Are patients with inflammatory bowel disease receiving adequate immunisation?

INTRODUCTION

Inflammatory Bowel Disease (IBD) treatment may increase the risk of infections. Vaccines are part of the comprehensive IBD patient care. The aim of this study was to describe indications and adherence of immunizations in IBD and identify possible associated factors.

METHODS

A cross-sectional, analytic study was conducted in patients from an IBD Program of a tertiary center in Chile, between April - June 2019. Patients were asked to answer a vaccine survey and information also was obtained from the National Immunization Registry. Descriptive and association statistic were used (χ²; p<0.05).

RESULTS

A total of 243 patients were included (148 ulcerative colitis (UC), 86 Crohn's disease (CD) and 9 non-classifiable IBD). Only six patients (2%) of IBD patients received a complete immunization schedule. The highest vaccine rates were against influenza (67%), hepatitis B virus (40%), 13-valent pneumococcal (34%) and 23-polysaccharide pneumococcal (16%). The influenza vaccine rate has significantly increased, reaching 67% in 2019. The survey showed that 23% of patients have not been immunized with any vaccine, mainly due to lack of time, lack of medical prescription and high cost.

CONCLUSIONS

In this cohort, although vaccination rates are higher than previously reported, adherence to IBD immunization program would be improved, being considered since diagnosis by the multidisciplinary team.

Pregnancy in Inflammatory Bowel Disease: Experience of a Chilean cohort

BACKGROUND

In inflammatory bowel disease (IBD) a high percentage of women are diagnosed during their reproductive age. IBD in remission is the ideal scenario when planning a pregnancy.

AIMS

To describe the clinical characteristics of pregnancy/newborn and assess disease activity at the time of conception and throughout the pregnancy in patients with IBD treated at a tertiary centre in Chile.

METHODS

We retrospectively reviewed women diagnosed with IBD who were pregnant or delivered between 2017 and 2020. Demographic, clinical, obstetric and delivery data were obtained from the IBD registry, approved by the local IRB. Descriptive statistics and association tests were performed (χ2, p ≤ 0.05).

RESULTS

Sixty women with IBD were included. At the beginning of pregnancy, 21 (35%) had active disease and 39 (65%) were in remission. Of those with active disease, 16 (66%) remained active and 6 had spontaneous abortions. In those who were in remission, 26 (69%) remained in this condition. Nine patients (15%) discontinued treatment, and 6 of these had inflammatory activity during pregnancy. Preconception counselling was performed in 23 of the 60 patients, being higher in the group that remained in remission during pregnancy (65% vs. 35%, p = 0.02). Patients who had a flare during pregnancy had more probability of preterm birth (<37 weeks) and newborn with lower weight compared with the group that always remained in remission (89% vs. 74%, p = 0.161) and (2.885 vs 3.370 g; p = 0.0014).

CONCLUSION

Remission presents better outcomes in pregnancy and preconception counselling would allow a better IBD control during pregnancy.

Infliximab in inflammatory bowel disease. Is premedication necessary?

BACKGROUND

The use of infliximab (IFX) in inflammatory bowel disease (IBD) has been associated with a 1-6% risk of infusion reactions. The usefulness of premedication with corticosteroids, paracetamol and /or antihistamines is controversial.

AIM

The aim of this study is to assess, in IBD patients on IFX, whether there are differences in secondary reactions to the infusion between those who use premedication or not.

METHODS

A retrospective cohort study was performed identifying patients with a diagnosis of IBD who received IFX at our institution between January 2009 and July 2019. Acute reactions were defined as those that occurred in the first 24 hours postinfusion and late reactions for more than 24 hours. Infusion reactions were classified as mild, moderate and severe. Descriptive and association statistics were used (χ²; p < 0.05).

RESULTS

Sixty-four patients were included with 1,263 infusions in total, 52% men. Median infusions per patient was 22 (2-66). All induction infusions were administered with premedication, and in maintenance in 57% of them. Premedication was given with hydrocortisone, chlorphenamine and paracetamol. Most of reactions were acute, mild or moderate in severity and no patient needed to discontinue IFX. In the maintenance group, there were 9/718 (1.2%) infusion reactions with premedication and 4/358 (1.1%) without it (p = 0.606). In the induction group, there were 8/187 (4.3%) infusion reactions, significantly higher when compared with both maintenance groups.

CONCLUSIONS

In this group, premedication use during maintenance was not effective at reducing the rate of infusion reactions. These results suggest that premedication would not be necessary.

Characterization of Chilean patients with sporadic colorectal cancer according to the three main carcinogenic pathways: Microsatellite instability, CpG island methylator phenotype and Chromosomal instability

Molecular classification of colorectal cancer is difficult to implement in clinical settings where hundreds of genes are involved, and resources are limited. This study aims to characterize the molecular subtypes of patients with sporadic colorectal cancer based on the three main carcinogenic pathways microsatellite instability (MSI), CpG island methylator phenotype (CIMP), and chromosomal instability (CIN) in a Chilean population. Although several reports have characterized colorectal cancer, most do not represent Latin-American populations. Our study includes 103 colorectal cancer patients who underwent surgery, without neoadjuvant treatment, in a private hospital between 2008 and 2017. MSI, CIN, and CIMP status were assessed. Frequent mutations in KRAS, BRAF, and PIK3CA genes were analyzed by Sanger sequencing, and statistical analysis was performed by Fisher's exact and/or chi-square test. Survival curves were estimated with Kaplan-Meier and log-rank test. Based on our observations, we can classify the tumors in four subgroups, Group 1: MSI-high tumors (15%) are located in the right colon, occur at older age, and 60% show a BRAF mutation; Group 2: CIN-high tumors (38%) are in the left colon, and 26% have KRAS mutations. Group 3: [MSI/CIN/CIMP]-low/negative tumors (30%) are left-sided, and 39% have KRAS mutations; Group 4: CIMP-high tumors (15%) were more frequent in men and left side colon, with 27% KRAS and 7% presented BRAF mutations. Three percent of patients could not be classified. We found that CIMP-high was associated with a worse prognosis, both in MSI-high and MSI stable patients (p = 0.0452). Group 3 (Low/negative tumors) tend to have better overall survival compared with MSI-high, CIMP-high, and CIN-high tumors. This study contributes to understanding the heterogeneity of tumors in the Chilean population being one of the few characterizations performed in Latin-America. Given the limited resources of these countries, these results allow to improve molecular characterization in Latin-American colorectal cancer populations and confirm the possibility of using the three main carcinogenic pathways to define therapeutic strategies.

Spectrum and Frequency of Tumors, Cancer Risk and Survival in Chilean Families with Lynch Syndrome: Experience of the Implementation of a Registry

Lynch syndrome (LS) is associated with the highest risk of colorectal (CRC) and several extracolonic cancers. In our effort to characterize LS families from Latin America, this study aimed to describe the spectrum of neoplasms and cancer risk by gender, age and gene, and survival in 34 Chilean LS families. Of them, 59% harbored path_MLH1, 23% path_MSH2, 12% path_PMS2 and 6% path_EPCAM variants. A total of 866 individuals at risk were identified, of which 213 (24.6%) developed 308 neoplasms. In males, CRC was the most common cancer (72.6%), while females showed a greater frequency of extracolonic cancers (58.4%), including uterus and breast (p < 0.0001). The cumulative incidence of extracolonic cancers was higher in females than males (p = 0.001). Path_MLH1 variants are significantly more associated with the development of CRC than extracolonic tumors (59.5% vs. 40.5%) when compared to path_MSH2 (47.5% vs. 52.5%) variants (p = 0.05018). The cumulative incidence of CRC was higher in path_MLH1/path_MSH2 carriers compared to path_PMS2 carriers (p = 0.03). In addition, path_MSH2 carriers showed higher risk of extracolonic tumors (p = 0.002). In conclusion, this study provides a snapshot of the LS profile from Chile and the current LS-associated diagnostic practice and output in Chile. Categorizing cancer risks associated with each population is relevant in the genetic counselling of LS patients.

Interleukin 33/ST2 Axis Components Are Associated to Desmoplasia, a Metastasis-Related Factor in Colorectal Cancer

In colorectal cancer (CRC), cancer-associated fibroblasts (CAFs) are the most abundant component from the tumor microenvironment (TM). CAFs facilitate tumor progression by inducing angiogenesis, immune suppression and invasion, thus altering the organization/composition of the extracellular matrix (i.e., desmoplasia) and/or activating epithelial-mesenchymal transition (EMT). Soluble factors from the TM can also contribute to cell invasion through secretion of cytokines and recently, IL-33/ST2 pathway has gained huge interest as a protumor alarmin, promoting progression to metastasis by inducing changes in TM. Hence, we analyzed IL-33 and ST2 content in tumor and healthy tissue lysates and plasma from CRC patients. Tissue localization and distribution of these molecules was evaluated by immunohistochemistry (using localization reference markers α-smooth muscle actin or α-SMA and E-cadherin), and clinical/histopathological information was obtained from CRC patients. In vitro experiments were conducted in primary cultures of CAFs and normal fibroblasts (NFs) isolated from tumor and healthy tissue taken from CRC patients. Additionally, migration and proliferation analysis were performed in HT29 and HCT116 cell lines. It was found that IL-33 content increases in left-sided CRC patients with lymphatic metastasis, with localization in tumor epithelia associated with abundant desmoplasia. Although ST2 content showed similarities between tumor and healthy tissue, a decreased immunoreactivity was observed in left-sided tumor stroma, associated to metastasis related factors (advanced stages, abundant desmoplasia, and presence of tumor budding). A principal component analysis (including stromal and epithelial IL-33/ST2 and α-SMA immunoreactivity with extent of desmoplasia) allowed us to distinguish clusters of low, intermediate and abundant desmoplasia, with potential to develop a diagnostic signature with benefits for further therapeutic targets. IL-33 transcript levels from CAFs directly correlated with CRC cell line migration induced by CAFs conditioned media, with rhIL-33 inducing a mesenchymal phenotype in HT29 cells. These results indicate a role of IL-33/ST2 in tumor microenvironment, specifically in the interaction between CAFs and epithelial tumor cells, thus contributing to invasion and metastasis in left-sided CRC, most likely by activating desmoplasia.

A Pilot Trial to Quantify Plasma Exosomes in Colorectal Cancer Screening from the International Collaborative Study between Chile and Japan

BACKGROUND

In Chile, a national colorectal cancer (CRC) screening program using immunochemical fecal occult blood tests and colonoscopy was started in 2012 as an international collaboration between Chile and Japan. In the present study, we quantified exosomes in the peripheral blood and evaluated the implication of the results for CRC screening.

METHODS

A total of 25 peripheral plasma samples from the participants of CRC screening in Punta Arenas, Chile, were analyzed for exosomes.

RESULTS

Plasma exosomes were obtained from 5 participants with adenocarcinoma (4 pTis and 1 pT1), 8 with high-grade adenoma, 4 with low-grade adenoma, 4 with hyperplastic polyps, and 4 with normal findings. Participants with adenocarcinoma had significantly higher amounts of plasma exosomes (2.1-3.2 fold) than participants with normal findings, hyperplastic polyps, or low-grade adenoma (p = 0.016, p = 0.0034, and p = 0.0042 respectively; Tukey's multiple comparisons test). The size of the representative lesion, the number of lesions, and the sum of those 2 factors in each participant correlated significantly with the exosome amounts (r = 0.56, r = 0.58, and r = 0.72, respectively; p < 0.01; Spearman's correlation coefficient test).

CONCLUSIONS

This pilot study demonstrated that quantification of plasma exosomes is a potential alternative screening method for detecting individuals with a high risk of colorectal malignancy.

[Environmental risk factors in the development and evolution of inflammatory bowel disease]

Environmental factors may influence the development of Inflammatory Bowel Disease and modify its natural history. The objective of this review is to evaluate current evidence about environmental factors associated with the disease. A better knowledge about the pathogenesis of the disease can lead to better treatment strategies and suggestions to prevent the disease.

The relationship between chemokines CCL2, CCL3, and CCL4 with the tumor microenvironment and tumor-associated macrophage markers in colorectal cancer

A complex network of chemokines can influence cancer progression with the recruitment and activation of hematopoietic cells, including macrophages to the supporting tumor stroma promoting carcinogenesis and metastasis. The aim of this study was to investigate the relation between tissue and plasma chemokine levels involved in macrophage recruitment with tumor-associated macrophage profile markers and clinicopathological features such as tumor-node-metastases stage, desmoplasia, tumor necrosis factor-α, and vascular endothelial growth factor plasma content. Plasma and tumor/healthy mucosa were obtained from Chilean patients undergoing colon cancer surgery. Chemokines were evaluated from tissue lysates (CCL2, CCL3, CCL4, CCL5, and CX3CL1) by Luminex. Statistical analysis was performed using Wilcoxon match-paired test ( p  < 0.05). Macrophage markers (CD68, CD163, and iNOS) were evaluated by immunohistochemistry samples derived from colorectal cancer patients. Correlation analysis between chemokines and macrophage markers and clinicopathological features were performed using Spearman's test. Plasmatic levels of chemokines and inflammatory mediators' vascular endothelial growth factor and tumor necrosis factor-α were evaluated by Luminex. Tumor levels of CCL2 (mean ± standard deviation = 530.1 ± 613.9 pg/mg), CCL3 (102.7 ± 106.0 pg/mg), and CCL4 (64.98 ± 48.09 pg/mg) were higher than those found in healthy tissue (182.1 ± 116.5, 26.79 ± 22.40, and 27.06 ± 23.69 pg/mg, respectively p < 0.05). The tumor characterization allowed us to identify a positive correlation between CCL4 and the pro-tumor macrophages marker CD163 ( p  = 0.0443), and a negative correlation of iNOS with desmoplastic reaction ( p  = 0.0467). Moreover, we identified that tumors with immature desmoplasia have a higher CD163 density compared to those with a mature/intermediated stromal tissue ( p  = 0.0288). Plasmatic CCL4 has shown a positive correlation with inflammatory mediators (tumor necrosis factor-α and vascular endothelial growth factor) that have previously been associated with poor prognosis in patients. In conclusion High expression of CCL4 in colon cancer could induce the infiltration of tumor-associated macrophages and specifically a pro-tumor macrophage profile (CD163⁺ cells). Moreover, plasmatic chemokines could be considered inflammatory mediators associated to CRC progression as well as tumor necrosis factor-α and vascular endothelial growth factor. These data reinforce the idea of chemokines as potential therapeutic targets or biomarker in CRC.

[Results of a multicentric colorectal cancer screening program in Chile]

BACKGROUND

Colorectal Cancer Screening Programs (CRCSP) are widely accepted in developed countries. Unfortunately, financial restrictions, low adherence rate and variability on colonoscopy standardization hamper the implementation of CRCSP in developing countries.

AIM

To analyze a multicentric pilot model of CRCSP in Chile.

MATERIAL AND METHODS

A prospective model of CRCSP was carried out in three cities, from 2012 to 2015. The model was based on CRC risk assessment and patient education. Health care personnel were trained about logistics and protocols. The endoscopy team was trained about colonoscopy standards. A registered nurse was the coordinator in each center. We screened asymptomatic population aged between 50 and 75 years. Immunological fecal occult blood test (FIT) was offered to all participants. Subjects with positive FIT underwent colonoscopy.

RESULTS

A total of 12,668 individuals were enrolled, with a FIT compliance rate of 93.9% and 2,358 colonoscopies were performed. Two hundred and fifty high-risk adenomas and 110 cancer cases were diagnosed. One patient died before treatment due to cardiovascular disease, 74 patients (67%) underwent endoscopic resection and 35 had surgical treatment. Ninety one percent of patients had an early stage CRC (0-I-II). Among colonoscopy indicators, 80% of cases had an adequate bowel preparation (Boston > 6), cecal intubation rate was 97.7%, adenoma detection rate was 36.5%, and in 94.5% of colonoscopies, withdrawal time was adequate (> 8 min).

CONCLUSIONS

This CRCS pilot model was associated to a high rate of FIT return and colonoscopy quality standards. Most CRCs detected with the program were treated by endoscopic resection.

Complementary and alternative medicine in patients with inflammatory bowel disease: A survey performed in a tertiary center in Chile

OBJECTIVES

The aim of this study was to assess the type and prevalence of complementary and alternative medicine (CAM) use in patients with inflammatory bowel disease (IBD) who are treated at our center.

DESIGN

Observational, cross-sectional questionnaire-based study that included patients from the IBD program of our center.

SETTING

Tertiary clinical center in Santiago, Chile.

MAIN OUTCOME MEASURES

Types of CAM being used by patients with IBD.

RESULTS

A total of 200 patients were included, 68% ulcerative colitis, 29% Crohn's disease, and 3% non-classifiable IBD. Overall, 25% of the patients reported current use of CAM, 30% reported using in it the past, and 45% indicated that they had never used it before. The use of CAM was recommended in 20% of the patients by other healthcare professionals and in 10% of the patients by the gastroenterologist. Forty-nine percent of the patients informed the gastroenterologist that they were using CAM. Overall, 86% of the patients did not modify the conventional medical treatment (CMT). None of the patients who were using curcumin, homeopathic medicine, acupuncture or biomagnetism modified the CMT.

CONCLUSIONS

The type of CAM being used plays an important role when the patient makes the decision to inform the gastroenterologist. Other healthcare professionals play an important role in providing the advice to start CAM. Gastroenterologists must be aware of the high prevalence of CAM use in IBD patients, actively ask about CAM use and guide the patients who want to use CAM in a responsible and safe manner.

Abstract 2337: Effect of Honokiol and Indol-3-carbinol in viability and apoptosis of colorectal cancer cell lines treated with Orexin-A

Introduction: Colorectal cancer (CRC) is the third leading cause of cancer deaths worldwide. Recently, much attention has been given to nutraceuticals. They are being investigated for prevention and treatment of cancer. It has been shown that they have antitumoral properties without secondary effects, and could be used as a complement to conventional therapy for CRC. Orexin-A (OXA) is a hypothalamic neuropeptide with various functions in central nervous system and peripheral tissues. Orexin receptor 1 (OX1R) is expressed in CRC tissues. Activation of OX1R by OXA in CRC cell lines triggers apoptosis and was proposed as a new alternative for therapy. The aim of this study was to evaluate different nutraceuticals that could decrease survival and increase apoptosis of CRC cells lines in synergism with OXA.

Material and Methods: Two CRC cell lines were obtained from ATCC: Caco2 and SW480. Cell lines were treated with Honokiol (HK) or Indol-3-carbinol (I3C) for 24h at different doses with or without 100nM OXA. Cell viability was determined using CellTiter Kit (Promega). Caspase 3/7 mediated apoptosis activity was assessed using ApoOne Kit (Promega). Real-time qPCR was performed to determine the effect of nutraceuticals on OX1R expression.

Results: In this study, HK decreases cellular viability on average of 47% in Caco2 and 80% SW480 cells lines, at 25uM, 50uM or 100uM. In Caco2 cell line an increase in caspase 3/7 mediated apoptosis of 60% and 76% was observed at 25uM and 50uM, respectively, unlike what was observed in SW480 in which there was an inhibition of 80% at the different doses used. The combined treatment of 50uM HK with 100nM OXA does not produce a synergistic effect in cell viability or apoptosis compared to use of HK alone in both cell lines. HK produces an inhibition in the OX1R expression that explains the lack of synergism with OXA. I3C produces a decrease of 25% to 95% of cell viability according to doses used with an increase in apoptosis of 6 % to 38% in Caco2 cell lines. The combined effect of 500uM I3C with 100nM OxA produces a synergistic effect of 95% decrease on cell viability, with an increase of OX1R expression, which is not explained by an increase in apoptosis mediated by caspase 3/7.

Conclusions: We found that HK and I3C can inhibit viability and induce apoptosis in Caco2 and SW480 cells. In Caco2 cell line this can be explained by an increase in 3/7 caspase-mediated apoptosis, unlike that observed for SW480 treated with HK. Only 13C has a synergistic effect with OXA on cell viability in Caco2 cell lines but was independent of caspase 3/7 mediated apoptosis at doses and times used. Treatments using new doses and times are necessary to improve response. In our results, I3C might be a better therapeutic agent than HK for CRC. In vivo studies and clinical trials are further required to evaluate physiologic efficacies of the combination treatment.

Fondecyt 1140012.

Citation Format: Ana Maria Wielandt, Cyntia Villarroel, Elea Gros, Mauricio Moreno, Claudia Hurtado, Udo Kronberg, Francisco Lopez-Kostner. Effect of Honokiol and Indol-3-carbinol in viability and apoptosis of colorectal cancer cell lines treated with Orexin-A [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2337.

[Rectal diffuse large B cell lymphoma appearing after immunosuppression for ulcerative colitis. Report of one case]

Primary colorectal lymphoma is a rare form of presentation of gastrointestinal tract lymphomas. Inflammatory bowel disease and its treatment are risk factors for its development. We report a 47-year-old male patient with Ulcerative Colitis of two years of evolution, treated initially with azathioprine and later on with infliximab. Due to a relapse in symptoms after the second dose of infliximab, a new coloncoscopy was performed showing a rectal ulcerative lesion, corresponding to a large cell Non-Hodgkin's Lymphoma. The patient was successfully treated with RCHOP chemotherapy (Rituximab cyclophosphamide doxorubicin vincristine prednisone). He is currently in disease remission.

Stem Cell Therapy in Refractory Perineal Crohn's Disease: Long-term Follow-up

AIM

To describe the long-term outcomes of adipose-mesenchymal stem cells, platelet-rich plasma, and endorectal advancement flaps in patients with Perineal Crohn's Disease.

METHOD

This was a single-center, prospective, observational pilot study performed between March 2013 and December 2016. The study included adult patients diagnosed with Perianal Crohn's Disease (with complex perianal fistulas) refractory to previous surgical and/or biological treatment. Patients underwent surgical treatment in two stages. Stage 1: Fistula mapping, drainage, seton placement and lipoaspiration to obtain adipose-mesenchymal stem cells were performed. Stage 2: The setons were removed, and the fistula tract was debrided. A small endorectal advancement flap was created, with closure of the previous internal fistula opening. Then, 100-120 million adipose-mesenchymal stem cells mixed with platelet-rich plasma were injected into the internal fistula opening and fistula tract.

RESULTS

The study included nine patients (seven females), with a median age of 36 years (r = 23-57). Eleven fistula tracks were treated, of which, two were pouch-vaginal fistulas. The median follow-up period was 31 months (r=21-37). At the end of the follow-up period, 10/11 (91%) fistulas were completely healed and 1/11 (9%) was partially healed. At the end of this period, there was no evidence of fistula relapse or adverse reactions in any patients. The Perianal Disease Activity Index and Inflammatory Bowel Disease Questionnaire scores significantly improved after the procedure.

CONCLUSION

Combined therapy with adipose-mesenchymal stem cells, platelet-rich plasma and endorectal advancement flaps yielded good results in patients with refractory Perineal Crohn's Disease. This article is protected by copyright. All rights reserved.

[Acute severe ulcerative colitis treated with accelerated infliximab induction. Case report]

Acute severe ulcerative colitis (ASUC) is a potentially life-threatening condition that requires early recognition, hospitalization and adequate treatment. Currently, the use of infliximab in ulcerative colitis (UC) is recommended in the case of severe disease refractory to corticosteroids, once that superimposed bacterial or viral infections (such as cytomegalovirus or Clostridium difficile) have been excluded. However, conventional weight-based regimens of infliximab might be insufficient for patients with ASUC. Accelerated infliximab induction regimen may increase its serum concentration levels and efficacy by reducing early colectomy rates in these patients. We report a 34 year old female presenting with an ASUC. She was initially treated with hydrocortisone 300 mg/day and mesalazine enemas 4 g/day with an unfavorable clinical response. At the fifth day of therapy, an accelerated induction therapy with infliximab was started in doses of 10 mg/kg at weeks 0, 1 and 4. After the second dose, there was a favorable response with reduction of abdominal pain, stool frequency and hematochezia. She was discharged with prednisone and azathioprine. After a year of starting infliximab, the patient remains in clinical remission.

Clinical, endoscopic and histological correlation and measures of association in ulcerative colitis

OBJECTIVE

To determine the correlation between clinical, fecal, endoscopic and histological activity in patients with ulcerative colitis (UC).

METHODS

A correlational cross-sectional analysis was performed in patients with UC who underwent colonoscopy between February and December 2016. Clinical, endoscopic, fecal and histological activities were determined using the partial Mayo subscore, Mayo endoscopic subscore and modified Mayo endoscopic subscore, fecal calprotectin and Geboes score and the presence of basal plasmacytosis, respectively. Scores were analyzed using Spearman's rank correlation test. To determine the association between scores and some clinical variables and active UC, univariate and multivariate logistic regressions were used.

RESULTS

Altogether 105 procedures (93 patients) were included. In 64.8% of the procedures, the mucosa was inflamed; however, 14.7% did not show histological inflammation. Endoscopic remission was observed in the other 35.2% of procedures; however, in biopsies 21.6% exhibited histological inflammation. Mayo endoscopic subscore and modified Mayo endoscopic score were well correlated but were only moderately correlated with clinical and histological scores. Furthermore, there was a moderate correlation between Mayo endoscopic score and Geboes score. Conversely, histological scores were poorly correlated with partial Mayo score. In multivariate analysis, Geboes score and basal plasmacytosis were predictive of active disease (OR 3.505, 95% CI 1.544-7.959 and OR 3.240, 95% CI 1.123-9.349, respectively), whereas biological therapy was found to be protective against UC (OR 0.021, 95% CI 0.000-0.641).

CONCLUSION

Clinical, endoscopic and histological activities were moderately correlated, while Geboes score and basal plasmacytosis were predictive of endoscopically active UC.

EGFR pathway subgroups in Chilean colorectal cancer patients, detected by mutational and expression profiles, associated to different clinicopathological features

Colorectal cancer is a multistep process affecting several signaling pathways including EGFR (epidermal growth factor receptor), a therapeutic target for metastatic disease. Our aim was to characterize the mutational and expression profiles of the EGFR pathway in colorectal tumors and to integrate these results according to five previously defined groups. We screened seven genes for mutations ( KRAS-BRAF-PIK3CA-PIK3R1-AKT1-MAP2K1-PTEN) and six proteins (EGFR-p110α-p85α-PTEN-phosphoAKT-phosphoMEK1) by immunohistochemistry, PTEN deletion, and MSI. At least one mutated gene was observed in 68% of tumors ( KRAS 45%, PIK3CA 21%, BRAF 14%, and PTEN 7%). PTEN deletion was observed in 10.7% of tumors and 19.6% were MSI-High. In all, 54% of tumors showed a high EGFR expression, 48% p110α, 4.4% phosphoAKT, and 22% phosphoMEK1; and 43% showed low PTEN expression and 22% p85α. In total, five groups of tumors were defined based on MSI, BRAF, and KRAS mutations. Three groups gather mainly early-stage tumors, whereas a fourth group is mostly conformed by advanced tumors. We described here that 71.4% of tumors from one group have a mutated PI3K/PTEN pathway, in comparison to other groups having 32%, 27%, and 25%. In addition, the five groups are differentiated by molecular features such as EGFR, p85α, p110α, and PTEN, showing variable expression among tumor groups. In conclusion, alterations on the EGFR pathway were found in a high percentage of colorectal cancer patients. Using the integration of diverse molecular markers, we ratified previous classification in an ethnic group having relevant genetic differences and living in a different environmental background, adding complementary molecular targets related to therapy.

[Characterization of patients with sporadic colorectal cancer following the new Consensus Molecular Subtypes (CMS)]

BACKGROUND

Colorectal cancer (CRC) is an heterogeneous disease. Three carcinogenic pathways determine its molecular profile: microsatellite instability (MSI), chromosomal instability (CIN) and CpG island methylator phenotype (CIMP). Based on the new molecular classification, four consensus CRC molecular subtypes (CMS) are established, which are related to clinical, pathological and biological characteristics of the tumor.

AIM

To classify Chilean patients with sporadic CRC according to the new consensus molecular subtypes of carcinogenic pathways.

MATERIAL AND METHODS

Prospective analytical study of 53 patients with a mean age of 70 years (55% males) with CRC, operated at a private clinic, without neoadjuvant treatment. From normal and tumor tissue DNA of each patient, CIN, MSI and CIMP were analyzed. Combining these variables, tumors were classified as CMS1/MSI-immune, CMS2/canonical, CMS3/metabolic and CMS4/mesenchymal.

RESULTS

CMS1 tumors (19%) were located in the right colon, were in early stages, had MMR complex deficiencies and 67% had an activating mutation of the BRAF oncogene. CMS2 tumors (31%) were located in the left colon, had moderate differentiation, absence of vascular invasion, lymphatic and mucin. CMS3 tumors (29%) were also left-sided, with absence of vascular and lymphatic invasion, and 29% had an activating mutation of the KRAS oncogene. CMS4 tumors (21%) showed advanced stages and presence of metastases.

CONCLUSIONS

This new molecular classification contributes to understanding the heterogeneity of tumors. It is possible to differentiate molecular subgroups of a single pathological diagnosis of adenocarcinoma, opening the door to personalized medicine.

Abstract 3943: Determination of the molecular profile of Chilean patients with sporadic colorectal cancer

Introduction: Colorectal cancer (CRC) represents a major health problem worldwide, ranking third among the most frequent cancers and fourth in cancer mortality. In Chile CRC is the third leading cause of cancer death. CRC is a heterogeneous disease, and three carcinogenic pathways have been described to determine the molecular profile: The microsatellite instability (MSI), chromosomal instability (CIN) and methylator phenotype (CIMP). Several studies have tried to propose CRC molecular subgroups based on the 3ways described above since CIN, MSI and CIMP are not mutually exclusive and overlapping of the 3 ways is still unclear. The most recent subtyping of CRC was in 2015, where four molecular subtypes consensus (CMS 1 to 4) were established according to clinicopathological features, molecular pathways involved and mutational status of KRAS, BRAF and PI3KCA genes in order to encourage clinical translation. 21% of tumors failed to be categorized into these subtypes. This classification allows us to understand and determine the clinical, pathological and biological characteristics of CCR to provide customized therapies to patients.

Aim: To describe the molecular profile of carcinogenic pathways CIN, MSI CIMP in Chilean patients with sporadic CRC.

Material and Methods: Prospective analytical study of 56 patients operated between 2010-2016 at Clinica Las Condes, without neo-adjuvant treatment. DNA was extracted from normal and tumor tissue of each patient and using PCR amplification of several markers CIN, MSI and CIMP were defined. By combining the 3 variables analyzed, tumors were classified in Group-A (MSI-high), Group-B (MSI-low / CIMP-high / CIN-high), Group-C (MSI-low / CIMP-high / CIN-low), Group-D (MSI-low / CIMP-low / CIN-high) and Group-E (MSI- neg / CIMP-neg / CIN-neg).

Results: In this study, tumors in Group-A (17%) are located on the right side in patients older than 60 years and early stages. Tumors Group-B / C (18,9%) occur in patients older than 60 years and BMI&gt;25 kg / m2, with wall invasion pT3-T4 and late stages. Tumors of Group-D / E (54,7%) are the most frequent, located on the left side, without vascular invasion and moderately differentiated.

Conclusions: This study allowed to classify Chilean patients in 3 subgroups considering the 3 main routes described for carcinogenesis development: CIN, MSI and CIMP, which are consistent with the percentages described by the global consortium. Studies that analyze MSI and CIMP or MSI and CIN have consistently shown that patients with MSI-high tumors have a better prognosis (in our case 17%). Despite therapeutic advances based on this molecular characterization, both the heterogeneity of tumors and the different combinations of pathways involved have shown that the response to therapy varies depending on the individual profile of each patient, therefore in clinical practice it would be important to establish that profile for each of them. Fondecyt 1140012

Citation Format: Ana Maria Wielandt, Cynthia Villarroel, Claudia Hurtado, Daniela Simian, Diego Zamorano, Maripaz Martinez, Magdalena Castro, Maria Teresa Vial, Udo Kronberg, Francisco Lopez-Kostner. Determination of the molecular profile of Chilean patients with sporadic colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3943. doi:10.1158/1538-7445.AM2017-3943

[Acute small bowel diverticulitis in a patient with crohn’s disease]

Diverticular disease of the small intestine is rare, especially when it is located in the jejunum. It is generally asymptomatic, but in some patients it may have complications such as acute diverticulitis with peritonitis, gastrointestinal bleeding or obstruction. In such cases, the recommended treatment is surgery. We report a 77-year-old patient with ileal Crohn’s disease with a long-standing inflammatory phenotype, who developed acute diverticulitis of the jejunum presenting a severe septic shock and secondary multiple-organ failure. It resolved with medical treatment and prolonged antibiotic therapy.

[Benign multicystic peritoneal mesothelioma in a patient with Crohn disease]

Benign multicystic peritoneal mesothelioma is an uncommon lesion arising from the peritoneal mesothelium. It is asymptomatic or presents with unspecific symptoms. Imaging techniques may reveal it, however the final diagnosis can only be made by histopathology. Surgery is the only effective treatment considering its high recurrence rate. We report a 19 years old male with Crohn’s disease. Due to persistent abdominal pain, an abdominal magnetic resonance imaging was performed, showing a complex cystic mass in the lower abdomen. The patient underwent surgery and the lesion was completely resected. The pathological study reported a benign multicystic peritoneal mesothelioma.

Assessment of disease-related knowledge and possible factors associated with the knowledge level among Chilean patients with inflammatory bowel disease

AIMS AND OBJECTIVES

To assess disease-related knowledge among patients with inflammatory bowel disease and to identify the factors that are possibly associated with the knowledge level.

BACKGROUND

Disease-related knowledge can positively influence the acceptance of the disease, increase treatment compliance and improve the quality of life in patients with inflammatory bowel disease.

DESIGN

An observational, cross-sectional study was conducted and prospectively included patients from the inflammatory bowel disease programme between October 2014-July 2015.

METHODS

A Spanish-translated version of the 24-item Crohn's and Colitis Knowledge score was used to assess disease-related knowledge. Patients also completed a demographic and clinical questionnaire.

RESULTS

A total of 203 patients were included, 62% were female, and 66% were diagnosed with ulcerative colitis; the median age was 34 years (range 18-79), and the median disease duration was four years. The median disease-related knowledge score was 9 (range 1-20). Only 29% of the patients answered more than 50% of the questions correctly. Lower disease-related knowledge was observed in questions related to pregnancy/fertility and surgery/complications. Patients older than 50 years, with ulcerative colitis, with disease durations less than five years and patients without histories of surgery exhibited lower disease-related knowledge. There was no association between the knowledge scores and the educational levels.

CONCLUSIONS

The patients who attended our inflammatory bowel disease programme exhibited poor disease-related knowledge that was similar to the knowledge levels that have been observed in developed countries. It is necessary to assess patient knowledge to develop educational strategies and evaluate the influences of these strategies on patient compliance and quality of life.

RELEVANCE TO CLINICAL PRACTICE

These results will allow the inflammatory bowel disease team to develop educational programmes that account for the disease-related knowledge of each patient. Inflammatory bowel disease nurses should evaluate their interventions to provide evidence that educating our patients contributes to improving their treatment outcomes and overall health statuses.

Abstract 5167: Expression levels of orexin receptor 1 in different stages of colorectal cancer

Introduction: Colorectal cancer (CRC) is the fourth leading cause of cancer death in Chile. Currently, treatment is surgical and adjuvance is based on chemotherapy mainly. One of the risk factors of CRC is obesity and metabolic syndrome. In search of factors that induce cell apoptosis, orexins were identified. Orexins are neuropeptides that regulate appetite, inhibit satiety and increase energy expenditure. The altered expression of orexin or its dysregulation has been associated with a wide range of human diseases such as narcolepsy, obesity, drug addiction and cancer. In rats and mice lacking orexin receptor, an increase in body mass index (BMI) was observed. Orexin Receptor 1 (OX1R) is overexpressed in CRC, but is not detected in normal colon tissue. Its activation by Orexin-A promotes apoptosis in cancer cell lines, and can be modulated by diet. Aim: To determine OX1R expression in the adenoma-carcinoma progression of CRC as possible therapeutic target, and its correlation with BMI. Material and Methods: Patients with neoplastic colorectal lesions undergoing surgical or endoscopic treatment between 2014 and 2015 were prospectively enrolled. Tissue samples of 29 patients were divided into 4 groups. Group A: control (n = 5), Group B: low-grade adenoma (n = 5), Group C: high-grade adenoma (n = 7), Group D: adenocarcinoma (n = 12). Formalin-fixed-paraffin-embedded samples were used to perform immunohistochemistry (IHC) of OX1R. Fresh tissues from Group D were used to assess protein and mRNA expression of OX1R by Western-blot and quantitative RT-PCR, respectively. Primary cultures were established from fresh tumor tissue of patients with adenocarcinoma. To compare OX1R expression levels we used the t-student test. Results: IHC expression of OX1R was detected both in the luminal membrane of colorectal epithelium and in the cytoplasm. We observed stained cells in 0-1% of the total area in Group A, B and C. In Group D, 7 samples showed staining 0-1%, 2 samples 1-10% and 3 samples 10-20%. High mRNA and protein expression was detected in stage III- IV adenocarcinoma samples compared to stage 0, I and II tumor samples. Normal adyacent tissue of CRC patients does not express OX1R. BMI is inversely associated with OX1R expression. Orexin A was able to induce apoptosis in primary cell cultures from advanced tumors in a dose dependent manner. Conclusions: OX1R is expressed scarcely in early stages of carcinogenesis. Its expression is induced significantly only in the most advanced adenocarcinomas, both at protein and mRNA levels, and is inversely associated with BMI. In primary cultures of patients with CRC, orexin A is able to induce apoptosis in a dose dependent manner. FONDECYT 1140012.

Citation Format: Ana M. Wielandt, Cynthia Villarroel, Claudia Hurtado, Kento Inada, Hiroshi Kawachi, Daniela Simian, Maria T. Vial, Marcela Figueroa, Magdalena Castro, Udo Kronberg, Francisco Lopez-Kostner. Expression levels of orexin receptor 1 in different stages of colorectal cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5167.

Inflammatory bowel disease: A descriptive study of 716 local Chilean patients

AIM: To demographically and clinically characterize inflammatory bowel disease (IBD) from the local registry and update data previously published by our group.

METHODS: A descriptive study of a cohort based on a registry of patients aged 15 years or older who were diagnosed with IBD and attended the IBD program at Clínica Las Condes in Santiago, Chile. The registry was created in April 2012 and includes patients registered up to October 2015. The information was anonymously downloaded in a monthly report, and the information on patients with more than one visit was updated. The registry includes demographic, clinical and disease characteristics, including the Montreal Classification, medical treatment, surgeries and hospitalizations for crisis. Data regarding infection with Clostridium difficile (C. difficile) were incorporated in the registry in 2014. Data for patients who received consultations as second opinions and continued treatment at this institution were also analyzed.

RESULTS: The study included 716 patients with IBD: 508 patients (71%) were diagnosed with ulcerative colitis (UC), 196 patients (27%) were diagnosed with Crohn’s disease (CD) and 12 patients (2%) were diagnosed with unclassifiable IBD. The UC/CD ratio was 2.6/1. The median age was 36 years (range 16-88), and 58% of the patients were female, with a median age at diagnosis of 29 years (range 5-76). In the past 15 years, a sustained increase in the number of patients diagnosed with IBD was observed, where 87% of the patients were diagnosed between the years 2001 and 2015. In the cohort examined in the present study, extensive colitis (50%) and colonic involvement (44%) predominated in the patients with UC and CD, respectively. In CD patients, non-stricturing/non-penetrating behavior was more frequent (80%), and perianal disease was observed in 28% of the patients. There were significant differences in treatment between UC and CD, with a higher use of corticosteroids, and immunosuppressive and biological therapies was observed in the patients with CD (P < 0.05 and P < 0.01). Significant surgical differences were also observed: 5% of the UC patients underwent surgery, whereas 38% of the CD patients required at least one surgery (P < 0.01). The patients with CD were hospitalized more often during their disease course than the patients with UC (55% and 35% of the patients, respectively; P < 0.01). C. difficile infection was acquired by 5% of the patients in each group at some point during the disease course. Nearly half of the patients consulted at the institution for a second opinion, and 32% of these individuals continued treatment at the institution.

CONCLUSION: IBD has continued to increase in the study cohort, slowly approaching the level reported in developed countries.

[Molecular analysis of sporadic colon cancer]

BACKGROUND

In Chile, colorectal cancer (CRC) is often diagnosed in late stages. Thus, surgical treatment must be complemented with chemotherapy. KRAS mutations and microsatellite instability have been detected in these tumors. However, the response to treatment in patients without KRAS mutations varies and requires a better understanding.

AIM

To determine the frequency and distribution of somatic point mutations in KRAS, BRAF and PIK3CA genes and microsatellite instability status (MSI) in patients with colon cancer (CC).

MATERIAL AND METHODS

A prospective observational study of patients undergoing surgery for colon cancer. Tumor-derived DNA was analyzed by polymerase chain reaction (PCR) for the most frequent mutations of KRAS, BRAF and PIK3CA. PCR was also used to analyze MSI.

RESULTS

Fifty-eight patients with sporadic CC were analyzed, 16 showed KRAS mutations (G12R, G12D, G12V, G13D) and out of the 42 patients that did not show any mutation, 10 had mutations in BRAF (V600E) and PIK3CA (E542K, E545D, E545K, Q546E, H1047R). BRAF mutations alone or in combination with PIK3CA mutations were observed in 27% of high MSI tumors and in 2% of tumors without instability (p < 0.049). A higher percentage of high MSI tumors were located in the right colon (p < 0.001), and showed BRAF mutation (p < 0.020).

CONCLUSIONS

The highest percentage of high MSI and BRAF mutations was observed in the right colon. Therefore, this study suggests the presence of different molecular features between right and left colon tumors that should be considered when defining the therapeutic management.

[Differences by age in clinical features of inflammatory bowel disease]

BACKGROUND

Approximately, 15% of patients with Inflammatory Bowel Disease (IBD) are diagnosed at 60 years of age or more.

AIM

To characterize and compare clinical variables between patients with IBD aged 60 years or more and their younger counterparts.

MATERIAL AND METHODS

Retrospective study based on a registry of IBD patients diagnosed between the years 1976 and 2014.

RESULTS

Four hundred and nine IBD patients were included. Among them, 294 had Ulcerative Colitis (UC), 104 had Crohn's Disease (CD) and eleven had an indeterminate IBD. Forty-six patients (11.2%) were older than 60 years and 16 (3.9%) had been diagnosed after this age. When comparing patients by age, those aged 60 years or more had a higher frequency of CD and indeterminate IBD (p < 0.01) and a lower ileocolic location in CD (p = 0.02). Both groups were similar in terms of hospitalization due to IBD flare, surgery, use of steroids, immunosuppressive or biological therapies and drug-related adverse events. When analyzing age at diagnosis of IBD, patients diagnosed at ages of 60 years or more had a lower frequency of UC (p < 0.01), a higher frequency of exclusive colonic involvement (p = 0.01), and lower use of mesalamine (p < 0.01). There were no differences in drug-related adverse events, hospitalizations due to IBD flares and surgery according to age at diagnosis.

CONCLUSIONS

In this population, clinical features of IBD in older patients were similar to those in younger patients.

International collaboration between Japan and Chile to improve detection rates in colorectal cancer screening

BACKGROUND

In Chile, mortality from colorectal cancer (CRC) has increased rapidly. To help address this issue, the Prevention Project for Neoplasia of the Colon and Rectum (PRENEC) program was initiated in 2012 with intensive support from Tokyo Medical and Dental University (TMDU) in Tokyo, Japan, as part of an international collaboration.

METHODS

From June 2012 to July 2014, a total of 10,575 asymptomatic participants were enrolled in PRENEC. Participants with positive immunochemical fecal occult blood test (iFOBT) results or a family history of CRC underwent colonoscopy. The colonoscopy results from a similar, previous project in Chile (PREVICOLON) were compared with those from PRENEC. Furthermore, the initial colonoscopies of 1562 participants in PRENEC were analyzed according to whether the colonoscopists were from TMDU or Chile.

RESULTS

The complete colonoscopy, adenoma detection, and cancer detection rates were 88.0%, 26.7%, and 1.1%, respectively, in PREVICOLON, while the corresponding values were 94.4%, 41.8%, and 6.0%, respectively, in PRENEC. In PRENEC, 107 cases of CRC were detected, amounting for 1.0% of all participants. Considering initial colonoscopies in PRENEC, the complete colonoscopy, adenoma detection, and cancer detection rates were 97.4%, 45.3%, and 9.3%, respectively, for physicians at TMDU and 93.3%, 41.5%, and 5.1%, respectively for Chilean physicians. The detection rates of intramucosal cancer were 7.3% and 3.7%, respectively, for TMDU and Chilean physicians.

CONCLUSIONS

Quality indicators of colonoscopy substantially improved from PREVICOLON to PRENEC. The assessments made by Chilean physicians alone were improved in PRENEC, but remained better in the TMDU group. Moreover, physicians from TMDU detected more CRCs than Chilean physicians, especially at earlier stages.

[Inflammatory bowel disease. Experience in 316 patients]

BACKGROUND

The incidence and prevalence of Inflammatory Bowel Disease (IBD) has increased.

AIM

To determine demographic and clinical characteristics of patients with IBD in a Chilean private hospital.

PATIENTS AND METHODS

Review of a prospective registry of patients with IBD, started on 2012. It includes clinical, imaging, endoscopical and pathological information of patients.

RESULTS

Data of 316 patients with IBD, aged 16 to 86 years (56% females), were analyzed. Ulcerative Colitis (UC), Crohn´s and non-classifiable IBD were diagnosed in 230, 77 and 9 patients, respectively. The disease was diagnosed in 82% of patients in the period between 2002 and 2012. There was a peak in the diagnosis of both UC and CD between 20 and 39 years of age, without gender differences. The disease switched from UC to CD in six patients. In four, there was a change in disease behavior. Thirty eight patients were treated with biological therapy. The median lapse between the diagnosis and the use of biological therapy was 1 year in patients diagnosed after 2007, compared with 5.5 years among those patients diagnosed before 2007 (p = 0.001). There was a trend towards a higher requirement of surgery until 2006. Subsequently there was a stabilization of the requirement, concomitant with the incorporation of biological therapy.

CONCLUSIONS

An adequate registry of IBD patients is necessary to improve demographic and clinical characteristics. A national registry is needed to assess the epidemiological changes of IBD in Chile.

[KRAS gene somatic mutations in Chilean patients with colorectal cancer]

BACKGROUND

The molecular testing of KRAS mutation status in metastatic colorectal cancer patients is mandatory to identify patients eligible for anti-epidermal growth factor receptor monoclonal antibody therapy.

AIM

To report the frequency of KRAS gene mutations in Chilean patients with colorectal cancer (CRC).

MATERIAL AND METHODS

A cohort of 262 Chilean patients with CRC aged 26 to 90 years (53% males), was studied. KRAS mutation status was analyzed by real-time polymerase chain reaction and correlated with clinicopathological data.

RESULTS

Ninety-eight patients (37%) were positive for KRAS mutations. G12D was the most common mutation with a frequency of 36.7%, followed by G12V (25.5%), G13D (17.3%), G12A (7.1%), G12C (6.1%), G12S (5.1%) and G12R (2%). The frequency of the mutation in left, right colon and rectal tumors was 37.8, 32.6 and 44.9%, respectively. Among tumors with mutations, 86.7% were well or moderately differentiated tumors and the rest were poorly differentiated. No significant associations between KRAS gene mutations and other clinicopathological features of the tumor were observed.

CONCLUSIONS

The frequencies of KRAS mutations reported in this study are similar to frequencies reported for European and North-American populations, lower than in a Spanish study and higher than in a Peruvian study.

[Development of malignant tumors in patients with inflammatory bowel disease]

BACKGROUND

The chronic inflammation of the intestinal mucosa, the extra-intestinal manifestations of the disease and the immunosuppressive treatment of inflammatory bowel disease may increase cancer risk.

AIM

To report the demographic and clinical features of patients with IBD who developed a malignant tumor.

MATERIAL AND METHODS

Retrospective analysis of an IBD patient registry of a private clinic, diagnosed between 1976 and 2014.

RESULTS

437 subjects were included, aged 15-88 years (58% women). Seventy two percent of patients had ulcerative colitis. The median time of follow up was 6 years. Ten patients (2.3%) developed a malignant tumor. In four, the tumor could be related to IBD (two colorectal cancers, one cholangiocarcinoma and one chronic myeloid leukemia (CML)). Two of 45 patients treated with biological therapy developed a tumor (CML and hypernephroma). Three of 170 patients on immunosuppressive treatment developed tumors. Only one had a tumor possibly related with the use of azathioprine (non-melanoma skin cancer). In only two patients, the treatment was changed at the time of their cancer diagnosis, from immunosuppressive medications to mesalamine.

CONCLUSIONS

Only a small proportion of these patients with IBD developed a malignant tumor. The treatment of IBD has to be determined by the severity of the disease and not by the fear of developing a neoplasia. Following recommendations is fundamental to decrease the possibility of developing this complication.

Abstract 2230: Gene mutations and deletions inactivates PTEN tumor suppressor in Chilean colon cancer patients

Introduction. Tumor suppressor PTEN acts as a negative regulator of the PI3K/AKT/mTOR pathway, thus controlling cell survival and proliferation. Mutations or deletions inactivating PTEN function lead to over-activation of the PI3K/AKT/mTOR pathway in cancer. PTEN gene alterations have been described in different types of tumors. In colon cancer these mutations range from 1% to 29% of the cases. The aim of this study was to determine the prevalence of PTEN mutations and/or deletions in Chilean colon cancer patients. Methods: ninety-one colon cancer patients were recruited for this study. Genomic DNA from normal and tumor tissue was obtained, and the deletion of PTEN locus was determined by PCR amplification of three STR markers flanking PTEN, and two intragenic markers. To search point mutations we amplified exons 7 and 8 by PCR, and sequenced. PTEN expression was evaluated through immunohistochemistry. Results: We observed deletion events in 9.8% (9/91) of tumors, and inactivating mutations in 5.5% (5/91). Two tumors presented a deletion in one allele and a mutation in the other. Immunohistochemistry detected a very weak expression of PTEN in 55/76 tumors. Conclusions: 15.4 % (12/91) of tumors have PTEN gene inactivated. We observed that deletion was a frequent mechanism for PTEN inactivation in Chilean colon cancer patients.

Note: This abstract was not presented at the meeting.

Citation Format: Gonzalo Encina, Karin Alvarez, Paulina Orellana, Ana María Wielandt, Cynthia Villarroel, Daniela Simian, Luis Contreras, Udo Kronberg, Francisco López, Pilar Carvallo. Gene mutations and deletions inactivates PTEN tumor suppressor in Chilean colon cancer patients. [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 2230. doi:10.1158/1538-7445.AM2014-2230

Abstract 2232: Next generation sequencing of the EGFR signaling pathway in colon cancer tumors from Chilean patients

Introduction: The Epidermal Growth Factor Receptor (EGFR) signaling pathway regulates key cell functions like proliferation and survival. This pathway presents two signaling cascades, RAS/RAF/MAPK and PIK3/PTEN/AKT/mTOR. Mutations in different components of the EGFR pathway have been described in different cancers. This pathway is a therapeutic target for monoclonal antibodies and tyrosine kinase inhibitors based therapies. Additionally, in advanced colorectal cancer patients, somatic KRAS mutations are response predictors for biological therapy with anti-EGFR antibody. The sensitivity of the mutations detection methods is key to a proper application of personalized therapeutic strategies. Traditionally, somatic mutations are detected by Sanger sequencing and real-time PCR. We determined the presence of mutations in specific genes of the EGFR pathway in colon cancer tumors from Chilean patients. Methods: DNA was extracted from twenty-eight fresh frozen tumor samples. DNA libraries were created using SureSelect (Agilent) designed for the analysis of EGFR, KRAS, BRAF, MAP2K1, PIK3CA, PIK3R1 and PTEN genes. Next generation sequencing was performed in MiSeq sequencer (Illumina) at Sistemas Genómicos (Spain). Results: Sequencing coverage varied between 100 and 250 readings between tumors, which assures the real presence of the changes. This technique allows detecting mutations that are present in a smaller percentage of tumoral cells, as low as 20% in the sample. Pathogenic mutations were identified in 19 out of the 28 tumors. Mutations were found in KRAS (p.Gly12Asp, p.Gly12Arg, p.Gly12Val and p.Gly12Cys), BRAF (p.Val600Glu and p.Gly606Glu), PIK3CA (p.Glu542Lys, p.Glu545Lys, p.Glu545Gln, p.Ala1035Val, p.Asp1045Val and p.His1047Arg) and PTEN (p.Lys267ArgfsX9). Five tumors presented mutations in both branches of the EGFR signaling pathway (KRAS-PIK3CA, BRAF-PIK3CA and BRAF-PTEN). Three allelic variants were identified in MAP2K1 and PIK3R1. Mutations that were identified in KRAS, BRAF and PIK3CA genes corresponded to gain of function mutations while a change found in PTEN gene corresponded to a loss of function mutation. Finally, mutations in PIK3CA and KRAS of 6 tumors were not previously detected by Sanger sequencing. Discussion: Mutations were found in 68% of analyzed tumors. Eighteen percent of the tumors presented mutations in two genes. Forty-six percent of mutations were identified in KRAS gene. Three allelic variants of unknown significance were detected which have not been described in cancer mutations nor in SPNs databases. Therefore, it is necessary to perform functional studies to determine the effect on protein function. Next generation sequencing allowed us to obtain more reliable and reproducible results, and was able to detect mutations present in a low percentage of tumoral cells in the sample, maybe due to tumoral heterogeneity or contamination with normal cells. FONDECYT 1111020

Citation Format: Karin Alvarez, Paulina Orellana, Cynthia Villarroel, Gonzalo Encina, Daniela Simian, Camila Estay, Maki Kobayashi, Hiroshi Kawashi, Udo Kronberg, Francisco Lopez, Pilar Carvallo. Next generation sequencing of the EGFR signaling pathway in colon cancer tumors from Chilean patients. [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 2232. doi:10.1158/1538-7445.AM2014-2232

[Lynch syndrome: selection of families by microsatellite instability and immunohistochemistry]

BACKGROUND

Selection of patients with Lynch Syndrome (LS) for a genetic study involves the application of clinical criteria. To increase the rate of identification of mutations, the use of molecular studies as Microsatellite Instability (MSI) and Immunohistochemistry (IHC) in the tumor has been proposed.

AIM

To demonstrate the usefulness of MSI and IHC in the detection of mutations in patients with LS.

MATERIAL AND METHODS

From our Familial Colorectal Cancer Registry, families suspected of LS were selected according to Amsterdam or Bethesda clinical criteria. Screening of germline mutations of MLH1, MSH2 and MSH6 genes was performed. In addition, analysis of MSI and IHC were performed in colorectal tumors.

RESULTS

A total of 35 families were studied (19 met Amsterdam and 16 met Bethesda criteria). Twenty one families harbored a germline alteration in MLH1, MSH2 or MSH6 (18 Amsterdam and 3 Bethesda). In these families, eighteen different alterations were found, 15 of which were mutations and 3 corresponded to variants of uncertain pathogenicity. On the other hand, 80% of the tumors showed positive microsatellite instability (27 MSI-high and 1 MSI-low), and immunohistochemical testing showed that 77% of tumors had the loss of a protein. Correlation between results of tumor molecular studies and the finding of germline nucleotide change showed that IHC and MSI predicted mutations in 81 and 100% of patients, respectively.

CONCLUSIONS

MSI and IHC can efficiently select patients with a high probability of carrying a mutation in DNA repair genes.

[Homozygous germline mutation in MUTYH gene in familial adenomatous polyposis]

Recently, MUTYH mutations have been reported to predispose to the development of polyposis. However, polyposis caused by mutations in MUTYH has been characterized as an autosomal recessive hereditary disease, different from the autosomal dominant pattern observed in polyposis caused by APC mutations. We report a 41-year-old female consulting for anemia. Colonoscopy detected multiple sessile polyps and a cecal carcinoma. The patient was operated and in the surgical piece, the tumor invaded serosa and there was lymph node involvement. Approximately 100 polyps were found. The patient received 5-fluorouracil, as adjuvant therapy. The patient had a sister (of a total of 12 brothers) with a colorectal carcinoma. The genetic study identified a homozygous mutation of the MUTYH gene, called c.340T > C, that produces an amino acid change of tyrosine for histidine called p.Y114H. The sister with colorectal cancer was a heterozygous carrier of this mutation.

Abstract 5551: Somatic mutations in KRAS, BRAF and PIK3CA genes in Chilean patients with sporadic colorectal cancer: Correlation with clinical and histological features

Background: KRAS, BRAF and PIK3CA proto-oncogenes encode for proteins involved in epidermal growth factor receptor (EGFR) signaling pathways. Activating mutations in these genes may contribute to tumor development and induce resistance to biological therapies in patients with metastatic colorectal cancer (CRC). Furthermore, microsatellite instability (MSI) has been proposed as a prognostic and predictive marker in sporadic CRC. Patients and methods: In tumors of patients undergoing surgery for sporadic CRC at our institution, somatic mutations in KRAS, BRAF and PIK3CA genes were assessed by single-strand conformation polymorphism(SSCP) and direct sequencing. MSI analysis was performed using the 5 markers of the standard NIH panel. Clinical and histopathological data of the patients were obtained from our prospectively maintained database. Results: A total of 58 patients with a nearly equal gender distribution and a mean age of 62 years were included. A total of 31 mutations in 26 patients were identified. The frequency of mutations was 28% for KRAS, 9% for BRAF and 17% for PIK3CA. No difference was found in the mutation frecuency between the different tumor locations (42,1% in right colon vs. 46,2% in left colon/rectum, P= NS) or lymphnode status (37,5% in node positive vs. 50% in node negative tumors, P=0,346). Tumors with deeper invasion showed a higher frecuency of mutations, but this tendency did not reach statistical significance (32% in pT1-2 vs. 51% in pT3-4, P=0,157). In 26% of the patients, MSI-high was observed, more frecuently in tumors of the right colon (57,9% vs 10,3%, P&lt;0,001). Patients with BRAF mutations, a higher proportion of MSI-high was found compared to BRAF wildtype (27% vs. 2,3%, P=0,013). There was no correlation between the lymphnode positivity and MSI status. Conclusion: Our results show that the frequency of mutations in patients with sporadic CRC in Chile is similar to that described in other countries. The presence of MSI-high is correlated with tumors in the right colon and with mutations in the BRAF gene. The tendency of finding more mutations in locally advanced and node-negative tumors needs to be confirmed in future studies with a larger number of patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5551. doi:1538-7445.AM2012-5551

Abstract 2229: Detection of somatic mutations in KRAS gene in Chilean patients with advanced colorectal cancer

Introduction: At present, the application of tailored oncologic therapies requires previous performance of mutational analysis of certain genes. In patients with advanced colorectal cancer (CRC), it is essential to detect the presence of activating mutations in the KRAS gene to predict the effectiveness of certain treatments.

Purpose: To determine the presence of KRAS mutations in Chilean patients with advanced CRC, and correlate the mutational status with clinical-pathological data.

Methods: Between October 2009 and August 2010, we prospectively studied the presence of somatic mutations in the KRAS gene in codons 12 and 13 in biopsies of patients with advanced colorectal cancer by allele specific and real time PCR kit. The results were registered in a database, along with the pathology results and clinical data of the patients. Statistical analysis was performed by Student T test and Chi-square test. A p&gt;0.05 was no significant.

Results: A total of 123 patients were analyzed, with a mean age of 61 years and male predominance (60%). Mutations were detected in 47 (39%) of them and only in 2 cases the study was inconclusive. The distribution of the different mutations was as follows: 12Asp (32%), 12Val (26%), 13Asp (19%), 12Cys (11%), 12Ala (6%) and 12Ser (6%). Separated by gender, the detection rate was higher in male patients (45% vs 30%) (p=0.59). Analyzing the data by location of tumor, we found that mutations in right colon tumors was present in 26% (6/23), whereas tumors of the left colon and sigmoid were 43% (16/37) (p=0.1). Mutations detected in patients with lymph node metastasis was 42% comparing to node-negative patients (32%) (p=0.3). In patients with poorly differentiated tumors we found 50% mutations compared to well differentiated (18%) (p=0.08). Finally, the mortality was similar when we compared between WT and mutations patients.

Conclusions: In Chile, 39% of patients with advanced CRC carry mutations in KRAS gene. This result is similar to that described in other populations. There is a tendency to a higher mutation rate in males, patients with left colon cancer, poorly differentiated tumors and patients with lymph nodal involvement.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2229. doi:10.1158/1538-7445.AM2011-2229

Abstract 2114: Deletions/Duplications detection by MLPA in Chilean families with hereditary colorectal cancer: Lynch syndrome and FAP

The main variants of colorectal cancer hereditary are Familial Adenomatous Polyposis (FAP) and Lynch Syndrome, which account for approximately 5% of total cases of colorectal cancer. Point mutations in APC and MMR genes are responsible of about 85% and 50% of Chilean FAP (classic phenotype) and Lynch Syndrome (Amsterdam criteria) families, respectively. Different molecular strategies are available for the detection of mutations in these genes. Studies in other populations have identified deletions and duplications of one or more consecutive exons account for around 50% and 10-20% of the total alterations in MMR and APC genes, respectively. The aim of our work was the detection of genomic deletion/duplication through Multiplex Ligation-Dependent Probe Amplification (MLPA) in Lynch Syndrome and FAP patients in Chile. In this study, we analized alterations in MLH1 and MSH2 in 26 Lynch Syndrome families (5 Amsterdam and 21 Bethesda families), and in APC in 10 FAP families (6 classic and 4 attenuated), all of them non carriers of point mutations in these genes. We identified 3 different alterations in the MLH1 in four Amsterdam families, all of them are 0.5 times deletion, which are located: exon 1 in one family, exon 19 in two families, and exons 14 and 15 in one family. In the MSH2, in one Amsterdam family we detected a 0.5 time deletion of exon 2. In the APC, we found 2 different alterations in three classic FAP families: in one family we detected a 0.5 times deletion of the whole gene including promoter region, and in two families we found a 1.5 time amplification of exons 1, 2 and 3. These alterations were confirmed in other relatives of these families and in two independent MLPA analysis. The deletion of exon 19 in MLH1 and the amplification of exons 1, 2 and 3 in APC have not been previously described in other populations. In conclusion, genomic deletions/duplications were only detected in 5 Lynch Syndrome families that fulfilled Amsterdam criteria, and in 3 FAP families with classic phenotype. The detection of different mutations involved in these syndromes, allows the development of prevention strategies of these diseases. Financed by Cleveland Clinic Foundation and Las Condes Clinic.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2114.