Reliability and Variability of Ki-67 Digital Image Analysis Methods for Clinical Diagnostics in Breast Cancer

Ki-67 is a nuclear protein associated with proliferation, and a strong potential biomarker in breast cancer, but is not routinely measured in current clinical management owing to a lack of standardization. Digital image analysis (DIA) is a promising technology that could allow high-throughput analysis and standardization. There is a dearth of data on the clinical reliability as well as intra- and interalgorithmic variability of different DIA methods. In this study, we scored and compared a set of breast cancer cases in which manually counted Ki-67 has already been demonstrated to have prognostic value (n = 278) to 5 DIA methods, namely Aperio ePathology (Lieca Biosystems), Definiens Tissue Studio (Definiens AG), Qupath, an unsupervised immunohistochemical color histogram algorithm, and a deep-learning pipeline piNET. The piNET system achieved high agreement (interclass correlation coefficient: 0.850) and correlation (R = 0.85) with the reference score. The Qupath algorithm exhibited a high degree of reproducibility among all rater instances (interclass correlation coefficient: 0.889). Although piNET performed well against absolute manual counts, none of the tested DIA methods classified common Ki-67 cutoffs with high agreement or reached the clinically relevant Cohen's κ of at least 0.8. The highest agreement achieved was a Cohen's κ statistic of 0.73 for cutoffs 20% and 25% by the piNET system. The main contributors to interalgorithmic variation and poor cutoff characterization included heterogeneous tumor biology, varying algorithm implementation, and setting assignments. It appears that image segmentation is the primary explanation for semiautomated intra-algorithmic variation, which involves significant manual intervention to correct. Automated pipelines, such as piNET, may be crucial in developing robust and reproducible unbiased DIA approaches to accurately quantify Ki-67 for clinical diagnosis in the future.

Author Correction: Transcription phenotypes of pancreatic cancer are driven by genomic events during tumor evolution

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale1-3. Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter4; identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation5,6; analyses timings and patterns of tumour evolution7; describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity8,9; and evaluates a range of more-specialized features of cancer genomes8,10-18.

A Four-Chemokine Signature Is Associated with a T-cell-Inflamed Phenotype in Primary and Metastatic Pancreatic Cancer

PURPOSE

The molecular drivers of antitumor immunity in pancreatic ductal adenocarcinoma (PDAC) are poorly understood, posing a major obstacle for the identification of patients potentially amenable for immune-checkpoint blockade or other novel strategies. Here, we explore the association of chemokine expression with effector T-cell infiltration in PDAC.

EXPERIMENTAL DESIGN

Discovery cohorts comprised 113 primary resected PDAC and 107 PDAC liver metastases. Validation cohorts comprised 182 PDAC from The Cancer Genome Atlas and 92 PDACs from the Australian International Cancer Genome Consortium. We explored associations between immune cell counts by immunohistochemistry, chemokine expression, and transcriptional hallmarks of antitumor immunity by RNA sequencing (RNA-seq), and mutational burden by whole-genome sequencing.

RESULTS

Among all known human chemokines, a coregulated set of four (CCL4, CCL5, CXCL9, and CXCL10) was strongly associated with CD8⁺ T-cell infiltration (P < 0.001). Expression of this "4-chemokine signature" positively correlated with transcriptional metrics of T-cell activation (ZAP70, ITK, and IL2RB), cytolytic activity (GZMA and PRF1), and immunosuppression (PDL1, PD1, CTLA4, TIM3, TIGIT, LAG3, FASLG, and IDO1). Furthermore, the 4-chemokine signature marked tumors with increased T-cell activation scores (MHC I presentation, T-cell/APC costimulation) and elevated expression of innate immune sensing pathways involved in T-cell priming (STING and NLRP3 inflammasome pathways, BATF3-driven dendritic cells). Importantly, expression of this 4-chemokine signature was consistently indicative of a T-cell-inflamed phenotype across primary PDAC and PDAC liver metastases.

CONCLUSIONS

A conserved 4-chemokine signature marks resectable and metastatic PDAC tumors with an active antitumor phenotype. This could have implications for the appropriate selection of PDAC patients in immunotherapy trials.

Transcription phenotypes of pancreatic cancer are driven by genomic events during tumor evolution

Pancreatic adenocarcinoma presents as a spectrum of a highly aggressive disease in patients. The basis of this disease heterogeneity has proved difficult to resolve due to poor tumor cellularity and extensive genomic instability. To address this, a dataset of whole genomes and transcriptomes was generated from purified epithelium of primary and metastatic tumors. Transcriptome analysis demonstrated that molecular subtypes are a product of a gene expression continuum driven by a mixture of intratumoral subpopulations, which was confirmed by single-cell analysis. Integrated whole-genome analysis uncovered that molecular subtypes are linked to specific copy number aberrations in genes such as mutant KRAS and GATA6. By mapping tumor genetic histories, tetraploidization emerged as a key mutational process behind these events. Taken together, these data support the premise that the constellation of genomic aberrations in the tumor gives rise to the molecular subtype, and that disease heterogeneity is due to ongoing genomic instability during progression.

Integration of Genomic and Transcriptional Features in Pancreatic Cancer Reveals Increased Cell Cycle Progression in Metastases

We integrated clinical, genomic, and transcriptomic data from 224 primaries and 95 metastases from 289 patients to characterize progression of pancreatic ductal adenocarcinoma (PDAC). Driver gene alterations and mutational and expression-based signatures were preserved, with truncations, inversions, and translocations most conserved. Cell cycle progression (CCP) increased with sequential inactivation of tumor suppressors, yet remained higher in metastases, perhaps driven by cell cycle regulatory gene variants. Half of the cases were hypoxic by expression markers, overlapping with molecular subtypes. Paired tumor heterogeneity showed cancer cell migration by Halstedian progression. Multiple PDACs arising synchronously and metachronously in the same pancreas were actually intra-parenchymal metastases, not independent primary tumors. Established clinical co-variates dominated survival analyses, although CCP and hypoxia may inform clinical practice.

Genomics-Driven Precision Medicine for Advanced Pancreatic Cancer: Early Results from the COMPASS Trial

Purpose: To perform real-time whole genome sequencing (WGS) and RNA sequencing (RNASeq) of advanced pancreatic ductal adenocarcinoma (PDAC) to identify predictive mutational and transcriptional features for better treatment selection.Experimental Design: Patients with advanced PDAC were prospectively recruited prior to first-line combination chemotherapy. Fresh tumor tissue was acquired by image-guided percutaneous core biopsy for WGS and RNASeq. Laser capture microdissection was performed for all cases. Primary endpoint was feasibility to report WGS results prior to first disease assessment CT scan at 8 weeks. The main secondary endpoint was discovery of patient subsets with predictive mutational and transcriptional signatures.Results: Sixty-three patients underwent a tumor biopsy between December 2015 and June 2017. WGS and RNASeq were successful in 62 (98%) and 60 (95%), respectively. Genomic results were reported at a median of 35 days (range, 19-52 days) from biopsy, meeting the primary feasibility endpoint. Objective responses to first-line chemotherapy were significantly better in patients with the classical PDAC RNA subtype compared with those with the basal-like subtype (P = 0.004). The best progression-free survival was observed in those with classical subtype treated with m-FOLFIRINOX. GATA6 expression in tumor measured by RNA in situ hybridization was found to be a robust surrogate biomarker for differentiating classical and basal-like PDAC subtypes. Potentially actionable genetic alterations were found in 30% of patients.Conclusions: Prospective genomic profiling of advanced PDAC is feasible, and our early data indicate that chemotherapy response differs among patients with different genomic/transcriptomic subtypes. Clin Cancer Res; 24(6); 1344-54. ©2017 AACR.

A renewed model of pancreatic cancer evolution based on genomic rearrangement patterns

Pancreatic cancer, a highly aggressive tumour type with uniformly poor prognosis, exemplifies the classically held view of stepwise cancer development. The current model of tumorigenesis, based on analyses of precursor lesions, termed pancreatic intraepithelial neoplasm (PanINs) lesions, makes two predictions: first, that pancreatic cancer develops through a particular sequence of genetic alterations (KRAS, followed by CDKN2A, then TP53 and SMAD4); and second, that the evolutionary trajectory of pancreatic cancer progression is gradual because each alteration is acquired independently. A shortcoming of this model is that clonally expanded precursor lesions do not always belong to the tumour lineage, indicating that the evolutionary trajectory of the tumour lineage and precursor lesions can be divergent. This prevailing model of tumorigenesis has contributed to the clinical notion that pancreatic cancer evolves slowly and presents at a late stage. However, the propensity for this disease to rapidly metastasize and the inability to improve patient outcomes, despite efforts aimed at early detection, suggest that pancreatic cancer progression is not gradual. Here, using newly developed informatics tools, we tracked changes in DNA copy number and their associated rearrangements in tumour-enriched genomes and found that pancreatic cancer tumorigenesis is neither gradual nor follows the accepted mutation order. Two-thirds of tumours harbour complex rearrangement patterns associated with mitotic errors, consistent with punctuated equilibrium as the principal evolutionary trajectory. In a subset of cases, the consequence of such errors is the simultaneous, rather than sequential, knockout of canonical preneoplastic genetic drivers that are likely to set-off invasive cancer growth. These findings challenge the current progression model of pancreatic cancer and provide insights into the mutational processes that give rise to these aggressive tumours.

Abstract 3124: Prognostic biomarkers for pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) has the lowest 5-year-survival rate of common cancers (&lt; 7%), but despite intensive research efforts over the past several decades, its dismal prognosis has barely improved. Recent genome-wide association studies (GWAS) have linked several genetic factors with pancreatic cancer, but there is generally poor overlap in the results from such studies, presumably due to population heterogeneity. In this study, we collected previously published pancreatic risk loci from multiple GWAS studies, and correlated these loci with clinical information gathered on a well-characterized cohort of 148 PDAC patients from the University Health Network in Toronto Canada, and several other North American hospitals, which have undergone whole-genome sequencing. Using this cohort, we attempted to identify prognostic genomic biomarkers by correlating the germline genomic alterations observed in our cohort to overall survival (OS). By understanding the mechanism of germline variants that alter OS, we hope to develop insights that will lead to improved detection and therapy for PDAC patients.

Among the 67 published risk loci we tested using a multivariate Cox proportional hazard model, we found a strong positive association of the single nucleotide polymorphism rs4785367 (RefSNP alleles: C/T on forward strand; MAF = 0.474) with overall survival of PDAC donors: HR = 0.426; CI = 0.268 - 0.686; p-value = 0.00029. A more detailed analysis at the genotype level revealed that the presence of the homozygous minor allele has a stronger effect than either the heterozygous or homozygous major allele. The SNP falls within the intergenic region between the ZNF423 and TMEM188 genes, within the exon 2 of lncRNA RP11-305A4.3 and overlaps a CTCF regulatory domain. Preliminary gene expression analysis from RNA sequencing data on a subset of PDAC donors (n = 28) shows that patients carrying the minor allele have significant higher TMEM188 expression than of the major type (p-value = 0.012), suggesting that this allele may influence the course of PDAC via TMEM188 activity. A recent study linked the gene product to activation of NK cells, which in turns increases the defense mechanism against the pathogens, infections and transformed tumors. These findings suggest a possible molecular mechanism influencing the course of PDAC. We are also exploring the effect of the presence of the minor allele on the regulatory CTCF region, by applying an integrative pipeline for risk SNP analysis to pancreatic cancer. This will possibly detect the effect on the NANOG motif binding and/or on CTCF looping.

In summary, the present study detected the rs4785367 as a prognostic biomarker for pancreatic cancer, with the novelty of increased TMEM188 gene expression being linked to the presence of the alternate allele in PDAC patients. Further investigations on this and on assessing the effect of the polymorphism on the regulatory CTCF feature are in progress.

Citation Format: Cristina Baciu, Robert Grant, Hansen He, Musaddeque Ahmed, Robert E. Denroche, Lee Timms, Gun Ho Jang, Ayelet Borgida, Xihui Lin, Paul C. Boutros, Dianne Chadwich, Sheng-Ben Liang, Sagedeh Shahabi, Michael H.A. Roehrl, Sean Cleary, Julie M. Wilson, John D. McPherson, Lincoln Stein, Steven Gallinger. Prognostic biomarkers for pancreatic cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3124.

Abstract A1-17: Genomic analysis of metachronous pancreatic ductal adenocarcinoma

Background: Improving outcomes for pancreatic ductal adenocarcinoma (PDAC) requires more complete understanding of pancreatic carcinogenesis, including tumor heterogeneity and mutational evolution. Such studies in PDAC are hampered by presentation at advanced stages and rarely operable recurrences. We present a case of metachronous PDAC managed by serial resections and interrogated by whole genome sequencing of all three lesions.

Methods: Tumors underwent either laser capture microscopy or flow cytometry of fresh frozen tissue. Germline DNA was obtained from normal tissue. Genomic DNA was isolated, and sequencing libraries were prepared. Whole genome sequencing was performed on the Illumina HiSeq2500 system. Pipeline analysis included quality control, alignment to the reference genome (hg19), variant calling and annotation. Structural variants were called by the union of two tools, DELLY and CREST. Copy number variants were called using an in-house tool. Single nucleotide polymorphisms and short insertions and deletions were identified by the intersection of two tools, Strelka and MuTect, and annotated using ANNOVAR. All structural, copy number and non-silent variants were manually reviewed in the Integrated Genome Viewer. Secondary analyses were done in R. Representative sections of the three tumors also underwent formalin fixation, paraffin embedding, sectioning at five micron thickness and hematoxylin and eosin staining for microscopic analysis.

Results: The first tumor was located in the head of the pancreas and resected by Whipple operation, the second and third in the body and tail, respectively, and resected by completion pancreatectomy 14 months later. The patient received chemotherapy in the interim.

Histologically, all 3 tumors were moderately differentiated adenocarcinomas with focal mucinous areas and extensive lymphovascular and perineural invasion. There were no distinguishing morphological features.

For the 3 lesions, we achieved average sequence coverage of 52.3x, 54.3x, and 70.7x, respectively.

A total of 69 structural variants and 62 copy number variants were identified, with concordance of 75% and 92% in all three lesions.

A total of 61 non-silent exonic variants were identified, with concordance of 33% in all three lesions. A KRAS (NM_004985) c.G34C missense and TP53 (NM_001126115) c.G418A missense were present in all three, whereas a SMAD4 (NM_005359) c.118delC frameshift was present in only the second and third tumors.

Hierarchical clustering by non-silent variants, copy number variants, and an intersect of all variants showed the tumors in the head and tail to be more closely related to one another than to the body lesion, whereas clustering by structural variants showed little difference between the three.

Conclusions: The highly similar structural and copy number profiles across the three lesions suggests that these tumors arose from a common precursor, and that large chromosomal changes occurred early in its mutational evolution.

The poor concordance of simple somatic mutations imply that these evolved gradually and are responsible for tumor heterogeneity and possibly acquired phenotypes, include therapeutic resistance.

This study also demonstrates that isolated, intra-parenchymal metastases (as opposed to de novo tumors within a “field defect”) are possible with PDAC, which has been suggested in case reports but never definitively proven, further implying that these patients may benefit from re-operation despite disease relapse.

Further analysis will include mathematical modeling of mutation rates and validation in three additional metachronous cases identified in our biospecimen repository and in specimens obtained by our rapid autopsy program.

Citation Format: Ashton A. Connor, Michelle Chan-Seng-Yue, Robert E. Denroche, Ayelet Borgida, Sheng-Ben Liang, Faiyaz Notta, Lincoln Stein, Michael H. Roehrl, John McPherson, Steven Gallinger. Genomic analysis of metachronous pancreatic ductal adenocarcinoma. [abstract]. In: Proceedings of the AACR Special Conference on Translation of the Cancer Genome; Feb 7-9, 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 1):Abstract nr A1-17.

Abstract B2-57: Genomic analysis of metachronous pancreatic ductal adenocarcinoma

Background: Improving outcomes for pancreatic ductal adenocarcinoma (PDAC) requires more complete understanding of pancreatic carcinogenesis, including tumor heterogeneity and mutational evolution. Such studies in PDAC are hampered by presentation at advanced stages and rarely operable recurrences. We present a case of metachronous PDAC managed by serial resections and interrogated by whole genome sequencing of all three lesions.

Methods: Tumors underwent either laser capture microscopy or flow cytometry of fresh frozen tissue. Germline DNA was obtained from normal tissue. Genomic DNA was isolated, and sequencing libraries were prepared. Whole genome sequencing was performed on the Illumina HiSeq2500 system. Pipeline analysis included quality control, alignment to the reference genome (hg19), variant calling and annotation. Structural variants were called by the union of two tools, DELLY and CREST. Copy number variants were called using an in-house tool. Single nucleotide polymorphisms and short insertions and deletions were identified by the intersection of two tools, Strelka and MuTect, and annotated using ANNOVAR. All structural, copy number and non-silent variants were manually reviewed in the Integrated Genome Viewer. Secondary analyses were done in R. Representative sections of the three tumors also underwent formalin fixation, paraffin embedding, sectioning at five micron thickness and hematoxylin and eosin staining for microscopic analysis.

Results: The first tumor was located in the head of the pancreas and resected by Whipple operation, the second and third in the body and tail, respectively, and resected by completion pancreatectomy 14 months later. The patient received chemotherapy in the interim.

Histologically, all 3 tumors were moderately differentiated adenocarcinomas with focal mucinous areas and extensive lymphovascular and perineural invasion. There were no distinguishing morphological features.

For the 3 lesions, we achieved average sequence coverage of 52.3x, 54.3x, and 70.7x, respectively.

A total of 69 structural variants and 62 copy number variants were identified, with concordance of 75% and 92% in all three lesions.

A total of 61 non-silent exonic variants were identified, with concordance of 33% in all three lesions. A KRAS (NM_004985) c.G34C missense and TP53 (NM_001126115) c.G418A missense were present in all three, whereas a SMAD4 (NM_005359) c.118delC frameshift was present in only the second and third tumors.

Hierarchical clustering by non-silent variants, copy number variants, and an intersect of all variants showed the tumors in the head and tail to be more closely related to one another than to the body lesion, whereas clustering by structural variants showed little difference between the three.

Conclusions: The highly similar structural and copy number profiles across the three lesions suggests that these tumors arose from a common precursor, and that large chromosomal changes occurred early in its mutational evolution.

The poor concordance of simple somatic mutations imply that these evolved gradually and are responsible for tumor heterogeneity and possibly acquired phenotypes, include therapeutic resistance.

This study also demonstrates that isolated, intra-parenchymal metastases (as opposed to de novo tumors within a “field defect”) are possible with PDAC, which has been suggested in case reports but never definitively proven, further implying that these patients may benefit from re-operation despite disease relapse.

Further analysis will include mathematical modeling of mutation rates and validation in three additional metachronous cases identified in our biospecimen repository and in specimens obtained by our rapid autopsy program.

Citation Format: Ashton A. Connor, Michelle Chan-Seng-Yue, Robert E. Denroche, Ayelet Borgida, Sheng-Ben Liang, Faiyaz Notta, Lincoln Stein, Michael H. Roehrl, John McPherson, Steven Gallinger. Genomic analysis of metachronous pancreatic ductal adenocarcinoma. [abstract]. In: Proceedings of the AACR Special Conference on Computational and Systems Biology of Cancer; Feb 8-11 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 2):Abstract nr B2-57.

Abstract 3381: Standardizing the analysis of Ki-67 immunohistochemical assays

Intro

Immunohistochemical assays of the proliferation marker, Ki-67, have been associated with poorer clinical prognosis in breast cancer. However, a high degree of inconsistency in scores has been demonstrated in inter-laboratory and intra-laboratory Ki-67 positivity scorings, this has limited its potential in clinical practice. In this study, we aim to find a more consistent method for scoring Ki-67 positivity among malignant breast tumours.

Methods

Six Tissue Microarray (TMA) blocks were sectioned and immunohistochemistry was performed with Anti-Ki-67 antibody. Slides were then evaluated and Ki-67 positive cells in invasive breast carcinoma were scored as a percent positivity manually by a trained analyst with random sample quality assurance (QA) by trained pathologists. This was used as the standard benchmark for the experiment as it has been correlated successfully with clinical outcome. Successively, the same six slides were then annotated on Aperio ePathology software by two observers with different levels of pathology training and experience. The annotated regions were analyzed for Ki-67 positivity with Aperio ePathology software on UHN BioBank servers. The computer analyzed scores were compared to the manual benchmark scores.

Results

The difference between computer-analyzed and manual-scores were relatively large, Observer-A-annotated-computer-analyzed vs. analyst-manual-scores had a difference of 4.23% to 16.96%, while Observer-B-annotated-computer-analyzed vs. analyst-manual-scores had a difference of 7.13% to 15.03%. Interestingly, Observer-A-annotated-computer-analyzed vs. Observer-B-annotated-computer-analyzed scores only had a difference of 0.49% to 2.91%. Pearson Correlation was calculated for all samples on a case-by-case basis and we found there to be a linear correlation of 0.564, with a P-value of 3.6082×10-8, between the computer scores and the manual scores; suggesting significant correlation between the computer scores and the manual score.

Conclusion

A significant linear correlation has been observed between the computer score and the manual score. However, while the data does not seem to support the idea that a semi-automatic method of computer scoring will replace analyst manual scoring, most of the large contributing variables have been identified. We plan in the next steps of the project to continue to decrease the effects of such variables. It is interesting that the inter-observer computer score displayed a minimal amount of difference, again with the variables identified. This could signify a more consistent method of Ki-67 scoring. Further experiments will be conducted to continue to reduce the variables and optimize the system to gain similar performance as manual scoring. Hopefully in the near future, computerized immunohistochemical analysis can replace the tedious task of manual scoring.

Citation Format: Tian Yu Liu, Trillium Chang, Adewunmi Adeoye, Willa Shi, Sheng-Ben Liang, Dianne Chadwick, Michael H.A. Roehrl, Naomi Miller, Fei-Fei Liu, Susan J. Done. Standardizing the analysis of Ki-67 immunohistochemical assays. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3381. doi:10.1158/1538-7445.AM2015-3381

Molecular target characterization and antimyeloma activity of the novel, insulin-like growth factor 1 receptor inhibitor, GTx-134

PURPOSE

Therapeutic strategies that target insulin-like growth factor 1 receptor (IGF-1R) hold promise in a wide variety of cancers including multiple myeloma (MM). In this study, we describe GTx-134, a novel small-molecule inhibitor of IGF-1R and insulin receptor (IR) and characterized its antitumor activity in preclinical models of MM.

EXPERIMENTAL DESIGN

The activity of GTx-134 as a single agent and in combination was tested in MM cell lines and primary patient samples. Downstream effector proteins and correlation with apoptosis was evaluated. Cytotoxcity in bone marrow stroma coculture experiments was assessed. Finally, the in vivo efficacy was evaluated in a human myeloma xenograft model.

RESULTS

GTx-134 inhibited the growth of 10 of 14 myeloma cell lines (<5 μmol/L) and induced apoptosis. Sensitivity to GTx-134 correlated with IGF-1R signal inhibition. Expression of MDR-1 and CD45 were associated with resistance to GTx-134. Coculture with insulin-growth factor-1 (IGF-1) or adherence to bone marrow stroma conferred modest resistance, but did not overcome GTx-134-induced cytotoxicity. GTx-134 showed in vitro synergies when combined with dexamethasone or lenalidomide. Further, GTx-134 enhanced the activity of PD173074, a fibroblast growth factor receptor 3 (FGFR3) inhibitor, against t(4;14) myeloma cells. Therapeutic efficacy of GTx-134 was shown against primary cells and xenograft tumors. Although dysregulation of glucose homeostasis was observed in GTx-134-treated mice, impairment of glucose tolerance was modest.

CONCLUSIONS

These studies support the potential therapeutic efficacy of GTx-134 in MM. Further, they provide a rationale for clinical application in combination with established antimyeloma treatments and novel targeted therapies.

Petrochemical wastewater odor treatment by biofiltration

The treatment of odorous pollutants by microorganisms on packed waste straw and cortex was investigated at the wastewater treatment plant of the Shanghai petrochemical factory. The removal efficiency of H(2)S, NH(3) and VOCs (volatile organic compounds) reached 98%, 91% and 90%, respectively after operation for one month at an empty bed retention time (EBRT) of 120s. The heterotrophic bacteria were found to be the dominant microorganism in the biofilter, while fungi and actinomycetes were also present. The bacteria were mostly identified as the members of the genus Bacillus (62.5% of cultured bacteria). The single strand conformation polymorphism (SSCP) results revealed that the genus Bacillus and Pseudomonas were the predominant bacteria. The microbial diversity gradually increased as the treatment progressed, which indicated that the microbial community in the biofilter became more stable upon pollutant removal. The scanning electron microscopy (SEM) was performed to evaluate the microorganism growth on the media. It was found that the waste straw and cortex were suitable for microorganism attachment and growth, and may have potential application in odor treatment.

The Bcl-2 family protein inhibitor, ABT-737, has substantial antimyeloma activity and shows synergistic effect with dexamethasone and melphalan

PURPOSE

The aim of this study is to investigate the antimyeloma activity of a novel Bcl-2 family inhibitor, ABT-737, in preclinical treatment of multiple myeloma.

EXPERIMENTAL DESIGN

The antimyeloma activity of ABT-737 was evaluated in cultured myeloma cell lines and patient myeloma samples, and in a xenograft mouse myeloma model. Drug combination therapy using ABT-737 with other commonly used myeloma drugs was also investigated.

RESULTS

MY5 and JJN3 cell lines exhibited the most sensitivity to ABT-737 with an EC(50) of 0.2 and 0.5 micromol/L, respectively, with increased cell apoptosis and elevated activated caspase-3. We identified two distinct groups of myeloma patient samples that were either sensitive or resistant to the drug. Four of 15 patient bone marrow samples (27%) were highly sensitive to ABT-737 at doses of 0.25 and 0.5 micromol/L, which eliminated 80% to 90% of myeloma cells as a result of cellular apoptosis 3 days after drug treatment. ABT-737 showed a synergistic effect when combined with dexamethasone or melphalan in inducing myeloma cell death. Furthermore, the dexamethasone-resistant MM1(Dex)R myeloma cell line was highly sensitive to 0.2 micromol/L ABT-737. As determined by colony assay, little or no detectable toxicity to patient hematologic progenitor cells was observed at 1 micromol/L ABT-737. ABT-737 dose dependently suppressed tumor growth in a xenograft MY5 mouse model.

CONCLUSIONS

These studies show substantial antimyeloma activity of ABT-737 as a single agent or in combination with dexamethasone or melphalan and suggest a rationale for future clinical trials.

Multiple Reduced-intensity Conditioning Regimens Facilitate Correction of Fabry Mice After Transplantation of Transduced Cells

Hematopoietic cell transplantation can impact lysosomal storage disorders (LSDs) and will be enhanced by gene therapy. Transduced cells in LSDs often secrete the therapeutic hydrolase, which can be used by bystander cells. However, toxicity associated with myeloablative transplant preparative regimens limits many applications of this approach in gene therapy. We hypothesized that reduced-intensity (RI) conditioning regimens would allow stable engraftment of therapeutically transduced cells and allow correction of Fabry disease. We transplanted transduced cells into Fabry mice receiving eight different clinically relevant chemotherapy- and/or radiotherapy-based RI conditioning regimens generating modest and transient lymphoid/myeloid cell depletion. Two comprehensive transplantation Protocols were performed. Firstly, transplantation of 0.38 x 10(6) gene-modified stem/progenitor cells was nominally effective; none of the RI regimens led to stable alpha-galactosidase A (alpha-gal A) correction. Secondly, transduced cells were preselected for functional transgene expression and transplanted at a higher dose (0.72 x 10(6) cells). Each RI regimen yielded engraftment of functional transgene-positive cells through 180 days along with increased plasma alpha-gal A activity. Importantly, the RI regimens mediated broad organ enzyme correction and were not associated with immune responses against alpha-gal A. RI conditioning thus has an important role in gene therapy for LSDs; a variety of regimens can be effective in this context.

The inhibitory anti-FGFR3 antibody, PRO-001, is cytotoxic to t(4;14) multiple myeloma cells

The association of fibroblast growth factor receptor 3 (FGFR3) expression with t(4;14) multiple myeloma (MM) and the demonstration of the transforming potential of this receptor tyrosine kinase (RTK) make it a particularly attractive target for drug development. We report here a novel and highly specific anti-FGFR3-neutralizing antibody (PRO-001). PRO-001 binds to FGFR3 expressed on transformed cells and inhibits FGFR3 autophosphorylation and downstream signaling. The antibody inhibited the growth of FGFR3-expressing FDCP cells (IC(50) of 0.5 microg/mL) but not that of cells expressing FGFR1 or FGFR2, and potently inhibited FGFR3-dependent solid tumor growth in a mouse xenograft model. Furthermore, PRO-001 inhibited the growth of the FGFR3-expressing, human myeloma cell line, UTMC2. Inhibition of viability was still observed when cells were cocultured with stroma or in the presence of IL-6 or IGF-1. PRO-001 did not inhibit constitutive activation of K650E, G384D, and Y373C FGFR3 in myeloma cell lines and failed to inhibit the growth of these cells. Most importantly, however, PRO-001 induced cytotoxic responses in primary t(4;14)(+) MM samples with an increase in apoptotic index of 20% to 80% as determined by annexin V staining. The data demonstrate that PRO-001 is a potent and specific inhibitor of FGFR3 and deserves further study for the treatment of FGFR3-expressing myeloma.

Efficient transfer of PSA and PSMA cDNAs into DCs generates antibody and T cell antitumor responses in vivo

Gene therapy for prostate cancer may be realized through transduction of whole genes, such as PSA or PSMA, into immunotherapeutic dendritic cells (DCs). An oncoretroviral vector encoding human PSMA and a bicistronic oncoretroviral vector encoding human PSA and cell surface CD25 cDNAs were constructed. Remarkably, transfer of PSA/CD25 or PSMA cDNA during murine hematopoietic cell differentiation into DCs occurred with approximately 80% efficiency. In vitro, transduced DCs retained allostimulatory function and primed syngeneic T cells for tumor antigen-specific IFN-gamma secretion. In test experiments designed to elucidate mechanisms in vivo, syngeneic recipients of transduced DCs had increased anti-human PSA antibody titers and tumor-specific CD8(+) T cell IFN-gamma secretion with no detectable immune response to CD25. Gene-modified DC recipients had increased protection from specific tumor challenge for at least 18 weeks post-vaccination. DC vaccination also protected both male and female recipients. Gene-modified DC vaccination mediated regression of established, specific gene-expressing, TRAMP-C1 prostate cancer cell tumors. These findings indicate that antibody and cellular responses generated through PSA and PSMA gene transfer into DC yielded protective immunity, thereby providing further preclinical support for the implementation of immuno-gene therapy approaches for prostate cancer.

Down-regulation of a novel actin-binding molecule, skeletrophin, in malignant melanoma

In the present study, we cloned and characterized a novel actin-binding molecule, designated skeletrophin, from aggregated neuroblastoma cells. The putative amino acid sequence of human skeletrophin cDNA contained a cysteine-rich zinc-finger motif which was also found in dystrophin and five ankyrin repeats. Northern blot analysis revealed that the 3.2-kb skeletrophin mRNA was expressed in normal skeletal muscle, and to a lesser extent in heart, brain, and kidney. Specific antibody was prepared to human skeletrophin peptide, and a single protein band with an approximate molecular weight of 70 kd was detected in tissue extracts by immunoblotting using the antibody. To better understand the biological properties of skeletrophin, we used a yeast two-hybrid system to screen for molecules interacting with skeletrophin and found that skeletrophin bound to actin monomer. Co-immunoprecipitation experiments also demonstrated that skeletrophin was able to bind to actin monomer. Fluorescence in situ hybridization mapped the skeletrophin gene on human chromosome 1p36.2-36.3, in which putative tumor suppressor genes for malignant melanoma have been postulated to exist. We therefore immunohistochemically stained benign nevi and malignant melanoma tissues. Notably, 23 of 25 benign nevi expressed skeletrophin in cytoplasm, but 18 of 38 cases of primary skin melanoma appeared to lack skeletrophin expression. Treatment with a demethylating agent, 5'-aza-2-deoxycytidine, restored skeletrophin expression in cultured Mewo melanoma cells. The present findings suggest that skeletrophin may be a novel actin-binding cytoskeleton-related molecule, expression of which is silenced in a considerable number of melanoma specimens.

Downregulation of expression of a novel cadherin molecule, T-cadherin, in basal cell carcinoma of the skin

T-cadherin appears to act as a tumor-suppressor factor in various cancers. Downregulation of T-cadherin is caused by a combination of allelic loss and hypermethylation of the T-cadherin promoter region and is related to cancer invasion. To elucidate the molecular mechanism of invasiveness of basal cell carcinoma of the skin, T-cadherin expression was investigated in archival pathological tissue sections made up of normal counterparts of skin and various types of basal cell carcinoma. Immunohistochemical staining showed that T-cadherin was not expressed in 38 of 51 (75%) basal cell carcinoma specimens, whereas normal counterparts of the skin appeared to express abundant T-cadherin. Loss of heterozygosity in intron 1 of the T-cadherin gene was found in four of 20 informative cases that did not express T-cadherin. Aberrant methylation of the T-cadherin promoter region also was found in six of 25 basal cell carcinomas by methylation-specific polymerase chain reaction. In contrast, no structural alternations were found in two loss of heterozygosity-positive basal cell carcinomas on sequence analysis. These findings indicated that T-cadherin expression was downregulated by a combination of allelic loss and aberrant methylation in basal cell carcinoma of the skin. Loss of T-cadherin expression might be related to the biological behavior of basal cell carcinoma. In addition, results of the present study suggested that downregulation of T-cadherin in various cancers might be related to tumor invasiveness rather than metastasis, because basal cell carcinoma of the skin principally lacks metastatic activity.

Loss of T-cadherin (CDH13, H-cadherin) expression in cutaneous squamous cell carcinoma

We previously reported that T-cadherin (CDH13, H-cadherin), a unique cadherin molecule, was expressed on the basal cell layer in normal murine and human epidermis. In the present study, T-cadherin expression in archival human skin specimens comprising a spectrum of human squamous cell neoplasia was investigated. T-cadherin expression was observed in both normal epidermal basal cells and adnexal epithelial cells of formalin-fixed and paraffin-embedded tissue sections. Western immunoblotting also revealed that mature T-cadherin protein was expressed in cultured human skin tissue equivalent. Atypical keratinocytes in 27 of 53 specimens of actinic keratosis and 23 of 30 specimens of Bowen's disease expressed T-cadherin. In contrast, T-cadherin was focally expressed in 6 of 56 invasive cutaneous squamous cell carcinomas. To explore the molecular mechanism of down-regulation of T-cadherin expression in invasive squamous cell carcinoma, loss of heterozygosity, genetic alternations, and methylation status in the 5' region of the T-cadherin gene were investigated. Loss of heterozygosity at intron 1 of the T-cadherin gene was observed in 8 of 28 informative cases of invasive squamous cell carcinoma. Although no structural genomic alternations were found by sequence analysis, aberrant promoter methylation of the T-cadherin gene was found in 12 of 28 invasive squamous cell carcinomas. T-cadherin expression was restored in cultured A431 cells, in which aberrant methylation was found by treatment with the demethylating agent 5'-aza-2-deoxycytidine. These findings suggest that a combination of deletion and aberrant methylation of the T-cadherin gene may play a role in loss of gene expression in a considerable number of invasive cutaneous squamous cell carcinomas.

Expression of T-cadherin in Basal keratinocytes of skin

T-cadherin is a unique member of the cadherin superfamily that shares the ectodomain organization with classical cadherins, but lacks both transmembrane and cytoplasmic regions and is instead anchored to the plasma membrane through a glycosyl-phosphatidylinositol (GPI) moiety. The function of T-cadherin has not been revealed yet. The special structure of T-cadherin might endow this molecule with specific intracellular targeting properties and functions that are distinct from classical cadherins. T-cadherin was originally cloned from chicken embryo brain and then was also found in mouse and human nervous and cardiovascular systems; however, T-cadherin in the keratinocytes and skin tissue is still an unknown area that remains to be explored. To test whether the unusual truncated T-cadherin is expressed in keratinocytes, we performed the reverse transcriptase-polymerase chain reaction of T-cadherin, as well as several classical cadherins (E-, P-, and N-cadherin), on the mouse keratinocyte cell line Pam212, fibroblast NIH3T3, and melanoma cell B16. The result indicated that mouse keratinocytes expressed the mRNA of truncated T-cadherin apart from classical cadherins, E-, and P-cadherin. To confirm the expression of T-cadherin in mouse keratinocytes, immunocytochemistry staining was carried out on Pam212 cells by using rabbit anti-T-cadherin antibody and rat antimouse E- and P-cadherin antibody. The result of immunofluorescence staining proved that T-cadherin was expressed in mouse keratinocytes. In order to analyze the distribution patterns of T-cadherin and classical cadherins on the keratinocytes, 3D scanning was performed by using a confocal microscope. From the Z-sections and XZ-sections, it was clearly demonstrated that T-cadherin was distributed diffusely on the whole cell surface, while E- and P-cadherin were concentrated on the cell-cell contacts. To examine the expression and the localization of T-cadherin on skin tissue, the frozen sections of the mouse back skin were immunohistochemically labeled by using anti-T-cadherin antibody. It was found that T-cadherin was intensively expressed only on the basal cell layer of the mouse skin. Apart from mouse keratinocytes and mouse skin, we further examined the expression of T-cadherin in human keratinocytes and human skin by western blot, immunocytochemistry, and immunohistochemistry staining. The same results were achieved with human samples. In this study, we found and verified that T-cadherin was expressed on the mouse and human keratinocytes and specifically localized on the basal cell layer of skin. The nature of T-cadherin function and its mechanism of localization at the basal cell layer of skin are important issues to be addressed concerning this unique member of the cadherin family and its physiologic and pathologic roles in the skin.

Reduced human mismatch repair protein expression in the development of precancerous skin lesions to squamous cell carcinoma

Loss of human mismatch repair (hMSH2) gene function has been linked to hereditary non-polyposis colorectal cancer (HNPCC), Muir-Torre syndrome (MTS), and sporadic cancers, excluding skin cancers unrelated to MTS. We immunohistochemically examined 125 squamous cell carcinomas (SCCs) using a monoclonal antibody to the hMSH2 protein and compared the results with those for 106 precursor lesions of SCC, consisting of actinic keratosis (AK), Bowenoid type of actinic keratosis (BAK), and Bowen's disease (BOD). In contrast to the homogeneous immunoreactivity of proliferating cells composed of AK, BAK, and BOD, heterogeneous and diminished immunostaining to hMSH2 was observed in tumor cells of SCCs examined. In addition, two SCCs (2 of 125; 1.6%) at multiple loci exhibited a complete lack of immunoreaction to hMSH2. Immunohistochemical staining of hMSH2 was semiquantitatively scored as 0 (0% of total cells examined), 1 (less than 10%), 2 (10-50%), or 3 (more than 50%). Percentage preservation of and average score for hMSH2 expression in normal, AK, BAK, BOD, and SCC were 56% and 2.06, 100% and 2.80, 94% and 2.88, 83% and 2.78, 63% and 2.36, respectively. The percentage preservation of and average scores for hMSH2 in AK, BAK, and BOD were significantly higher than those in presumably normal skin (P<0.01). There were no significant differences in the percentage preservation of and average scores for hMSH2 between presumably normal skin and SCC. The score for hMSH2 expression was significantly correlated with score for sun exposure in presumably normal skin of each lesion (R=0.70). These findings for hMSH2 expression in precursor lesions and SCC suggest that promotion or activation of hMSH2 expression may be induced by the increased DNA damage caused by sun exposure and that diminished expression of it might occur according to the transformation from precancerous lesions to SCC.

Tetrasomy 12 in ovarian tumors of thecoma-fibroma group: A fluorescence in situ hybridization analysis using paraffin sections

Recent cytogenetical studies have indicated that trisomy 12 is a feature of ovarian tumors in the thecoma-fibroma group. Ten cases of these ovarian tumors were studied in total, including two thecomas, two fibrothecomas, four fibromas, one cellular fibroma and one fibrosarcoma, to clarify the relationship between polysomy 12 and proliferative activity in these tumors. Each formalin-fixed, paraffin-embedded tumor tissue was examined by fluorescence in situ hybridization to determine copy numbers of chromosome 12 and by immunohistochemical staining of Ki-67 for evaluation of tumor cell proliferation. Gains of trisomy 12 were found in seven of the 10 cases, and the percentage of cells with tetrasomy 12, but not that of cells with trisomy 12, was significantly and positively correlated with percentage of Ki-67-positive cells, but significantly and inversely correlated with patient age. These findings suggest that tetrasomy 12 is an age-related aberration of chromosome 12 in ovarian tumors of the thecoma-fibroma group, and that such tumors exhibit more active proliferation in younger patients.

Multinucleated giant cells in submucosal layer of human urinary bladder: an immunohistochemical and electron microscopic study

Multinucleated giant cells (MGC) detected in the submucosal layer of human urinary bladder mainly associated with transitional cell carcinoma were examined immunohistochemically and ultrastructurally. The cases examined totaled 29, namely 14 cases with transitional cell carcinoma and another 15 cases mostly with malignancy in other organs. Histologically, MGC were smooth, irregular or dendritic in shape, and tended to increase in number in the vicinity of cancer or marked inflammation. They were consistently positive for not only vimentin, but also MB-2, and CD34, and were mostly positive for proliferating cell nuclear antigen (PCNA), but not MIB-1 (Ki-67) and HLA-DRalpha antigens. On occasion, antibodies to alpha-smooth muscle actin (alpha-SMA), muscle actin (M-actin), CD68 (KP-1) and alpha subunit of S-100 protein also yielded positive reactions. Interestingly, aggregated short bulbous processes were ultrastructurally observed on their surface in parts. These findings suggested that MGC in the submucosal layer of human urinary bladder were MB-2 and CD34-positive multipotential mesenchymal cells with no mitotic activity expressing fibroblastic (vimentin), myofibroblastic (alpha-SMA), or histiocytic (CD68) markers mostly in the vicinity of malignancy, and that these MGC were formed by fusion of mononuclear cells expressing identical markers with those of MGC. Further investigations are needed to clarify the exact function of MGC in human urinary bladder.

Expression of T-cadherin (CDH13, H-Cadherin) in human brain and its characteristics as a negative growth regulator of epidermal growth factor in neuroblastoma cells

In the present study, we first examined the expression of T-cadherin in human CNS by northern blot analysis, immunohistochemical staining, and in situ hybridization. Northern blot analysis demonstrated expression of T-cadherin in human adult cerebral cortex, medulla, thalamus, and midbrain. Immunohistochemical staining with a newly generated monoclonal antibody, designated MA-511, revealed strong expression of T-cadherin in neural cell surface membrane and neurites in adult cerebral cortex, medulla oblongata, and nucleus olivaris. Little or no expression of T-cadherin was found in spinal cord. We further examined T-cadherin expression in various developing nervous systems, and found that T-cadherin expression was lower in developing brain than in adult brain. In situ hybridization revealed that neural cells in medulla oblongata and nucleus olivaris, but not in spinal cord, possessed T-cadherin molecules. We transfected T-cadherin-negative TGW and NH-12 neuroblastoma cells with a T-cadherin cDNA-containing expression vector. T-cadherin-expressing neuroblastoma cells lost mitogenic proliferative response to epidermal growth factor. Epidermal growth factor is known to be required for proliferation of neural stem cells. This finding, together with those of the present study, suggests that T-cadherin functions as a negative regulator of neural cell growth.

Overexpression of cyclin D1 in nonmelanocytic skin cancer

Although the overexpression of cyclin D1 has been believed to play important roles in neoplastic transformation of some tumors, little is known about the function of cyclin D1 protein in carcinogenesis in human skin. A total of 307 patients with nonmelanocytic skin cancer, being 46 with Bowen's disease (BOD), 134 with squamous cell carcinoma (SCC) and 127 with basal cell carcinoma (BCC), were investigated immunohistochemically using monoclonal antibody to cyclin D1 by the LSAB method, to assess the expression of cyclin D1 in skin cancer including its precursors. The positive rates of cyclin D1 immunostaining in BOD, SCC and BCC were 63.0%, 69.4% and 54.3%, respectively. The positive rates in dysplasia adjoining BOD, SCC and BCC were 43.6%, 67.9% and 59.8%, respectively. In morphologically normal skin, however, only 2 cases, 1 of SCC and 1 of BCC, exhibited positive staining. These findings suggested that overexpression of cyclin D1 is an early event in dysplastic lesions of skin. Overexpression of cyclin D1 was related to sun exposure, especially in dysplasia of SCC. The score for cyclin D1 expression in dysplasia of BCC was correlated with age. Expression of cyclin D1 markedly increased from normal skin through dysplasia to BOD, but was not significantly related to the degree of SCC differentiation. These findings demonstrate that the effect of cyclin D1 overexpression is restricted to proliferation of cells, so that they gain a growth advantage, but their differentiation is not increased. Comparison with the results for p53 protein expression in these tumors, a significant correlation with cyclin D1 expression was found in dysplasia in BOD and SCC, and in patients with BCC who were less than 74 years old. These findings suggested the hypothesis that prior aberrant p53 expression may affect or regulate the overexpression of cyclin D1.

Co-overexpression of p53 protein and epidermal growth factor receptor in human papillary thyroid carcinomas correlated with lymph node metastasis, tumor size and clinicopathologic stage

Expressions of p53 protein and epidermal growth factor receptor (EGFR) were immunohistochemically investigated in 111 patients with papillary thyroid carcinomas (PTC) in order to evaluate their co-expression in relation to lymph node metastases (LNM), tumor size and clinicopathologic stage. In PTC, positive staining for p53 in dewaxed sections was present in nuclei or cytoplasm, or in both, whereas surface linear or cytoplasmic staining for EGFR was observed with varying degrees of extent and intensity. Positive reaction (more than 10% of tumor cells positive) was observed in 65 cases (58. 5%) for p53, and in 87 cases (78.4%) for EGFR. A significant correlation was found between p53 protein and EGFR overexpressions (p<0.01). Notably, p53-positive cases always exhibited positive staining for EGFR. Forty-four patients (39.6%) exhibited concomitant LNM, most of whom had both p53 and EGFR expression in primary foci. Statistical analysis revealed that co-expression of p53 protein and EGFR was significantly correlated with LNM, tumor size and clinicopathologic stage, but no correlation was found between their co-expression and age or sex. Our findings suggest that overexpression of p53 protein or EGFR in PTC tends to be associated with a high frequency of LNM, increased tumor size and advanced clinicopathologic stage, and that co-expression of both p53 protein and EGFR may predispose to growth and progression of PTC. Our findings also suggest that p53 protein and EGFR expressions may be clinicopathologic and prognostic indicators of PTC.

Overexpression of c-Met protein in human thyroid tumors correlated with lymph node metastasis and clinicopathologic stage

To examine the expression of c-Met protein in thyroid tumors and the correlation of c-MET protein expression with lymph node metastasis (LNM) and pathological stage, 111 papillary thyroid carcinomas (PTC), including 44 with synchronous LNM, and 117 follicular adenomas (FA) were immunohistochemically examined using dewaxed sections of formalin-fixed, paraffin-embedded tissues. Immunohistochemical results were confirmed by Western blot analysis. For PTC, positive immunostaining was observed in 107 of 111 (96.4%) cases and was diffusely present in either cytoplasm and nucleus, or only cytoplasm or only nucleus of cancer cells at varying intensities. Staining tended to be stronger in the periphery of cancer cell nests. Positive reaction was also found in 44 of 117 (37.6%) cases of FA. However, the extent and intensity of c-Met immunostaining in FA were far less than those in PTC (p < 0.0001). Forty-four PTC cases (39.6%) exhibited LNM, and the extent and intensity of c-Met expression were significantly correlated with both LNM (p < 0.0001) and pathological stage (p < 0.0001). No significant correlation of c-Met expression with age, sex or tumor size was found. Our findings suggest that PTC expresses c-Met protein much more strongly and intensively than does FA, and that strong and intense overexpression of c-Met protein may be an indicator of the presence of lymph node metastasis and advanced pathological stage of papillary thyroid carcinoma.

Sun-exposure- and aging-dependent p53 protein accumulation results in growth advantage for tumour cells in carcinogenesis of nonmelanocytic skin cancer

Three hundred and sixteen patients with nonmelanocytic skin cancer, including 46 cases of Bowen's disease (BOD), 134 cases of squamous cell carcinoma (SCC), and 136 cases of basal cell carcinoma (BCC), were examined immunohistochemically using monoclonal antibody DO-7 to assess p53 protein accumulation related to sun exposure and ageing, and growth and differentiation of skin cancer and its precursors. The rates of p53 immunostaining of BOD, SCC and BCC were 80.4%, 76.1% and 70.6%, respectively. p53-positive cells were present not only in cancer nests, but also in dysplastic and even morphologically normal epidermis adjoining cancers. Sun exposure was statistically correlated with the p53 immunostaining scores in morphologically normal epidermis of the three skin cancers and in cancer nests of SCC and BCC. The positivity and score of p53 protein often differed significantly among the three types of cancer, especially in regions of dysplasia. Interestingly, differentiation of SCC was correlated with individual p53 scores for dysplasia and cancer nests, especially for dysplasia. BOD, as the precursor of SCC, demonstrated the strongest p53 expression. Furthermore, 12.3% cases with p53 negative cancer nests showed p53-positive reaction in dysplasia and in morphologically normal epidermis. It seems that the accumulation of p53 protein plays a part in precancerous lesions and in the genesis of more highly differentiated types of skin cancer and affects mainly the growth of tumour cells rather than their differentiation. For BCC, however, age was significantly related to p53 expression. Our findings suggest that overexpression of p53 in normal skin and cancer nests of SCC and BCC is significantly related to sun exposure, that the expression of p53 in BCC is an age-dependent process, and that the early accumulation of p53 protein may be a useful predictor for the detection of nonmelanocytic skin cancer.

Human mismatch repair gene (hMSH2) product expression in relation to recurrence of transitional cell carcinoma of the urinary bladder

BACKGROUND

Several convincing studies have shown that the hMSH2 gene plays major roles in mismatch repair by recognizing mismatched bases and preventing mutations during DNA replication. Loss of this function may result in the accumulation of DNA replication errors or even the mutator phenotype (which may be responsible for the multiple mutations required for multistep carcinogenesis), and it has been found to affect the prognosis of patients. Thus, the authors felt that it would be of interest to study the expression patterns of hMSH2 protein in malignant tumors and to assess the correlation of hMSH2 protein to various clinical and pathologic features in these patients.

METHODS

The authors examined the expression patterns of hMSH2 protein in 115 patients with transitional cell carcinoma (TCC) of the urinary bladder by immunohistochemical technique using monoclonal antibody to hMSH2 protein.

RESULTS

The group in which hMSH2 was preserved (>20% of nuclei were positive for staining by anti-hMSH2 antibody) included 86 of 115 (75%) of the TCCs, whereas the remaining 29 cases (25%) belonged to the group in which hMSH2 was preserved (< or = 20% of tumor nuclei were positive), including 2 negative cases. Univariate analysis indicated that reduced expression of hMSH2 protein was significantly more frequent in high grade tumors than in low grade tumors (P = 0.04). Furthermore, statistical multivariate analysis revealed that hMSH2 reduction was significantly related to the recurrence (P = 0.02).

CONCLUSIONS

These results suggest that abnormal expression of hMSH2 protein might be involved in tumorigenic processes and in the progression of some TCCs, and that the loss of hMSH2 protein expression might be a useful predictor of recurrence of TCC.

Human mismatch repair gene (hMSH2) product expression in relation to recurrence of transitional cell carcinoma of the urinary bladder

BACKGROUND

Several convincing studies have shown that the hMSH2 gene plays major roles in mismatch repair by recognizing mismatched bases and preventing mutations during DNA replication. Loss of this function may result in the accumulation of DNA replication errors or even the mutator phenotype (which may be responsible for the multiple mutations required for multistep carcinogenesis), and it has been found to affect the prognosis of patients. Thus, the authors felt that it would be of interest to study the expression patterns of hMSH2 protein in malignant tumors and to assess the correlation of hMSH2 protein to various clinical and pathologic features in these patients.

METHODS

The authors examined the expression patterns of hMSH2 protein in 115 patients with transitional cell carcinoma (TCC) of the urinary bladder by immunohistochemical technique using monoclonal antibody to hMSH2 protein.

RESULTS

The group in which hMSH2 was preserved (>20% of nuclei were positive for staining by anti-hMSH2 antibody) included 86 of 115 (75%) of the TCCs, whereas the remaining 29 cases (25%) belonged to the group in which hMSH2 was preserved (< or = 20% of tumor nuclei were positive), including 2 negative cases. Univariate analysis indicated that reduced expression of hMSH2 protein was significantly more frequent in high grade tumors than in low grade tumors (P = 0.04). Furthermore, statistical multivariate analysis revealed that hMSH2 reduction was significantly related to the recurrence (P = 0.02).

CONCLUSIONS

These results suggest that abnormal expression of hMSH2 protein might be involved in tumorigenic processes and in the progression of some TCCs, and that the loss of hMSH2 protein expression might be a useful predictor of recurrence of TCC.

Osteoclast-like giant cell tumor of the pancreas with metastases to gallbladder and lymph nodes. A case report

Osteoclast-like giant cell tumor of the pancreas (OGTP) is a rare neoplasm, of which the histogenesis is still controversial. Here we report a case of OGTP involving the head of the pancreas in a 71-year-old woman with metastases to the gallbladder and lymph nodes. The primary and metastatic tumors had identical histopathological, immunohistochemical, ultrastructural and molecular biological features. Microscopically, the tumors were characterized by atypical, often pleomorphic mononuclear cells associated with the proliferation of benign-appearing osteoclast-like giant cells (OGCs). Electron microscopic observation provided ultrastructural evidence of epithelial differentiation of the mononuclear cells, including microvilli and desmosomes, which was not obtained for OGCs. On immunohistochemical study, OGCs stained for CD68 (KP-1), LCA and HAM56, whereas mononuclear cells only reacted with PCNA. These findings clearly suggest that mononuclear cells are capable of differentiation and proliferation and may have been the only true tumor cells in this neoplasm, and that OGCs may have been a paraneoplastic product of this rare tumor. On examination of DNA from dewaxed sections of the tumor, we found no p53 mutation in the tumor tissue, but found two K-ras mutations in codon 12; this pattern of mutation commonly occurs in pancreatic carcinoma, indicating a somewhat genetic relationship of OGTP to pancreatic carcinoma. Although OGTP often has a favorable prognosis, the outcome in the present case was poor due to early tumor spread, with less than two years postoperative survival.

Multilocular thymic cysts associated with thymoma. A case report

The association of multilocular thymic cysts (MTC) with thymoma is exceedingly rare, and the pathogenesis of this combination is controversial. We describe the case of a 42-year-old man with an anterior mediastinal mass found to contain MTC and thymoma. A multilocular cystic mass, measuring 13 x 6.5 x 2 cm, was found in the right lobe of the thymus, and contained a 4.7 x 2 cm thymoma in its center. Microscopic thymomas, lipomatously involuted remaining thymic tissue, and lymphoid follicles with germinal centers were found in the walls of MTC as well as in the left thymic lobe. Non-specific chronic inflammation was also present in the walls. In addition, microcysts, which were only found at the periphery of the thymoma and covered with epithelium, might have been formed secondarily by dilatation of the perivascular spaces and of Hassall's corpuscles. These findings suggest that a chronic inflammatory process was responsible for the early formation and enlargement of this patient's MTC, and that while the cavities of the MTC expanded to various degrees, the thymoma, which originated from one of the microscopic thymomas in the walls of MTC, increased in size, and grew to involve the remaining thymic tissue.

[The relationship between thymus involution and diseases in childhood]

70 thymuses obtained at autopsy from children who died of various diseases were studied with histological, immunohistochemical and ultrastructural methods. In the immunohistochemical study, antibodies against 8 lymphocyte differentiation antigens, including CD4, CD8, CD3, CD1, CD2, CD25, CD22 and T9 as well as those against keration and S-100 protein were used. The findings suggest that thymus involution can occur in different diseases. The differentiation process of thymocytes and the distribution of different sub-populations of T cells in the thymus are not changed by thymus involution. Among the major changes of thymus involution, the decrease in number of dendritic cells and the degeneration of epithelial cells are more important than the decrease in the number of thymocytes. Phagocytosis of macrophages seems to be the secondary way to dispose of the degenerated and dead thymocytes.