Increased Risk of Colorectal Cancer in Patients With Multiple Serrated Polyps and Their First-Degree Relatives.

BACKGROUND & AIMS: We investigated whether patients with multiple serrated polyps, but not meeting the World Health Organization criteria for serrated polyposis syndrome, and their relatives have similar risks for colorectal cancer (CRC) as those diagnosed with serrated polyposis. METHODS: We collected data from patients with more than 10 colonic polyps, recruited in 2008-2009 from 24 hospitals in Spain for a study of causes of multiple colonic polyps. We analyzed data from 53 patients who met the criteria for serrated polyposis and 145 patients who did not meet these criteria, but who had more than 10 polyps throughout the colon, of which more than 50% were serrated. We calculated age- and sex-adjusted standardized incidence ratios (SIRs) for CRC in both groups, as well as in their first-degree relatives. RESULTS: The prevalence of CRC was similar between patients with confirmed serrated polyposis and multiple serrated polyps (odds ratio, 1.35; 95% confidence interval [CI], 0.64-2.82; P = .40). The SIR for CRC in patients with serrated polyposis (0.51; 95% CI, 0.01-2.82) did not differ significantly from the SIR for CRC in patients with multiple serrated polyps (0.74; 95% CI, 0.20-1.90; P = .70). The SIR for CRC also did not differ significantly between first-degree relatives of these groups (serrated polyposis: 3.28, 95% CI, 2.16-4.77; multiple serrated polyps: 2.79, 95% CI, 2.10-3.63; P = .50). Kaplan-Meier analysis showed no differences in the incidence of CRC between groups during the follow-up period (log-rank, 0.6). CONCLUSIONS: The risk of CRC in patients with multiple serrated polyps who do not meet the criteria for serrated polyposis, and in their first-degree relatives, is similar to that of patients diagnosed with serrated polyposis.

Endoscopic surveillance in patients with multiple (10-100) colorectal polyps.

BACKGROUND AND STUDY AIMS: Endoscopic surveillance in patients with multiple colorectal polyps aims to reduce colorectal cancer (CRC) incidence and mortality, as well as the need for colorectal surgery. The aim of this study was to determine the risk of developing CRC or the need for surgery during endoscopic surveillance in a cohort of patients with multiple (10 - 100) colorectal polyps. PATIENTS AND METHODS: This was a multicentrer, longitudinal, observational study in 15 CRC high risk clinics in Spain, carried out between January 2009 and December 2010. Patients who were included in the EPIPOLIP trial and had at least 1 year of follow-up were included in the study. The primary outcome of interest was the incidence of CRC at least 1 year following the initial colonoscopy. The secondary outcome was the need for colorectal surgery. RESULTS: A total of 265 patients were followed for a median of 3.8 years. Patients underwent a median of 5 colonoscopies, and 17 patients (6.4 %) were diagnosed with CRC. A total of 32 patients (12.1 %) underwent surgery, including 15 (5.7 %) for prophylaxis without a diagnosis of CRC. The corresponding incidence density rates for CRC and colorectal surgery were 1.4 (95 % confidence interval [CI] 0.7 to 2.1) and 2.7 (95 %CI 1.7 to 3.6) per 100 patient-years, respectively. Only the presence of symptoms at first colonoscopy was independently associated with CRC diagnosis (hazard ratio [HR] 7.7, 95 %CI 1.1 to 59.3) and colorectal surgery (HR 4.6, 95 %CI 1.02 to 20.6). CONCLUSIONS: Patients with more than 10 neoplastic polyps required frequent colonoscopies within a short follow-up period. More than 10 % of patients required colorectal surgery within 4 years, more than half for incident CRC.

Prevalence of MLH1 constitutional epimutations as a cause of Lynch syndrome in unselected versus selected consecutive series of patients with colorectal cancer.

BACKGROUND: The prevalence of MLH1 constitutional epimutations in the general population is unknown. We sought to analyse the prevalence of MLH1 constitutional epimutations in unselected and selected series of patients with colorectal cancer (CRC). METHODS: Patients with diagnoses of CRC (n=2123) were included in the unselected group. For comparison, a group of 847 selected patients with CRC who fulfilled the revised Bethesda guidelines (rBG) were also included. Somatic and constitutional MLH1 methylation was assayed via methylation-specific multiplex ligation-dependent probe amplification of cases lacking MLH1 expression. Germline alterations in mismatch-repair (MMR) genes were assessed via Sanger sequencing and methylation-specific multiplex ligation-dependent probe amplification. RESULTS: Loss of MLH1 expression occurred in 5.5% of the unselected series and 12.5% of the selected series (p<0.0001). No constitutional epimutations in MLH1 were detected in the unselected population (0/62); five cases from the selected series were positive for MLH1 epimutations (15.6%, 5/32; p=0.004). CONCLUSIONS: Our results suggest a negligible prevalence of MLH1 constitutional epimutations in unselected cases of CRC. Therefore, MLH1 constitutional epimutation analysis should be conducted only for patients who fulfil the rBG and who lack MLH1 expression with methylated MLH1.

Risk of cancer in cases of suspected lynch syndrome without germline mutation.

BACKGROUND & AIMS: Colorectal cancers (CRCs) with microsatellite instability (MSI) and a mismatch repair (MMR) immunohistochemical deficit without hypermethylation of the MLH1 promoter are likely to be caused by Lynch syndrome. Some patients with these cancers have not been found to have pathogenic germline mutations and are considered to have Lynch-like syndrome (LLS). The aim of this study was to determine the risk of cancer in families of patients with LLS. METHODS: We studied a population-based cohort of 1705 consecutive patients, performing MSI tests and immunohistochemical analyses of MMR proteins. Patients were diagnosed with Lynch syndrome when they were found to have pathogenic germline mutations. Patients with MSI and loss of MSH2 and/or MSH6 expression, isolated loss of PMS2 or loss of MLH1 without MLH1 promoter hypermethylation, and no pathogenic mutation were considered to have LLS. The clinical characteristics of patients and the age- and sex-adjusted standardized incidence ratios (SIRs) of cancer in families were compared between groups. RESULTS: The incidence of CRC was significantly lower in families of patients with LLS than in families with confirmed cases of Lynch syndrome (SIR for Lynch syndrome, 6.04; 95% confidence interval [CI], 3.58-9.54; SIR for LLS, 2.12; 95% CI, 1.16-3.56; P < .001). However, the incidence of CRC was higher in families of patients with LLS than in families with sporadic CRC (SIR for sporadic CRC, 0.48; 95% CI, 0.27-0.79; P < .001). CONCLUSIONS: The risk of cancer in families with LLS is lower that of families with Lynch syndrome but higher than that of families with sporadic CRC. These results confirm the need for special screening and surveillance strategies for these patients and their relatives.

Clinical subtypes and molecular characteristics of serrated polyposis syndrome.

BACKGROUND & AIMS: We investigated clinical and molecular differences between the different phenotypes of serrated polyposis syndrome (SPS) and the frequency of mutations in BRAF or KRAS in polyps from patients with SPS. METHODS: We collected data on clinical and demographic characteristics of 50 patients who fulfilled the criteria for SPS. Polymerase chain reaction and sequence analysis were used to identify BRAF and KRAS mutations in 432 polyps collected from 37 patients; we analyzed CpG island methylator phenotypes in 272 of these polyps. RESULTS: Fifteen patients (30%) had type 1 SPS and 35 had type 2 SPS. There were no significant differences in age at diagnosis, sex, smoking frequency, body mass index, or colorectal cancer predisposition between groups of patients, or in the pathologic or molecular characteristics of their polyps. A familial history of colorectal cancer or colonic polyps was reported more frequently by patients with type 2 SPS. BRAF mutations were found in 63% of polyps and KRAS mutations were found in 9.9%; 43.4% of polyps had the CpG island methylator phenotype-high phenotype. A per-patient analysis revealed that all patients had a BRAF or KRAS mutation in more than 25% of their polyps; 84.8% of patients had a mutation in BRAF or KRAS in more than 50% of their polyps. CONCLUSIONS: Except for a greater likelihood of familial history of colorectal cancer or colonic polyps in patients with type 2 SPS, we found no significant demographic, pathologic, or molecular differences between types 1 and 2 SPS. All patients had a BRAF or KRAS mutation in at least 25% of their polyps.

Comparison between universal molecular screening for Lynch syndrome and revised Bethesda guidelines in a large population-based cohort of patients with colorectal cancer.

BACKGROUND: The selection of patients for genetic testing to rule out Lynch syndrome is currently based on fulfilment of at least one of the revised Bethesda criteria followed by mismatch repair (MMR) status analysis. A study was undertaken to compare the present approach with universal MMR study-based strategies to detect Lynch syndrome in a large series of patients with colorectal cancer (CRC). METHODS: 2093 patients with CRC from the EPICOLON I and II cohorts were included. Immunohistochemistry for MMR proteins and/or microsatellite instability (MSI) analysis was performed in tumour tissue. Germline MLH1 and MSH2 mutation analysis was performed in patients whose tumours showed loss of MLH1 or MSH2 staining, respectively. MSH6 genetic testing was done in patients whose tumours showed lack of MSH6 expression or a combined lack of MSH2 and MSH6 expression but did not have MSH2 mutations. PMS2 genetic testing was performed in patients showing isolated loss of PMS2 expression. In patients with MSI tumours and normal or not available MMR protein expression, all four MMR genes were studied. RESULTS: A total of 180 patients (8.6%) showed loss of expression of some of the MMR proteins and/or MSI. Four hundred and eighty-six patients (23.2%) met some of the revised Bethesda criteria. Of the 14 (0.7%) patients who had a MMR gene mutation, 12 fulfilled at least one of the revised Bethesda criteria and two (14.3%) did not. CONCLUSIONS: Routine molecular screening of patients with CRC for Lynch syndrome using immunohistochemistry or MSI has better sensitivity for detecting mutation carriers than the Bethesda guidelines.

5-Fluorouracil adjuvant chemotherapy does not increase survival in patients with CpG island methylator phenotype colorectal cancer.

BACKGROUND & AIMS: 5-Fluorouracil (5-FU)-based adjuvant chemotherapy does not increase survival times of patients with colorectal tumors with microsatellite instability. We determined the response of patients with colorectal tumors with the CpG island methylator phenotype (CIMP) to 5-FU-based therapy. METHODS: We analyzed a population-based cohort of 302 patients with colorectal cancer (CRC) for a median follow-up time of 50.7 months. CIMP status was determined by analysis of the CACNAG1, SOCS1, RUNX3, NEUROG1, and MLH1 promoters; tumors were considered to be CIMP positive if at least 3 promoters were methylated. RESULTS: Tumors from 29.5% of patients (89/302) were CIMP positive; CIMP status did not influence disease-free survival (DFS; log-rank = 0.3). Of tumors of TNM stages II-III (n = 196), 32.7% were CIMP positive. Among patients with stages II-III CRC who did not receive adjuvant 5-FU chemotherapy, those with CIMP-positive tumors had longest times of DFS (log-rank = 0.04); In patients who received chemotherapy, those with CIMP-positive tumors had shorter times of DFS (log-rank = 0.02). In patients with CIMP-negative tumors, adjuvant 5-FU chemotherapy significantly increased time of DFS (log-rank = 0.00001). However, in patients with CIMP-positive tumors, adjuvant 5-FU chemotherapy did not affect time of DFS (log-rank = 0.7). Multivariate analysis showed a significant, independent interaction between 5-FU treatment and CIMP status (hazard ratio [HR], 0.6; 95% confidence interval [CI], 0.5-0.8). Among patients with CIMP-positive tumors, adjuvant chemotherapy was not an independent predictor of outcome (HR, 0.8; 95% CI, 0.3-2.0). In patients who did not receive adjuvant 5-FU chemotherapy, CIMP status was the only independent predictor of survival (HR, 2.0; 95% CI, 1.1-3.8). CONCLUSIONS: Patients with CIMP-positive colorectal tumors do not benefit from 5-FU-based adjuvant chemotherapy.

Transcriptional regulation of chemokine network by biologic monotherapy in ileum of patients with Crohn's disease.

BACKGROUND: Crohn's disease (CD) exacerbation is marked by an intense cellular trafficking. We set out to determine the specific impact of biologic therapies on regulating chemokine network gene expression in healthy, mildly and severely inflamed tissue of CD patients. METHODS: Twenty CD patients on biologics (adalimumab, ustekinumab, vedolizumab) or untreated undergoing colonoscopy due to clinical symptoms of flare. Healthy, mildly and severely inflamed ileum biopsies from each patient were collected. Chemokines and receptors gene expression was analyzed and a STRING analysis for functional enrichment was performed. RESULTS: The chemokine network exhibited wide transcriptional differences among tissues in active untreated patients, whereas all biologic treatments reduced these differences and homogenized their transcriptional activity. In mildly inflamed tissue, all treatments showed gene upregulation while ustekinumab additionally maintained the downregulation of genes such as CCL2, CCL3, CCL17 or CCL23, involved in T cell chemotaxis, inflammatory monocyte and NK trafficking. In severely inflamed tissue, all treatments shared a downregulatory effect on chemokines controlling T cell response (i.e. CXCL16, CXCR3). Adalimumab and vedolizumab significantly reduced the expression of genes promoting antigen presentation by DCs and the initiation of leukocyte extravasation (i.e. CXCL12, CCL25, CCR7). Ustekinumab significantly reduced genes positively regulating Th1 cytokine production and IL-8 mediated signaling (i.e. IL1B, XCL1, CXCR1, CXCR2). CONCLUSION: Biologic therapies differentially target the chemokine network gene expression profile in the ileal tissue of active CD patients. These results may contribute to better understanding cell homing and to defining future personalized therapeutic strategies for CD patients.

Susceptibility genetic variants associated with colorectal cancer risk correlate with cancer phenotype.

BACKGROUND & AIMS: Ten common low-penetrant genetic variants have been consistently associated with colorectal cancer (CRC) risk; little is known about the correlation between these variants and CRC phenotype. Characterization of such a correlation would improve CRC management and prevention programs. We assessed the association between these genetic variants and CRC phenotype in patients and modeled pairwise combinations to detect epistasis. METHODS: The validation population corresponded to a prospective, multicenter, population-based cohort (EPICOLON I) of 1096 patients with newly diagnosed CRC. The replication set was an independent, prospective, multicenter Spanish cohort (EPICOLON II) of 895 patients with newly diagnosed CRC. For individual single nucleotide polymorphism (SNP) association analyses, a multivariate method using logistic regression was applied in EPICOLON I and subsequently prospectively validated in EPICOLON II. Interactions between SNPs were assessed using the likelihood ratio test. RESULTS: Validated results confirmed that the C allele on 8q23.3 (rs16892766) was significantly associated with advanced-stage tumors (odds ratio [OR], 1.48; 95% confidence interval [CI], 1.15-1.90; P value = 4.9 x 10(-3)). The G allele on 8q24.21 (rs6983267) was more common in patients with a familial history of CRC (OR, 2.02; 95% CI, 1.35-3.03; P value = 3.9 x 10(-4)). The combination of rs6983267 on 8q24.21 and rs9929218 on 16q22.2 was associated with a history of colorectal adenoma (carriers of GG and AA, respectively; OR, 2.28; 95% CI, 1.32-3.93; P = 5.0 x 10(-4)). CONCLUSIONS: CRC susceptibility variants at 8q23.3, 8q24.21, and 16q22.2 appear to be associated with cancer phenotype. These findings might be used to develop screening and surveillance strategies.

Evidence for classification of c.1852_1853AA>GC in MLH1 as a neutral variant for Lynch syndrome.

BACKGROUND: Lynch syndrome (LS) is an autosomal dominant inherited cancer syndrome characterized by early onset cancers of the colorectum, endometrium and other tumours. A significant proportion of DNA variants in LS patients are unclassified. Reports on the pathogenicity of the c.1852_1853AA>GC (p.Lys618Ala) variant of the MLH1 gene are conflicting. In this study, we provide new evidence indicating that this variant has no significant implications for LS. METHODS: The following approach was used to assess the clinical significance of the p.Lys618Ala variant: frequency in a control population, case-control comparison, co-occurrence of the p.Lys618Ala variant with a pathogenic mutation, co-segregation with the disease and microsatellite instability in tumours from carriers of the variant. We genotyped p.Lys618Ala in 1034 individuals (373 sporadic colorectal cancer [CRC] patients, 250 index subjects from families suspected of having LS [revised Bethesda guidelines] and 411 controls). Three well-characterized LS families that fulfilled the Amsterdam II Criteria and consisted of members with the p.Lys618Ala variant were included to assess co-occurrence and co-segregation. A subset of colorectal tumour DNA samples from 17 patients carrying the p.Lys618Ala variant was screened for microsatellite instability using five mononucleotide markers. RESULTS: Twenty-seven individuals were heterozygous for the p.Lys618Ala variant; nine had sporadic CRC (2.41%), seven were suspected of having hereditary CRC (2.8%) and 11 were controls (2.68%). There were no significant associations in the case-control and case-case studies. The p.Lys618Ala variant was co-existent with pathogenic mutations in two unrelated LS families. In one family, the allele distribution of the pathogenic and unclassified variant was in trans, in the other family the pathogenic variant was detected in the MSH6 gene and only the deleterious variant co-segregated with the disease in both families. Only two positive cases of microsatellite instability (2/17, 11.8%) were detected in tumours from p.Lys618Ala carriers, indicating that this variant does not play a role in functional inactivation of MLH1 in CRC patients. CONCLUSIONS: The p.Lys618Ala variant should be considered a neutral variant for LS. These findings have implications for the clinical management of CRC probands and their relatives.

Case-control study for colorectal cancer genetic susceptibility in EPICOLON: previously identified variants and mucins.

BACKGROUND: Colorectal cancer (CRC) is the second leading cause of cancer death in developed countries. Familial aggregation in CRC is also important outside syndromic forms and, in this case, a polygenic model with several common low-penetrance alleles contributing to CRC genetic predisposition could be hypothesized. Mucins and GALNTs (N-acetylgalactosaminyltransferase) are interesting candidates for CRC genetic susceptibility and have not been previously evaluated. We present results for ten genetic variants linked to CRC risk in previous studies (previously identified category) and 18 selected variants from the mucin gene family in a case-control association study from the Spanish EPICOLON consortium. METHODS: CRC cases and matched controls were from EPICOLON, a prospective, multicenter, nationwide Spanish initiative, comprised of two independent stages. Stage 1 corresponded to 515 CRC cases and 515 controls, whereas stage 2 consisted of 901 CRC cases and 909 controls. Also, an independent cohort of 549 CRC cases and 599 controls outside EPICOLON was available for additional replication. Genotyping was performed for ten previously identified SNPs in ADH1C, APC, CCDN1, IL6, IL8, IRS1, MTHFR, PPARG, VDR and ARL11, and 18 selected variants in the mucin gene family. RESULTS: None of the 28 SNPs analyzed in our study was found to be associated with CRC risk. Although four SNPs were significant with a P-value < 0.05 in EPICOLON stage 1 [rs698 in ADH1C (OR = 1.63, 95% CI = 1.06-2.50, P-value = 0.02, recessive), rs1800795 in IL6 (OR = 1.62, 95% CI = 1.10-2.37, P-value = 0.01, recessive), rs3803185 in ARL11 (OR = 1.58, 95% CI = 1.17-2.15, P-value = 0.007, codominant), and rs2102302 in GALNTL2 (OR = 1.20, 95% CI = 1.00-1.44, P-value = 0.04, log-additive 0, 1, 2 alleles], only rs3803185 achieved statistical significance in EPICOLON stage 2 (OR = 1.34, 95% CI = 1.06-1.69, P-value = 0.01, recessive). In the joint analysis for both stages, results were only significant for rs3803185 (OR = 1.12, 95% CI = 1.00-1.25, P-value = 0.04, log-additive 0, 1, 2 alleles) and borderline significant for rs698 and rs2102302. The rs3803185 variant was not significantly associated with CRC risk in an external cohort (MCC-Spain), but it still showed some borderline significance in the pooled analysis of both cohorts (OR = 1.08, 95% CI = 0.98-1.18, P-value = 0.09, log-additive 0, 1, 2 alleles). CONCLUSIONS: ARL11, ADH1C, GALNTL2 and IL6 genetic variants may have an effect on CRC risk. Further validation and meta-analyses should be undertaken in larger CRC studies.

xDEEP-MSI: Explainable Bias-Rejecting Microsatellite Instability Deep Learning System in Colorectal Cancer.

The prediction of microsatellite instability (MSI) using deep learning (DL) techniques could have significant benefits, including reducing cost and increasing MSI testing of colorectal cancer (CRC) patients. Nonetheless, batch effects or systematic biases are not well characterized in digital histology models and lead to overoptimistic estimates of model performance. Methods to not only palliate but to directly abrogate biases are needed. We present a multiple bias rejecting DL system based on adversarial networks for the prediction of MSI in CRC from tissue microarrays (TMAs), trained and validated in 1788 patients from EPICOLON and HGUA. The system consists of an end-to-end image preprocessing module that tile samples at multiple magnifications and a tissue classification module linked to the bias-rejecting MSI predictor. We detected three biases associated with the learned representations of a baseline model: the project of origin of samples, the patient's spot and the TMA glass where each spot was placed. The system was trained to directly avoid learning the batch effects of those variables. The learned features from the bias-ablated model achieved maximum discriminative power with respect to the task and minimal statistical mean dependence with the biases. The impact of different magnifications, types of tissues and the model performance at tile vs patient level is analyzed. The AUC at tile level, and including all three selected tissues (tumor epithelium, mucin and lymphocytic regions) and 4 magnifications, was 0.87 ± 0.03 and increased to 0.9 ± 0.03 at patient level. To the best of our knowledge, this is the first work that incorporates a multiple bias ablation technique at the DL architecture in digital pathology, and the first using TMAs for the MSI prediction task.

Effects of Somatic Methylation in Colonic Polyps on Risk of Developing Metachronous Advanced Colorectal Lesions.

The utility of molecular markers for predicting the risk of metachronous advanced colorectal lesions (MACLs) remains poorly investigated. We examined the relationship between somatic hypermethylation in polyps at baseline and the risk of developing MACL. This retrospective cohort study included 281 consecutive patients with colonic polyps who were enrolled between 2007 and 2009 and followed-up until 2014. MACLs were defined as adenomas of ≥10 mm, high-grade dysplasia, or with a villous component; and serrated lesions of ≥10 mm or with dysplasia. In total, 595 polyps were removed at baseline colonoscopy and analyzed for pathological characteristics and CpG island methylator phenotype (CIMP) using the MS-MLPA (Methylation-Specific -- Multiplex Ligation-dependent Probe Amplification) technique. Forty-five patients (16.0%) showed at least one CIMP+ polyp. MACL risk was higher in patients with CIMP+ polyps (odds ratio (OR), 4.50; 95% CI, 1.78-11.4; p = 0.002). Patients with CIMP+ polyps also exhibited shorter time to MACL development (33.8 months vs. 50.1 months; p < 0.001), even with adjustment for polyp size and number (OR, 2.40; 95% CI, 1.33-4.34). Adding CIMP analysis improved the sensitivity (57.0% to 70.9%), negative predictive value (71.1% to 77.3%), and overall accuracy (49.8% to 52.0%) for MACL risk estimation. These results highlight that CIMP may be a useful marker for endoscopic surveillance.

Utility of p16 immunohistochemistry for the identification of Lynch syndrome.

PURPOSE: Immunohistochemistry for mismatch repair proteins has shown utility in the identification of Lynch syndrome, but majority of tumors with loss of MLH1 expression are due to sporadic hypermethylation of the MLH1 promoter. These tumors can also show epigenetic silencing of other genes, such as p16. The aim of our study is to evaluate the utility of p16 immunohistochemistry in the prediction of MLH1 germline mutations. EXPERIMENTAL DESIGN: p16 immunohistochemistry was appropriately evaluated in 79 colorectal cancers with loss of MLH1 expression. Methylation of MLH1 and p16 were quantitatively studied using real-time PCR assay Methylight. BRAF V600E mutation in tumor tissue was also investigated. Genetic testing for germline mutation of MLH1 was made on 52 patients. RESULTS: Loss of p16 expression was seen in 21 of 79 samples (26.6%). There was found statistically significant association between p16 expression and p16 methylation (P < 0.001), MLH1 methylation (P < 0.001), and BRAF mutation (P < 0.005). All tumors with loss of p16 expression showed hypermethylation of p16 (21 of 21), 95.2% (20 of 21) showed MLH1 methylation, and 71.4% (15 of 21) were mutated for BRAF V600E. Mutational analysis showed pathogenic germline mutations in 8 of the patients, harboring 10 tumors. All 10 of these tumors showed normal staining of p16 in the immunochemical analysis. CONCLUSIONS: p16 immunohistochemistry is a good surrogate marker for p16 and MLH1 epigenetic silencing due to hypermethylation, and is useful as screening tool in the selection of patients for genetic testing in Lynch syndrome.

A Very Rare Case of Right Insular Lobe Langerhans Cell Histiocytosis (CD1a+) Mimicking Glioblastoma Multiforme in a Young Adult.

BACKGROUND: Langerhans cell histiocytosis (LCH) is a multisystemic dendritic cell proliferation that is relatively uncommon in adults. Central nervous system LCH outside the pituitary gland is even more uncommon. CASE DESCRIPTION: We report the case of a 42-year-old man who had complained of right-side hemicranial pain and left arm minor paresis. The symptoms were due to a right insular lobe heterogeneous-enhancing lesion associated with extensive vasogenic edema. The first diagnostic impression suggested glioblastoma multiforme or localized metastasis. The thoracic, abdominal, pelvic computed tomography scan only detected small upper lung inactive nodules suggesting silent focal LCH. A very hard lesion was almost completely removed through a pterional craniotomy approach, with no fluorescence after aminolevulinic acid infusion. The intraoperative biopsy findings ruled out glioma but could not confirm lymphoma. The definitive cerebral biopsy findings showed lymphocytes and histiocytes (CD1a+, S-1001+), with a diagnosis of intracerebral parenchymal LCH. Fractioned radiotherapy resulted in clinical and radiological remission. CONCLUSIONS: The present case is so rare it should not be used as a guide. We probably will never see a single intraparenchymal supratentorial central nervous system LCH lesion. However, we hope our report will help colleagues in the future with the thought process.

A prospective, multicenter, population-based study of BRAF mutational analysis for Lynch syndrome screening.

BACKGROUND & AIMS: Mismatch repair (MMR) deficiencies are the hallmark of tumors arising in Lynch syndrome, however, in approximately 15% of sporadic colorectal cancers (CRC) these deficiencies most often are associated with somatic methylation of the MMR gene MLH1. Recently, an oncogenic mutation in the BRAF gene has been involved in sporadic CRC showing MMR deficiencies as a result of MLH1 promoter methylation. The aim of this study was to evaluate the contribution of BRAF V600E mutation analysis in the identification of MSH2/MLH1 gene mutation carriers in newly diagnosed CRC patients. METHODS: BRAF V600E mutation was analyzed in CRC patients with MMR deficiencies (microsatellite instability and/or lack of MLH1/MSH2 protein expression) in the EPICOLON population-based study. The effectiveness and efficiency of different strategies were evaluated with respect to the presence of MSH2/MLH1 germline mutations. RESULTS: MMR deficiencies were detected in 119 of the 1222 CRC patients with tumors showing either microsatellite instability (n = 111) or loss of protein expression (n = 81). BRAF mutation was detected in 22 (18.5%) of the patients. None of the patients with unambiguous germline mutation had BRAF mutation. Regardless of the strategy used to identify MSH2/MLH1 gene carriers, the introduction of BRAF analysis in these patients slightly improves their effectiveness. The introduction of BRAF mutation analysis as a step before germline genetic testing in patients with MMR deficiencies achieved a significant reduction in costs per mutation detected. CONCLUSIONS: Detection of BRAF V600E mutation could simplify and improve the cost effectiveness of genetic testing for hereditary nonpolyposis colorectal cancer, especially in patients whose family history is incomplete or unknown.

Identification of MYH mutation carriers in colorectal cancer: a multicenter, case-control, population-based study.

BACKGROUND & AIMS: Whereas it has conclusively been demonstrated that biallelic MutY human homolog (MYH) mutations confer a significant risk for colorectal cancer (CRC), the influence of monoallelic mutations remains controversial. Characterization of MYH-associated CRC is critical to identify individuals who might benefit from preventive strategies. This prospective, multicenter, case-control, population-based study was aimed at (1) establishing the CRC risk associated with specific germline MYH mutations and (2) devising a set of clinical criteria to identify MYH carriers among newly diagnosed CRC. METHODS: Genotyping for Y165C and G382D was performed by TaqMan technology. Single-stranded conformation polymorphism analysis was performed in heterozygotes to screen for mutations in the entire gene. All individuals were re-screened for any additional pathogenic variant. RESULTS: Biallelic and monoallelic MYH mutations were found in 8 (0.7%) and 19 (1.7%) of 1116 CRC patients, respectively. None of the 934 control subjects carried biallelic mutations, whereas 22 (2.3%) of them were monoallelic carriers. In a meta-analysis including all previous case-control studies, monoallelic MYH carriers were not at increased risk for CRC (odds ratio, 1.11; 95% confidence interval, 0.90-1.37), although a significant association was found with the Y165C mutation in either homozygotes or heterozygotes (odds ratio, 1.67; 95% confidence interval, 1.17-2.40). Furthermore, presence of more than 15 synchronous colorectal adenomas or CRC diagnosed before the age of 50 years was the most effective set of criteria for the identification of biallelic MYH mutation carriers. CONCLUSIONS: This study proposes the first set of clinical criteria designed to identify CRC patients with biallelic MYH mutations, and it argues against an increased risk for monoallelic carriers.

Analysis of HER2 by chromogenic in situ hybridization and immunohistochemistry in lymph node-negative breast carcinoma: Prognostic relevance.

In patients with lymph node-negative breast carcinoma (LNNBC), the prevalence of HER2 overexpression and gene amplification and their prognostic value have not been extensively evaluated. We examined 162 patients with LNNBC with complete follow-up. Immunohistochemistry (IHC) for HER2, Ki67, and p53 was performed. HER2 gene status was analyzed by chromogenic in situ hybridization (CISH) and discordant cases by fluorescence in situ hybridization. HER2 overexpression was seen in 24.7% of cases (40/162) and amplification by CISH in 17.6% (28/159). Agreement between IHC and CISH was achieved in 147 (92.5%) cases. Amplification was seen in 21 (100%) of 21 (3+), 6 (35.3%) of 17 (2+), and 1 (0.6%) of 121 (0-1+) tumors. Fluorescence in situ hybridization detected 3 (1.8%) additional cases. HER2 overexpression and amplification were present in tumors of high grade, with necrosis and lymph-vascular invasion (LVI) (all P < .027). In addition, amplified tumors showed Ki67 of more than 20% and p53 overexpression (P < .05). By univariate analysis, shorter disease-free survival (DFS) and overall survival (OS) were seen for patients with tumors showing HER2 amplification, LVI, and Ki67 of more than 20% (P < .05) (Kaplan-Meier). However, the multivariate analysis (Cox regression) demonstrated only Ki67 as an independent prognostic factor for both DFS (P = .017) and OS (P = .010), and as a trend for HER2 gene status (OS, P = .087) and LVI (DFS, P = .11; OS, P = .063). We conclude that IHC is a reliable method for detecting HER2 expression that can be complemented by CISH in nondefinitive cases (2+). Moreover, CISH is a valuable tool for the assessment of HER2 gene status with potential prognostic value and, therefore, in clinical decision making for treatment of high-risk LNNBC.

Cyclooxygenase 2 expression in colorectal cancer with DNA mismatch repair deficiency.

BACKGROUND: Cyclooxygenase 2 (COX-2) overexpression is a frequent but not universal event in colorectal cancer. It has been suggested that COX-2 protein expression is reduced in colorectal cancer with a defective mismatch repair (MMR) system, a phenomenon commonly associated with hereditary nonpolyposis colorectal cancer (HNPCC) but also present in up to 15% of sporadic tumors. AIM: To assess COX-2 expression in a large series of fully characterized colorectal cancer patients with respect to the MMR system and to dissect the mechanisms responsible for altered COX-2 expression in this setting. PATIENTS AND METHODS: MMR-deficient colorectal cancer were identified in a nationwide, prospective, multicenter study (EPICOLON project). Control MMR-proficient colorectal cancer patients were randomly selected. COX-2 expression was evaluated by immunohistochemistry. Personal and familial characteristics, as well as MSH2/MLH1 expression and germ line mutations, were evaluated. RESULTS: One hundred fifty-three patients, 46 with MMR deficiency and 107 with MMR proficiency, were included in the analysis. Overall, tumor COX-2 overexpression was observed in 107 patients (70%). COX-2 overexpression was observed in 85 patients (79%) with a MMR-proficient system, but only in 22 patients (48%) with a MMR-deficient colorectal cancer (P < 0.001). The lack of COX-2 overexpression was independently associated with a MMR-deficient system (odds ratio, 3.89; 95% confidence interval, 1.78-8.51; P = 0.001) and a poor degree of differentiation (OR, 3.83; 95% CI, 1.30-11.31; P = 0.015). In the subset of patients with a MMR-deficient colorectal cancer, lack of COX-2 overexpression correlated with a poor degree of differentiation, no fulfillment of Amsterdam II criteria, absence of MSH2/MLH1 germ line mutations, presence of tumor MSH2 expression, and lack of tumor MLH1 expression. CpG island promoter hypermethylation of COX2 was observed in 6 of 18 (33%) tumors lacking COX-2 expression in comparison with 2 of 28 (7%) tumors expressing this protein (P = 0.04). CONCLUSIONS: Up to half of MMR-deficient colorectal cancer do not show COX-2 overexpression, a fact observed almost exclusively in patients with sporadic forms. COX2 hypermethylation seems to be responsible for gene silencing in one third of them. These results suggest the potential utility of nonsteroidal anti-inflammatory drugs in HNPCC chemoprevention and may explain the lack of response of this approach in some sporadic tumors.