% (0/1,494), respectively. Therefore, we determined that the ovarian tumor was metastatic. Although p53 gene mutation analysis has been applied in some cases, this modality is very useful for the differential diagnosis of primary and metastatic cancer.

Purpose: The mechanism of Oxaliplatin (OHP) resistance is partly understood and no molecular marker for prediction of the sensitivity is available in clinic. We analyzed OHP resistant clones to establish the molecular marker for OHP sensitivity in colorectal cancer. Experimental design: We established several OHP-resistant clones from human colon cancer cell lines, DLD1 and HCT116. Then we assayed IC50 of OHP- resistant clones against OHP, 5-FU, and CPT-11. We measured gene expression profiling by microarray analysis and gene mutations by exome sequencing. Based on these results, we selected candidate genes associated with OHP sensitivity, which had gene mutations with significant change of gene expression. To validate the results, we assessed the gene expression of candidate genes in colorectal cancer patients. Results: All OHP-resistant clones derived from HCT116 were also resistant against 5-FU and CPT-11, although all OHP-resistant clones derived from DLD1 were still sensitive against 5-FU and CPT-11. Microarray analysis and exon sequencing indicated gene mutations in SMAD7 and IRF9 with amplified gene expression were candidate molecular markers for multidrug resistance in OHP-resistant clones derived from HCT116, although the gene expression in tumors of these genes were lower than normal mucosa in most of colorectal cancer patients. Conclusions: The mechanisms of OHP resistance were different between OHP-resistant clones derived from DLD1 and those from HCT116, but the same among the clones if the parental cells were same. SMAD7 and IRF9 were candidate molecular markers to predict multidrug resistance. Citation Format: Tomoki Yamano, Shuji Kubo, Aya Yano, Naohiro Tomita. Different mechanism of Oxaliplatin resistance in human colorectal cancer cell lines. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5453. doi:10.1158/1538-7445.AM2015-5453

Purpose: We have reported that SF3B1 gene mutations are rare in colorectal cancer patients and SF3B1 gene mutations in codon 1074 are responsible for resistance to SF3B1 inhibitor (FR901464, FR) at the AACR annual meeting 2013. SF3B1 gene mutations in hematological malignancies are considered to be related to tumor progression. To elucidate the influence by SF3B1 gene mutation in colorectal cancer, we assessed the tumor growth of colorectal cancer cells bearing SF3B1 gene mutation in vitro and in vivo. ExperimentalDesign: We assessed the tumor growth in vitro and in vivo using FR resistant clones (DLD/FR1, DLD/FR2, DLD/FR3, HCT/FR1, HCT/FR2, and LoVo/FR1) derived from DLD1, HCT116, and LoVo. We also performed microarray analysis of DLD1, DLD/FR1, HCT116, and HCT/FR1 with or without FR for 24 h to compare the change of gene expression by FR or SF3B1 gene mutation. Results: Doubling time of growth in DLD/FR1, DLD/FR2, HCT/FR1, and HCT/FR2 in vitro was same as their parental cells. However, doubling time of growth in DLD/FR3 and LoVo/FR1 in vitro was longer than their parental cells. In mouse subcutaneous xenograft models, the tumor volume of DLD1/FR1, HCT/FR1, and HCT/FR2 were 61%, 32 %, and 25%, to compared to that of their parental DLD1 or HCT116 one month after inoculation, respectively. Microarray analysis showed the genes and pathways affected by SF3B1 inhibitor and SF3B1 gene mutation did not match at all. Though SF3B1 inhibitor strongly inhibited pathways related to cell cycle, Fanconi anemia, homologous recombination, ubiquitin mediated proteolysis, nucleotide excision repair, oocyte meiosis, basal transcription factors, and endocytosis, SF3B1 gene mutation did not influence these pathways. The genes influenced by SF3B1 gene mutations included MHC class I/II, MHC MYC, BCL2, IL2, and IL10. Conclusion: Our data indicated SF3B1 gene mutation in colorectal cancer induced disadvantage in cancer progression by the different pathway from SF3B1 inhibitor. Citation Format: Tomoki Yamano, Shuji Kubo, Nagahide Matsubara, Aya Yano, Naohiro Tomita. Influence of SF3B1 gene mutation is different from that of Sf3B1 inhibitor in colorectal cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4615. doi:10.1158/1538-7445.AM2014-4615

Purpose: FR901464 (FR) is an antitumor agent that specifically binds to and inhibits the function of splicing factor 3B subunit 1 (SF3B1). Higher frequencies of SF3B1 gene mutations and their relevance to cancer progression have been shown in studies of hematological malignancies. We assessed the frequencies of SF3B1 gene mutations in colorectal cancer (CRC) and the correlation of SF3B1 mutations and FR sensitivity in CRC. Experimental Design: We measured FR sensitivity in CRC cell lines to establish FR-resistant clones and performed DNA sequencing of all 25 SF3B1 exons in nine CRC cell lines, FR-resistant clones, and 16 CRC patients. On the basis our results, we performed further DNA sequencing in 80 CRC patients. Results: The FR IC50 values in all CRC cell lines were < 1ng/ml. Six FR-resistant clones were established: three from DLD1, two from HCT116, and one from LoVo cells. The FR IC50 of the FR-resistant clones was > 500-fold greater than that of their parental cells, although the IC50 of oxaliplatin or 5-fuluorouracil were the same. We found nonsense mutations in exon 10 of DLD1 cells and no significant mutations in the other samples. All the FR-resistant clones had the missense mutations in codon 1073 of exon 22. We found no mutation in exons 10, 22, and 12-15, which were previously reported in hematological malignancies in 80 CRC patients. Conclusion: Our data indicated the usefulness of the SF3B1 inhibitor as a novel molecular targeted drug for CRC and the other malignancies without codon 1073 mutations. Citation Format: Tomoki Yamano, Hidenori Nakajima, Satoshi Tsuda, Shuji Kubo, Mie Hamanaka, Masayoshi Kobayashi, Daisuke Yamagishi, Takashi Kuno, Kiyoshi Tsukamoto, Astuko Tamamoto, Masafumi Noda, Nagahide Matsubara, Dave SB Hoon, Naohiro Tomita. Low frequencies of SF3B1 mutations indicate SF3B1 inhibitor as a novel moleculartargeted drug for colorectal cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4350. doi:10.1158/1538-7445.AM2013-4350

The aim of the study was to identify a set of discriminating genes that could be used for the prediction of Lymph node (LN) metastasis in human colorectal cancer (CRC), and for this, we compared the whole genome profiles of two CRC cell lines (the primary cell line SW480 and its LN metastatic variant, SW620) and identified eight genes [S100 calcium-binding protein P; aldo–keto reductase family 1(AKR1), member B1 (aldose reductase; AKR1B1); AKR1, member C3 (AKR1C3); calponin 3, acidic; metastasis associated in colon cancer 1; hemoglobin, epsilon 1; trefoil factor 3; and FGGY carbohydrate kinase domain containing]. These genes were examined by quantitative RT-PCR in tissues and LNs in 14 CRC patients and 11 control patients. The level of AKR1C3 mRNA expression was significantly different between the Dukes’ stage A, B, and C groups and the control group (p