Comprehensive proteogenomic characterization of rare kidney tumors

Non-clear cell renal cell carcinomas (non-ccRCCs) encompass diverse malignant and benign tumors. Refinement of differential diagnosis biomarkers, markers for early prognosis of aggressive disease, and therapeutic targets to complement immunotherapy are current clinical needs. Multi-omics analyses of 48 non-ccRCCs compared with 103 ccRCCs reveal proteogenomic, phosphorylation, glycosylation, and metabolic aberrations in RCC subtypes. RCCs with high genome instability display overexpression of IGF2BP3 and PYCR1. Integration of single-cell and bulk transcriptome data predicts diverse cell-of-origin and clarifies RCC subtype-specific proteogenomic signatures. Expression of biomarkers MAPRE3, ADGRF5, and GPNMB differentiates renal oncocytoma from chromophobe RCC, and PIGR and SOSTDC1 distinguish papillary RCC from MTSCC. This study expands our knowledge of proteogenomic signatures, biomarkers, and potential therapeutic targets in non-ccRCC.

Proteogenomic insights suggest druggable pathways in endometrial carcinoma

We characterized a prospective endometrial carcinoma (EC) cohort containing 138 tumors and 20 enriched normal tissues using 10 different omics platforms. Targeted quantitation of two peptides can predict antigen processing and presentation machinery activity, and may inform patient selection for immunotherapy. Association analysis between MYC activity and metformin treatment in both patients and cell lines suggests a potential role for metformin treatment in non-diabetic patients with elevated MYC activity. PIK3R1 in-frame indels are associated with elevated AKT phosphorylation and increased sensitivity to AKT inhibitors. CTNNB1 hotspot mutations are concentrated near phosphorylation sites mediating pS45-induced degradation of β-catenin, which may render Wnt-FZD antagonists ineffective. Deep learning accurately predicts EC subtypes and mutations from histopathology images, which may be useful for rapid diagnosis. Overall, this study identified molecular and imaging markers that can be further investigated to guide patient stratification for more precise treatment of EC.

Histopathologic and proteogenomic heterogeneity reveals features of clear cell renal cell carcinoma aggressiveness

Clear cell renal cell carcinomas (ccRCCs) represent ∼75% of RCC cases and account for most RCC-associated deaths. Inter- and intratumoral heterogeneity (ITH) results in varying prognosis and treatment outcomes. To obtain the most comprehensive profile of ccRCC, we perform integrative histopathologic, proteogenomic, and metabolomic analyses on 305 ccRCC tumor segments and 166 paired adjacent normal tissues from 213 cases. Combining histologic and molecular profiles reveals ITH in 90% of ccRCCs, with 50% demonstrating immune signature heterogeneity. High tumor grade, along with BAP1 mutation, genome instability, increased hypermethylation, and a specific protein glycosylation signature define a high-risk disease subset, where UCHL1 expression displays prognostic value. Single-nuclei RNA sequencing of the adverse sarcomatoid and rhabdoid phenotypes uncover gene signatures and potential insights into tumor evolution. In vitro cell line studies confirm the potential of inhibiting identified phosphoproteome targets. This study molecularly stratifies aggressive histopathologic subtypes that may inform more effective treatment strategies.

Neoplastic cell enrichment of tumor tissues using coring and laser microdissection for proteomic and genomic analyses of pancreatic ductal adenocarcinoma

BACKGROUND

The identification of differentially expressed tumor-associated proteins and genomic alterations driving neoplasia is critical in the development of clinical assays to detect cancers and forms the foundation for understanding cancer biology. One of the challenges in the analysis of pancreatic ductal adenocarcinoma (PDAC) is the low neoplastic cellularity and heterogeneous composition of bulk tumors. To enrich neoplastic cells from bulk tumor tissue, coring, and laser microdissection (LMD) sampling techniques have been employed. In this study, we assessed the protein and KRAS mutation changes associated with samples obtained by these enrichment techniques and evaluated the fraction of neoplastic cells in PDAC for proteomic and genomic analyses.

METHODS

Three fresh frozen PDAC tumors and their tumor-matched normal adjacent tissues (NATs) were obtained from three sampling techniques using bulk, coring, and LMD; and analyzed by TMT-based quantitative proteomics. The protein profiles and characterizations of differentially expressed proteins in three sampling groups were determined. These three PDACs and samples of five additional PDACs obtained by the same three sampling techniques were also subjected to genomic analysis to characterize KRAS mutations.

RESULTS

The neoplastic cellularity of eight PDACs ranged from less than 10% to over 80% based on morphological review. Distinctive proteomic patterns and abundances of certain tumor-associated proteins were revealed when comparing the tumors and NATs by different sampling techniques. Coring and bulk tissues had comparable proteome profiles, while LMD samples had the most distinct proteome composition compared to bulk tissues. Further genomic analysis of bulk, cored, or LMD samples demonstrated that KRAS mutations were significantly enriched in LMD samples while coring was less effective in enriching for KRAS mutations when bulk tissues contained a relatively low neoplastic cellularity.

CONCLUSIONS

In addition to bulk tissues, samples from LMD and coring techniques can be used for proteogenomic studies. The greatest enrichment of neoplastic cellularity is obtained with the LMD technique.

Proteogenomic characterization of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer with poor patient survival. Toward understanding the underlying molecular alterations that drive PDAC oncogenesis, we conducted comprehensive proteogenomic analysis of 140 pancreatic cancers, 67 normal adjacent tissues, and 9 normal pancreatic ductal tissues. Proteomic, phosphoproteomic, and glycoproteomic analyses were used to characterize proteins and their modifications. In addition, whole-genome sequencing, whole-exome sequencing, methylation, RNA sequencing (RNA-seq), and microRNA sequencing (miRNA-seq) were performed on the same tissues to facilitate an integrated proteogenomic analysis and determine the impact of genomic alterations on protein expression, signaling pathways, and post-translational modifications. To ensure robust downstream analyses, tumor neoplastic cellularity was assessed via multiple orthogonal strategies using molecular features and verified via pathological estimation of tumor cellularity based on histological review. This integrated proteogenomic characterization of PDAC will serve as a valuable resource for the community, paving the way for early detection and identification of novel therapeutic targets.

Rare cases of medulloblastoma with hypermutation

BACKGROUND

Medulloblastoma is the most common malignant brain tumor of childhood and is considered a tumor with low mutational burden (~1 Mut/Mb). Therefore, though the medulloblastoma genomes have been extensively characterized in literature, reports on potential hypermutations and underlying mutagenic processes in medulloblastomas are limited.

AIM

In this report, we studied the landscape of mutational burden in primary and recurrent medulloblastoma. Furthermore, we wanted to understand the differences in underlying mutagenic mechanisms in medulloblastoma with low and high mutational burdens.

METHODS

Fifty-three primary and recurrent medulloblastoma genomic sequence were downloaded from the European Genome Archive as BAM files. Thirty-three cases were obtained from formalin-fixed paraffin-embedded tissues from pathology diagnostic archives of Spectrum Health and Cooperative Human Tissue Network. Somatic mutations were called using Mutect2, following best practices guidelines for Genome Analysis Toolkit V4. Mutational signatures were analyzed using deconstructSigs.

RESULTS

We identified nine medulloblastoma cases with high mutational burden (>5 Mut/Mb). Of them, five cases met the criteria of hypermutation (>10Mut/Mb), two of the five tumors had canonical mutations in the POLE proof-reading domain, where a large proportion of mutations in these tumor genomes contributed to signature 10. The hypermutated cases also demonstrated mutational signatures 14, 15, and 21, indicating the role of mis match repair deficiency in their mutagenesis. Of the four known molecular subgroups in medulloblastoma-SHH, WNT, Group 3, and Group 4-both the POLE-mutated cases belonged to the SHH subgroup. This report identifies rare cases of hypermutation in medulloblastoma driven by defects in DNA repair mechanisms.

CONCLUSION

Hypermutation in medulloblastoma can impact therapeutic decisions, especially at recurrence in otherwise fatal high risk SHH-medulloblastomas. A defect in DNA repair leading to SHH -medulloblastoma is yet another important mechanism that should be further investigated in the genesis of these tumors. Therefore, this report provides important scientific and clinical rationale for future research looking for incidence of hypermutation in large cohorts of medulloblastoma patients.

A proteogenomic portrait of lung squamous cell carcinoma

Lung squamous cell carcinoma (LSCC) remains a leading cause of cancer death with few therapeutic options. We characterized the proteogenomic landscape of LSCC, providing a deeper exposition of LSCC biology with potential therapeutic implications. We identify NSD3 as an alternative driver in FGFR1-amplified tumors and low-p63 tumors overexpressing the therapeutic target survivin. SOX2 is considered undruggable, but our analyses provide rationale for exploring chromatin modifiers such as LSD1 and EZH2 to target SOX2-overexpressing tumors. Our data support complex regulation of metabolic pathways by crosstalk between post-translational modifications including ubiquitylation. Numerous immune-related proteogenomic observations suggest directions for further investigation. Proteogenomic dissection of CDKN2A mutations argue for more nuanced assessment of RB1 protein expression and phosphorylation before declaring CDK4/6 inhibition unsuccessful. Finally, triangulation between LSCC, LUAD, and HNSCC identified both unique and common therapeutic vulnerabilities. These observations and proteogenomics data resources may guide research into the biology and treatment of LSCC.

Impact of Preanalytical Factors on the Measurement of Tumor Tissue Biomarkers Using Immunohistochemistry

Analysis of formalin-fixed paraffin-embedded (FFPE) tissue by immunohistochemistry (IHC) is commonplace in clinical and research laboratories. However, reports suggest that IHC results can be compromised by biospecimen preanalytical factors. The National Cancer Institute's Biospecimen Preanalytical Variables Program conducted a systematic study to examine the potential effects of delay to fixation (DTF) and time in fixative (TIF) on IHC using 24 cancer biomarkers. Differences in IHC staining, relative to controls with a DTF of 1 hr, were observed in FFPE kidney tumor specimens after a DTF of ≥2 hr. Reductions in H-score and/or staining intensity were observed for c-MET, p53, PAX2, PAX8, pAKT, and survivin, whereas increases were observed for RCC1, EGFR, and CD10. Prolonged TIF of 72 hr resulted in significantly reduced H-scores of CD44 and c-Met in kidney tumor specimens, compared with controls with 12-hr TIF. An elevated probability of altered staining intensity due to DTF was observed for nine antigens, whereas for prolonged TIF an elevated probability was observed for one antigen. Results reported here and elsewhere across tumor types and antigens support limiting DTF to ≤1 hr when possible and fixing tissues in formalin for 12-24 hr to avoid confounding effects of these preanalytical factors on IHC.

Abstract 5118: Proteogenomics characterization of HPV-negative head and neck squamous cell carcinomas

Patients with head and neck squamous cell carcinomas (HNSCCs) are treated with surgery, radiation, chemotherapy, and limited targeted therapies. Compared to human papillomavirus (HPV)-positive HNSCCs, HPV-negative cases have worse treatment response and prognosis and represent an unmet clinical need. We performed comprehensive proteogenomic characterization of tumor specimens, matched normal adjacent tissues (NATs), and blood samples from 109 HPV-negative HNSCC patients. This cohort is dominated by tumors from oral cavity (45, 41%) and larynx (49, 45%). Somatic mutation and somatic copy number analyses validated previously reported genomic aberrations in HPV-negative HNSCC. Proteomics analysis linked p53 loss of heterozygosity to increased expression of EPCAM, a stemness marker. Additionally, FAT1 truncation mutations were associated with increased expression of proteins involved in keratinization, a key feature of SCC differentiation. Deletions of 3p and 9p led to the loss of genes encoding p16, chemokine receptors, and interferon/JAK/STAT signaling pathway proteins, whereas amplifications of 3q and 11q led to overexpression of proteins involved in cell proliferation and anti-apoptosis pathways. Comparative analysis of tumor and NAT proteomes and phosphoproteomes identified putative diagnostic biomarkers and druggable targets, and proteogenomic integration further identified putative neoantigens. Tumor site-specific characterization associated epigenetic silencing of neurofilaments with laryngeal but not oral cavity SCC. Protein targets of FDA approved or investigational drugs for HNSCC treatment showed high inter-tumor heterogeneity in their protein abundances. DNA copy number and RNA expression level were good surrogates of protein abundance for some targets, such as EGFR and PD-L1, but they failed to reflect protein levels or kinase activities for other targets, such as MMP9 and MTOR. Thus, there is a critical need for protein biomarker-driven treatment stratification. Deconvolution of bulk tumor gene expression data revealed an immune-hot subgroup and an immune-cold subgroup. Immune-hot tumors broadly overexpressed multiple immune checkpoints including PD-L1, IDO1, and CTLA4, underscoring the necessity of combination immune checkpoint inhibition to improve treatment efficacy. Immune-cold tumors were characterized by smoking, chromosomal instability, and activation of the CDK4/6-pRb axis, suggesting they could be targeted by CDK4/6 inhibitors. We also noted that EGFR-amplified tumors frequently harbor copy number aberrations of downstream signaling components of the EGFR pathway. This may explain the low response rate of EGFR-amplified tumors to EGFR inhibitors, and targeting multiple pathway components, including EGFR, PIK3CA and STAT3, may be required for these tumors. In summary, our integrative proteogenomic characterization revealed multiple novel insights into the pathogenesis and treatment of HPV-negative HNSCCs.

Citation Format: Chen Huang, Lijun Chen, Yize Li, Sara Savage, Michael Schnaubelt, Felipe V. Leprevost, Marcin Cieslik, Yongchao Dou, Bo Wen, Jonathan T. Lei, Kai Li, Eric Jaehnig, Zhiao Shi, Meenakshi Anurag, Jianbo Pan, Yingwei Hu, Rodrigo V. Eguez, David J. Clark, Matthew Wyczalkowski, Saravana M. Dhanasekaran, Chandan Kumar, Antonio Colaprico, Karsten Krug, Michael Gillette, D. R. Mani, Seungyeul Yoo, Jiayi Ji, Xiaoyu Song, Weiping Ma, Xi Steven Chen, Alex Pico, Nathan J. Edwards, Scott D. Jewell, Mathangi Thiagarajan, Emily S. Boja, Henry Rodriguez, Andrew Sikora, Pei Wang, Matthew Ellis, Gilbert S. Omenn, Li Ding, Alexey I. Nesvizhskii, Adel K. EI-Naggar, Daniel W. Chan, Hui Zhang, Bing Zhang, Clinical Proteomic Tumor Analysis Consortium. Proteogenomics characterization of HPV-negative head and neck squamous cell carcinomas [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5118.

Proteogenomic Characterization Reveals Therapeutic Vulnerabilities in Lung Adenocarcinoma

To explore the biology of lung adenocarcinoma (LUAD) and identify new therapeutic opportunities, we performed comprehensive proteogenomic characterization of 110 tumors and 101 matched normal adjacent tissues (NATs) incorporating genomics, epigenomics, deep-scale proteomics, phosphoproteomics, and acetylproteomics. Multi-omics clustering revealed four subgroups defined by key driver mutations, country, and gender. Proteomic and phosphoproteomic data illuminated biology downstream of copy number aberrations, somatic mutations, and fusions and identified therapeutic vulnerabilities associated with driver events involving KRAS, EGFR, and ALK. Immune subtyping revealed a complex landscape, reinforced the association of STK11 with immune-cold behavior, and underscored a potential immunosuppressive role of neutrophil degranulation. Smoking-associated LUADs showed correlation with other environmental exposure signatures and a field effect in NATs. Matched NATs allowed identification of differentially expressed proteins with potential diagnostic and therapeutic utility. This proteogenomics dataset represents a unique public resource for researchers and clinicians seeking to better understand and treat lung adenocarcinomas.

The College of American Pathologists Biorepository Accreditation Program: Results from the First 5 Years

The College of American Pathologists (CAP) developed the Biorepository Accreditation Program (BAP) in 2012. This program integrates best practices from the International Society for Biological and Environmental Biorepositories, the National Cancer Institute, the Organisation for Economic Cooperation and Development, the Center for Medicare and Medicaid Services, and the CAP Laboratory Accreditation Program. The goal of this elective program is to provide requirements for standardization in biorepository processes that will result in high-quality specimens that can be used to support research, drug discovery, and personalized medicine. CAP uses a peer inspection model to ensure the inspectors have proper expertise and to promote educational efforts through information sharing. Lead inspectors are comprised of pathologists, PhDs, and managers of biorepositories and they are often supported by CAP staff inspectors. Accreditation is a 3-year continuous cycle of quality with a peer inspection occurring at the start of year 1 and a self-inspection and CAP desk assessment at the start of year 2 and 3. At this time 53 biorepositories are fully CAP BAP accredited and 13 are in the process of obtaining accreditation. There are currently 273 established standards with requirement lists customized based on the scope of activities performed by a biorepository. A total of 90 inspections were completed between May 2012 and December 2016. Sixty-one were initial inspections and 29 were reinspections. A total of 527 deficiencies were identified in the areas of Equipment/Instrumentation (22%), Information Technology (18%), Specimen Handling and QC (15%), Quality Management (16%), Personnel (11%), Safety (10%), Facilities (6%), and Regulatory (2%). Assessment of common deficiencies identifies areas of focus for continuous improvement and educational opportunities. Overall success of the program is high based on the current enrollment of 66 biorepositories, anecdotal participant feedback and increasing national recognition of the BAP in federal documents.

Abstract 361: Illuminating the effects of tissue degradation to improve the management of tissues used in cancer research or clinical applications

The collection and preservation of tissues from surgery to the lab affects the quality and value of research and/or healthcare applications for cancer patients. To this end we are further defining best practices in the management of surgically resected tissues through the analysis of a systems biology model. In the first steps of this process we defined an experimental animal model to assess gene expression signatures of biological pathways related to preservation intervals. Athymic nude murine tissues (kidney, liver, brain, and PDX-models) were excised at baseline and immediately aliquots of tissue were incubated at varying intervals (t=0, 0.5, 1, 3, 6, 9 hours, temperature during intervals was maintained at 37°C). All tissues were preserved at -80C and total RNA was extracted from these tissues using a uniform RNA isolation kit (RNeasy Mini Kit from Qiagen, Inc.) by the same technician. The RNA Integrity Number (RIN) was obtained using the Agilent's BioAnalyzer 2100 and RNA concentration using the Nanodrop 8000. Subsequently, cDNA was synthesized using Thermo Scientific's RevertAid First Strand cDNA Synthesis Kit, and qPCR analysis of each tissue was performed using the Qiagen RT2 Profiler PCR Arrays including the Cell Death PathwayFinder (murine origin liver, kidney, brain) and Hypoxia Signaling Pathway (human origin PDX-model) arrays. Results show a variation of transcripts s that were upregulated (Bax, Bcl2, Fos, Egr1, Tnfrsf10b) or downregulated (Ctss, Hmox1, Epo, Snca) with increased length of tissue incubation and tissue-specific patterns of regulation were observed. Furthermore, these changes in gene expression did not correlate with a decrease in RIN scores, which raises questions about the suitability of RIN as a comprehensive assessment of RNA quality at the transcript level. These findings have important implications for cancer research, namely that tissues that have not been stabilized within several minutes of excision from the host might have undergone degradation of RNA templates that reflect tissue management-related biological activity versus disease-related transcriptome. In future work, we plan to compare macroanalytes such as microRNAs, non-coding RNAs and proteins across different tissue types with an assumption that gene signatures and biological effects will differ per tissue type. We will use results from our experimental biopreservation model to continue the emphasis on transcriptome changes within the context of biological relevance.

Citation Format: Scott D. Jewell, Eric Collins, John Beck, David Monsma, Dawna Dylewski, Andrew Borgman, Mary Winn, Galen Hostetter. Illuminating the effects of tissue degradation to improve the management of tissues used in cancer research or clinical applications. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 361. doi:10.1158/1538-7445.AM2014-361

Veterinary and human biobanking practices: enhancing molecular sample integrity

Animal models have historically informed veterinary and human pathophysiology. Next-generation genomic sequencing and molecular analyses using analytes derived from tissue require integrative approaches to determine macroanalyte integrity as well as morphology for imaging algorithms that can extend translational applications. The field of biospecimen science and biobanking will play critical roles in tissue sample collection and processing to ensure the integrity of macromolecules, aid experimental design, and provide more accurate and reproducible downstream genomic data. Herein, we employ animal experiments to combine protein expression analysis by microscopy with RNA integrity number and quantitative measures of morphologic changes of autolysis. These analyses can be used to predict the effect of preanalytic variables and provide the basis for standardized methods in tissue sample collection and processing. We also discuss the application of digital imaging with quantitative RNA and tissue-based protein measurements to show that genomic methods augment traditional in vivo imaging to support biospecimen science. To make these observations, we have established a time course experiment of murine kidney tissues that predicts conventional measures of RNA integrity by RIN analysis and provides reliable and accurate measures of biospecimen integrity and fitness, in particular for time points less than 3 hours post-tissue resection.

A call to standardize preanalytic data elements for biospecimens

CONTEXT

Biospecimens must have appropriate clinical annotation (data) to ensure optimal quality for both patient care and research. Clinical preanalytic variables are the focus of this study.

OBJECTIVE

To define the essential preanalytic variables (data fields) that should be attached to every collected biospecimen and to provide a complete list of such variables, along with their relative importance, which can vary, depending on downstream use, institutional needs, and information technology capabilities.

DESIGN

The College of American Pathologists Diagnostic Intelligence and Health Information Technology Committee sponsored a Biorepository Working Group to develop a ranked list of the preanalytic variables for annotating biospecimens. Members of the working group were experts in anatomic, clinical, and molecular pathology; biobanking; medical informatics; and accreditation. Several members had experience with federal government programs, such as the National Cancer Institute's Biospecimens and Biorepository Branch and the National Cancer Institute's Community Cancer Center Program. Potential preanalytic variables were identified and ranked along with available supporting evidence, definitions, and potential negative effects if the variable was not attached to the biospecimen. Additional national and international stakeholders reviewed the draft manuscript.

RESULTS

The ranked listing of 170 preanalytic variables produced can be used as a guide for site-specific implementation into patient care and/or research biorepository processes. Conclusions.-In our collective experience, it is often difficult to choose which of the many preanalytic variables to attach to any specific set of biospecimens used for patient care and/or research. The provided ranked list should aid in the selection of preanalytic variables for a given biospecimen collection.

Basal cell carcinoma: stressful life events and the tumor environment

CONTEXT

Child emotional maltreatment can result in lasting immune dysregulation that may be heightened in the context of more recent life stress. Basal cell carcinoma (BCC) is the most common skin cancer, and the immune system plays a prominent role in tumor appearance and progression.

OBJECTIVE

To address associations among recent severe life events, childhood parental emotional maltreatment, depression, and messenger RNA (mRNA) coding for immune markers associated with BCC tumor progression and regression.

DESIGN

We collected information about early parent-child experiences, severe life events in the past year as assessed by the Life Events and Difficulties Schedule, depression, and mRNA for immune markers associated with BCC tumor progression and regression from patients with BCC tumors.

SETTING

University medical center.

PARTICIPANTS

Ninety-one patients with BCC (ages, 23-92 years) who had a previous BCC tumor.

MAIN OUTCOME MEASURES

The expression of 4 BCC tumor mRNA markers (CD25, CD3ε, intercellular adhesion molecule 1, and CD68) that have been linked to BCC tumor progression and regression were assessed in BCC tumor biopsy specimens.

RESULTS

Both maternal and paternal emotional maltreatment interacted with the occurrence of severe life events to predict the local immune response to the tumor (adjusted P = .009 and P = .03, respectively). Among BCC patients who had experienced a severe life event within the past year, those who were emotionally maltreated by their mothers (P = .007) or fathers (P = .02) as children had a poorer immune response to the BCC tumor. Emotional maltreatment was unrelated to BCC immune responses among those who did not experience a severe life event. Depressive symptoms were not associated with the local tumor immune response.

CONCLUSIONS

Troubled early parent-child relationships, in combination with a severe life event in the past year, predicted immune responses to a BCC tumor. The immunoreactivity observed in BCCs and the surrounding stroma reflects an anti-tumor-specific immune response that can be altered by stress.

Tumor site immune markers associated with risk for subsequent basal cell carcinomas

Background

Basal cell carcinoma (BCC) tumors are the most common skin cancer and are highly immunogenic.

Objective

The goal of this study was to assess how immune-cell related gene expression in an initial BCC tumor biopsy was related to the appearance of subsequent BCC tumors.

Materials and Methods

Levels of mRNA for CD3ε (a T-cell receptor marker), CD25 (the alpha chain of the interleukin (IL)-2 receptor expressed on activated T-cells and B-cells), CD68 (a marker for monocytes/macrophages), the cell surface glycoprotein intercellular adhesion molecule-1 (ICAM-1), the cytokine interferon-γ (IFN-γ) and the anti-inflammatory cytokine IL-10 were measured in BCC tumor biopsies from 138 patients using real-time PCR.

Results

The median follow-up was 26.6 months, and 61% of subjects were free of new BCCs two years post-initial biopsy. Patients with low CD3ε CD25, CD68, and ICAM-1 mRNA levels had significantly shorter times before new tumors were detected (p = 0.03, p = 0.02, p = 0.003, and p = 0.08, respectively). Furthermore, older age diminished the association of mRNA levels with the appearance of subsequent tumors.

Conclusions

Our results show that levels of CD3ε, CD25, CD68, and ICAM-1 mRNA in BCC biopsies may predict risk for new BCC tumors.

Biospecimen reporting for improved study quality (BRISQ)

Human biospecimens are subject to a number of different collection, processing, and storage factors that can significantly alter their molecular composition and consistency. These biospecimen preanalytical factors, in turn, influence experimental outcomes and the ability to reproduce scientific results. Currently, the extent and type of information specific to the biospecimen preanalytical conditions reported in scientific publications and regulatory submissions varies widely. To improve the quality of research utilizing human tissues, it is critical that information regarding the handling of biospecimens be reported in a thorough, accurate, and standardized manner. The Biospecimen Reporting for Improved Study Quality (BRISQ) recommendations outlined herein are intended to apply to any study in which human biospecimens are used. The purpose of reporting these details is to supply others, from researchers to regulators, with more consistent and standardized information to better evaluate, interpret, compare, and reproduce the experimental results. The BRISQ guidelines are proposed as an important and timely resource tool to strengthen communication and publications around biospecimen-related research and help reassure patient contributors and the advocacy community that the contributions are valued and respected.

Cancer and Leukemia Group B Pathology Committee guidelines for tissue microarray construction representing multicenter prospective clinical trial tissues

Practice-changing evidence requires confirmation, preferably in multi-institutional clinical trials. The collection of tissue within such trials has enabled biomarker studies and evaluation of companion diagnostic tests. Tissue microarrays (TMAs) have become a standard approach in many cooperative oncology groups. A principal goal is to maximize the number of assays with this precious tissue. However, production strategies for these arrays have not been standardized, possibly decreasing the value of the study. In this article, members of the Cancer and Leukemia Group B Pathology Committee relay our experiences as array facility directors and propose guidelines regarding the production of high-quality TMAs for cooperative group studies. We also discuss statistical issues arising from having a proportion of patients available for TMAs and the possibility that patients with TMAs fail to represent the greater study population.

Biospecimen reporting for improved study quality (BRISQ)

Human biospecimens are subjected to collection, processing, and storage that can significantly alter their molecular composition and consistency. These biospecimen preanalytical factors, in turn, influence experimental outcomes and the ability to reproduce scientific results. Currently, the extent and type of information specific to the biospecimen preanalytical conditions reported in scientific publications and regulatory submissions varies widely. To improve the quality of research that uses human tissues, it is crucial that information on the handling of biospecimens be reported in a thorough, accurate, and standardized manner. The Biospecimen Reporting for Improved Study Quality (BRISQ) recommendations outlined herein are intended to apply to any study in which human biospecimens are used. The purpose of reporting these details is to supply others, from researchers to regulators, with more consistent and standardized information to better evaluate, interpret, compare, and reproduce the experimental results. The BRISQ guidelines are proposed as an important and timely resource tool to strengthen communication and publications on biospecimen-related research and to help reassure patient contributors and the advocacy community that their contributions are valued and respected.

Biospecimen Reporting for Improved Study Quality

Human biospecimens are subject to a number of different collection, processing, and storage factors that can significantly alter their molecular composition and consistency. These biospecimen preanalytical factors, in turn, influence experimental outcomes and the ability to reproduce scientific results. Currently, the extent and type of information specific to the biospecimen preanalytical conditions reported in scientific publications and regulatory submissions varies widely. To improve the quality of research utilizing human tissues, it is critical that information regarding the handling of biospecimens be reported in a thorough, accurate, and standardized manner. The Biospecimen Reporting for Improved Study Quality recommendations outlined herein are intended to apply to any study in which human biospecimens are used. The purpose of reporting these details is to supply others, from researchers to regulators, with more consistent and standardized information to better evaluate, interpret, compare, and reproduce the experimental results. The Biospecimen Reporting for Improved Study Quality guidelines are proposed as an important and timely resource tool to strengthen communication and publications around biospecimen-related research and help reassure patient contributors and the advocacy community that the contributions are valued and respected.

p27Kip1 in stage III colon cancer: implications for outcome following adjuvant chemotherapy in cancer and leukemia group B protocol 89803

BACKGROUND

In retrospective studies, loss of p27(Kip1) (p27), a cyclin-dependent kinase inhibitor, has been associated with poor prognosis following colorectal cancer treatment. In a prospective study, we validated this relationship in patients enrolled on a trial of adjuvant chemotherapy for stage III colon cancer.

METHODS

Cancer and Leukemia Group B protocol 89803 randomized 1,264 stage III colon cancer patients to receive weekly bolus 5-fluorouracil/leucovorin or weekly bolus irinotecan, 5-fluorouracil, and leucovorin (IFL). The primary endpoint was overall survival (OS); disease-free survival was a secondary endpoint. Expression of p27 and DNA mismatch repair proteins were determined by immunohistochemistry in primary tumor and normal tissue from paraffin blocks. Data were analyzed using log-rank test.

RESULTS

Of 601 tumors analyzed, 207 (34.4%) showed p27 loss, 377 (62.8%) retained p27, and 17 (2.8%) were indeterminate. Patients with p27-negative tumors showed reduced OS [5-year OS 66%: 95% confidence interval (95% CI), 0.59-0.72 versus 75%: 95% CI, 0.70-0.79; log-rank P = 0.021]. This relationship was not influenced by treatment arm. Combination of p27 status with mismatch repair status, however, identified a small subset of patients that may benefit from IFL (n = 36; 5-year disease-free survival 81%: 95% CI, 0.64-0.98 versus 47%: 95% CI, 0.21-0.72; log-rank P = 0.042; 5-year OS 81%: 95% CI, 0.64-0.98 versus 60%: 95% CI, 0.35-0.85; log-rank P = 0.128).

CONCLUSIONS

Loss of p27 is associated with reduced survival in stage III colon cancer but by itself does not indicate a significant difference in outcome between patients treated IFL or 5-fluorouracil/leucovorin.

Microsatellite instability predicts improved response to adjuvant therapy with irinotecan, fluorouracil, and leucovorin in stage III colon cancer: Cancer and Leukemia Group B Protocol 89803

PURPOSE

Colon cancers exhibiting DNA mismatch repair (MMR) defects demonstrate distinct clinical and pathologic features, including better prognosis and reduced response to fluorouracil (FU) -based chemotherapy. This prospective study investigated adjuvant chemotherapy containing FU and irinotecan in patients with MMR deficient (MMR-D) colon cancers.

PATIENTS AND METHODS

Cancer and Leukemia Group B 89803 randomly assigned 1,264 patients with stage III colon cancer to postoperative weekly bolus FU/leucovorin (LV) or weekly bolus irinotecan, FU, and LV (IFL). The primary end point was overall survival; disease-free survival (DFS) was a secondary end point. Tumor expression of the MMR proteins, MLH1 and MSH2, was determined by immunohistochemistry (IHC). DNA microsatellite instability was also assessed using a panel of mono- and dinucleotide markers. Tumors with MMR defects were those demonstrating loss of MMR protein expression (MMR-D) and/or microsatellite instability high (MSI-H) genotype.

RESULTS

Of 723 tumor cases examined by genotyping and IHC, 96 (13.3%) were MMR-D/MSI-H. Genotyping results were consistent with IHC in 702 cases (97.1%). IFL-treated patients with MMR-D/MSI-H tumors showed improved 5-year DFS as compared with those with mismatch repair intact tumors (0.76; 95% CI, 0.64 to 0.88 v 0.59; 95% CI, 0.53 to 0.64; P = .03). This relationship was not observed among patients treated with FU/LV. A trend toward longer DFS was observed in IFL-treated patients with MMR-D/MSI-H tumors as compared with those receiving FU/LV (0.57; 95% CI, 0.42 to 0.71 v 0.76; 95% CI, 0.64 to 0.88; P = .07; hazard ratio interaction between tumor status and treatment, 0.51; likelihood ratio P = .117).

CONCLUSION

Loss of tumor MMR function may predict improved outcome in patients treated with the IFL regimen as compared with those receiving FU/LV.

Recommendations for collection and handling of specimens from group breast cancer clinical trials

Recommendations for specimen collection and handling have been developed for adoption across breast cancer clinical trials conducted by the Breast International Group (BIG)-sponsored Groups and the National Cancer Institute (NCI)-sponsored North American Cooperative Groups. These recommendations are meant to promote identifiable standards for specimen collection and handling within and across breast cancer trials, such that the variability in collection/handling practices that currently exists is minimized and specimen condition and quality are enhanced, thereby maximizing results from specimen-based diagnostic testing and research. Three working groups were formed from the Cooperative Group Banking Committee, BIG groups, and North American breast cancer cooperative groups to identify standards for collection and handling of (1) formalin-fixed, paraffin-embedded (FFPE) tissue; (2) blood and its components; and (3) fresh/frozen tissue from breast cancer trials. The working groups collected standard operating procedures from multiple group specimen banks, administered a survey on banking practices to those banks, and engaged in a series of discussions from 2005 to 2007. Their contributions were synthesized into this document, which focuses primarily on collection and handling of specimens to the point of shipment to the central bank, although also offers some guidance to central banks. Major recommendations include submission of an FFPE block, whole blood, and serial serum or plasma from breast cancer clinical trials, and use of one fixative and buffer type (10% neutral phosphate-buffered formalin, pH 7) for FFPE tissue across trials. Recommendations for proper handling and shipping were developed for blood, serum, plasma, FFPE, and fresh/frozen tissue.

Analysis of micrometastatic disease in sentinel lymph nodes from resectable colon cancer: results of Cancer and Leukemia Group B Trial 80001

PURPOSE

To determine whether sentinel lymph node (LN) sampling (SLNS) could reduce the number of nodes required to characterize micrometastatic disease (MMD) in patients with potentially curable colon cancer.

PATIENTS AND METHODS

Cancer and Leukemia Group B 80001 was a study to determine whether SLNS could identify a subset of LNs that predicted the status of the nodal basin for resectable colon cancer and, therefore, could be extensively evaluated for the presence of micrometastases. Patients enrolled onto this study underwent SLNS after injection of 1% isosulfan blue, and both sentinel nodes (SNs) and non-SNs obtained during primary tumor resection were sectioned at multiple levels and stained using anti-carcinoembryonic antigen and anticytokeratin antibodies.

RESULTS

Using standard histopathology, SNs failed to predict the presence of nodal disease in 13 (54%) of 24 node-positive patients. Immunostains were performed for patients whose LNs were negative by standard histopathology. Depending on the immunohistochemical criteria used to assign LN positivity, SN examination resulted in either an unacceptably high false-positive rate (20%) or a low sensitivity for detection of MMD (40%).

CONCLUSION

By examining both SNs and non-SNs, this multi-institutional study showed that SNs did not accurately predict the presence of either conventionally defined nodal metastases or MMD. As a result, SLNS is not a useful technique for the study of MMD in patients with colon cancer.

Analysis of the molecular quality of human tissues: an experience from the Cooperative Human Tissue Network

The scientific usefulness of the data obtained from tissue analysis is related to specimen quality, which may be affected by conditions that may contribute to the degradation of the specimen before processing and analysis. We determined the usability of nucleic acids extracted from banked human tissues for further molecular analyses. We assayed 151 tissue specimens, storedfor various times at 4 divisions of the Cooperative Human Tissue Network, National Cancer Institute, Bethesda, MD, for DNA and RNA degradation. Simple electrophoresis, polymerase chain reaction (PCR), reverse-transcriptase (RT)-PCR, and Northern blot analysis were compared to determine the optimal quality control procedure. In addition, a time course degradation procedure was performed on human lung tissue. Gel electrophoresis was as informative as PCR, RT-PCR, and Northern blot analysis in determining the molecular usefulness of the human tissues. Overall, 80% of the stored human tissues had good-quality DNA, and 60% had good-quality RNA. Electrophoresis procedures for DNA and RNA offer a quick and valuable measure of the molecular quality of stored human tissues. The DNA and RNA degradation of one tissue type (lung) was stable for both nucleic acids for up to 5 hours after excision.

Suppression of experimental autoimmune encephalomyelitis using peptide mimics of CD28

The B7:CD28/CTLA-4 costimulatory pathway plays a critical role in regulating the immune response and thus provides an ideal target for therapeutic manipulation of autoimmune disease. Previous studies have shown that blockade of CD28 signaling by mAbs can both prevent and exacerbate experimental autoimmune encephalomyelitis (EAE). In this study, we have designed two CD28 peptide mimics that selectively block B7:CD28 interactions. By surface plasmon resonance, both the end group-blocked CD28 peptide (EL-CD28) and its retro-inverso isomer (RI-CD28) compete effectively with the extracellular domain of CD28 for binding to B7-1. Both the CD28 peptide mimics inhibited expansion of encephalitogenic T cells in vitro. A single administration of EL-CD28 or RI-CD28 peptide significantly reduced disease severity in EAE. Importantly, we show that either CD28 peptide mimic administered during acute disease dramatically improved clinical signs of EAE, suppressing ongoing disease. The ratio of CD80:CD86 expression was significantly lower on CD4(+) and F4/80(+) spleen cells in CD28 peptide-treated mice. Peripheral deletion of Ag-specific CD4(+) T cells occurs following in vivo blockade of CD28 with synthetic CD28 peptides.

Evaluation of TGF-alpha and EGFR expression in oral leukoplakia and oral submucous fibrosis by quantitative immunohistochemistry

OBJECTIVE

Oral leukoplakia (OL) and oral submucous fibrosis (OSMF) are clinically distinct preneoplastic states that precede the development of oral squamous cell carcinoma. Recently, attempts are being made to identify specific molecular event(s) as prognostic markers to identify oral precancerous lesions with higher malignant potential. The goal of the present study was to evaluate the expression of EGFR and its ligand TGF-alpha in OL with dysplasia and OSMF as intermediate markers of malignancy by quantitative immunohistochemistry.

METHODS

Oral tissues were stained with monoclonal antibodies to TGF-alpha and EGFR. The results were analyzed with Photoquant image analysis software.

RESULTS

The expression of TGF-alpha and EGFR was upregulated in OL, OSMF and oral squamous cell carcinomas relative to normal oral mucosa. The area and intensity of staining of TGF-alpha in the proliferative layers (stratum germinativum) increased linearly in OL with mild, moderate and severe dysplasia as compared to control mucosa (p < 0.05). EGFR levels increased linearly in the stratum spinosum in OL with increasing degrees of dysplasia (p < 0.05). In general, the expression of both proteins in OSMF was similar to that in OL with moderate dysplasia.

CONCLUSIONS

EGFR and TGF-alpha represent early markers of malignancy in OL with dysplasia. Quantitative measurement of these proteins may provide intermediate endpoints in prospective chemopreventive trials.

Quantitative estimation of PCNA, c-myc, EGFR and TGF-alpha in oral submucous fibrosis--an immunohistochemical study

The objectives of the present study were to evaluate the expression of three proliferation markers, viz., epidermal growth factor receptor (EGFR), transforming growth factor-alpha (TGF-alpha) and proliferating cell nuclear antigen (PCNA) and one genomic marker, c-myc in OSMF. Oral tissues were stained with monoclonal antibodies to PCNA, c-myc, TGF-alpha and EGFR. The results were analyzed with Photoquant image analysis software. The expression of PCNA, c-myc, TGF-alpha and EGFR was higher in oral submucous fibrosis (OSMF) than in normal control oral mucosa. The oral epithelium was divided into a proliferative compartment (stratum germinativum) and a differentiated compartment (stratum spinosum). A differential pattern of expression of PCNA and c-myc was observed in OSMF. While the intensity of staining decreased, the percent area of expression of PCNA and c-myc increased in stratum germinativum in OSMF (P<0.05). This suggests that greater proportions of cells exhibit PCNA and c-myc immunoreactivity and are in the proliferative pool in OSMF. TGF-alpha levels increased in the proliferative layers and EGFR levels increased in the differentiated layers (P<0.05) of the oral epithelium in OSMF. Quantitative measurement of these oncoproteins substantiates the precancerous nature of OSMF and may provide intermediate end-points in prospective chemopreventive trials.

Immunohistochemical staining for ganglioside GD1b as a diagnostic and prognostic marker for primary human brain tumors

Immunohistochemical staining intensity for ganglioside GD1b was determined for 108 human neuroectodermal tumors. Most of the tissue elements that immunostained were tumor cells; only a few axons and occasional neurons reacted in some specimens. All pilocytic astrocytomas stained very positively, whereas none of the ependymomas and only 11% of primitive neuroectodermal tumors, 20% of glioblastomas, and 28% of anaplastic astrocytomas showed more than faint staining. A similar association between grade and immunostaining was seen in tumors containing an oligodendrogliomatous component, but reactivity was not as strong as in astrocytic tumors or primitive neuroectodermal tumors. Results of Cox regression showed significant associations between immunostaining intensity and survival for all cases taken together (P = 0.007); for the group consisting of astrocytomas, oligoastrocytomas, and oligodendrogliomas (P = 0.002); and for astrocytomas alone (P = 0.04). Results were also significant using a proportional hazards model controlling for patient age (all cases P = 0.005; astrocytomas only P = 0.02), but not when controlling for tumor grade. Our results indicate that immunohistochemical staining for GD1b is correlated with tumor grade and that it may be of prognostic utility in some primary human brain tumors, especially astrocytomas.

Oral tolerance as therapy for experimental autoimmune encephalomyelitis and multiple sclerosis: demonstration of T cell anergy

Experimental autoimmune encephalomyelitis (EAE) is an important model for developing therapies for multiple sclerosis (MS). The oral administration of the central nervous system antigen, myelin basic protein (MBP), to Lewis rats and susceptible mouse strains prior to MBP immunization prevents the induction of EAE. Clinical trials administering myelin orally to MS patients have met with only partial success, and thus require that oral tolerance be further studied to improve this treatment strategy. Clonal anergy, clonal deletion, immune deviation from Th1 to Th2 T cell subsets, and active suppression by TGF-beta-secreting T cells have all been implicated as possible mechanisms in oral tolerance. Which mechanism predominates depends on antigen dosage, frequency of feeding, and timing of antigen administration. In this study, we have characterized T cells derived from MBP-fed rats and determined the level of their unresponsiveness. Myelin basic protein-specific T cells are indeed present although in reduced numbers in lymphoid tissue of orally tolerized animals. Following several cell divisions in the presence of IL-2, these MBP-specific T cells undergo a dramatic reversal of unresponsiveness, proliferate in response to MBP and are capable of transferring EAE. These results support clonal anergy as an important mechanism for oral tolerance. Recent developments in clinical trials of oral tolerance are described.

Transforming growth factor-alpha overexpression in proliferative verrucous leukoplakia and oral squamous cell carcinoma: an immunohistochemical study

Proliferative verrucous leukoplakia is a unique type of oral leukoplakia that has a high risk of malignant transformation. The aim of this study was to examine the expression of transforming growth factor-alpha in proliferative verrucous leukoplakia, oral squamous cell carcinoma, and normal mucosa. Transforming growth factor-alpha, a potent mitogen, is known to play an important role in various neoplasms including oral squamous cell carcinoma. Immunohistochemical localization of transforming growth factor-alpha in archival paraffin-embedded sections was performed with commercially available monoclonal antibodies. Ten cases each of normal mucosa, proliferative verrucous leukoplakia, and oral squamous cell carcinoma were stained. Quantification of the staining intensity, expressed as the cytoplasmic optical density, was done with the Roche Image Analysis System. The data were statistically analyzed with the one-way analysis of variance and Tukey tests. Notably, the mean cytoplasmic optical density of proliferative verrucous leukoplakia was significantly higher than the mean cytoplasmic optical density of normal mucosa (p < 0.01). The mean cytoplasmic optical density of proliferative verrucous leukoplakia was slightly higher than that of oral squamous cell carcinoma, however, this difference was not significant (p > 0.05). The mean cytoplasmic optical density values demonstrate that increased transforming growth factor-alpha immunoreactivity occurs in proliferative verrucous leukoplakia and oral squamous cell carcinoma relative to normal mucosa.

Rat peritoneal mast cells present antigen to a PPD-specific T cell line

Rat peritoneal mast cells were examined to determine whether mast cells can stimulate T cell proliferation through antigen presentation. Mast cells were obtained by peritoneal lavage and purified to 98% using density gradient centrifugation. Purified peritoneal mast cells expressed MHC class II molecules as determined by flow cytometry using monoclonal antibody OX6 specific for common determinants of rat class II. The intensity of class II expression by mast cells was not significantly increased upon incubation with recombinant rat IFN-gamma. Peritoneal mast cells also were found to express the accessory molecules ICAM-1 (CD54) and LFA-1 beta (CD18) but not LFA-1 alpha (CD11a). In the presence of antigen, purified mast cells stimulated proliferation of an autologous CD4+, PPD-specific T cell line. This stimulation was blocked by OX6 antibody, confirming that the proliferation was class II dependent. T cell proliferation was similarly induced by purified mast cell populations that were completely monocyte and macrophages depleted. These results demonstrate that mast cells, through their expression of MHC class II and accessory molecules, are capable of antigen presentation.

Intraoperative radioimmunolocalization of colorectal carcinoma with a hand-held gamma probe and MAb B72.3: comparison of in vivo gamma probe counts with in vitro MAb radiolocalization

A new intraoperative approach to tumor localization using radiolabelled monoclonal antibody (MAb) B72.3 involves the use of a hand-held gamma-detecting probe (GDP) by the surgeon and, subsequently, the pathologist. We report here the use of 125I-labelled MAb B72.3 IgG and a GDP to localize primary and metastatic colorectal cancer in 31 patients. The patients were administered radiolabelled MAb i.v., and all underwent surgical exploration 5 to 35 days post-injection. In vivo localization of the MAb was evaluated using a GDP, with tumor and normal tissue counts being obtained. In each case, the subsequent tumor and normal tissue that were resected were analyzed in vitro for MAb localization; this was evaluated by calculating the radiolocalization index, i.e., the ratio of the injected dose per gram localized to tumor versus that of normal tissue. When the GDP was used intraoperatively, MAb B72.3 localized tumors in 68% (21/31) of the patients; the arbitrary criterion of tumor-to-normal tissue ratios higher than or equal to 2.0:1 in vivo being taken as positive. Resected tumor radiolocalization indices ranged from 0.5 to 543, and 71% (22/31) of the patients studied had tumors with radiolocalization indices higher than or equal to 3. Of 50 carcinoma biopsies, 34 that were probe-positive were antigen-positive when B72.3 was used in immunoperoxidase assays, while 4 carcinoma biopsies that were probe-negative were also antigen-negative. Twelve of 50 biopsies were probe-negative and antigen-positive, but many of these lesions only contained a few antigen-positive cells; none of the 50 was probe-positive and antigen-negative. Tumors of all histologic grades localized injected MAb and, in general, higher in vivo probe ratios and radiolocalization indices were obtained from patients who underwent surgery 20 to 35 days following injection of the MAb. MAb B72.3 localized tumor in all sites to which colon carcinoma commonly metastasizes, including mesenteric and peri-aortic lymph nodes, liver, lung, and peri-rectal soft tissue. There was a strong statistical correlation (p = 0.001) between detecting MAb B72.3 localization to tumors using the GDP intraoperatively and subsequent in vitro analysis of cpm/g for tumor versus normal tissues. These studies thus further validate the use of 125I-labelled MAb B72.3 IgG and of a hand-held gamma probe for the intraoperative detection of carcinomatous lesions.

Tumor-associated antigen expression of primary and metastatic colon carcinomas detected by monoclonal antibody 17-1A

Murine monoclonal antibody (MAb) 17-1A has been used in radioimmunodetection and immunotherapy trials of intestinal adenocarcinoma in humans. Tumor heterogeneity of antigen expression has been recognized as a potential limiting factor in such studies. The authors report a study designed to evaluate the degree of heterogeneity of 17-1A antigen expression among primary and metastatic human colon carcinomas. All 141 specimens, including 74 primary or metastatic colonic adenocarcinomas, were evaluated with the use of an avidin-biotin complex immunoperoxidase technic on briefly fixed frozen tissue sections. All of these showed at least focal staining with MAb 17-1A. However, well- or moderately differentiated tumors generally showed diffuse cytoplasmic immunostaining, whereas poorly differentiated tumors showed minimal immunostaining with no detectable antigen in most areas. In 16 cases that had both primary and metastatic adenocarcinomas or multiple metastatic tumors, 17-1A antigen expression was similar among the tumor sites except for one case. This case showed variation in tumor differentiation and corresponding variation in 17-1A antigen expression. Of 36 additional malignant tumors that were not of colonic epithelial origin, adenocarcinomas of the stomach, duodenum, endometrium, ovary, and breast showed 17-1A antigen expression.