Investigating a clinically actionable BRAF mutation for monitoring low-grade serous ovarian cancer: A case report.

Low-grade serous ovarian cancer (LGSOC) poses a specific clinical challenge due to advanced presentation at diagnosis and the lack of effective systemic treatments. The aim of this study was to use a precision medicine approach to identify clinically actionable mutations in a patient with recurrent LGSOC. Primary, metastatic and recurrence tissue, and blood samples were collected from a stage IV LGSOC patient. Single-gene testing for clinically actionable mutations (BRAF V600, KRAS and NRAS) and subsequent whole-exome sequencing (WES) were performed. Droplet digital PCR was used to evaluate the presence of an identified BRAF D594G mutation in the matched plasma cell-free DNA (cfDNA). No clinically actionable mutations were identified using single-gene testing. WES identified a BRAF D594G mutation in six of seven tumor samples. The patient was commenced on a MEK inhibitor, trametinib, but with minimal clinical response. A newly designed ddPCR assay detected the BRAF alteration in the matched tissues and liquid biopsy cfDNA. The identification and sensitive plasma detection of a common "druggable" target emphasises the impact of precision medicine on the management of rare tumors and its potential contribution to novel monitoring regimens in this field.

Muir-Torre syndrome: a case of unusual coexisting genetic mutations.

Patients with Muir-Torre syndrome (MTS) commonly have germline mismatch repair mutations in MLH1, MSH2 or MSH6, with a strong predominance in MSH2. A subset of approximately one-third of patients will instead have an autosomal recessive base excision repair mutation in MUTYH called MUTYH polyposis. To the best of our knowledge, this is the first report of coexisting germline MSH2 and MUTYH mutations in a patient with MTS.

Tumor regression grading after neoadjuvant treatment of esophageal and gastroesophageal junction adenocarcinoma: results of an international Delphi consensus survey.

Complete histopathologic tumor regression after neoadjuvant treatment is a well-known prognostic factor for survival among patients with adenocarcinomas of the esophagus and gastroesophageal junction. The aim of this international Delphi survey was to reach a consensus regarding the most useful tumor regression grading (TRG) system that could represent an international standard for histopathologic TRG grading of gastroesophageal carcinomas. Fifteen pathologists with special interest in esophageal and gastric pathology participated in the online survey. The initial questionnaire contained of 43 statements that addressed the following topics: (1) specimen processing, (2) gross examination, (3) cross sectioning, (4) staining, (5) Barrett's esophagus, (6) TRG systems, and (7) TRG in lymph node (LN). Participants rated the items using a 5-point Likert style scale and were encouraged to write comments for each statement. The expert panel recommended a 4-tiered TRG system for assessing the primary tumor: grade 1: No residual tumor (complete histopathologic tumor regression), grade 2: less than 10% residual tumor (near-complete regression), grade 3: 10%-50% residual tumor (partial regression), grade 4: greater than 50% residual tumor (minimal/no regression), combined with a 3-tiered system for grading therapeutic response in metastatic LNs: grade a: no residual tumor (complete histopathologic TRG), grade b: partial regression (tumor cells and regression), grade c: no regression (no sign of tumor response). This TRG grading system can be recommended as an international standard for histopathologic TRG grading in esophageal and gastroesophageal junction adenocarcinoma.

Clinicopathological features and oncological outcomes of patients with young-onset rectal cancer.

BACKGROUND: The incidence of rectal cancer among adults aged less than 50 years is rising. Survival data are limited and conflicting, and the oncological benefit of standard neoadjuvant and adjuvant therapies is unclear. METHODS: Disease-specific outcomes of patients diagnosed with rectal cancer undergoing surgical resection with curative intent between 2006 and 2016 were analysed. RESULTS: A total of 797 patients with rectal cancer were identified, of whom 685 had surgery with curative intent. Seventy patients were younger than 50 years and 615 were aged 50 years or more. Clinical stage did not differ between the two age groups. Patients aged less than 50 years were more likely to have microsatellite instability (9 versus 1·6 per cent; P = 0·003) and Lynch syndrome (7 versus 0 per cent; P < 0·001). Younger patients were also more likely to receive neoadjuvant chemoradiotherapy (67 versus 53·3 per cent; P = 0·003) and adjuvant chemotherapy (41 versus 24·2 per cent; P = 0·006). Five-year overall survival was better in those under 50 years old (80 versus 72 per cent; P = 0·013). The 5-year disease-free survival rate was 81 per cent in both age groups (P = 0·711). There were no significant differences in the development of locoregional recurrence or distant metastases. CONCLUSION: Despite accessing more treatment, young patients have disease-specific outcomes comparable to those of their older counterparts.

ANTECEDENTES: La incidencia de cáncer de recto entre adultos menores de 50 años está aumentando. Los datos de supervivencia son limitados y contradictorios, y el beneficio oncológico de los tratamientos neoadyuvantes y adyuvantes estándares no está claro. MÉTODOS: Se analizaron los resultados específicos relacionados con la enfermedad en pacientes diagnosticados de cáncer de recto operados con intención curativa entre 2006 y 2016. RESULTADOS: Se identificaron un total de 797 pacientes con cáncer de recto, de los cuales 685 fueron intervenidos quirúrgicamente con intención curativa. Setenta tenían menos de 50 años y 615 tenían 50 años o más. No hubo diferencias en el estadio clínico entre los dos grupos de edad. Los pacientes menores de 50 años tenían más probabilidades de tener inestabilidad de microsatélites (9% versus 2%, P = 0,003) y síndrome de Lynch (7% versus 0%, P ≤ 0,001). La supervivencia global a los 5 años fue mayor en los pacientes de menos de 50 años (80% y 72%; P = 0,013). La supervivencia libre de enfermedad a los 5 años fue del 81% en ambos grupos de edad (P = 0,711). No hubo diferencias significativas en el desarrollo de recidiva locorregional o metástasis a distancia. Los pacientes más jóvenes tenían más probabilidades de recibir quimiorradioterapia neoadyuvante (67% versus 53%, P = 0,003) y quimioterapia adyuvante (41% versus 24%, P = 0,006). CONCLUSIÓN: A pesar de tener acceso a más tratamientos, los pacientes jóvenes han presentado resultados específicos relacionados con la enfermedad comparables a sus homólogos de mayor edad.

Colorectal Serrated Neoplasia: An Institutional 12-Year Review Highlights the Impact of a Screening Programme.

BACKGROUND: As the malignant potential of sessile serrated lesions/polyps (SSL/Ps) and traditional serrated adenomas (TSAs) has been clearly demonstrated, it is important that serrated polyps are identified and correctly classified histologically. AIM: Our aim was to characterize the clinicopathological features of a series of SSL/Ps & TSAs, to assess the accuracy of the pathological diagnosis, the incidence, and the rate of dysplasia in SSL/Ps & TSAs. METHODS: We identified all colorectal serrated polyps between 01/01/2004 and 31/05/2016, by searching the laboratory information system for all cases assigned a "serrated adenoma" SNOMED code. All available and suitable slides were reviewed by one pathologist, who was blinded to the original diagnosis and the site of the polyp. Subsequently discordant cases, SSL/Ps with dysplasia, and all TSAs were reviewed by a second pathologist. RESULTS: Over a 149-month period, 759 "serrated adenoma" polyps were identified, with 664 (from 523 patients) available for review. 41.1% were reviewed by both pathologists; 15.1% (100/664) were reclassified, with the majority being changed from SSL/P to hyperplastic polyp (HYP) (66/664; 9.9%). 80.3% of these HYPs were located in the left colon, and the majority exhibited prolapse effect. There were 520 SSL/Ps (92.2%) & 40 TSAs (7.1%). The majority of SSL/Ps were in the right colon (86.7%) and were small (64.5% <1 cm), while most TSAs were in the left colon (85.7%) and were large (73.1%≥1 cm). 6.7% of SSL/Ps exhibited dysplasia, the majority of which were large (66.7%≥1 cm). Following consensus review, 13/520 (2.5%) SSL/Ps were downgraded from SSL/P with dysplasia to SSL/P without dysplasia. Detection of SSL/Ps peaked in the most recent years reviewed (87.5% reported between 2013 and 2016, inclusive), coinciding with the introduction of "BowelScreen" (the Irish FIT-based colorectal cancer screening programme). CONCLUSIONS: Awareness of, and adherence to, diagnostic criteria is essential for accurate classification of colorectal polyps.

Effects of CDX2 on prognosis and chemotherapy responsiveness in mismatch repair-deficient colorectal cancer.

BACKGROUND: Caudal-related homeobox transcription factor 2 (CDX2) is an intestine-specific transcription factor implicated in tumour differentiation, proliferation, cell adhesion and migration. Negative CDX2 status (CDX2-) is associated with worse prognosis in colorectal cancer and may identify high-risk stage II disease that benefits from adjuvant chemotherapy. This observational study investigated whether CDX2- is associated with prognosis or response to chemotherapy in the mismatch repair-deficient (dMMR) phenotype of colorectal cancer. METHODS: Patients with resectable dMMR colorectal cancer were eligible for inclusion. The prognostic and predictive value of CDX2 expression on the presence of lymph node metastasis (LNM) and survival was investigated. CDX2 status was determined via immunohistochemistry using the Leica Bond™ CDX2 (clone EP25) ready-to-use primary antibody. RESULTS: Some 235 of 238 consecutive dMMR tumours were assessed for CDX2 status. CDX2- was observed in 15·7 per cent of colorectal cancer. Interobserver agreement was excellent (κ = 0·863; P < 0·001). CDX2- was significantly associated with female sex, increased size, advanced stage, worse conventional and poorly differentiated cluster (PDC) grade, mucinous morphology, perineural and lymphovascular invasion, and pN status (all P ≤ 0·038). CDX2- was not associated with LNM or survival in multivariable analysis. Independent predictors of LNM were PDC grade (odds ratio (OR) 4·12, 95 per cent c.i. 1·76 to 9·63; P = 0·001) and extramural venous invasion (OR 3·79, 1·62 to 8·85; P = 0·002). Budding (hazard ratio (HR) 2·79, 95 per cent c.i. 1·60 to 4·87; P < 0·001), pT status (HR 3·59, 1·29 to 10·01; P = 0·015) and adjuvant chemotherapy (HR 2·07, 1·15 to 3·74; P = 0·016) were independently associated with worse disease-free survival. CONCLUSION: CDX2- does not confer a worse prognosis in the dMMR phenotype of colorectal cancer. The MMR status of patients with colorectal cancer should be determined before assessing CDX2 status.

Transcriptional subtyping and CD8 immunohistochemistry identifies poor prognosis stage II/III colorectal cancer patients who benefit from adjuvant chemotherapy.

PURPOSE: Transcriptomic profiling of colorectal cancer (CRC) has led to identification of four consensus molecular subtypes (CMS1-4), which have prognostic value in stage II/III disease. More recently, the Colorectal Cancer Intrinsic Subtypes (CRIS) classification system has helped to define the biology specific to the epithelial component of colorectal tumors. However, the clinical value of these classifications in predicting response to standard-of-care adjuvant chemotherapy remains unknown. PATIENTS AND METHODS: Using samples from 4 European sites, we assembled a novel stage II/III CRC patient cohort and performed transcriptomic profiling on 156 samples, targeted sequencing and generated a tissue microarray to enable integrated "multi-omics" analyses. We also accessed data from 2 published stage II/III CRC patient cohorts: GSE39582 and GSE14333 (479 and 185 samples respectively). RESULTS: The epithelial-rich CMS2 subtype of CRC benefitted significantly from adjuvant chemotherapy treatment in both stage II and III disease (p=0.02 and p<0.0001 respectively), while the CMS3 subtype significantly benefitted in stage III only (p=0.00073). Following CRIS sub-stratification of CMS2, we observed that only the CRIS-C subtype significantly benefitted from adjuvant chemotherapy in stage II and III disease (p=0.0081 and p<0.0001 respectively), while CRIS-D significantly benefitted in stage III only (p=0.0034). We also observed that CRIS-C patients with low levels of CD8+ tumor-infiltrating lymphocytes were most at risk of relapse in both stage II and III disease (p=0.0031). CONCLUSION: Patient stratification using a combination of transcriptional subtyping and CD8 immunohistochemistry analyses is capable of identifying poor prognostic stage II/III patients who benefit from adjuvant standard-of-care chemotherapy. These findings are particularly relevant for stage II disease, where the overall benefit of adjuvant chemotherapy is marginal.

Recommendations for reporting tumor budding in colorectal cancer based on the International Tumor Budding Consensus Conference (ITBCC) 2016

Tumor budding is a well-established independent prognostic factor in colorectal cancer but a standardized method for its assessment has been lacking. The primary aim of the International Tumor Budding Consensus Conference (ITBCC) was to reach agreement on an international, evidence-based standardized scoring system for tumor budding in colorectal cancer. The ITBCC included nine sessions with presentations, a pre-meeting survey and an e-book covering the key publications on tumor budding in colorectal cancer. The 'Grading of Recommendation Assessment, Development and Evaluation' method was used to determine the strength of recommendations and quality of evidence. The following 10 statements achieved consensus: tumor budding is defined as a single tumor cell or a cell cluster consisting of four tumor cells or less (22/22, 100%). Tumor budding is an independent predictor of lymph node metastases in pT1 colorectal cancer (23/23, 100%). Tumor budding is an independent predictor of survival in stage II colorectal cancer (23/23, 100%). Tumor budding should be taken into account along with other clinicopathological features in a multidisciplinary setting (23/23, 100%). Tumor budding is counted on H&E (19/22, 86%). Intratumoral budding exists in colorectal cancer and has been shown to be related to lymph node metastasis (22/22, 100%). Tumor budding is assessed in one hotspot (in a field measuring 0.785 mm2) at the invasive front (22/22, 100%). A three-tier system should be used along with the budding count in order to facilitate risk stratification in colorectal cancer (23/23, 100%). Tumor budding and tumor grade are not the same (23/23, 100%). Tumor budding should be included in guidelines/protocols for colorectal cancer reporting (23/23, 100%). Members of the ITBCC were able to reach strong consensus on a single international, evidence-based method for tumor budding assessment and reporting. It is proposed that this method be incorporated into colorectal cancer guidelines/protocols and staging systems.

An isolated cuboid dislocation. A case report.

INTRODUCTION: Isolated cuboid dislocations are rare injuries Jacobson (1990). It is clinically significant and important in surgical education, as it is an injury and a source of lateral foot pain that can be misdiagnosed at the time of initial presentation and may be difficult to identify clinically or with imaging Drummond and Hastings (1969). PRESENTATION OF CASE: We present a case report in a 33year old rugby player, who was injured during a match after a tackle. The patient had ongoing concerns that he was not recovering following initial discharge, as he was unable to weight bear since his initial presentation to the Emergency Department (E.D.), and he had ongoing lateral foot pain. DISCUSSION: Important clinical findings include lateral foot pain, a palpable gap at the cuboid level and difficulty weight-bearing. Closed reduction is usually difficult as it can be blocked mechanically by the extensor digitorum brevis muscle or peroneus longus tendon Dobbs et al. (1969). Initial X-Rays may be inconclusive with this presentation. CT scanning is indicated if suspicion for pathology is high. Open reduction and internal fixation with Kirschner wires are usually necessary for isolated cuboid dislocations. CONCLUSION: Our take home message from this case report is that cuboid dislocations are rare injuries and are important to be aware of in reviewing X-rays in the E.D. Particularly in patients with inversion and plantar flexion type injuries to their foot and ankle joint, with an inability to weight bear and lateral midfoot pain following their injury.

The current value of determining the mismatch repair status of colorectal cancer: A rationale for routine testing.

Colorectal Cancer (CRC) is the third most prevalent cancer in men and women. Up to 15% of CRCs display microsatellite instability (MSI). MSI is reflective of a deficient mismatch repair (MMR) system and is most commonly caused by hypermethylation of the MLH1 promoter. However, it may also be due to autosomal dominant constitutional mutations in DNA MMR, termed Lynch Syndrome. MSI may be diagnosed via polymerase chain reaction (PCR) or alternatively, immunohistochemistry (IHC) can identify MMR deficiency (dMMR). Many institutions now advocate universal tumor screening of CRC via either PCR for MSI or IHC for dMMR to guide Lynch Syndrome testing. The association of sporadic MSI with methylation of the MLH1 promoter and an activating BRAF mutation may offer further exclusion criteria for genetic testing. Aside from screening for Lynch syndrome, MMR testing is important because of its prognostic and therapeutic implications. Several studies have shown MSI CRCs exhibit different clinicopathological features and prognosis compared to microsatellite-stable (MSS) CRCs. For example, response to conventional chemotherapy has been reported to be less in MSI tumours. More recently, MSI tumours have been shown to be responsive to immune-checkpoint inhibition providing a novel therapeutic strategy. This provides a rationale for routine testing for MSI or dMMR in CRC.

The lymph node ratio does not provide additional prognostic information compared with the N1/N2 classification in Stage III colon cancer.

AIM: The ratio of positive nodes to total nodes, the lymph node ratio (LNR), is a proposed alternative to the current N1/N2 classification of nodal disease. The true clinical benefit of adopting the LNR, however, has not been definitively demonstrated. This study compared the LNR with the current N1/N2 classification of Stage III colon cancer. METHOD: Patients with Stage III colon cancer were identified from a prospectively maintained database (1996-2012). The specificity and sensitivity of the N1/N2 classification in the prediction of overall survival were determined using R. A cut-off point for the LNR was determined by setting the specificity the same as for the N1/N2 classification. The sensitivity of the two methods was then compared, and bootstrapping 1000-fold was performed. This was then repeated for disease-specific survival. RESULTS: The specificity and sensitivity of the N1/N2 classification in predicting 3-year overall survival in this cohort (n = 402) was 62.2% and 52.1%, respectively. The cut-off point for the LNR was determined to be 0.27 for these data. On comparing LNR with the N1/N2 classification showed that for a given specificity, the LNR did not provide a statistically significant improvement in sensitivity (52.8% vs 52.1%, P = 0.31). For disease-specific death at 3 years, the specificity and sensitivity were 60.8% and 54.6%, respectively. The LNR did not provide a statistically significant improvement (55.4% vs 54.6%, P = 0.44). CONCLUSION: Both the N1/N2 system and the LNR predict survival in colon cancer, but both have low specificity and sensitivity. The LNR does not provide additional prognostic value to current staging for overall or disease-specific survival for a given cut-off point.

Organ preservation with local excision or active surveillance following chemoradiotherapy for rectal cancer.

BACKGROUND: Organ preservation has been proposed as an alternative to radical surgery for rectal cancer to reduce morbidity and mortality, and to improve functional outcome. METHODS: Locally advanced non-metastatic rectal cancers were identified from a prospective database. Patients staged ⩾T3 or any stage N+ were referred for neoadjuvant chemoradiotherapy (CRT) (50-54 Gy and 5-fluorouracil), and were reassessed 6-8 weeks post treatment. An active surveillance programme ('watch and wait') was offered to patients who were found to have a complete endoluminal response. Transanal excision was performed in patients who were found to have an objective clinical response and in whom a residual ulcer measured ⩽3 cm. Patients were followed up clinically, endoscopically and radiologically to assess for local recurrence or disease progression. RESULTS: Of 785 patients with rectal cancer between 2005 and 2015, 362 had non-metastatic locally advanced tumours treated with neoadjuvant CRT. Sixty out of three hundred and sixty-two (16.5%) patients were treated with organ-preserving strategies - 10 with 'watch and wait' and 50 by transanal excision. Fifteen patients were referred for salvage total mesorectal excision post local excision owing to adverse pathological findings. There was no significant difference in overall survival (85.6% vs 93.3%, P=0.414) or disease-free survival rate (78.3% vs 80%, P=0.846) when the outcomes of radical surgery were compared with organ preservation. Tumour regrowth occurred in 4 out of 45 (8.9%) patients who had organ preservation. CONCLUSIONS: Organ preservation for locally advanced rectal cancer is feasible for selected patients who achieve an objective endoluminal response to neoadjuvant CRT. Transanal excision defines the pathological response and refines decision-making.

Systematic review and meta-analysis of the impact of tumour budding in colorectal cancer.

BACKGROUND: Tumour budding is a histological finding in epithelial cancers indicating an unfavourable phenotype. Previous studies have demonstrated that it is a negative prognostic indicator in colorectal cancer (CRC), and has been proposed as an additional factor to incorporate into staging protocols. METHODS: A systematic review of papers until March 2016 published on Embase, Medline, PubMed, PubMed Central and Cochrane databases pertaining to tumour budding in CRC was performed. Study end points were the presence of lymph node metastases, recurrence (local and distal) and 5-year cancer-related death. RESULTS: A total of 7821 patients from 34 papers were included, with a mean rate of tumour budding of 36.8±16.5%. Pooled analysis suggested that specimens exhibiting tumour budding were significantly associated with lymph node positivity (OR 4.94, 95% CI 3.96-6.17, P<0.00001), more likely to develop disease recurrence over the time period (OR 5.50, 95% CI 3.64-8.29, P<0.00001) and more likely to lead to cancer-related death at 5 years (OR 4.51, 95% CI 2.55-7.99, P<0.00001). CONCLUSIONS: Tumour budding in CRC is strongly predictive of lymph node metastases, recurrence and cancer-related death at 5 years, and its incorporation into the CRC staging algorithm will contribute to more effective risk stratification.

Microsatellite instability is associated with reduced disease specific survival in stage III colon cancer.

BACKGROUND: Up to 15% of colorectal cancers exhibit microsatellite instability (MSI), where errors in replication go unchecked due to defects in the mismatch repair system. This study aimed to determine survival in a large single-centre series of 1250 consecutive colorectal cancers subjected to universal MSI testing. METHODS: Clinical and pathological features of patients with colorectal cancer identified on prospectively maintained colorectal and pathology databases at St. Vincent's University Hospital from 2004 to May 2012 were examined. Mismatch repair (MMR) status was determined by immunohistochemistry. Kaplan-Meier curves, the log-rank test and Cox regression were used to associate survival with clinical and pathological characteristics. RESULTS: Of the 1250 colorectal cancers in the study period, 11% exhibited MSI (n = 138). Patients with MSI tumours had significantly lower rates of lymph node and distant metastases (MSI N+ rate: 24.8% compared with MSS N+ rate: 46.2%, p < 0.001). For Stage I and II disease MSI was associated with improved disease free survival (DSS) compared with MSS colon cancer. However, patients with Stage III MSI colon cancers had a worse DSS than those with MSS tumours. Stage III MSI tumours exhibited higher rates of lymphovascular invasion and perineural invasion than Stage I/II MSI tumours. CONCLUSION: MSI is associated with a reduced risk of nodal and distant metastases, with an improved DSS in Stage I/II colon cancer. However, when MSI tumours progress to Stage III these patients had worse outcomes and pathological features. New strategies for this cohort of patients may be required to improve outcomes.

A radiological and pathological assessment of ileocolic pedicle length as a predictor of lymph node retrieval following right hemicolectomy for caecal cancer.

BACKGROUND: In colon cancer, the number of harvested lymph nodes is critical for pathological staging. It has been proposed that the more central the mesenteric vascular ligation, the greater the nodal yield. The aim of the current study was to determine the association of radiological and pathological ileocolic pedicle length on nodal harvest following right hemicolectomy for caecal cancer. METHODS: A series of 50 patients undergoing right hemicolectomy for adenocarcinoma underwent specimen evaluation. Preoperative computed tomography images were reconstructed and analysed to determine the direct (vessel origin to caecum) ileocolic pedicle length. RESULTS: The median pathological distance from the tumour to the high vascular tie was 80 mm, and median nodal yield was 16.5 nodes. Radiological pedicle length did not correlate with the pathological distance from the tumour to the high vascular tie or nodal yield; however, the pathological pedicle length did correlate with the total nodal yield (r (2): 0.343, p = 0.015). The median pathologically determined length of colon resected (r (2): 0.153, p = 0.289), ileum resected (r (2): 0.087, p = 0.568) and total specimen length resected (r (2): 0.182, p = 0.205) did not correlate with the total nodal yield. An ileal specimen length ≤25 mm [hazard ratio (HR) 14.8, 95 % confidence interval (CI) 1.1-194.5, p = 0.040] and a well-differentiated tumour (HR 10.5, 95 % CI 1.1-95.9, p = 0.037) increased the likelihood of retrieving <12 lymph nodes. CONCLUSIONS: Based on these data, pathologic pedicle length is a determining factor in lymph node retrieval. Preoperative radiological calculation of pedicle length does not help predict the number of lymph nodes retrieved.

Altered expression of caspases-4 and -5 during inflammatory bowel disease and colorectal cancer: Diagnostic and therapeutic potential.

Caspases are a group of proteolytic enzymes involved in the co-ordination of cellular processes, including cellular homeostasis, inflammation and apoptosis. Altered activity of caspases, particularly caspase-1, has been implicated in the development of intestinal diseases, such as inflammatory bowel disease (IBD) and colorectal cancer (CRC). However, the involvement of two related inflammatory caspase members, caspases-4 and -5, during intestinal homeostasis and disease has not yet been established. This study demonstrates that caspases-4 and -5 are involved in IBD-associated intestinal inflammation. Furthermore, we found a clear correlation between stromal caspase-4 and -5 expression levels, inflammation and disease activity in ulcerative colitis patients. Deregulated intestinal inflammation in IBD patients is associated with an increased risk of developing CRC. We found robust expression of caspases-4 and -5 within intestinal epithelial cells, exclusively within neoplastic tissue, of colorectal tumours. An examination of adjacent normal, inflamed and tumour tissue from patients with colitis-associated CRC confirmed that stromal expression of caspases-4 and -5 is increased in inflamed and dysplastic tissue, while epithelial expression is restricted to neoplastic tissue. In addition to identifying caspases-4 and -5 as potential targets for limiting intestinal inflammation, this study has identified epithelial-expressed caspases-4 and -5 as biomarkers with diagnostic and therapeutic potential in CRC.

Spatial variation of the colonic microbiota in patients with ulcerative colitis and control volunteers.

OBJECTIVES: The relevance of spatial composition in the microbial changes associated with UC is unclear. We coupled luminal brush samples, mucosal biopsies and laser capture microdissection with deep sequencing of the gut microbiota to develop an integrated spatial assessment of the microbial community in controls and UC. DESIGN: A total of 98 samples were sequenced to a mean depth of 31,642 reads from nine individuals, four control volunteers undergoing routine colonoscopy and five patients undergoing surgical colectomy for medically-refractory UC. Samples were retrieved at four colorectal locations, incorporating the luminal microbiota, mucus gel layer and whole mucosal biopsies. RESULTS: Interpersonal variability accounted for approximately half of the total variance. Surprisingly, within individuals, asymmetric Eigenvector map analysis demonstrated differentiation between the luminal and mucus gel microbiota, in both controls and UC, with no differentiation between colorectal regions. At a taxonomic level, differentiation was evident between both cohorts, as well as between the luminal and mucosal compartments, with a small group of taxa uniquely discriminating the luminal and mucosal microbiota in colitis. There was no correlation between regional inflammation and a breakdown in this spatial differentiation or bacterial diversity. CONCLUSIONS: Our study demonstrates a conserved spatial structure to the colonic microbiota, differentiating the luminal and mucosal communities, within the context of marked interpersonal variability. While elements of this structure overlap between UC and control volunteers, there are differences between the two groups, both in terms of the overall taxonomic composition and how spatial structure is ascribable to distinct taxa.