Tissue-print and print-phoresis as platform technologies for the molecular analysis of human surgical specimens: mapping tumor invasion of the prostate capsule

Impact of molecular surgical margin analysis on the prediction of pancreatic cancer recurrences after pancreaticoduodenectomy

BACKGROUND

Pancreatic cancer is one of the lethal cancers among solid malignancies. Pathological diagnosis of surgical margins is sometimes unreliable due to tissue shrinkage, invisible field cancerization and skipped lesions like tumor budding. As a result, tumor recurrences sometimes occur even from the pathologically negative surgical margins.

METHODS

We applied molecular surgical margin (MSM) analysis by tissue imprinting procedure to improve the detection sensitivity of tiny cancerous cells on the surgical specimen surface after pancreatoduodenectomy. Surgical specimens were collected from 45 pancreatic cancer cases who received subtotal stomach preserving pancreatoduodenectomy at Nagoya University Hospital during 2017-2019. Quantitative methylation-specific PCR (QMSP) of the original methylation marker panel (CD1D, KCNK12, PAX5) were performed and analyzed with postoperative survival outcomes.

RESULTS

Among 45 tumors, 26 cases (58%) were QMSP-positive for CD1D, 25 (56%) for KCNK12 and 27 (60%) for PAX5. Among the 38 tumors in which at least one of the three markers was positive, CD1D-positive cancer cells, KCNK12-positive cancer cells, and PAX5-positive cancer cells were detected at the surgical margin in 8 cases, 7 cases and 10 cases, respectively. Consequently, a total of 17 patients had at least one marker detected at the surgical margin by QMSP, and these patients were defined as MSM-positive. They were associated with significantly poor recurrence-free survival (p = 0.002) and overall survival (p = 0.005) than MSM-negative patients. Multivariable analysis showed that MSM-positive was the only significant independent factor for worse recurrence-free survival (hazard ratio: 3.522, 95% confidence interval: 1.352-9.179, p = 0.010). On the other hand, a significant proportion of MSM-negative cases were found to have received neoadjuvant chemotherapy (p = 0.019).

CONCLUSION

Pancreatic cancer-specific methylation marker panel was established to perform MSM analysis. MSM-positive status might represent microscopically undetectable cancer cells on the surgical margin and might influence the postoperative long-term outcomes.

Nitrocellulose tissue prints: an innovative approach to preparing high quality DNA and RNA from prostate biopsies without compromising the cores for pathology diagnosis

Much of the research that has been done on prostate cancer tissue biomarkers has relied on radical prostatectomies for biospecimens. However, it is well recognized that important groups of patients are under-represented or missing entirely from biorepository collections of radical prostatectomy specimens. Using prostate biopsy tissues for molecular biomarker research significantly expands the range of available patients to include men whose biopsies show no cancer as well as men who are treated non-surgically or who choose active surveillance. However, one of the challenges of biopsy-based biomarker research is the limited amount of tissue that can be obtained from each core. To address this challenge, we have developed and fully implemented innovative biopsy tissue print technologies that allow us to obtain high quality RNA and DNA from each biopsy core without compromising the specimen for a pathologic diagnosis. Prostate biopsy tissue print samples have been successfully utilized for gene expression profiling, genotyping, DNA methylation and sequencing analyses. Emerging biopsy tissue print applications include studies using viable cells to study tumor metabolism and drug response.

Depression promotes prostate cancer invasion and metastasis via a sympathetic-cAMP-FAK signaling pathway

Depression drives cancer progression and induces poor clinical outcome. However, the mechanisms underlying depression and cancer outcomes are unclear. In this work, we investigated 98 prostate cancer patients and found that patients with high score of psychological depression were correlated with tumor invasion and metastasis. We found focal adhesion kinase (FAK) was increased in cancer patients with metastatic features and high score of depression. FAK knockdown completely blocked depression-promoted tumor invasion in orthotopic transplantation tumors. In Hi-myc mice and a murine model of depression, sympathetic activation was detected in the prostate tissue. Further we showed that FAK activation was dependent on a cAMP-PKA signaling pathway. Our results demonstrated that the activation of a sympathetic-FAK signaling pathway in prostate cancer patients with high degrees of depression facilitates tumor invasion. We suggest that blocking β2AR with propranolol or inhibiting FAK activation with PF562 271 may be novel strategies for depressed patients with invasive prostate cancer.

Epigenetic risk score improves prostate cancer risk assessment

BACKGROUND

Early detection of aggressive prostate cancer (PCa) remains crucial for effective treatment of patients. However, PCa screening remains controversial due to a high rate of overdiagnosis and overtreatment. To better reconcile both objectives, more effective methods for assessing disease severity at the time of diagnosis are needed.

METHODS

The relationship between DNA-methylation and high-grade PCa was examined in a cohort of 102 prospectively enrolled men who received standard 12-core prostate biopsies. EpiScore, an algorithm that quantifies the relative DNA methylation intensities of GSTP1, RASSF1, and APC in prostate biopsy tissue, was evaluated as a method to compensate for biopsy under-sampling and improve risk stratification at the time of diagnosis.

RESULTS

DNA-methylation intensities of GSTP1, RASSF1, and APC were higher in biopsy cores from men diagnosed with GS ≥ 7 cancer compared to men with diagnosed GS 6 disease. This was confirmed by EpiScore, which was significantly higher for subjects with high-grade biopsies and higher NCCN risk categories (both P < 0.001). In patients diagnosed with GS ≥ 7, increased levels of DNA-methylation were present, not only in the high-grade biopsy cores, but also in other cores with no or low-grade disease (P < 0.001). By combining EpiScore with traditional clinical risk factors into a logistic regression model, the prediction of high GS reached an AUC of 0.82 (95%CI: 0.73-0.91) with EpiScore, DRE, and atypical histological findings as most important contributors.

CONCLUSIONS

In men diagnosed with PCa, DNA-methylation profiling can detect under-sampled high-risk PCa in prostate biopsy specimens through a field effect. Predictive accuracy increased when EpiScore was combined with other clinical risk factors. These results suggest that EpiScore could aid in the detection of occult high-grade disease at the time of diagnosis, thereby improving the selection of candidates for Active Surveillance.

Factors Affecting the Use of Human Tissues in Biomedical Research: Implications in the Design and Operation of a Biorepository

The availability of high-quality human tissues is necessary to advance medical research. Although there are inherent and induced limitations on the use of human tissues in research, biorepositories play critical roles in minimizing the effects of such limitations. Specifically, the optimal utilization of tissues in research requires tissues to be diagnosed accurately, and the actual specimens provided to investigators must be carefully described (i.e., there must be quality control of each aliquot of the tissue provided for research, including a description of any damage to tissues). Tissues also should be collected, processed, stored, and distributed (i.e., handled) uniformly under a rigorous quality management system (QMS). Frequently, tissues are distributed to investigators by tissue banks which have collected, processed, and stored them by standard operating procedures (SOPs). Alternatively, tissues for research may be handled via SOPs that are modified to the specific requirements of investigators (i.e., using a prospective biorepository model). The primary goal of any type of biorepository should be to ensure its specimens are of high quality and are utilized appropriately in research; however, approaches may vary based on the tissues available and requested. For example, extraction of specific molecules (e.g., microRNA) to study molecular characteristics of a tissue may require less clinical annotation than tissues that are utilized to identify how the molecular expression might be used to clarify a clinical outcome of a disease or the response to a specific therapy. This review focuses on the limitations of the use of tissues in research and how the design and operations of a tissue biorepository can minimize some of these limitations.

Paired box 5 methylation detection by droplet digital PCR for ultra-sensitive deep surgical margins analysis of head and neck squamous cell carcinoma

Molecular deep surgical margin analysis has been shown to predict locoregional recurrences of head and neck squamous cell carcinoma (HNSCC). To improve the accuracy and versatility of the analysis, we used a highly tumor-specific methylation marker and highly sensitive detection technology to test DNA from surgical margins. Histologically cancer-negative deep surgical margin samples were prospectively collected from 82 eligible HNSCC surgeries by an imprinting procedure (n = 75) and primary tissue collection (n = 70). Bisulfite-treated DNA from each sample was analyzed by both conventional quantitative methylation-specific PCR (QMSP) and QMSP by droplet digital PCR (ddQMSP) targeting Paired box 5 (PAX5) gene promoter methylation. The association between the presence of PAX5 methylation and locoregional recurrence-free survival (LRFS) was evaluated. PAX5 methylation was found in 68.0% (51 of 75) of tumors in the imprint samples and 71.4% (50 of 70) in the primary tissue samples. Among cases that did not have postoperative radiation (n = 31 in imprint samples, n = 29 in tissue samples), both conventional QMSP and ddQMSP revealed that PAX5 methylation-positive margins was significantly associated with poor LRFS by univariate analysis. In particular, ddQMSP increased detection of the PAX5 marker from 29% to 71% in the nonradiated imprint cases. Also, PAX5 methylated imprint margins were an excellent predictor of poor LRFS [HR, 3.89; 95% confidence interval (CI), 1.19-17.52; P = 0.023] by multivariate analysis. PAX5 methylation appears to be an excellent tumor-specific marker for molecular deep surgical margin analysis of HNSCC. Moreover, the ddQMSP assay displays increased sensitivity for methylation marker detection.

Correlation of gene methylation in surgical margin imprints with locoregional recurrence in head and neck squamous cell carcinoma

BACKGROUND

Securing negative surgical margins is a critical goal for head and neck surgery. Local recurrence develops even in some patients who have histologically negative surgical margins. Minimal residual tumor cells may lead to locoregional recurrence despite clear histologic margins reported at the time of resection of head and neck squamous cell carcinoma (HNSCC). To identify subclinical residual disease, the authors analyzed deep margin imprint samples collected on 1-layer nitrocellulose sheets.

METHODS

Bisulfite-treated DNA samples from 73 eligible patients were amplified by quantitative methylation-specific polymerase chain reaction (QMSP) targeting 6 genes (deleted in colorectal cancer [DCC], endothelin receptor type B [EDNRB], homeobox protein A9 [HOXA9], kinesin family member 1A [KIF1A], nidogen-2 [NID2], and N-methyl D-aspartate receptor subtype 2B [NR2B]). QMSP values were dichotomized as positive or negative. Associations between the QMSP status of deep margin samples and clinical outcomes were evaluated.

RESULTS

Two-gene methylation combinations among the genes DCC, EDNRB, and HOXA9 were associated with decreased locoregional recurrence-free survival, recurrence-free survival, and overall survival. The methylated gene combination of EDNRB and HOXA9 in margin imprints was the most powerful predictor of poor locoregional recurrence-free survival (hazard ratio [HR], 3.31; 95% confidence interval [CI], 1.30-8.46; P = .012) independent of standard histologic factors. In addition, methylation of both EDNRB and HOXA9 indicated a trend toward reduced recurrence-free survival (HR, 2.74; 95% CI, 0.90-8.33; P = .075) and reduced OS (HR, 5.78; 95% CI, 0.75-44.7; P = .093) in multivariable analysis.

CONCLUSIONS

A panel of gene methylation targets in deep surgical margin imprints provides a potential predictive marker of postoperative locoregional recurrence. Intraoperative use of molecular margin imprint analysis may assist surgeons in obtaining rigorously negative surgical margins and improve the outcome of head and neck surgery.

Use of human specimens in research: the evolving United States regulatory, policy, and scientific landscape

The use of human specimens in research has contributed to significant scientific and medical advancements. However, the development of sophisticated whole genome and informatics technologies and the increase in specimen and data sharing have raised new questions about the identifiability of specimens and the protection of participants in human specimen research. In the US, new regulations and policies are being considered to address these changes. This review discusses the current and proposed regulations as they apply to specimen research, as well as relevant policy discussions. It summarizes the ways that researchers and other stakeholders can provide their input to these discussions and policy development efforts. Input from all the stakeholders in specimen research will be essential for the development of policies that facilitate such research while at the same time protecting the rights and welfare of research participants.

Issues in collecting, processing and storing human tissues and associated information to support biomedical research

The availability of human tissues to support biomedical research is critical to advance translational research focused on identifying and characterizing approaches to individualized (personalized) medical care. Providing such tissues relies on three acceptable models - a tissue banking model, a prospective collection model and a combination of these two models. An unacceptable model is the "catch as catch can" model in which tissues are collected, processed and stored without goals or a plan or without standard operating procedures, i.e., portions of tissues are collected as available and processed and stored when time permits. In the tissue banking model, aliquots of tissues are collected according to SOPs. Usually specific sizes and types of tissues are collected and processed (e.g., 0.1 gm of breast cancer frozen in OCT). Using the banking model, tissues may be collected that may not be used and/or do not meet specific needs of investigators; however, at the time of an investigator request, tissues are readily available as is clinical information including clinical outcomes. In the model of prospective collection, tissues are collected based upon investigator requests including specific requirements of investigators. For example, the investigator may request that two 0.15 gm matching aliquots of breast cancer be minced while fresh, put in RPMI media with and without fetal calf serum, cooled to 4°C and shipped to the investigator on wet ice. Thus, the tissues collected prospectively meet investigator needs, all collected specimens are utilized and storage of specimens is minimized; however, investigators must wait until specimens are collected, and if needed, for clinical outcome. The operation of any tissue repository requires well trained and dedicated personnel. A quality assurance program is required which provides quality control information on the diagnosis of a specimen that is matched specifically to the specimen provided to an investigator instead of an overall diagnosis of the specimen via a surgical pathology report. This is necessary because a specific specimen may not match the diagnosis of the case due to many factors such as necrosis, unsuspected tumor invasion of apparently normal tissue, and areas of fibrosis which are mistaken grossly for tumor. Aliquots for quality control (QC) may or may not be collected at the time of collection and in some cases, QC may not occur until specimens are distributed to investigators. In establishing a tumor repository, multiple issues need to be considered. These include the available resources, long term support, space and equipment. The needs of the potential users need to be identified as to the types of tissues and services needed and the annotation expected. Other specific issues to be considered include collection of specimens potentially infected with blood borne pathogens (e.g., hepatitis B), charge back mechanisms, informatics needs and support, and investigator requirements (e.g., recognition of repository contributions in publications). In general, the repository should not perform the research of the investigators, but should provide the infrastructure necessary to support the research of the investigator. Thus, the goals of the repository must be established. Similarly, ethical and regulatory issues must be evaluated. In general, tissue repositories need ethical (e.g., IRB) and privacy (e.g., HIPAA) review. Also, safety issues need to be considered as well as how biohazards will be addressed by investigator-users. Considerations involving the transfer of specimens to other organization usually require a material transfer agreement (MTA). A MTA should address biohazards as well as indemnification. Thus, many issues must be considered and addressed in order to establish and operate successfully a biorepository.

Tissue imprint for molecular mapping of deep surgical margins in patients with head and neck squamous cell carcinoma

BACKGROUND

Tissue imprinting can generate molecular marker maps of tumor cells at deep surgical margins. The purpose of this study was to evaluate the feasibility of this method for detection of residual head and neck squamous cell carcinoma (HNSCC).

METHODS

Paired fresh tissue and nitrocellulose membrane imprints of tumor and deep margins were collected from 17 HNSCC resections. DNA was amplified using quantitative methylation-specific polymerase chain reaction (qMSP) for p16, DCC, KIF1A, and EDNRB. Levels of methylation in tumors and deep margins were compared.

RESULTS

DNA from imprints was adequate for qMSP. Hypermethylation of target genes was present in 12 of 17 tumors and in 8 deep margins. Methylation level was better from margin imprints than tissue. During follow-up (median, 13 months), local or regional recurrences occurred in 6 cases of which 5 had molecularly positive margins.

CONCLUSION

Tissue imprinting is feasible for molecular detection of residual tumor at deep surgical margins and may correlate with locoregional recurrence.

Pathology in prostate research: optimizing tissue quality

The collection of tissue from the prostate gland for research creates unique challenges in the identification of cancer and in preserving pathological material.

VALUE AND USES OF FORMALIN FIXED TISSUE

Formalin fixed paraffin embedded (FFPE) tissue is often available in abundance after pathological processing and reporting of specimens but is limited in value for detailed molecular tests. Tissue micro-array if carefully performed is a helpful technique for examining many FFPE specimens with immunohistochemical or fluorescence in situ hybridization tests.

VALUE AND USES OF FROZEN TISSUE

The collection of fresh tissue prior to formalin fixation and later validation samples of fresh prostate cancer is difficult as prostate cancer is very difficult to identify macroscopically on cut prostate specimens. Also, the act of manipulation and dissection of the gland while fresh and without compromising surgical margins is challenging. Methods which have been used to dissect the fresh prostate gland and also collect fresh tissue from other prostatic specimens are discussed. The ethical challenges of collecting research tissue without compromising patient care are discussed.

CONCLUSIONS

Prostate cancer tissue banks, particularly of frozen tissue are still relatively few in number. Enhanced collection methods which do not prohibit full pathological examination are available but require expertise to maximize their potential.

Tissue print of prostate biopsy: a novel tool in the diagnostic procedure of prostate cancer

Background

Nowadays, the histological examination of prostate core needle biopsies is still regarded as the gold standard in the diagnosis of prostate cancer (PCa). We investigated if the tissue print of core needle biopsy (biopsy print) could be used as adjunctive molecular investigative procedures in conjunction with routine histological examination of biopsy to improve PCa diagnosis.

Methods

The direct contact of PCa core biopsy to nitrocellulose membrane resulted in the release of a cellular micropeel that was used for downstream analytical procedures.

Results

By zymogram print-phoresis we demonstrated that matrix metalloproteases MMP-2 and MMP-9 could be visualized in biopsy prints and that the gelatinolytic activity was positively correlated with immunohistochemistry analysis of the same markers in matched bioptic specimens. Moreover, we compared the ability to detect the PCa-associated hypermethylation of GSTP1 promoter in DNA extracted from biopsy prints with those of the corresponding core needle biopsies. Biopsy prints demonstrated the same specificity of biopsies in detecting PCa (50%) while the sensitivity and the positive predictive value were lower than biopsies (56% vs 78% and 63% vs 70%, respectively).

Conclusions

Biopsy print, combining a molecular point of view to the routinely hystopathological analysis of prostate biopsies, should be a useful tool to improve the diagnosis of PCa.

CCL5 secreted by senescent aged fibroblasts induces proliferation of prostate epithelial cells and expression of genes that modulate angiogenesis

There is increased interest in the effects of secretory products from aged cells on promoting both benign and malignant cell growth. We identified a human fibroblast line, AG04382, from an aged donor that naturally demonstrated senescence-associated features and whose conditioned media significantly induced proliferation of benign prostatic hyperplasia (BPH1) cells. Candidate cytokines mediating this effect were identified with protein arrays and validated by ELISA. We found that the AG04382 fibroblast line secreted high levels of CXCL5, CCL5, and CCL2, but relative to the other lines, its conditioned media was unique in its increased expression of CCL5. Blocking studies using specific antibodies against CXCL5, CCL5, and CCL2 in the conditioned media of AG04382 showed that only CCL5 contributed significantly to BPH1 proliferation. Stimulation of BPH1 cells with rhuCCL5 resulted in increased proliferation and migration, as well as significant changes in the expression of genes that influence angiogenesis. These data suggest that CCL5 is a candidate chemokine secreted by aged cells that promotes prostate growth and regulates angiogenesis.

Prediction of prostate cancer recurrence using magnetic resonance imaging and molecular profiles

PURPOSE

To evaluate whether pretreatment magnetic resonance imaging (MRI)/MR spectroscopic imaging (MRSI) findings and molecular markers in surgical specimens correlate with each other and with pretreatment clinical variables (biopsy Gleason score, clinical stage, and prostate-specific antigen level) and whether they contribute incremental value in predicting prostate cancer recurrence.

EXPERIMENTAL DESIGN

Eighty-eight prostate cancer patients underwent MRI/MRSI before radical prostatectomy; imaging findings were scored on a scale of 1 to 7 (no tumor seen-lymph node metastasis). Ki-67, phospho-Akt, and androgen receptor expression in surgical specimens were assessed by immunohistochemistry. To examine correlations between markers and imaging scores, Spearman's correlation was used. To test whether markers and imaging scores differed by clinical stage or Gleason score, Wilcoxon's rank sum test was used. To examine time to recurrence, the methods of Kaplan-Meier were used. Cox proportional hazards models were built and their concordance indices (C-indices) were calculated to evaluate prediction of recurrence.

RESULTS

All markers correlated moderately strongly with MRI/MRSI score (all correlation coefficients >0.5). Markers and MRI/MRSI score were strongly associated with clinical stage and biopsy Gleason score (P < 0.01 for all). At last follow-up, 27 patients had recurrence. C-indices for MRI/MRSI score and all markers were associated with time to recurrence and ranged from 0.78 to 0.89. A Cox model combining all clinical predictors had a C-index of 0.89; the C-index increased to 0.95 when MRI/MRSI score was added and to 0.97 when markers were also added.

CONCLUSIONS

MRI/MRSI findings and molecular markers correlated well with each other and contributed incremental value to clinical variables in predicting prostate cancer recurrence.

An illustration of the potential for mapping MRI/MRS parameters with genetic over-expression profiles in human prostate cancer

INTRODUCTION

Magnetic resonance imaging (MRI) and MR spectroscopy can probe a variety of physiological (e.g. blood vessel permeability) and metabolic characteristics of prostate cancer. However, little is known about the changes in gene expression that underlie the spectral and imaging features observed in prostate cancer. Tumor induced changes in vascular permeability and angiogenesis are thought to contribute to patterns of dynamic contrast enhanced (DCE) MRI images of prostate cancer even though the genetic basis of tumor vasculogenesis is complex and the specific mechanisms underlying these DCEMRI features have not yet been determined.

MATERIALS AND METHODS

In order to identify the changes in gene expression that correspond to MRS and DCEMRI patterns in human prostate cancers, we have utilized tissue print micropeel techniques to generate "whole mount" molecular maps of radical prostatectomy specimens that correspond to pre-surgical MRI/MRS studies. These molecular maps include RNA expression profiles from both Affymetrix GeneChip microarrays and quantitative reverse transcriptase PCR (qrt-PCR) analysis, as well as immunohistochemical studies.

RESULTS

Using these methods on patients with prostate cancer, we found robust over-expression of choline kinase a in the majority of primary tumors. We also observed overexpression of neuropeptide Y (NPY), a newly identified angiogenic factor, in a subset of prostate cancers, visualized on DCEMRI.

CONCLUSION

These studies set the stage for establishing MRI/MRS parameters as validated biomarkers for human prostate cancer.

Biorepository standards and protocols for collecting, processing, and storing human tissues

Recent advances in high-throughput assays for gene expression (genomics), proteins (proteomics), and metabolites (metabolomics) have engendered a parallel need for well-annotated human biological samples. Samples from both diseased and unaffected normal tissues are often required. Biorepositories consist of a specimen bank linked to a database of information. Assuring chain of custody and annotation of samples with relevant clinical information is required. The value of samples to end users is generally commensurate with the quality and extent of relevant clinical data included with the samples. Procurement of tissues is often done with parallel pre- and/or post-treatment venipuncture to obtain blood and tissue samples from the same subject. Biorepositories must also process, preserve, and distribute samples to end users. Like traditional libraries, biorepositories are meant to be used, and they are most useful when the needs of end users (researchers) are considered in the planning and development process. Ethics review and an awareness of regulatory requirements for storage, transport, and distribution are required. In the USA, Institutional Review Boards are the local regulatory entities that review protocols for banking of human biological tissues. Governmental and professional agencies and organizations provide some guidelines for standard operating procedures. The Food and Drug Administration (FDA), the Centers For Disease Control (CDC), and professional organizations such as the American Association of Tissue Banks (AATB), the American Association of Blood Banks, The International Red Cross, International Society for Biological Repositories (ISBER) and other organizations provide guidelines for biorepositories and banking of human tissues (see Table 1). To date, these guidelines are directed largely toward procurement, banking, and distribution of human tissues for therapeutic uses. In the international setting, the World Health Organization provides ethical guidelines for procurement and operating procedures. The most commonly available tissues are formalin-fixed paraffin-embedded tissues (FFPET). While FFPET can be used for immunohistochemistry, certain DNA-based assays, and even RNA, frozen tissues are best suited for isolation and characterization of proteins and RNA. Freezers, back-up systems, monitors, and alarm systems and appropriate physical security are needed for long-term storage of frozen tissues. Other storage formats such as blotting onto filter paper for storage at room temperature are more commonly used for blood and can provide important "fingerprinting" for chain of custody, linking a given subject to a tissue sample.

Prostate Postbrachytherapy Seed Distribution: Comparison of High-Resolution, Contrast-Enhanced, T1- and T2-Weighted Endorectal Magnetic Resonance Imaging Versus Computed Tomography: Initial Experience

PURPOSE

To compare contrast-enhanced, T1-weighted, three-dimensional magnetic resonance imaging (CEMR) and T2-weighted magnetic resonance imaging (T2MR) with computed tomography (CT) for prostate brachytherapy seed location for dosimetric calculations.

METHODS AND MATERIALS

Postbrachytherapy prostate MRI was performed on a 1.5 Tesla unit with combined surface and endorectal coils in 13 patients. Both CEMR and T2MR used a section thickness of 3 mm. Spiral CT used a section thickness of 5 mm with a pitch factor of 1.5. All images were obtained in the transverse plane. Two readers using CT and MR imaging assessed brachytherapy seed distribution independently. The dependency of data read by both readers for a specific subject was assessed with a linear mixed effects model.

RESULTS

The mean percentage (+/- standard deviation) values of the readers for seed detection and location are presented. Of 1205 implanted seeds, CEMR, T2MR, and CT detected 91.5% +/- 4.8%, 78.5% +/- 8.5%, and 96.1% +/- 2.3%, respectively, with 11.8% +/- 4.5%, 8.5% +/- 3.5%, 1.9% +/- 1.0% extracapsular, respectively. Assignment to periprostatic structures was not possible with CT. Periprostatic seed assignments for CEMR and T2MR, respectively, were as follows: neurovascular bundle, 3.5% +/- 1.6% and 2.1% +/- 0.9%; seminal vesicles, 0.9% +/- 1.8% and 0.3% +/- 0.7%; periurethral, 7.1% +/- 3.3% and 5.8% +/- 2.9%; penile bulb, 0.6% +/- 0.8% and 0.3% +/- 0.6%; Denonvillier's Fascia/rectal wall, 0.5% +/- 0.6% and 0%; and urinary bladder, 0.1% +/- 0.3% and 0%. Data dependency analysis showed statistical significance for the type of imaging but not for reader identification.

CONCLUSION

Both enumeration and localization of implanted seeds are readily accomplished with CEMR. Calculations with MRI dosimetry do not require CT data. Dose determinations to specific extracapsular sites can be obtained with MRI but not with CT.

DNA degradation test predicts success in whole-genome amplification from diverse clinical samples

The need to apply modern technologies to analyze DNA from diverse clinical samples often stumbles on suboptimal sample quality. We developed a simple approach to assess DNA fragmentation in minute clinical samples of widely different origin and the likelihood of success of degradation-tolerant whole genome amplification (restriction and circularization-aided rolling circle amplification, RCA-RCA) and subsequent polymerase chain reaction (PCR). A multiplex PCR amplification of four glyceraldehyde-3-phosphate dehydrogenase amplicons of varying sizes was performed using genomic DNA from clinical samples, followed by size discrimination on agarose gel or fluorescent denaturing high-performance liquid chromatography (dHPLC). RCA-RCA followed by real-time PCR was also performed, for correlation. Even minimal quantities of longer PCR fragments ( approximately 300 to 400 bp), visible via high-sensitivity fluorescent dHPLC or agarose gel, were essential for the success of RCA-RCA and subsequent PCR-based assays. dHPLC gave a more accurate correlation between DNA fragmentation and sample quality than agarose gel electrophoresis. Multiplex-PCR-dHPLC predicted correctly the likelihood of assay success in formalin-fixed, paraffin-embedded samples fixed under controlled conditions and of different ages, in laser capture microdissection samples, in tissue print micropeels, and plasma-circulating DNA. Estimates of the percent information retained relative to snap-frozen DNA are derived for real-time PCR analysis. The assay is rapid and convenient and can be used widely to characterize DNA from any clinical sample of unknown quality.

Mapping geographic zones of cancer risk with epigenetic biomarkers in normal breast tissue

PURPOSE

Genetic alterations were previously identified in normal epithelia adjacent to invasive cancers. The aim of this study was to determine DNA methylation in histologically normal tissues from multiple geographic zones adjacent to primary breast tumors.

EXPERIMENTAL DESIGN

First, methylation status of a 4-kb region of RASSF1A promoter was interrogated using oligonucleotide-based microarray in 144 samples (primary tumors, 47; adjacent normals, 69; reduction mammoplasty tissues, 28). Second, allelic imbalance (AI)/loss of heterozygosity (LOH) surrounding RASSF1A promoter were analyzed in 30 samples (tumors, 8; adjacent normals, 22). Third, global methylation screening of 49 samples (tumors, 12; adjacent normals, 25; reduction mammoplasty, 12) was done by differential methylation hybridization. Real-time quantitative methylation-specific PCR was used to validate the microarray findings.

RESULTS

DNA methylation in the core RASSF1A promoter was low in reduction mammoplasty tissues (P=0.0001) when compared with primary tumors. The adjacent normals had an intermediate level of methylation. The regions surrounding the core were highly methylated in all sample types. Microsatellite markers showed AI/LOH in tumors and some of the adjacent normals. Concurrent AI/LOH and DNA methylation in RASSF1A promoter occurred in two of six tumors. Global methylation screening uncovered genes more methylated in adjacent normals than in reduction mammoplasty tissues. The methylation status of four genes was confirmed by quantitative methylation-specific PCR.

CONCLUSIONS

Our findings suggest a field of methylation changes extending as far as 4 cm from primary tumors. These frequent alterations may explain why normal tissues are at risk for local recurrence and are useful in disease prognostication.

Tissue print micropeel: a new technique for mapping tumor invasion in prostate cancer

Because of widely adopted screening programs for early detection of prostate cancers, many patients who undergo radical prostatectomy have tumors that are not grossly evident, and the extent and distribution of the cancer in the gland can only be determined by a microscopic examination of the surgical specimen. Historically, one of the most important predictors of the quality of cancer control following surgical resection of a solid tumor is the absence of cancer at the surgical margins. Although the clinical significance of cancer at the margins of a radical prostatectomy specimen has been a source of controversy in recent years, surgical pathology assessment of radical prostatectomy margins remains an important part of prostate cancer clinical care. However, a comprehensive histopathologic review of every radical prostatectomy specimen is beyond the resources of most hospitals. Tissue print micropeel technologies, combined with appropriate markers, provide a new strategy that combines a relatively simple technique for sampling specimen margins with a method for obtaining molecular information about the cancer that can add to the macroscopic and microscopic anatomical findings. This new tissue printing approach for incorporating molecular markers into the assessment of radical prostatectomy margins is reviewed in this article.

Meeting report on the 12th International Congress of Histochemistry and Cytochemistry (ICHC)

The International Congress of Histochemistry and Cytochemistry (ICHC) promoted in San Diego La Jolla (CA, USA), the 12th meeting where researchers of all over the world presented their work and the most innovative methods in histochemical disciplines. A summary of the last meeting is reported. © 2005 Wiley‐Liss, Inc.