Sporadic Colorectal Carcinomas Research Articles

Epithelial Smad4 Deletion Up-Regulates Inflammation and Promotes Inflammation-Associated Cancer.

Background & AimsChronic inflammation is a predisposing condition for colorectal cancer. Many studies to date have focused on proinflammatory signaling pathways in the colon. Understanding the mechanisms that suppress inflammation, particularly in epithelial cells, is critical for developing therapeutic interventions. Here, we explored the roles of transforming growth factor β (TGFβ) family signaling through SMAD4 in colonic epithelial cells.MethodsThe Smad4 gene was deleted specifically in adult murine intestinal epithelium. Colitis was induced by 3 rounds of dextran sodium sulfate in drinking water, after which mice were observed for up to 3 months. Nontransformed mouse colonocyte cell lines and colonoid cultures and human colorectal cancer cell lines were analyzed for responses to TGFβ1 and bone morphogenetic protein 2.ResultsDextran sodium sulfate treatment was sufficient to drive carcinogenesis in mice lacking colonic Smad4 expression, with resulting tumors bearing striking resemblance to human colitis–associated carcinoma. Loss of SMAD4 protein was observed in 48% of human colitis–associated carcinoma samples as compared with 19% of sporadic colorectal carcinomas. Loss of Smad4 increased the expression of inflammatory mediators within nontransformed mouse colon epithelial cells in vivo. In vitro analysis of mouse and human colonic epithelial cell lines and organoids indicated that much of this regulation was cell autonomous. Furthermore, TGFβ signaling inhibited the epithelial inflammatory response to proinflammatory cytokines.ConclusionsTGFβ suppresses the expression of proinflammatory genes in the colon epithelium, and loss of its downstream mediator, SMAD4, is sufficient to initiate inflammation-driven colon cancer. Transcript profiling: GSE100082.

Clinical, Histologic, and Immunophenotypic Features of Serrated Polyps in Patients With Inflammatory Bowel Disease.

BackgroundColorectal serrated polyps (SP), which include hyperplastic polyps (HP), sessile serrated adenomas/polyps (SSA/P), and traditional serrated adenomas, are not uncommon and have been implicated to play a role in the pathogenesis in a subset of sporadic colorectal carcinomas; however, their significance in patients with prolonged inflammatory bowel disease (IBD) remains unclear.MethodsWe retrospectively studied the clinicopathologic features, BRAF and β-catenin immunohistochemistry staining patterns in 36 SPs from 28 patients with IBD compared with 40 SPs in patients without IBD.ResultsEleven SSA/Ps and 25 HPs from IBD and site-matched controls were included. SSA/Ps in the study group were slightly more commonly seen in males (55% vs. 41%, P = 0.7) and older patients (55.2 vs. 47.8 years, P = 0.2) compared to patients with HP. They were moderately larger (7.13 mm vs. 4.83 mm, P = 0.14) and more likely located on the right (63.6% vs. 32%, P = 0.46). Smaller percentage of SSA/Ps showed BRAF staining compared to controls (55.6% vs. 73.3%, P = 0.41) and HPs showed similar features (52.0% vs. 54.2%, P = 1). β-catenin was negative in all cases. During follow-up, only one patient in the SSA/P group developed carcinoma 42 months after at the same site and two developed adenoma-like low-grade dysplasia but no patients with HPs had such findings.ConclusionsOur findings show that SPs in IBD share similar clinicodemographic and immunophenotypical features with sporadic SPs. However, patients with SSA/Ps may have a slight increase in risk of developing dysplasia compared to patients with HPs in IBD.

Oestrogen receptor beta isoform expression in sporadic colorectal cancer, familial adenomatous polyposis and progressive stages of colorectal cancer

BackgroundAmong the sex hormones, oestrogen may play a role in colorectal cancer, particularly in conjunction with oestrogen receptor-β (ERβ). The expression of ERβ isoform variants and their correlations with familial adenomatous polyposis (FAP) syndrome and sporadic colorectal carcinomas are poorly described.MethodsThis study aimed to investigate the expression levels of the ERβ1, ERβ2, ERβ4 and ERβ5 isoform variants using quantitative RT-PCR (921 analyses) in FAP, normal mucosa, adenomatous polyps and sporadic colorectal carcinomas.ResultsDecreased expression of ERβ isoforms was identified in sporadic polyps and in sporadic colorectal cancer as well as in polyps from FAP syndrome patients compared with normal tissues (p < 0.001). In FAP patients, ERβ1 and ERβ5 isoforms showed significant down-expression in polyps (p < 0.001) compared with matched normal tissues. However, no differences were observed when sporadic colorectal carcinomas were compared to normal mucosa tissues. These findings suggest an association of the ERβ isoform variants in individuals affected by germline mutations of the APC gene. Progressively decreased expression of ERβ was found in polyps at early stages of low-grade dysplasia, followed by T1-T2 and T3-T4 tumours (p < 0.05). In sporadic colorectal cancer, the loss of expression was an independent predictor of recurrence, and ERβ1 and ERβ5 expression levels were associated with better disease-free survival (p = 0.002).ConclusionThese findings may provide a better understanding of oestrogens and their potential preventive and therapeutic effects on sporadic colorectal cancer and cancers associated with FAP syndrome.

In search of germline variants associated with metastasis risk in sporadic colorectal carcinomas: towards personalized therapeutic decision

In search of germline variants associated with metastasis risk in sporadic colorectal carcinomas: towards personalized therapeutic decision

Abstract 4578: Does poor prognosis in African Americans with MSI-H colorectal cancer associate with altered immune markers

Abstract BACKGROUND: Microsatellite instability high (MSI-H) of sporadic colorectal carcinomas (CRC) is usually associated with improved prognosis and a high density of tumor-infiltrating lymphocytes. However, African Americans with MSI-H have poor prognosis. AIM: To evaluate whether or not expression of different immune and tumor markers individually or in combination in African American MSI-H CRC associate with the prognosis status. METHODS: Tissues Microarray (TMA) were prepared by microdissection from FFPE (Formalin Fixed Paraffin Embedded) blocks of 15 MSI-H patients. Immune markers (CD8+, Granzymes, Perforins, CD4+, STAT1, IRF1 and IRF5) and PD-L1 status were analyzed by immunohistochemistry (IHC). Demography and clinical data including TNM, tumor grading (WHO standard), histological type of the tumor, date of diagnosis, date of the last follow-up examination, treatment, comorbidities, metastasis, recurrence, 5-year disease-free survival and death were collected. RESULTS: There were 4 patients with improved prognosis (27%) with relatively high CD4 density (2 with &amp;gt;50% and 2 with 11-50%) regardless of PD-L1 status (3+/1-), stage (II,III), and other immune markers (CD8, CD4, Granzymes, Perforins, IRF1, IRF5 and STAT1). One of the improved prognosis patients with KRAS mutation has elevated expression of all considered immune markers besides CD4. There were 9 patients (6 dead, 3 alive) with poor prognosis, with different immune and tumor markers level (3 were PD-L1+ and 5 have relatively high CD4 count; but with low level of STAT1. There were also 2 patients with expected improved prognosis based on their immune markers level (stage II), however, they died within the 5 year period post-diagnosis, due to their age (98 and 87 years old). Conclusion: MSI-H Colorectal cancer from African American patients has poor prognosis which may correlate with the nature of tumor-associated immune response. Other factors such as MSH3 defects might cancel the positive prognosis of MSI-H status. Nonetheless, low STAT1 and low CD4 may be indicators of poorer prognosis. Citation Format: Umamaheshwari Golconda, Lena Sokol, Babak Shokrani, Edward Lee, Donna Hansel, Oluwole Fadare, Sandip Patel, Mehdi Nouraie, Hooman Soleimani, Zaki Sharif, Ali Afsari, Fareed Daremipouran, Hassan Brim, Hassan Ashktorab. Does poor prognosis in African Americans with MSI-H colorectal cancer associate with altered immune markers [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 4578. doi:10.1158/1538-7445.AM2017-4578

Sessile Serrated Polyps and Colon Cancer Prevention.

Evidence suggests that up to one fifth of colorectal carcinomas develop from serrated polyps, named for their pattern of colonic crypts, and include the sessile serrated adenoma/polyp (SSA/P) that has malignant potential. SSA/Ps are typically located in the proximal colon and have molecular features of hypermethylation of CpG islands in gene promoters and activating point mutations (V600E) in the BRAF oncogene. Both of these features are seen in sporadic colorectal carcinomas with microsatellite instability (MSI) which is potentially consistent with an origin of these cancers from precursor SSA/Ps. Dysplasia is detected in a subset of SSA/Ps with a high risk of progression to carcinoma. An uncommon serrated polyp is the traditional serrated adenoma that is typically found in the left colon, has a tubulovillous architecture, and frequently harbors mutant KRAS To date, the epidemiology of these serrated lesions is poorly understood, and limited observational data suggest a potential chemopreventive benefit of nonsteroidal anti-inflammatory drugs. The current primary strategy to reduce the risk of colorectal carcinoma from serrated polyps is to enhance their detection at colonoscopy and to ensure their complete removal. This review provides insight into the epidemiologic, clinical, histopathologic, and molecular features of serrated polyps and includes data on their endoscopic detection and chemoprevention. Cancer Prev Res; 10(5); 270-8. ©2017 AACR.

Local recurrences at the anastomotic area are clonally related to the primary tumor in sporadic colorectal carcinoma.

PurposeAnastomotic recurrences (AR) occur in 2–10% of colorectal carcinoma cases after resection of primary tumor (PT). Currently, there are no molecular data investigating their genetic profile and multiple theories exist about their pathogenesis. The aim of our study was to compare the genomic profile of AR to that of the patients’ corresponding matched PT and, when available, to a distant metastasis (DM).Experimental DesignThirty-six tumors from 14 patients were genotyped using a capture-based, next-generation assay to define the mutational status of 341 cancer-associated genes. All patients had R0 resection of their PT and AR occurred 1.1−7.0 years following PT resection. A DM or a second AR was analyzed in 8 patients. All tumors were microsatellite stable except in one patient with Lynch syndrome.ResultsA total of 254 somatic mutations were detected including 138 mutations in the microsatellite stable (MSS) cases. The most commonly mutated genes were APC, KRAS, TP53, PIK3CA, ATM and PIK3R1. In all patients with MSS tumors the AR and PT shared between 50−100% of mutations, including mutations in key driver genes, consistent with these tumors being clonally related. Genetic events private to DM were not detected in AR and phylogenetic analysis showed that ARs were more closely related to PT than DM. In the Lynch syndrome patient the PT and AR showed distinct somatic mutations consistent with independent primaries.ConclusionsARs are clonally related to PT in sporadic colorectal carcinomas and do not appear to represent seeding of the anastomotic site by distant metastases.

Template for Reporting Results of Biomarker Testing of Specimens From Patients With Carcinoma of the Endometrium.

Template for Reporting Results of Biomarker Testing of Specimens From Patients With Carcinoma of the Endometrium.

A meta-analysis of the clinicopathological characteristics and survival outcomes of inflammatory bowel disease associated colorectal cancer.

The current study aims to use meta-analytical techniques to compare the clinicopathological characteristics and survival outcomes of inflammatory bowel disease (IBD) associated and sporadic colorectal carcinoma (CRC). Patients with IBD have an established increased risk of developing CRC. There is no consensus, however, on the clinicopathological characteristics and survival outcomes of IBD associated CRC when compared to sporadic CRC. A comprehensive search for published studies comparing IBD associated and sporadic CRC was performed. Random effect methods were used to combine data. This study adhered to the recommendations of the MOOSE guidelines. Data were retrieved from 20 studies describing 571,278 patients. IBD associated CRC had an increased rate of synchronous tumors (OR 4.403, 95% CI 2.320-8.359; p<0.001), poor differentiation (OR 1.875, 95% CI 1.425-2.466; p<0.001), and a reduced rate of rectal cancer (OR 0.827, 95% CI 0.735-0.930; p=0.002). IBD associated CRC however did not affect the frequency of T3/T4 tumors (OR 0.931, 95% CI 0.782-1.108; p=0.421), lymph node positivity (OR 1.061, 95% CI 0.929-1.213; p=0.381), metastasis at presentation (OR 0.970, 95% CI 0.776-1.211; p=0.786), sex distribution (OR 0.978, 95% CI 0.890-1.074; p=0.640), or 5-year overall survival (OR 1.105, 95% CI 0.414-2.949; p=0.842). In this large analysis of available data, IBD associated CRC was characterized by less rectal tumors and more synchronous and poorly differentiated tumors compared with sporadic cancers, but no discernable difference in sex distribution, stage at presentation, or survival could be identified.

Prognostic significance of vascular endothelial growth factor polymorphisms in colorectal cancer patients.

AIMTo investigate the associations of the genetic polymorphisms of vascular endothelial growth factor A (VEGF-A) -1498C>T and -634G>C, with the survival of patients with colorectal cancer (CRC).METHODSA prospective cohort consisting of 131 Brazilians patients consecutively operated on with a curative intention as a result of sporadic colorectal carcinoma was studied. DNA was extracted from peripheral blood and its amplification and allelic discrimination for each genetic polymorphism was performed using the technique of polymerase chain reaction (PCR) in real-time. The real-time PCR technique was used to identify the VEGF-A -1498C>T (rs833031) and -634G>C (rs2010963) polymorphisms. Genotyping was validated for VEGF-A -1498C>T polymorphism in 129 patients and for VEGF-A -634G>C polymorphism in 118 patients. The analysis of association between categorical variables was performed using logistic regression, survival by Kaplan-Meier method and multivariate analysis by the Cox regression method.RESULTSIn the univariate analysis there was a significant association (OR = 0.32; P = 0.048) between genotype CC of the VEGF-A -1498C>T polymorphism and the presence of CRC liver metastasis. There was no association between VEGF-A -1498C>T polymorphism and VEGF-A -634G>C polymorphism with further clinical or anatomopathologic variables. The genotype CC of the VEGF-A -1498C>T polymorphism was significantly correlated with the 5-year survival (P = 0.032), but not significant difference (P = 0.27) was obtained with the VEGF-A -634G>C polymorphism with the 5-year survival in the univariate analysis. The genotype CT (HR = 2.79) and CC (HR = 4.67) of the polymorphism VEGF-A -1498C>T and the genotype CC (HR = 3.76) of the polymorphism VEGF-A -634C>G acted as an independent prognostic factor for the risk of death in CRC patients.CONCLUSIONThe CT and CC genotypes of the VEGF-A -1498C>T and the CC genotype of the VEGF-A -634C>G polymorphisms are prognostic factors of survival in Brazilians patients with sporadic colorectal carcinoma.

Surgical treatment of multiple sporadic colorectal carcinoma.

Aim: Many aspects of the surgical management of multiple sporadic colorectal cancer syndrome, either synchronous and metachronous, remain to be cleared, in particular the prognostic influence of the extent of surgical resection. Method: A retrospective review was performed of patients diagnosed with multiple colorectal cancer from 1982 to May 2010. Clinical and pathologic data were collected and reviewed. Survival analysis was performed. Results: We identified 23 patients with multiple sporadic colorectal cancers, of which 8 had synchronous (SC) and 15 metachronous cancers (MC). Of the MC patients, 2 (13%) had the second cancer within 2 years, 4 (27%) in the time period of 2-5 years and 9 (60%) after 5 years. Twenty-one patients underwent multiple segmental resections; 2 patients underwent subtotal colectomy. The 5-year overall survival rate of SC and MC patients was 100% and 87% (p<0.001) respectively. The 5-year overall survival rate of multiple segmental resection patients and subtotal colectomy was 94% and 75% (p=0.655) respectively. Conclusion: Either synchronous and metachronous MSCRC patients showed good prognosis independently from to the extent of resection. Our results support a less aggressive biological behaviour allowing a more conservative management. Multiple segmental colorectal resections seem appropriate from an oncologic point of view in MSCRC patients. (www.actabiomedica.it)

Abstract 2419: Anastomotic recurrences are clonally related to primary tumors in sporadic colorectal carcinoma

Abstract Background: Anastomotic recurrences occur in 2-10% of colorectal carcinoma (CRC) cases after surgical resection of the primary tumor. To date there are no molecular data investigating their genetic profile and multiple theories exist as to their pathogenesis including re-growth of tumor cells present within local lymphatics after initial surgery, seeding of anastomosis by metastatic tumor cells and a second primary tumor. The aim of our study was to compare the genomic profile of anastomotic recurrences to that of matched primary tumors and, where available, to that of distant metastases. Design: Thirty-six tumors from 14 patients were genotyped using a hybridization capture-based next-generation sequencing assay for targeted deep sequencing of all exons and selected introns of 341 key cancer genes. All patients had resection of their primary tumor with clear margins and recurred either at the anastomotic line or in the peri-anastomotic area 1.1 to 7.0 years following resection of their primary tumor. In 3 patients 2 consecutive anastomotic recurrences were sequenced, while in 6 patients a distant metastasis that occurred 1.2 to 3 years prior to the anastomotic recurrence was also analyzed. All tumors were microsatellite stable except in one patient with genetically confirmed Lynch syndrome. Results: A total of 254 somatic mutations were detected including 140 mutations in the microsatellite stable cases. The most commonly mutated genes (mutated in &amp;gt; 3 patients) were APC, KRAS, TP53, PIK3CA, ATM and PIK3R1. In 13/14 patients the anastomotic recurrence(s) and primary tumor shared between 50-100% of mutations, including mutations in key driver genes such as APC, KRAS and TP53, consistent with these tumors being clonally related. In the patient with the Lynch syndrome the 2 tumors showed distinct somatic mutations suggestive of independent primaries. We identified eleven genetic events present in a distant metastasis and not in a primary tumor and none of these events was detected in the anastomotic recurrence arguing against re-seeding of the anastomotic site by a metastatic clone. All five patients with isolated anastomotic recurrence were free of disease 0.9 to 6.1 years following resection of their recurrent CRC. Conclusions: Anastomotic recurrences appear to be clonally related to the primary tumor in sporadic CRC cases. Our data also provide molecular data in support of the treatment of anastomotic recurrences as localized disease. Citation Format: Efsevia Vakiani, Ronak H. Shah, Christine Iacobuzio-Donahue, David B. Solit, Martin R. Weiser. Anastomotic recurrences are clonally related to primary tumors in sporadic colorectal carcinoma. [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 2419.

Abstract 1857: Dysregulation of transsulfuration enzymes contribute to malignant transformation in a murine model of colitis-associated carcinogenesis

Abstract Introduction: Ulcerative colitis (UC) is a highly morbid, chronic inflammatory disease characterized by mucosal ulceration of the colonic mucosa and is associated with the higher risk of colitis-associated cancer (CAC). The exact mechanism(s) causing UC progression to CAC is currently unknown. The balanced activity of transsulfuration pathway enzymes, cystathionine-gamma-lyase (CSE) and cystathionine-beta-synthase (CBS), and their production of endogenous hydrogen sulfide gas, are critical to maintenance of the colonic homeostasis. CSE activity is suggested to be important for wound healing and mucosal protection. Consistent with this, we have previously showed a decrease CSE expression in human colonic mucosa obtained from patients with chronic UC, compared to normal colonic mucosa by immunocytochemistry. By contrast, increased CBS expression is implicated in the progression of sporadic colorectal carcinoma. However, the role of these enzymes in CAC is unknown. We hypothesize that the dysregulation in CSE/CBS expression and activity is important to the progression from UC to CAC. Methods: CSE null mice and wild type Sv129/B6 (control) mice were used in azoxymethane-dextran sodium sulfate (AOM-DSS) colon cancer model which mimics human CAC. The disease development was followed up to day 80. Confocal microscopy and Western blot was used to assess the gene expression during cancer development. Size, number, and time interval to tumor formation, as well inflammation were assessed. Results: Abrogation of CSE expression using CSE null animals in AOM-DSS model of CAC accelerated the time to tumor development and resulted in an increase in both tumor size (p&amp;lt;0.001) and number (p&amp;lt;0.001) compared to wild-type controls. CBS protein expression was increased within the colonic tumor when compared to the normal margin in AOM-DSS treated animals by Western blot analysis and tissue immunostaining. Interestingly, CAC liver metastases, an exceedingly rare finding in this mouse model, were identified. Conclusion: Taken together, our human and murine data suggest that dysregulation in the transsulfuration pathway enzymes CSE and CBS expression/activity may be critical contributor to the CAC development in UC and may serve as a potential biomarker for disease progression in the future. Citation Format: Paul Johnson, Ches’Que M. Phillips, Carl Grim, John R. Zatarain, Aakash H. Gajjar, Suimin Qiu, Rui Wang, Celia Chao, Iryna V. Pinchuk, Mark R. Hellmich. Dysregulation of transsulfuration enzymes contribute to malignant transformation in a murine model of colitis-associated carcinogenesis. [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 1857.

Immunohistochemical staining for p16 and BRAFV600E is useful to distinguish between sporadic and hereditary (Lynch syndrome-related) microsatellite instable colorectal carcinomas.

DNA mismatch repair (MMR) protein analysis by immunohistochemistry (IHC) can identify colorectal cancer (CRC) with microsatellite instability (MSI). As MLH1-deficient CRC can be hereditary or sporadic, markers to distinguish between them are needed. MLH1 promoter methylation assay is the reference method; however, sometimes, it is challenging on formalin-fixed paraffin-embedded tissue samples. We assessed by IHC the expression of BRAFV600E, p16, MGMT, and CDX2 in 55 MLH1-deficient MSI CRC samples (of which 8 had a germline MLH1 mutation) to determine whether this panel differentiates between sporadic and hereditary CRCs. We also analyzed MLH1 promoter methylation by methylation-specific PCR and pyrosequencing and BRAF status by genotyping. None of the hereditary CRCs showed MLH1 methylation, BRAF mutation, BRAFV600E-positive immunostaining, or loss of p16 expression. We detected MLH1 promoter methylation in 67% and a BRAF mutation in 42% of CRC, all showing MLH1 promoter methylation. BRAFV600E IHC and BRAF genotyping gave concordant results in all but two samples. Loss of expression of p16 was found in 30% of CRC with methylation of the MLH1 promoter, but its expression was retained in all non-methylated and part of MLH1-methylated tumors (100% specificity, 30% sensitivity). CDX2 and MGMT expression was not associated with MLH1 status. Thus, BRAFV600E and p16 IHC may help in differentiating sporadic from hereditary MLH1-deficient CRC with MSI. Specifically, p16 IHC might be used as a surrogate marker for MLH1 promoter methylation, because all p16-negative CRCs displayed MLH1 methylation, whereas hereditary CRCs were all p16-positive.

Establishment and characterization of HROC69 - a Crohn´s related colonic carcinoma cell line and its matched patient-derived xenograft.

Colitis-associated colorectal cancer (CAC) seems to be a rather unique entity and differs in its genetic alterations, tumour formation capacities, and clinical features from sporadic colorectal carcinoma. Most descriptions about tumour biology of CAC refer to ulcerative colitis; data about Crohn´s colitis related carcinomas are scarce. The majority of patients with Crohn´s disease are under immunosuppression which generates a different environment for tumour growth. We first describe the clinical case of a fast growing CAC in a long-term immunosuppressed patient with Crohn´s disease and successful establishment and characterization of carcinoma cell lines along with their corresponding patient-derived xenograft. Subsequently, these tumor models were molecularly and functionally analysed. Beside numerous chromosomal alterations, mutations in TP53, APC, PTEN and SMAD3 were identified. The cell lines express numerous cancer testis antigens, surface molecules involved in immune evasion but low levels of HLA class I molecules. They show strong invasive but in comparison weak migratory activity. The present work is the first description of patient-derived in vitro and in vivo models for CAC from a Crohn´s disease patient. They might be valuable tools for analysis of genetic and epigenetic alterations, biomarker identification, functional testing, including response prediction, and the development of specific therapeutical strategies.

BRAF V600E Gene Mutation in Colonic Adenocarcinomas. Immunohistochemical Detection Using Tissue Microarray and Clinicopathologic Characteristics

The detection of BRAF mutation in colorectal cancer has several clinical applications: enabling the discrimination between sporadic and Lynch syndrome-related colorectal carcinoma, and providing warning of a poorer prognosis. Few immunohistochemical studies using whole-tissue tumor section staining have recently been performed on colorectal cancer. The aim of this study was to evaluate the detection of BRAF mutation by immunohistochemistry (IHC) on tissue microarray (TMA). IHC was performed with the BRAF-specific antibody using TMA on a retrospective series of 86 colonic adenocarcinomas with known BRAF status. IHC using BRAF-specific antibody allowed to detect 20/21 BRAF mutated colonic adenocarcinomas and 60/65 BRAF wild-type cases. The staining was equivocal because of equivocal staining in 4 cases and heterogeneity in 3 cases. When compared with TaqMan real-time PCR, the sensitivity and specificity were 95.2% and 92.3%, respectively. Comparison with the whole section immunostaining improved sensitivity to 100% and specificity to 95.4%. Furthermore, in this study we found that BRAF mutated colonic adenocarcinoma were significantly more frequent in women, older patients, and right-sided. Moreover, morphologic features significantly associated with BRAF mutation were: serrated adenocarcinoma subtype, adenocarcinomas with a mucinous component, high histologic grade, pushing margins, stromal inflammation. BRAF-specific antibody can be used on TMA to screen BRAF-mutated colorectal carcinomas. Cases with equivocal or heterogenous staining must be compared with whole section staining. Moreover, BRAF mutated colonic carcinomas have distinct clinical and histopathologic features.

Inflammatory bowel disease and cancer: The role of inflammation, immunosuppression, and cancer treatment

In patients with inflammatory bowel disease (IBD), chronic inflammation is a major risk factor for the development of gastrointestinal malignancies. The pathogenesis of colitis-associated cancer is distinct from sporadic colorectal carcinoma and the critical molecular mechanisms underlying this process have yet to be elucidated. Patients with IBD have also been shown to be at increased risk of developing extra-intestinal malignancies. Medical therapies that diminish the mucosal inflammatory response represent the foundation of treatment in IBD, and recent evidence supports their introduction earlier in the disease course. However, therapies that alter the immune system, often used for long durations, may also promote carcinogenesis. As the population of patients with IBD grows older, with longer duration of chronic inflammation and longer exposure to immunosuppression, there is an increasing risk of cancer development. Many of these patients will require cancer treatment, including chemotherapy, radiation, hormonal therapy, and surgery. Many patients will require further treatment for their IBD. This review seeks to explore the characteristics and risks of cancer in patients with IBD, and to evaluate the limited data on patients with IBD and cancer, including management of IBD after a diagnosis of cancer, the effects of cancer treatment on IBD, and the effect of IBD and medications for IBD on cancer outcomes.

Immunohistochemical expression of proinflammatory enzyme COX-2 and p53 in ulcerative colitis and its associated dysplasia and colorectal carcinoma

Background/aimUlcerative colitis (UC) patients are at increased risk for colorectal carcinoma (CRC). It is suggested that cyclooxygenase-2 (COX-2) plays a role in sporadic CRC. The p53 gene is a tumor-suppressor gene and the most frequent site of genetic alteration found in human cancer. The aim of this study was to analyze the immunoexpression of proinflammatory enzyme COX-2 and p53 in UC, UC-associated dysplasia, and CRC, in comparison with each other and with different clinical and histopathological parameters, to clarify if they have a possible role in the pathogenesis of CRC in UC patients. Materials and methodsIn this cross-sectional study, 98 patients were divided into three groups: 39 patients with UC without dysplasia, 32 patients with UC with dysplasia, and 27 patients with colorectal cancer on top of UC, in addition to 10 healthy controls. All patients underwent colonoscopy, and multiple biopsies were taken for histopathological and COX-2 and p53 immunohistochemical studies. ResultsThere was significant difference in the expression of COX-2 and p53 in UC-related dysplasia either without or with CRC, compared with their expression in the UC group without dysplasia. ConclusionAdding immunohistochemical analysis of COX-2 enzyme and p53 gene to routine histological assessment may improve the accuracy of early detection of dysplasia and colorectal cancer. COX-2 and p53 can be promising chemotherapeutic/chemopreventive targets in UC patients.

Contribution of rare germline copy number variations and common susceptibility loci in Lynch syndrome patients negative for mutations in the mismatch repair genes.

In colorectal carcinoma (CRC), 35% of cases are known to have a hereditary component, while a lower proportion (∼ 5%) can be explained by known genetic factors. In this study, copy number variations (CNVs) were evaluated in 45 unrelated patients with clinical hypothesis of Lynch syndrome (Amsterdam or Bethesda criteria); negative for MLH1, MSH2, MSH6, PMS2, CHEK2*1100delC and TP53 pathogenic mutations; aiming to reveal new predisposing genes. Analyses with two different microarray platforms (Agilent 180K and Affymetrix CytoScan HD) revealed 35 rare CNVs covering 67 known genes in 22 patients. Gains (GALNT6 and GALNT11) and losses (SEMA3C) involving the same gene families related to CRC susceptibility were found among the rare CNVs. Segregation analysis performed on four relatives from one family suggested the involvement of GALNT11 and KMT2C in those at risk of developing CRC. Notably, in silico molecular analysis revealed that 61% (41/67) of the genes covered by rare CNVs were associated with cancer, mainly colorectal (17 genes). Ten common SNPs, previously associated with CRC, were genotyped in 39 index patients and 100 sporadic CRC cases. Although no significant, an increased number of risk alleles was detected in the index cases compared with the sporadic CRC patients. None of the SNPs were covered by CNVs, suggesting an independent effect of each alteration in cancer susceptibility. In conclusion, rare germline CNVs and common SNPs may contribute to an increased risk for hereditary CRC in patients with mismatch repair proficiency.

Aberrant DNA methylation profiles of inherited and sporadic colorectal cancer

BackgroundAberrant DNA methylation has been widely investigated in sporadic colorectal carcinomas (CRCs), and extensive work has been performed to characterize different methylation profiles of CRC. Less information is available about the role of epigenetics in hereditary CRC and about the possible clinical use of epigenetic biomarkers in CRC, regardless of the etiopathogenesis. Long interspersed nucleotide element 1 (LINE-1) hypomethylation and gene-specific hypermethylation of 38 promoters were analyzed in multicenter series of 220 CRCs including 71 Lynch (Lynch colorectal cancer with microsatellite instability (LS-MSI)), 23 CRCs of patients under 40 years in which the main inherited CRC syndromes had been excluded (early-onset colorectal cancer with microsatellite stability (EO-MSS)), and 126 sporadic CRCs, comprising 28 cases with microsatellite instability (S-MSI) and 98 that were microsatellite stable (S-MSS). All tumor methylation patterns were integrated with clinico-pathological and genetic characteristics, namely chromosomal instability (CIN), TP53 loss, BRAF, and KRAS mutations.ResultsLS-MSI mainly showed absence of extensive DNA hypo- and hypermethylation. LINE-1 hypomethylation was observed in a subset of LS-MSI that were associated with the worse prognosis. Genetically, they commonly displayed G:A transition in the KRAS gene and absence of a CIN phenotype and of TP53 loss. S-MSI exhibited a specific epigenetic profile showing low rates of LINE-1 hypomethylation and extensive gene hypermethylation. S-MSI were mainly characterized by MLH1 methylation, BRAF mutation, and absence of a CIN phenotype and of TP53 loss. By contrast, S-MSS showed a high frequency of LINE-1 hypomethylation and of CIN, and they were associated with a worse prognosis. EO-MSS were a genetically and epigenetically heterogeneous group of CRCs. Like LS-MSI, some EO-MSS displayed low rates of DNA hypo- or hypermethylation and frequent G:A transitions in the KRAS gene, suggesting that a genetic syndrome might still be unrevealed in these patients. By contrast, some EO-MSS showed similar features to those observed in S-MSS, such as LINE-1 hypomethylation, CIN, and TP53 deletion. In all four classes, hypermethylation of ESR1, GATA5, and WT1 was very common.ConclusionsAberrant DNA methylation analysis allows the identification of different subsets of CRCs. This study confirms the potential utility of methylation tests for early detection of CRC and suggests that LINE-1 hypomethylation may be a useful prognostic marker in both sporadic and inherited CRCs.Electronic supplementary materialThe online version of this article (doi:10.1186/s13148-015-0165-2) contains supplementary material, which is available to authorized users.