Does biomarker use in oncology improve clinical trial failure risk? A large-scale analysis.

PURPOSE: To date there has not been an extensive analysis of the outcomes of biomarker use in oncology. METHODS: Data were pooled across four indications in oncology drawing upon trial outcomes from www.clinicaltrials.gov: breast cancer, non-small cell lung cancer (NSCLC), melanoma and colorectal cancer from 1998 to 2017. We compared the likelihood drugs would progress through the stages of clinical trial testing to approval based on biomarker status. This was done with multi-state Markov models, tools that describe the stochastic process in which subjects move among a finite number of states. RESULTS: Over 10000 trials were screened, which yielded 745 drugs. The inclusion of biomarker status as a covariate significantly improved the fit of the Markov model in describing the drug trajectories through clinical trial testing stages. Hazard ratios based on the Markov models revealed the likelihood of drug approval with biomarkers having nearly a fivefold increase for all indications combined. A 12, 8 and 7-fold hazard ratio was observed for breast cancer, melanoma and NSCLC, respectively. Markov models with exploratory biomarkers outperformed Markov models with no biomarkers. CONCLUSION: This is the first systematic statistical evidence that biomarkers clearly increase clinical trial success rates in three different indications in oncology. Also, exploratory biomarkers, long before they are properly validated, appear to improve success rates in oncology. This supports early and aggressive adoption of biomarkers in oncology clinical trials.

The Value of Activated Ion Electron Transfer Dissociation for High-Throughput Top-Down Characterization of Intact Proteins.

High-throughput top-down proteomic experiments directly identify proteoforms in complex mixtures, making high quality tandem mass spectra necessary to deeply characterize proteins with many sources of variation. Collision-based dissociation methods offer expedient data acquisition but often fail to extensively fragment proteoforms for thorough analysis. Electron-driven dissociation methods are a popular alternative approach, especially for precursor ions with high charge density. Combining infrared photoactivation concurrent with electron transfer dissociation (ETD) reactions, i.e., activated ion ETD (AI-ETD), can significantly improve ETD characterization of intact proteins, but benefits of AI-ETD have yet to be quantified in high-throughput top-down proteomics. Here, we report the first application of AI-ETD to LC-MS/MS characterization of intact proteins (<20 kDa), highlighting improved proteoform identification the method offers over higher energy-collisional dissociation (HCD), standard ETD, and ETD followed by supplemental HCD activation (EThcD). We identified 935 proteoforms from 295 proteins from human colorectal cancer cell line HCT116 using AI-ETD compared to 1014 proteoforms, 915 proteoforms, and 871 proteoforms with HCD, ETD, and EThcD, respectively. Importantly, AI-ETD outperformed each of the three other methods in MS/MS success rates and spectral quality metrics (e.g., sequence coverage achieved and proteoform characterization scores). In all, this four-method analysis offers the most extensive comparisons to date and demonstrates that AI-ETD both increases identifications over other ETD methods and improves proteoform characterization via higher sequence coverage, positioning it as a premier method for high-throughput top-down proteomics.

Assessment of Tumor Sequencing as a Replacement for Lynch Syndrome Screening and Current Molecular Tests for Patients With Colorectal Cancer.

Importance: Universal tumor screening for Lynch syndrome (LS) in colorectal cancer (CRC) is recommended and involves up to 6 sequential tests. Somatic gene testing is performed on stage IV CRCs for treatment determination. The diagnostic workup for patients with CRC could be simplified and improved using a single up-front tumor next-generation sequencing test if it has higher sensitivity and specificity than the current screening protocol. Objective: To determine whether up-front tumor sequencing (TS) could replace the current multiple sequential test approach for universal tumor screening for LS. Design, Setting, and Participants: Tumor DNA from 419 consecutive CRC cases undergoing standard universal tumor screening and germline genetic testing when indicated as part of the multicenter, population-based Ohio Colorectal Cancer Prevention Initiative from October 2015 through February 2016 (the prospective cohort) and 46 patients with CRC known to have LS due to a germline mutation in a mismatch repair gene from January 2013 through September 2015 (the validation cohort) underwent blinded TS. Main Outcomes and Measures: Sensitivity of TS compared with microsatellite instability (MSI) testing and immunohistochemical (IHC) staining for the detection of LS. Results: In the 465 patients, mean age at diagnosis was 59.9 years (range, 20-96 years), and 241 (51.8%) were female. Tumor sequencing identified all 46 known LS cases from the validation cohort and an additional 12 LS cases from the 419-member prospective cohort. Testing with MSI or IHC, followed by BRAF p.V600E testing missed 5 and 6 cases of LS, respectively. Tumor sequencing alone had better sensitivity (100%; 95% CI, 93.8%-100%) than IHC plus BRAF (89.7%; 95% CI, 78.8%-96.1%; P = .04) and MSI plus BRAF (91.4%; 95% CI, 81.0%-97.1%; P = .07). Tumor sequencing had equal specificity (95.3%; 95% CI, 92.6%-97.2%) to IHC plus BRAF (94.6%; 95% CI, 91.9%-96.6%; P > .99) and MSI plus BRAF (94.8%; 95% CI, 92.2%-96.8%; P = .88). Tumor sequencing identified 284 cases with KRAS, NRAS, or BRAF mutations that could affect therapy for stage IV CRC, avoiding another test. Finally, TS identified 8 patients with germline DPYD mutations that confer toxicity to fluorouracil chemotherapy, which could also be useful for treatment selection. Conclusions and Relevance: Up-front TS in CRC is simpler and has superior sensitivity to current multitest approaches to LS screening, while simultaneously providing critical information for treatment selection.

Unsupervised Quality Assessment of Mass Spectrometry Proteomics Experiments by Multivariate Quality Control Metrics.

Despite many technological and computational advances, the results of a mass spectrometry proteomics experiment are still subject to a large variability. For the understanding and evaluation of how technical variability affects the results of an experiment, several computationally derived quality control metrics have been introduced. However, despite the availability of these metrics, a systematic approach to quality control is often still lacking because the metrics are not fully understood and are hard to interpret. Here, we present a toolkit of powerful techniques to analyze and interpret multivariate quality control metrics to assess the quality of mass spectrometry proteomics experiments. We show how unsupervised techniques applied to these quality control metrics can provide an initial discrimination between low-quality experiments and high-quality experiments prior to manual investigation. Furthermore, we provide a technique to obtain detailed information on the quality control metrics that are related to the decreased performance, which can be used as actionable information to improve the experimental setup. Our toolkit is released as open-source and can be downloaded from https://bitbucket.org/proteinspector/qc_analysis/ .

Assessment and biological significance of JC polyomavirus in colorectal cancer in Tunisia.

PURPOSE: Several reports have indicated the presence of JC polyomavirus (JCV) in many human tumors, including colorectal cancers (CRCs). The presence of JCV infection in CRC patients has not been investigated in African countries. METHODS: We examined the prevalence and the biological significance of JCV in Tunisian CRC patients. The presence of JCV was assessed by polymerase chain reaction (PCR) in a series of 105 CRCs and 89 paired non-tumor colonic mucosa samples from Tunisian patients. Results were correlated with the clinicopathological features and immunohistochemical expression of ß-catenin, p53, and the proliferation marker Ki-67. RESULTS: JCV DNA was detected in 58.1% (61/105) of CRC and in only 14.6% (13/89) of paired non tumor colonic mucosa samples (p=0.03). The presence of JCV was significantly correlated with tumor differentiation (p=0.03). Moreover, JCV presence was significantly correlated with nuclear accumulation of ß-catenin (p=0.008) and p53 accumulation (p=0.0001). Multivariate logistic regression analysis showed that tumor differentiation, ß-catenin and p53 accumulation were independent parameters significantly associated with the presence of JCV in CRC (p=0.04; p=0.05; p=0.001, respectively). CONCLUSION: We support a role of JCV in colorectal carcinogenesis in Tunisian patients, especially of well differentiated morphology.

Meta-analyses of randomized controlled trials show suboptimal validity of surrogate outcomes for overall survival in advanced colorectal cancer.

OBJECTIVES: To quantify and compare the treatment effects on three surrogate end points, progression-free survival (PFS), time to progression (TTP), and tumor response rate (TR) vs. overall survival (OS) based on a meta-analysis of randomized controlled trials (RCTs) of drug interventions in advanced colorectal cancer (aCRC). STUDY DESIGN AND SETTING: We systematically searched for RCTs of pharmacologic therapies in aCRC between 2003 and 2013. Trial characteristics, risk of bias, and outcomes were recorded based on a predefined form. Univariate and multivariate random-effects meta-analyses were used to estimate pooled summary treatment effects. The ratio of hazard ratios (HRs)/odds ratios (ORs) and difference in medians were used to quantify the degree of difference in treatment effects on the surrogate end points and OS. Spearman ρ, surrogate threshold effect (STE), and R(2) were also estimated across predefined trial-level covariates. RESULTS: We included 101 RCTs. In univariate and multivariate meta-analyses, we found larger treatment effects for the surrogates than for OS. Compared with OS, treatment effects were on average 13% higher when HRs were measured and 3% to 45% higher when ORs were considered; differences in median PFS/TTP were higher than on OS by an average of 0.5 month. Spearman ρ ranged from 0.39 to 0.80, mean R(2) from 0.06 to 0.65, and STE was 0.8 for HRPFS, 0.64 for HRTTP, or 0.28 for ORTR. The stratified analyses revealed high variability across all strata. CONCLUSION: None of the end points in this study were found to achieve the level of evidence (ie, mean R(2)trial > 0.60) that has been set to select high or excellent correlation levels by common surrogate evaluation tools. Previous surrogacy relationships observed between PFS and TTP vs. OS in selected settings may not apply across other classes or lines of therapy.

Practical value of the new system for Maspin assessment, in colorectal cancer.

Maspin is a serine protease which belongs to the serpin family and seems to play an important role in inhibiting angiogenesis and tumor proliferation. The significance of its expression in colorectal cancer (CRC) has not been elucidated so far. In our study, we tried to identify, based on Maspin expression, four groups of CRC, with possible prognostic impact. In 121 CRC, we analyzed the Maspin expression in correlation with the clinico-pathological features, microsatellite status and other markers such as p53, bax, bcl-2, VEGF (Vascular Endothelial Growth Factor) and CD31. Based on the percentage and intensity of Maspin expression in the tumor cells, the cases were grouped in four classes: negative, with cytoplasmic predominance, nuclear predominated, and cases with mixed (cytoplasmic-nuclear) expression. 9% of the cases were negative, 44% presented cytoplasmic predominance, the nuclear predominance was revealed in 24% of the cases, and the other 23% of CRC having a mixed Maspin positivity. The cytoplasmic predominance was correlated with a better prognosis, p53 negativity, bax positivity, and lack of tumor budding. Forty percent of microsatellite instable (MSI) cases presented mixed expression, this pattern being also related to a lower angiogenesis. Nuclear predominance was associated with p53 positivity, the lowest survival rate and intense VEGF expression. In conclusion, CRC with cytoplasmic predominance and mixed Maspin expression seems to present better prognosis whereas nuclear predominance is connected with high aggressivity.

Inferring serum proteolytic activity from LC-MS/MS data.

BACKGROUND: In this paper we deal with modeling serum proteolysis process from tandem mass spectrometry data. The parameters of peptide degradation process inferred from LC-MS/MS data correspond directly to the activity of specific enzymes present in the serum samples of patients and healthy donors. Our approach integrate the existing knowledge about peptidases' activity stored in MEROPS database with the efficient procedure for estimation the model parameters. RESULTS: Taking into account the inherent stochasticity of the process, the proteolytic activity is modeled with the use of Chemical Master Equation (CME). Assuming the stationarity of the Markov process we calculate the expected values of digested peptides in the model. The parameters are fitted to minimize the discrepancy between those expected values and the peptide activities observed in the MS data. Constrained optimization problem is solved by Levenberg-Marquadt algorithm. CONCLUSIONS: Our results demonstrates the feasibility and potential of high-level analysis for LC-MS proteomic data. The estimated enzyme activities give insights into the molecular pathology of colorectal cancer. Moreover the developed framework is general and can be applied to study proteolytic activity in different systems.

Analysis of differentially expressed proteins in colorectal cancer using hydroxyapatite column and SDS-PAGE.

Limitation on two dimensional (2D) gel electrophoresis technique causes some proteins to be under presented, especially the extreme acidic, basic, or membrane proteins. To overcome the limitation of 2D electrophoresis, an analysis method was developed for identification of differentially expressed proteins in normal and cancerous colonic tissues using self-pack hydroxyapatite (HA) column. Normal and cancerous colon tissues were homogenized and proteins were extracted using sodium phosphate buffer at pH 6.8. Protein concentration was determined and the proteins were loaded unto the HA column. HA column reduced the complexity of proteins mixture by fractionating the proteins according to their ionic strength. Further protein separation was accomplished by a simple and cost effective sodium dodecyl sulfate-polyacrylamide gel electrophoresis method. The protein bands were subjected to in-gel digestion and protein analysis was performed using electrospray ionization (ESI) ion trap mass spectrometer. There were 17 upregulated proteins and seven downregulated proteins detected with significant differential expression. Some of these proteins were low abundant proteins or proteins with extreme pH that were usually under presented in 2D gel analysis. We have identified brain mitochondrial carrier protein 1, T-cell surface glycoprotein CD1a, SOSS complex subunit B2, and Protein Jade 1 which were previously not detected in 2D gel analysis method.

Causal assessment of surrogacy in a meta-analysis of colorectal cancer trials.

When the true end points (T) are difficult or costly to measure, surrogate markers (S) are often collected in clinical trials to help predict the effect of the treatment (Z). There is great interest in understanding the relationship among S, T, and Z. A principal stratification (PS) framework has been proposed by Frangakis and Rubin (2002) to study their causal associations. In this paper, we extend the framework to a multiple trial setting and propose a Bayesian hierarchical PS model to assess surrogacy. We apply the method to data from a large collection of colon cancer trials in which S and T are binary. We obtain the trial-specific causal measures among S, T, and Z, as well as their overall population-level counterparts that are invariant across trials. The method allows for information sharing across trials and reduces the nonidentifiability problem. We examine the frequentist properties of our model estimates and the impact of the monotonicity assumption using simulations. We also illustrate the challenges in evaluating surrogacy in the counterfactual framework that result from nonidentifiability.

Newer pathologic assessment techniques for colorectal carcinoma.

The pathogenesis of colorectal carcinoma is characterized by progressive genetic abnormalities, which lead to proteomic and cellular changes that determine the cancer malignant phenotype. Phenotypic characteristics seen on histopathologic examination (e.g., tumor stage, histologic grade, and vasoinvasiveness) are essential to planning patient management and should continue to be the major focus of pathologists' efforts. Nonetheless, additional markers that improve the prognostic and predictive power of the pathologic analysis of the primary tumor have been the focus of intense research in recent years. Improved prognostic power may derive from advancements in histopathologic evaluation, more sensitive lymph node staging techniques, and specific molecular analysis methods, such as genetic tests or immunophenotypic profiles. Histopathologic improvements are needed to better standardize histologic grade determination and recognize tumor budding at the invasive front as a marker of aggressive biological behavior and an adverse parameter. Ultrastaging of mesenteric lymph nodes remains a controversial area. Genotypic studies are well developed in the areas of microsatellite instability and chromosome 18q deletion/loss of heterozygosity. Immunophenotypic studies are available in a range of areas including tumor suppressor gene/oncogene expression, proliferation/apoptosis, angiogenesis, and cell adhesion and signaling. Gene expression profiles identified by microarray techniques may help to subtype the large category of microsatellite-stable colorectal carcinoma and define immunophenotypic panels to subclassify tumors into prognostic and therapeutic groups. This brief review discusses the most promising of these approaches and evidence supporting their potential clinical utility.

Assessment of Epidermal Growth Factor Receptor (EGFR) signaling in paired colorectal cancer and normal colon tissue samples using computer-aided immunohistochemical analysis.

The Epidermal Growth Factor Receptor (EGFR) plays a role in multiple tumor cell processes and is targeted by several anticancer therapies. Although EGFR mutations may determine tumor susceptibility in a small proportion of patients, knowledge of the EGFR signaling pathway status in tumors may help guide further drug development and hypothesis-driven combination studies. We aimed to validate and apply a novel computer-aided immunohistochemical (IHC) technique to characterize the status of EGFR signaling in matched colorectal tumor and normal colon tissue samples. Tissue Microarrays (TMA)were made from both cancerous and normal colorectal tissue in 18 patients and stained with antibodies against EGFR, phospho-EGFR (pEGFR), Akt, pAkt, MAPK, and pMAPK. TMA's were quantitatively scored using the Automated Cellular Imaging System (ACIS II, Chromavision, Inc). ACIS was compared against cell line Western blotting, ELISA, and visual scoring (0-3+) by a pathologist. We found that ACIS analysis was highly reproducible and results were well correlated with other techniques. A post-scan "image microdissection" technique of analyzing heterogeneous human samples showed good correlation between paired human samples [Pearson correlation for tumors, 0.922 (p < .001)]. Cancer samples had markedly higher staining of pEGFR, Akt, pAkt, MAPK, and pMAPK. We conclude that ACIS IHC of human tissue samples is quantitative, reproducible, and correlates with Western blots and ELISA in cell line pellets as well as pathologist's scores of human samples. Colorectal tumors show higher staining of pEGFR and downstream effectors compared to matched normal colorectal tissues.

Assessment of staging, prognosis and mortality of colorectal cancer by tumor markers: receptor erbB-2 and cadherins

OBJETIVO: Avaliação da expressão tumoral das proteínas c-erbB-2 e E-caderina e sua relação com o prognóstico, estadiamento e grau de diferenciação celular, em doentes com câncer colo-retal . MÉTODOS: O estudo incluiu 117 doentes com média de idade de 63.1 anos e com acompanhamento médio de 28.1 meses. O intervalo livre de doença, sobrevida, índice de recidiva e mortalidade específica foram os parâmetros avaliados. Anticorpos anti-oncoproteína c-erbB-2 (Dako) foram utilizados pela técnica da estreptavidiva-biotina. Considerou-se como positiva a presença desta proteína quando mais de 10% das células tumorais estivessem coradas. A proteína E-caderina foi estudada pelo anticorpo anti-E-caderina (Dako), sendo computada como positiva a amostra que apresentasse 50% ou mais das células coradas. A análise estatística utilizou o teste do qui-quadrado de Pearson, o teste exato de Fischer, a curva de Kaplan-Meier, o teste de log-rank e o teste de Wilcoxon ( variante de Breslow),sendo estabelecido nível de significância de 5%( p<0,05). RESULTADOS: 52 de 108 doentes estudados para c-erbB-2 foram positivos (48,1%), 47 de 93 doentes estudados para E-caderina foram negativos (50,5%). Estes dados não mostraram relação com estadiamento TNM (tumor, nódulo e metástase), com o grau de diferenciação celular e índice de recidiva tumoral. O intervalo livre de doença para os doentes positivos para c-erbB-2 e negativos para E-caderina foi de 68.0 meses e não diferiu daqueles que foram negativos para c-erbB-2 e positivos para E-caderina ( 55.0 meses - p = 0.5510). A sobrevida média para os doentes positivos para c-erbB-2 e negativos para E-caderina foi 75 meses sem diferença estatisticamente significante com o outro grupo de comparação( 61 meses - p = 0.5256). A mortalidade específica foi de 20.0% dos casos e não se correlacionou com a expressão do c-erbB-2 (p=0,446) ou da E-caderina(p=0,883). CONCLUSÃO: A expressão das proteínas c-erbB-2 e E-caderina em doentes portadores de adenocarcinoma colo-retal não apresentou correlação com o estadiamento e grau de diferenciação celular. Não houve da mesma forma relação com o prognóstico, no que diz respeito ao índice de recidiva da doença, intervalo livre de doença, sobrevida e mortalidade específica.

Assessment of staging, prognosis and mortality of colorectal cancer by tumor markers: receptor erbB-2 and cadherins.

PURPOSE: To evaluate the prognostic significance and correlation with staging and degree of cell differentiation of the tumoral expression of the proteins c-erbB-2 and E-cadherin, in patients with colorectal adenocarcinoma. METHODS: The study included 117 patients with an average age of 63.1 years and an average follow-up duration of 28.1 months. The disease-free interval, survival, incidence of recurrence and specific mortality were evaluated. c-erbB-2 anti-oncoprotein antibodies (Dako) were utilized via the streptavidin-biotin technique. Samples were considered to be positive for c-erbB-2 if 10% or more of the tumor cell membranes were stained. The anti-E-cadherin antibodies (Dako), evaluated this protein and is considered positive, if 50% or more of the cell membranes were stained. Statistical analysis was performed using Pearson's chi-squared test, Fisher's exact test, Kaplan-Meier's estimator, the log-rank test and Wilcoxon's test (Breslow version), setting the level of statistical significance at 5% (p<0.05). RESULTS: 52 of 108 patients studied for c-erbB-2 were positive (48.1%), 47 of 93 patients studied for E-cadherin were negative (50.5%). These data do not express any correlation with TNM (tumor, node and metastasis) staging and the degree of cell differentiation or with the tumor recurrence rate. The disease-free interval among patients who were positive for c-erbB-2 and negative for E-cadherin was 68.0 months and did not differ from those with c-erbB-2 negative and E-cadherin positive (55.0 months--p = 0.5510). The average survival among patients positive for c-erbB-2 and negative for E-cadherin was 75 months without statistical significance difference with the other group (61 months--p = 0.5256). Specific mortality occurred in 20.0% of the cases and did not correlate with the expression of c-erbB-2 (p=0.446), E-cadherin (p=0.883). CONCLUSION: The tumoral expression of c-erbB-2 and E-cadherin did not demonstrate a correlation with the staging and degree of cell differentiation, and it did not present prognostic value regarding disease recurrence, disease-free interval, survival and specific mortality among patients with colorectal adenocarcinoma.

Tissue CA-19.9 content in colorectal adenomas and its value in the assessment of dysplasia.

BACKGROUND: occasionally, the risk of malignant transformation may be difficult to establish in adenomatous polyps due to the fact that they contain areas with variable grades of dysplasia. A measurement of tissue tumor markers may be useful to recognize these adenomas. OBJECTIVES: the aims of this study were: to established firstly the relationship between carbohydrate antigen 19.9 (CA-19.9) content in the colorectal mucosa and the characteristics of polyps, and secondly, the diagnostic value of the formers measurement. PATIENTS AND METHODS: tissue CA-19.9 concentration was measured in 155 colorectal samples obtained from 145 patients (21 normal mucosa; 113 adenomatous polyps; 21 adenocarcinoma). Cytosol CA-19.9 content was determined by enzyme-linked immunoadsorbant assay, and the measurement of this protein was achieved by quantitative assay. Tissue samples were also processed for histological examination. RESULTS: we demonstrated that CA-19.9 levels in adenomatous polyps and adenocarcinomas were significantly higher than in the normal mucosa. These levels varied significantly according to polyp size, histological type, and grade of dysplasia. CA-19.9 contents were higher in polyps with a high risk of malignant transformation than in those with a low risk of severe dysplasia. The cut-off value 214 U/mg of protein properly differentiated both types of risk. The area under the receiver operating characteristic (ROC) curves showed that cytosol CA-19.9 levels allow classifying polyps according to their histological features. CONCLUSIONS: we concluded that the measurement of CA-19.9 content in adenomatous polyps may be useful to classify these tumors and confirm the feasibility to separate adenomas into two groups: low and high risk of malignant change.

Assessment of apoptosis by M30 immunoreactivity and the correlation with morphological criteria in normal colorectal mucosa, adenomas and carcinomas.

AIMS: To investigate the monoclonal antibody M30 for the assessment of apoptosis in colorectal tissues. Although Terminal deoxyribonucleotidyl transferase mediated nick end labelling (TUNEL) and in-situ end labelling (ISEL) are the methods most often used to demonstrate and quantify apoptosis in histological tissue sections, the interpretation and specificity of these techniques have been controversial. Immunohistochemistry using the monoclonal antibody M30 that recognizes caspase-cleaved cytokeratin 18 is considered to be a promising alternative but has yet to be validated against a generally accepted standard. METHODS AND RESULTS: Paraffin sections of normal colonic mucosa (n = 30), normal mucosa obtained from resection margins from carcinomas (n = 30), colorectal adenomas (n = 84) and carcinomas (n = 40) were studied. Apoptosis of epithelial cells was assessed by M30 immunoreactivity and morphological criteria and expressed as a proportion of the total number of cells counted (apoptotic index). Mean apoptotic indices using M30 were 0.18 +/- 0.04% in normal mucosa, 0.42 +/- 0.04% in adenomas and 1.97 +/- 0.24% in carcinomas. Using morphological criteria, these indices were 0.23 +/- 0.03%, 0.62 +/- 0.06% and 1.78 +/- 0.19%, respectively. Apoptotic counts were higher in normal mucosa obtained from resection margins than in genuinely normal mucosa using the M30 antibody. Apoptotic indices obtained by M30 immunoreactivity and morphological criteria were positively correlated (r = 0.71, P < 0.01). CONCLUSION: Assessment of apoptotic cells by M30 immunoreactivity correlates well with morphological criteria. Apoptotic indices increase in the course of the adenoma-carcinoma sequence. Apoptosis in normal mucosa obtained from resection margins differs from genuinely normal mucosa necessitating caution when interpreting studies of apoptosis in normal colonic mucosa. Our findings support the use of the M30 method in the study of apoptosis in colorectal tissues.

Assessment of human colorectal biopsies by 1H MRS: correlation with histopathology.

Samples (3 mm3) of histopathologically normal (n = 15) and carcinomatous tissue (n = 15) were obtained from colectomy specimens and examined by 1H MRS. A combination of one- and two-dimensional spectra, obtained with appropriate acquisition and processing parameters, provide multiple diagnostic parameters allowing the distinction between normal and carcinomatous tissue. The diagnostic parameters include resonances from choline, choline-based, and other metabolites, cell surface fucosylation, and altered lipid profiles. Tissues histopathologically classified as normal, while remaining distinct from the malignant spectral profile, were found to fit into two categories, one of which had some of the spectral characteristics of malignancy. These results indicate that 1H MRS identifies abnormal colorectal mucosa, which is not morphologically manifest. Such abnormalities have been reported previously to exist in premalignant colorectal tissue by monoclonal antibody studies. Collectively, these results suggest that a clinical study of colorectal biopsies by 1H MRS could provide support for the use of MRS as an adjunct to current pathological procedures.