Biological and therapeutic implications of RKIP in Gastrointestinal Stromal Tumor (GIST): an integrated transcriptomic and proteomic analysis.

BACKGROUND: Gastrointestinal stromal tumors (GIST) represent a significant clinical challenge due to their metastatic potential and limited treatment options. Raf kinase inhibitor protein (RKIP), a suppressor of the MAPK signaling pathway, is downregulated in various cancers and acts as a metastasis suppressor. Our previous studies demonstrated low RKIP expression in GIST and its association with poor outcomes. This study aimed to expand on the previous findings and investigate the biological and therapeutic implications of RKIP loss on GIST. METHODS: To validate the RKIP prognostic significance, its expression was evaluated by immunohistochemistry in 142 bona fide GIST cases. The functional role of RKIP was evaluated in vitro, using the GIST-T1 cell line, which was knocked out for RKIP. The biological and therapeutic implications of RKIP were evaluated by invasion, migration, apoptosis, and 2D / 3D viability assays. Additionally, the transcriptome and proteome of RKIP knockout cells were determined by NanoString and mass spectrometry, respectively. RESULTS: Immunohistochemical analysis revealed the absence of RKIP in 25.3% of GIST cases, correlating with a tendency toward poor prognosis. Functional assays demonstrated that RKIP knockout increased GIST cells' invasion and migration potential by nearly 60%. Moreover, we found that RKIP knockout cells exhibited reduced responsiveness to Imatinib treatment and higher cellular viability in 2D and 3D in vitro models, as assessed by apoptosis-related protein expression. Through comprehensive genetic and proteomic profiling of RKIP knockout cells, we identified several putative RKIP-regulated proteins in GIST, such as COL3A1. CONCLUSIONS: Using a multidimensional integrative analysis, we identified, for the first time in GIST, molecules and pathways modulated by RKIP that may potentially drive metastasis and, consequently, poor prognosis in this disease.

Frequency of Human Papillomavirus Detection in Chagasic Megaesophagus Associated or Not with Esophageal Squamous Cell Carcinoma.

BACKGROUND: Chagasic megaesophagus (CM) as well as the presence of human papillomavirus (HPV) has been reported as etiological factors for esophageal squamous cell carcinoma (ESCC). OBJECTIVE: We assessed the prevalence of HPV DNA in a series of ESCCs associated or not with CM. Data obtained were further correlated to the pathological and clinical data of affected individuals. METHODS: A retrospective study was performed on 92 formalin-fixed and paraffin-embedded tissues collected from patients referred to 3 different hospitals in São Paulo, Brazil: Barretos Cancer Hospital, Barretos, São Paulo; Federal University of Triângulo Mineiro, Uberaba, Minas Gerais; and São Paulo State University, Botucatu, São Paulo. Cases were divided into 3 groups: (i) 24 patients with CM associated with ESCC (CM/ESCC); (ii) 37 patients with ESCC without CM (ESCC); and (iii) 31 patients with CM without ESCC (CM). Detection of HPV DNA was assessed in all samples by a genotyping assay combining multiplex polymerase chain reaction and bead-based Luminex technology. RESULTS: We identified a high prevalence of high-risk HPV in patients in the CM group (12/31, 38.8%) and CM/ESCC (8/24, 33.3%), compared to individuals in the ESCC group (6/37, 16.3%). The individuals in the groups with cancer (ESCC and CM/ESCC) had a higher frequency of HPV-16 (4/9, 44.5% and 2/8, 25.0%). The other types of high-risk HPVs detected were HPV-31, 45, 51, 53, 56, 66, and 73. We also observed in some samples HPV coinfection by more than one viral type. Despite the high incidence of HPV, it did not show any association with the patient's clinical-pathological and molecular (TP53 mutation status) characteristics. CONCLUSION: This is the first report of the presence of HPV DNA in CM associated with ESCC. HPV infection was more presence in megaesophagus lesions. Further studies are needed to confirm and better understand the role of persistent HPV infection in patients with CM.

Methylation profile of colon cancer genes in colorectal precursor lesions and tumor tissue: perspectives for screening.

AIMS: Epigenetic alterations of genes involved in colorectal carcinogenesis are likely to be informative biomarkers for early detection. We assessed the methylation profile of a panel of seven colon cancer-related genes comparing normal colon, colorectal cancer (CRC) precursor lesions and cancer tissues from a Brazilian cohort. METHODS: The cohort comprised 114 CRC patients, including 40 matched normal tissue, 47 patients with adenomas, 33 with serrated polyps and 8 with normal colonic biopsy. DNA methylation status of SEPT9, ALX4, NDRG4, BMP3, APC, p16 and MLH1 was determined by pyrosequencing and correlated with clinicopathological features. Sensitivity, specificity, positive predictive value and negative predictive value were calculated for all genes using cancer endpoint. RESULTS: The most frequently methylated genes in cancer and in precancer lesions were SEPT9, ALX4, NDRG4, and BMP3, ranging from 55.3 to 95% of the samples. Overall, the frequency of methylation of these four genes in normal colonic tissue was significantly lower as compared to cancer or precursor lesions both in adenoma-carcinoma (p < .001 and p < .050) and serrated (sessile-serrated lesion) (p < .001 and p < .050) pathways. Additionally, sensitivity for the cancer endpoint ranged from 65.6 to 91.8%, and specificity from 17.9 to 62.9% for SEPT9, ALX4, NDRG4, and BMP3 genes. Moreover, the comethylation of ≥4 genes was higher in sessile-serrated lesion (87.5%) and conventional adenomas (78.7%) than in hyperplastic polyps (43.7%) (p = .025) and was significantly associated with proximal cancers (p = .042). CONCLUSIONS: Our study suggests the DNA methylation can constitute potential biomarkers in CRC screening of Brazilian population.

The Role of Fusobacterium nucleatum in Colorectal Carcinogenesis.

Colorectal cancer (CRC) is one of the most frequent and deadly neoplasms worldwide. Genetic factors, lifestyle habits, and inflammation are important risk factors associated with CRC development. In recent years, growing evidence has supporting the significant role of the intestinal microbiome in CRC carcinogenesis. Disturbances in the healthy microbial balance, known as dysbiosis, are frequently observed in these patients. Pathogenic microorganisms that induce intestinal dysbiosis have become an important target to determine the role of bacterial infection in tumorigenesis. Interestingly, the presence of different bacterial strains, such as Fusobacterium nucleatum, has been detected in tissue and stool from patients with CRC and associated with substantial clinical and molecular features, as well as with patient therapy response. Therefore, understanding how the presence and levels of F. nucleatumstrains in the gut affect the risk of CRC onset and progression may inform suitable candidates for interventions focused on modulation of this bacteria. Here we review new insights into the role of gut microbiota in CRC carcinogenesis and the clinical utility of using the detection of F. nucleatum in different settings such as screening, prognosis, and microbiota modulation as a means to prevent cancer, augment therapies, and reduce adverse effects of treatment.

Cap-assisted endoscopy increases ampulla of Vater visualization in high-risk patients.

BACKGROUND: Periampullary adenocarcinoma is a major clinical problem in high-risk patients including FAP population. A recent modification for visualizing the ampulla of Vater (AV) involves attaching a cap to the tip of the forward-viewing endoscope. Our aim was to compare the rates of complete visualization of AV using this cap-assisted endoscopy (CAE) approach to standard forward-viewing endoscopy (FVE). We also determined: (i) the rates of complications and additional sedation; (ii) the mean time required for duodenal examination; and (iii) the reproducibility among endoscopists performing this procedure. METHODS: We performed esophagogastroduodenoscopy for AV visualization in 102 > 18 years old using FVE followed by CAE. Video recordings were blinded and randomly selected for independent expert endoscopic evaluation. RESULTS: The complete visualization rate for AV was higher in CAE (97.0%) compared to FVE (51.0%) (p <  0.001). The additional doses of fentanyl, midazolam, and propofol required for CAE were 0.05, 1.9 and 36.3 mg. in 0.9, 24.5, and 77.5% patients, respectively. The mean time of duodenal examination for AV visualization was lower on CAE compared to FVE (1.41 vs. 1.95 min, p <  0.001). Scopolamine was used in 34 FVE and 24 CAE, with no association to AV complete visualization rates (p = 0.30 and p = 0.14). Three more ampullary adenomas were detected using CAE compared to FVE. Cap displacement occurred in one patient, and there was no observed adverse effect of the additional sedatives used. Kappa values for agreement between endoscopists ranged from 0.60 to 0.85. CONCLUSIONS: CAE is feasible, reproducible and safe, with a higher success rate for complete visualization compared to FVE. TRIAL REGISTRATION: ClinicalTrials.gov , NCT02867826 , 16 August 2016.

The Diagnostic Accuracy (DA) of ColonView Fecal Immunochemical Test (FIT) in Detecting Colorectal Adenoma (CRA) Can Be Improved by the Diagnostic Models (DM) that Include Triage and Risk Features of CRA.

BACKGROUND/AIM: This study assessed whether the diagnostic accuracy (DA) of ColonView (CV) fecal immunochemical test (FIT) in detecting colorectal adenoma (CRA) can be improved by the diagnostic models (DM) that include triage and risk features of CRA. PATIENTS AND METHODS: A total of 5,090 participants of colorectal neoplasia (CRN) screening were recruited prospectively between January 2014 and December 2016. The CRN cohort of 486 patients included 222 CRA patients and 264 non-CRA patients of whom three consecutive fecal samples were analyzed by two fecal occult blood (FOB) assays (CV FIT test, HemoccultSENSA test). Hierarchical multilevel logistic models were used to test the DA of CV test and DMs, visualised as hierarchical summary receiving operating characteristic (HSROC) curves. RESULTS: In conventional receiving operating characteristic (ROC) analysis, the area under the curve (AUC) values of the age, height, weight, and body mass index (BMI) were 0.60, 0.57, 0.54, and 0.51, respectively. The AUC values for different DMs ranged from 0.69 (for DM without triage I/II and SENSA), and the highest AUC value of 0.70 was reached for DM with all variables included. In HSROC analysis, the AUC values for i) lowR variables, ii) highR variables, and ii) DMs were as follows: i) AUC=0.506, ii) AUC=0.566 and iii) AUC=0.732. The differences in AUC values were: between i) and ii) p=0.008; between i) and iii) p<0.0001; between ii) and iii) p<0.0001. CONCLUSION: The results demonstrated that DMs, particularly those including risk factors, significantly improved the DA of the CV FIT test in detecting CRA compared to traditional low-risk (lowR) and high-risk (highR) features alone. This study provides novel evidence supporting the enhanced diagnostic performance of DMs in combination with CV FIT testing for the detection of CRA.

Enhancing Colorectal Cancer Screening with Droplet Digital PCR (ddPCR) Analysis of Fusobacterium nucleatum in Fecal Immunochemical Test (FIT) Samples.

Fecal immunochemical test (FIT) followed by colonoscopy in positive cases is commonly used for population-based colorectal cancer (CRC) screening. However, specificity of FIT for CRC is not ideal, and has poor performance for advanced adenoma detection. Fecal Fusobacterium nucleatum (Fn) detection has been proposed as a potential non-invasive biomarker for CRC and advanced adenoma detection. We aimed to evaluate the diagnostic performance of Fn detection using droplet digital PCR (ddPCR) in FIT samples from individuals enrolled in a CRC screening program with colorectal adenoma or cancer. We evaluated Fn presence in DNA isolated from FIT leftover material of 300 participants in a CRC Screening Program using ddPCR. The Fn DNA amount was classified as Fn-low/negative and Fn-high, and the association with patients clinicopathological features and accuracy measurements was calculated. Fn high levels were more prevalent in FIT-positive (47.2%n=34 of72) than FIT-negative samples (28.9%, n=66 of 228) (p<0.04). Among FIT-positive samples, high Fn levels were significantly more frequent in cancer patients (CA, n=8) when compared to normal (NT, n=16) (p=0.02), non-advanced adenomas (NAA, n=36) (p=0.01), and advanced adenomas (AA, n=12) (p=0.01). Performance analysis of Fn in FIT-positive samples for colorectal cancer detection yielded an AUC of 0.8203 (CI: 0.6464-0.9942), with high sensitivity (100%) and specificity of 50%%. Concluding, we showed the feasibility of detecting Fn in FIT leftovers using the ultrasensitive ddPCR technique. Furthermore, we highlighted the potential use of Fn levels in fecal samples to ameliorate CRC detection.

Fecal Immunochemical Test (FIT) in Triage of Bleed-positive (Crab+) and Bleed-negative Colorectal Adenoma (Crab-) Patients in Colorectal Neoplasia Screening.

BACKGROUND/AIM: Fecal immunochemical tests (FITs) are sensitive and specific for detecting colorectal cancer (CRC), but their diagnostic accuracy (DA) in bleed-positive (CRAb+) and bleed-negative colorectal adenomas (CRAb-) has been rarely tested. PATIENTS AND METHODS: A total of n=506 patients were included in the study, each collecting 3 consecutive stool samples for analysis. The stool samples were analyzed by the ColonView FIT (CV) and Hemoccult SENSA tests. A total of 484/5,090 (9.5%) patients returned all 3 samples and were subjected to final analysis. Hierarchical summary receiver operating characteristic (HSROC) analysis with different cut-offs for hemoglobin/haptoglobin (Hb and Hb/Hp) complex was performed to assess the DA of CV. RESULTS: In the HSROC analysis, the AUC values were as follows: i) bleed-positive adenoma patients by visual analysis mode (VA), AUC=0.566, ii) bleed-positive adenoma patients by automatic analysis mode (AA), AUC=0.546, iii) bleed-negative adenoma patients by VA, AUC=0.534 and iv) bleed-negative adenoma patients by AA, AUC=0.589: In roccomp analysis, there were significant differences in AUC values between iii) and iv) p=0.045. CONCLUSION: When stratified by the 'blood in stool' (as b+ or b- endpoint), the DA of the CV test is quite similar for CRAb+ and CRAb-. However, of the two modes (VA/AA) of the CV test, the AA reading gives a slightly higher DA both CRAb+ and CRAb-.

Diagnostic Accuracy of Fecal Immunochemical Test (FIT) in Bleed-positive and Bleed-negative Colorectal Cancer (CRC) Among a Cohort of 5,090 Subjects who Participated in the Colorectal Neoplasia (CRN) Screening in Brazil.

BACKGROUND/AIM: This study assessed the diagnostic accuracy (DA) of fecal immunochemical test (FIT) ColonView (CV) and guaiac-based fecal occult blood test (HemoccultSENSA) among bleed-positive (history or signs of intestinal bleeding) and bleed-negative participants (no history or signs of intestinal bleeding) (n=5,090) in colorectal neoplasia (CRN) screening in Brazil. PATIENTS AND METHODS: The eligible patients for the study (n=506) collected three consecutive stool samples, to be analyzed by both assays (CV, SENSA). Finally, 421/5090 (8.3%) patients returned both samples, which were subjected to final analysis. Receiver operating characteristic (ROC) analysis with different cut-offs was performed to assess the DA. RESULTS: The area under curve (AUC) values for i) visually analyzed (VA) CV for bleed-positive CRC, ii) automatically analyzed (AA) CV for bleed-positive CRC, iii) VA CV for bleed-negative CRC, and iv) AA CV for bleed-negative CRC as endpoints were as follows: i) AUC=0.864, ii) AUC=0.933, iii) AUC=0.836, and iv) AUC=0.892. In roccomp analysis, the differences in AUC values were: between i) and ii) p=0.068; between i) and iii) p=0.497; between i) and iv) p=0.488; between ii) and iii) p=0.0058; between ii) and iv) p=0.229; and between iii) and iv) p=0.138. CONCLUSION: This is the first investigation where two modes of CV test, VA, and AA, for bleed-positive and bleed-negative CRC patients were used as the endpoint. The AA reading of the CV test showed higher DA in bleed-positive than in bleed-negative CRC patients.

Triage Process at Endoscopy With ColonView Fecal Immunochemical Test (FIT) Will Enhance Diagnostic Accuracy (DA) of Colorectal Cancer Screening.

BACKGROUND/AIM: This study assessed the diagnostic accuracy (DA) of the predictive features of colorectal cancer (CRC, predictCRC), triage process (triage), and ColonView (CV) fecal immunochemical test (FIT) in a CRC screening setting. The diagnostic score models (DMs) including predictCRC with triage and CV test were also calculated. PATIENTS AND METHODS: The study cohort of 544 patients included 58 CRC patients and 486 non-CRC patients who submitted three consecutive fecal samples for analysis, by two fecal occult blood (FOB) assays (CV FIT test, HemoccultSENSA test). Hierarchical multilevel logistic models were used to test the DA (for CRC) of each item of predictCRC (with triage I and II) and DMs, visualized as hierarchical summary receiving operating characteristic (HSROC) curves. RESULTS: The DA of the predictCRC location of neoplasm (Loc), triage I, and triage II showed 49%, 41%, and 93% sensitivity (Se), and 70%, 99.5%, and 88% specificity (Sp), respectively. The PPV+ of triage I (92%) was higher than that of Loc (22%) or triage II test (45%). In the conventional receiver operating characteristic (ROC) analysis, the area under the curve (AUC) values for the different DMs ranged from 0.880 (for DM without triage I and II), whereas the highest AUC value of 0.960 was reached for DM with triage I and II included in the formula. In the HSROC analysis, the AUC values were as follows: i) with all predictCRCs, AUC=0.717 and ii) with DMs, AUC=0.937. In the roccomp analysis, the difference in AUC values between i) and ii) was statistically significant (p<0.0001). CONCLUSION: In the detection of CRC, the DA of the new DMs with triage was far superior to that of DMs without triage. This is the first study to report evidence of improved DA in the detection of CRC using DMs including predictCRC with triage and CV FIT test.

Colorectal cancer spatial pattern in the northeast region of São Paulo, Brazil.

Background: This study examined the spatial pattern of the colorectal cancer (CRC) in the 18 municipalities that compose the Regional Health Department of Barretos (RHD-V), which is in the northeast of the state of São Paulo, Brazil. Methods: All incident cases and deaths from CRC between 2002 and 2016 were included. Age-standardized rates (ASR) for incidence and mortality per 100,000 person-years were used to evaluate the spatial distribution for the total and five-year periods. The lethality rates were also assessed. Excess risk maps compared the observed and expected events. Age-standardized net survival was used to evaluate CRC survival. Results: For CRC incidence, the ASR value for the general population over the entire period (2002-2016) was 17.7 (95% CI: 16.7, 18.6), ranging from 16.7 (95% CI: 14.9, 18.4) (2002-2006) to 20.0 (95% CI: 18.3, 21.7) (2012-2016) per 100,000. When males and females were compared, the ASR was 20.1 (95% CI: 18.6, 21.6) and 15.7 (95% CI: 14.5, 17.0) per 100,000, respectively. For CRC mortality (2002-2016), the ASR was 8.2 (95% CI: 7.6, 8.9), ranging from 9.0 (95% CI: 7.8, 10.3) (2002-2006) to 8.2 (95% CI: 7.2, 9.3) (2012-2016) per 100,000. Overall, the excess risk up to 2.0 was more frequent. In terms of survival, municipalities with large port populations had lower survival in comparison with medium port. Conclusions: This study showed a variation in CRC incidence and mortality, with differences considering five-year periods and gender, being the incidence higher in males than females in the entire period, with mortality equivalent to half the incidence. The survival was lower in municipalities with large port populations in comparison with medium port. Knowing spatial patterns of incidence, mortality, lethality, and survival can be necessary to support policymakers to advance or implement effective cancer control programs.

Combined SEPT9 and BMP3 methylation in plasma for colorectal cancer early detection and screening in a Brazilian population.

BACKGROUND: Colorectal cancer (CRC) screening can help to reduce its incidence and mortality. Noninvasive strategies, such as plasma analysis of epigenetic alterations, can constitute important biomarkers of CRC detection. OBJECTIVE: This study aimed to evaluate the plasma methylation status of SEPT9 and BMP3 promoters as biomarkers for detection of CRC and its precursor lesions in a Brazilian population. METHODS: Plasma samples from 262 participants of the CRC screening program of Barretos Cancer Hospital who had a positive fecal occult blood test and underwent colonoscopy and cancer patients were analyzed. Participants were grouped according to the worst lesion detected in the colonoscopy. Cell-free circulating DNA (cfDNA) was bisulfite treated followed by the analysis of SEPT9 and BMP3 methylation status using a droplet digital PCR system (ddPCR). The best methylation cutoff value for group discrimination was calculated by receiver operating characteristic (ROC) curve analysis. RESULTS: Among the 262 participants, 38 were diagnosed with CRC, 46 with advanced adenomas 119 with nonadvanced adenomas, three with sessile serrated lesions, and 13 with hyperplastic polyps. In 43 participants, no lesion was detected in the colonoscopy and were used as controls. The CRC group showed the highest cfDNA concentration (10.4 ng/mL). For the SEPT9 gene, a cutoff of 2.5% (AUC = 0.681) that discriminates between CRC and the control group resulted in CRC sensitivity and specificity of 50% and 90%, respectively. Concerning the BMP3 gene, a cutoff of 2.3% (AUC = 0.576) showed 40% and 90% of sensitivity and specificity for CRC detection, respectively. Combining SEPT9, BMP3 status, and age over 60 years resulted in a better performance for detecting CRC (AUC = 0.845) than the individual gene models, yielding 80% and 81% of sensitivity and specificity, respectively. CONCLUSION: The present study suggests that a combination of SEPT9 and BMP3 plasma methylation, along with age over 60 years, showed the highest performance in detecting CRC in a Brazilian population. These noninvasive biomarkers can potentially serve as useful tools for CRC screening programs.

Involvement of signaling molecules in the prediction of response to imatinib treatment in metastatic GIST patients.

Imatinib therapy has undoubtedly contributed to the treatment of metastatic gastrointestinal stromal (GIST) tumors that were previously untreatable. However, disease progression during treatment with tyrosine kinase inhibitors remains an issue in clinical practice not fully explained by KIT and PDGFRA mutation status. We investigated the role of three important signaling molecules (insulin-like growth factor 1 receptor [IGF1R], protein kinase C-θ [PKCθ], and Raf kinase inhibitor protein [RKIP]) that have been implicated in GIST pathogenesis as potential biomarkers for prediction of response to imatinib treatment. We retrospectively reviewed 76 patients with metastatic GIST submitted to imatinib treatment between 2002 and 2007, and analyzed 63 of them. Insulin-like growth factor 1, total PKCθ, phosphorylated PKCθ, and RKIP immunohistochemical expression were correlated with objective response to imatinib treatment and progression-free and overall survival. Median follow-up was 31.2 mo (95% confidence interval, 26.3-36.1 mo). There was a statistically significant association between IGF1R expression and type of response to imatinib treatment (P = 0.05)-that is, higher IGF1R expression was related to lower objective response. However, IGF1R higher expression did not affect progression-free and overall survival. Insulin-like growth factor 1, but not PKCθ and RKIP, emerges as a potential biomarker for prediction of response to imatinib treatment in metastatic GISTs. Validation studies are warranted.

Site-specific Performance of ColonView (CV) Fecal Immunochemical Test (FIT) With Differences Between Proximal and Distal Colorectal Adenoma.

BACKGROUND/AIM: The aim of this study was to assess the diagnostic accuracy (DA) of a ColonView (CV) test in proximal versus distal colorectal adenoma (pCRA versus dCRA). PATIENTS AND METHODS: The colorectal neoplasia (CRN) screening cohort included 5,090 individuals and 506/5,090 (10%) were eligible for the study. Finally, only 127/506 were included in the CRA analysis and hierarchical summary ROC (HSROC) curves were used to show the pooled overall DA of visually analyzed (VA) and automatically analyzed (AA) techniques in pCRA and dCRA detection. RESULTS: The overall specificity (Sp) of the AA technique for the pCRA and dCRA endpoint was 46% and 43%, respectively. The most sensitive AA test in pCRA patients showed 76% sensitivity (Se) versus 58% Se in dCRA patients. In the HSROC analysis, area under the curve (AUC) values were as follows: i) VA in pCRA: AUC=0.503, ii) AA in pCRA: AUC=0.560, iii) VA in dCRA: AUC=0.552 and iv) AA in dCRA: AUC=0.486. In Roccomp analysis, the statistically significant AUC values were available between VA and AA reading modes in pCRA (p=0.044) and in AA reading between pCRA and dCRA (p=0.024). CONCLUSION: As compared with the CRC endpoint, the DA value of the CV test is far inferior for the CRA endpoint, as determined by the AUC values.

The ColonView (CV) Quick Test for Fecal Occult Blood Shows Significantly Higher Diagnostic Accuracy in Detecting Distal than Proximal Colorectal Cancer.

AIM: The present study compared the accuracy of ColonView (CV) quick test in detecting proximal versus distal colorectal cancer (CRC). A traditional guaiac-based fecal occult blood test (gFOBT) (Hemoccult SENSA) was used as a reference. PATIENTS AND METHODS: A cohort of 368 colonoscopy-referral patients were asked to collect 3 consecutive fecal samples, to be analyzed by both assays (CV, SENSA). Receiver operating characteristic (ROC) analysis was used to find the optimal cut-off values for both Hb and Hb/Hp of the CV test. Summary hierarchical ROC (HSROC) curves were used to visualize the pooled overall accuracy of visually analysed (VA) and automatically analyzed (AA) reading modes in proximal and distal CRC detection. RESULTS: The overall specificity (Sp) of the AA reading mode for the proximal CRC and distal CRC endpoint was 73% and 76%, respectively. For proximal CRC, the two most sensitive AA tests showed 90% sensitivity (Se), while for distal CRC, the two most sensitive AA tests showed 100% Se. In the HSROC analysis, the AUC values were as follows: i) VA in proximal CRC: 0.765, ii) AA in proximal CRC: 0.878, iii) VA in distal CRC: 0.955 and iv) AA in distal CRC: 0.961. In roccomp analysis, AUC values were significantly different in: VA vs. AA in proximal CRC p=0.009; VA in proximal vs. VA in distal CRC p<0.0001; VA in proximal vs. AA in distal CRC p<0.0001; AA in proximal vs. VA in distal CRC p=0.021; AA in proximal CRC vs. AA in distal CRC p=0.006. CONCLUSION: The applicability of the CV test (a new-generation FIT) in CRC screening was confirmed. The AA reading was superior to VA (or SENSA) in its diagnostic accuracy in detecting proximal CRC patients. Distal CRCs were more accurately detected than proximal CRCs by both reading modes.

Association of microsatellite instability (MSI) status with the 5-year outcome and genetic ancestry in a large Brazilian cohort of colorectal cancer.

Colorectal cancer (CRC) has a high incidence and mortality worldwide. Microsatellite instability (MSI) is crucial in CRC, with distinct molecular and clinicopathological features in patients. Nowadays, it is a predictive marker for immunotherapy. We proposed to evaluate the 5-year outcome of MSI status in 1002 Brazilian CRC, and associate it with genetic ancestry, molecular and clinicopathological features. MSI evaluation was performed using molecular markers. MSI+ tumors were analyzed for alterations in 23 MSI-targeted genes. Genetic ancestry was evaluated using an Ancestry-Informative markers panel. MSI status was analyzed in relation to CRC specific survival and other clinical and genetic variables. MSI+ status was observed in 10.5% of cases. MSI+ status was significantly associated with the anatomic site right colon, mucinous histological type, clinical stage II, histological grade III/undifferentiated, no recurrence of disease, and live cases without cancer. No association of MSI status with genetic ancestry components was observed. MSI-targeted genes analyses showed the most frequently altered genes: ATM, EGFR, MRE11, ROCK1, and TGFBRII. There was a statistically significant difference in cancer-specific survival between cases according to MSI status. This study constitutes the most comprehensive analyses of the MSI impact on the Brazilian CRC. MSI+ frequency in Brazilian CRC agreed with the literature and was associated with several clinicopathological features related with less aggressive tumors, independently of their genetic ancestry.

Somatic targeted mutation profiling of colorectal cancer precursor lesions.

BACKGROUND: Most colorectal cancers (CRC) arise from precursor lesions. This study aimed to characterize the mutation profile of colorectal cancer precursor lesions in a Brazilian population. METHODS: In total, 90 formalin-fixed paraffin-embedded colorectal precursor lesions, including 67 adenomas, 7 sessile serrated lesions, and 16 hyperplastic polyps, were analyzed by next-generation sequencing using a panel of 50 oncogenes and tumor suppressor genes. The genetic ancestry of the patients was estimated. RESULTS: Somatic driver mutations were identified in 66.7% of cases, including alterations in APC (32.2%), TP53 (20.0%), KRAS (18.9%), BRAF (13.3%) and EGFR (7.8%). Adenomas displayed a higher number of mutations, mainly in APC, compared to serrated polyps (73.1% vs. 47.8%, p = 0.026). Advanced adenomas had a significantly higher frequency of mutation in KRAS and a high overall mutation rate than early adenomas (92.9% vs. 59%, p = 0.006). A high degree of ancestry admixture was observed in the population studied, with a predominance of European components (mean of 73%) followed by African (mean of 11.3%). No association between genetic ancestry and type of lesions was found. The mutation profile of Brazilian colorectal precursor lesions exhibits alteration in APC, KRAS, TP53, and BRAF at different frequencies according to lesion type. CONCLUSIONS: These results bestow the knowledge of CRC's biologic history and support the potential of these biomarkers for precursor lesions detection in CRC screening of the Brazilian population.

Accuracy and Clinical Relevance of Intra-Tumoral Fusobacterium nucleatum Detection in Formalin-Fixed Paraffin-Embedded (FFPE) Tissue by Droplet Digital PCR (ddPCR) in Colorectal Cancer.

The use of droplet digital PCR (ddPCR) to identify and quantify low-abundance targets is a significant advantage for accurately detecting potentially oncogenic bacteria. Fusobacterium nucleatum (Fn) is implicated in colorectal cancer (CRC) tumorigenesis and is becoming an important prognostic biomarker. We evaluated the detection accuracy and clinical relevance of Fn DNA by ddPCR in a molecularly characterized, formalin-fixed, paraffin-embedded (FFPE) CRC cohort previously analyzed by qPCR for Fn levels. Following a ddPCR assay optimization and an analytical evaluation, Fn DNA were measured in 139 CRC FFPE cases. The measures of accuracy for Fn status compared to the prior results generated by qPCR and the association with clinicopathological and molecular patients' features were also evaluated. The ddPCR-based Fn assay was sensitive and specific to positive controls. Fn DNA were detected in 20.1% of cases and further classified as Fn-high and Fn-low/negative, according to the median amount of Fn DNA that were detected in all cases and associated with the patient's worst prognosis. There was a low agreement between the Fn status determined by ddPCR and qPCR (Cohen's Kappa = 0.210). Our findings show that ddPCR can detect and quantify Fn in FFPE tumor tissues and highlights its clinical relevance in Fn detection in a routine CRC setting.

The Barretos Cancer Hospital Animal Facility: Implementation and Results of a Dedicated Platform for Preclinical Oncology Models.

The Barretos Cancer Hospital Animal Facility (BCHAF) is a unique facility in Brazil exclusively dedicated to working with animal models for cancer research. In this article, we briefly present our modern facility and the main experiments performed, focusing on mutant strains of mice (PTCH-knockout and ApcMin mice), xenograft models, and patient-derived xenografts (PDXs). Our results show the progress and challenges in establishing these models and the need for having an appropriate representation of our cancer population to better understand tumor biology and to identify cancer biomarkers, which could be putatively targeted, allowing for personalized therapy.