Changing Trends and Practices in Cytopathology

OBJECTIVE

To explore the current and anticipated changes in the practice of cytopathology.

STUDY DESIGN

The present review is based on a review of recent literature and an evaluation of the authors' personal experiences.

RESULTS AND CONCLUSION

In recent years the practice of cytopathology, nationwide and in our institute, has witnessed a major change affecting gynecologic and nongynecologic cytology. There has been a decline in the number of Papanicolaou tests which has affected the utilization of cytotechnologists and provoked a reorganization of their work flow. The "need to do more with less" in the era of targeted therapy/personalized medicine has resulted in an increasing preference for needle core biopsy when performing a rapid on-site evaluation. We feel that this change is unavoidable. It is pertinent that cytopathologists as a group recognize this change and prepare themselves and the trainees not only to become adapt but also to use this as an opportunity to discover the yet unexplored world of cytology.

The Histochemistry and Cell Biology compendium: a review of 2012

The year 2012 was another exciting year for Histochemistry and Cell Biology. Innovations in immunohistochemical techniques and microscopy-based imaging have provided the means for advances in the field of cell biology. Over 130 manuscripts were published in the journal during 2012, representing methodological advancements, pathobiology of disease, and cell and tissue biology. This annual review of the manuscripts published in the previous year in Histochemistry and Cell Biology serves as an abbreviated reference for the readership to quickly peruse and discern trends in the field over the past year. The review has been broadly divided into multiple sections encompassing topics such as method advancements, subcellular components, extracellular matrix, and organ systems. We hope that the creation of this subdivision will serve to guide the reader to a specific topic of interest, while simultaneously providing a concise and easily accessible encapsulation of other topics in the broad area of Histochemistry and Cell Biology.

Digital cytology: current state of the art and prospects for the future

The growth of digital methods in pathology is accelerating. Digital images can be used for a variety of applications in cytology, including rapid interpretations, primary diagnosis and second opinions, continuing education and proficiency testing. All of these functions can be performed using small static digital images, real-time dynamic digital microscopy, or whole-slide images. This review will discuss the general principles of digital pathology, its methods and applications to cytologic specimens. As cytologic specimens have unique features compared to histopathology specimens, the key differences will be discussed. Technical and administrative issues in digital pathology applications and the outlook for the future of the field will be presented.

Zytologie im Internet

Computer-based learning (E-learning) is of increasing importance for the education of students and professionals. Various publicly accessible online courses for cytologists now exist and some of these are presented in this paper. For the learning platform Patho-Basiliensis (http://www.unibas.ch/patho/) we have developed several learning materials: a database of 726 cytology images, a cytopathology course to teach the basics of cytopathology, and a game testing histologic-cytologic correlation. Tests on lung and urinary cytology were attended by 383 international participants. The virtual microscopy technology will revolutionize telecytology and cytology education.

Cytomics - importance of multimodal analysis of cell function and proliferation in oncology

Cancer is a highly complex and heterogeneous disease involving a succession of genetic changes (frequently caused or accompanied by exogenous trauma), and resulting in a molecular phenotype that in turn results in a malignant specification. The development of malignancy has been described as a multistep process involving self-sufficiency in growth signals, insensitivity to antigrowth signals, evasion of apoptosis, limitless replicative potential, sustained angiogenesis, and finally tissue invasion and metastasis. The quantitative analysis of networking molecules within the cells might be applied to understand native-state tissue signalling biology, complex drug actions and dysfunctional signalling in transformed cells, that is, in cancer cells. High-content and high-throughput single-cell analysis can lead to systems biology and cytomics. The application of cytomics in cancer research and diagnostics is very broad, ranging from the better understanding of the tumour cell biology to the identification of residual tumour cells after treatment, to drug discovery. The ultimate goal is to pinpoint in detail these processes on the molecular, cellular and tissue level. A comprehensive knowledge of these will require tissue analysis, which is multiplex and functional; thus, vast amounts of data are being collected from current genomic and proteomic platforms for integration and interpretation as well as for new varieties of updated cytomics technology. This overview will briefly highlight the most important aspects of this continuously developing field.

[Cell culture, tissue engineering and regenerative medicine. Part I]

Tissue engineering is an interdisciplinary field that applies the principles and methods of engineering and the cell culture toward the development of biomaterials that restore, maintain or improve tissue function. The amalgamation of engineering and medicine has interested many scientists for at last two hundred years. What was the goal of cell culture? First, for progress in life sciences achievement and subsequent for virology and toxicology development. In vitro studies are done because of many problems with carrying out animal experiments. In this work the authors present the attempts of physicians, anatomopathologists, embryologists and biologists which contributed to fast development of new area in medicine--tissue engineering.

Cytomics, the human cytome project and systems biology: top-down resolution of the molecular biocomplexity of organisms by single cell analysis

A large amount of structural and functional information is obtained by molecular cell phenotype analysis of tissues, organs and organisms at the single cell level by image or flow cytometry in combination with bioinformatic knowledge extraction (cytomics) concerning nuclei acids, proteins and metabolites (cellular genomics, proteomics and metabolomics) as well as cell function parameters like intracellular pH, transmembrane potentials or ion gradients. In addition, differential molecular cell phenotypes between diseased and healthy cells provide molecular data patterns for (i) predictive medicine by cytomics or for (ii) drug discovery purposes using reverse engineering of the data patterns by biomedical cell systems biology. Molecular pathways can be explored in this way including the detection of suitable target molecules, without detailed a priori knowledge of specific disease mechanisms. This is useful during the analysis of complex diseases such as infections, allergies, rheumatoid diseases, diabetes or malignancies. The top-down approach reaching from single cell heterogeneity in cell systems and tissues down to the molecular level seems suitable for a human cytome project to systematically explore the molecular biocomplexity of human organisms. The analysis of already existing data from scientific studies or routine diagnostic procedures will be of immediate value in clinical medicine, for example as personalized therapy by cytomics.

Conventional Pap smear and liquid-based cytology as screening tools in low-resource settings in Latin America: experience of the Latin American screening study

OBJECTIVE

To evaluate the performance of the conventional Pap test and liquid-based cytology (LBC) in an ongoing multicenter trial testing optional screening tools (cytology, screening colposcopy, visual inspection with acetic acid, visual inspection with Lugol's Iodine, cervicography and Hybrid Capture II [HCII] (Digene Brazil, São Paulo, Brazil) conventional and self-sampling), for cervical cancer in Brazil and Argentina.

STUDY DESIGN

A cohort of 12,107 women attending four clinics (Campinas, São Paulo, Porto Alegre, Buenos Aires) were randomized into the 8 diagnostic arms. Women testing positive with any of the tests were referred for colposcopy, and cervical biopsies were used as the gold standard to assess performance characteristics of the diagnostic tests. Conventional Pap smears were sampled by all clinics (n = 10,240), and LBC (Autocyte PREP, [TriPath Imaging, Burlington, North Carolina, U.S.A.], n=320, and DNA-Citoliq [Digene Brazil], n =1,346) was performed by 1 of the clinics.

RESULTS

Conventional Pap smears showed no squamous intraepithelial lesions (normal) in 8,946 (87.4%) and LBC in 1,373 (82.4%). Using high grade squamous intraepithelial lesions (HSIL) as the cutoff, Pap smears predicted high grade (cervical intraepithelial neoplasia [CIN] 3) with OR 63.0 (95% CI, 36.90-107.70), standard error (SE) 59%, SP 97.8%, positive predictive value (PPV) 68.1% and negative predictive value (NPV) 96.7%. The same figures for Autocyte PREP were: OR 9.0 (95% CI, 2.43-33.24), sensitivity (SE) 33.3%, specificity (SP) 100%, PPV 100% and negative PV (NPV) 88.8%. DNA-Citoliq detected CIN 3 as follows: OR 11.8 (95% CI 2.60-53.26), SE 40.0%, SP 94.6%, PPV 40.0% and NPV 94.6%. Lowering the cutoff to low grade squamous intraepithelial lesions increased SE and NPV but compromised SP and PPV. The detection rates for high grade lesions after an atypical squamous cells of undetermined significance diagnosis were similar with the 3 techniques. In our settings, the 3 methods of cervical cytology were slightly different in performance. The conventional Pap smear had the highest SE, while Autocyte PREP had 100% SP and PPV in detecting CIN3 with the HSIL cutoff. All 3 tests had lower SE but higher SP as compared to HCII.

Bridging the imaging gap: visualizing subcellular architecture with electron tomography

Transmission electron microscopy is a powerful tool that is used to explore the internal structure of tissues, cells, organelles and macromolecular complexes. By integrating data from a series of images in which the orientation of the specimen is progressively varied relative to the incident electron beam it is also possible to extend electron microscopic imaging into the third dimension. This approach, commonly referred to as electron tomography, has been greatly aided in recent years by advances in technology for imaging specimens at cryogenic temperatures, as well as by substantial progress in procedures for automated data collection and image processing. The intense pace of developments in this field is inspired, in a large part, by the hope that the quality of the data will ultimately be good enough to allow interpretation of tomograms of cells, organelles, bacteria and viruses in terms of the three-dimensional spatial arrangements of the constituent molecules.

[Evaluation of frozen sections and cytological diagnosis during surgery]

When a surgeon feels it to be necessary to carry out morphological diagnosis during the operation, the pathologist may assist him or her with rapid cell or tissue diagnosis. This must be a conscious decision to introduce an additional step into the chain of laboratory procedures from the taking of the sample to the reporting of the result. Because this additional phase requires a longer stay in the operating room and additional effort on the part of the laboratory staff, together with an increased risk of misclassification of the disease process, this step should only be taken after careful consideration of the pros en cons. On the one hand, the need for intra-operative diagnosis has decreased because of the availability of better and more accurate pre-operative diagnostic techniques; on the other hand, there are new developments such as the introduction of sentinel-node biopsy, in which one must weigh the advantages of a rapid intra-operative diagnosis against the slower but surer results of a more comprehensive lymph-node investigation. Routine examination of the cut edges during an operation is hardly ever done any longer as a result of changed biological knowledge regarding the margins needed for radical surgery.

Grading follicular lymphoma on fine needle aspiration specimens. Comparison with proliferative index by DNA image analysis and Ki-67 labeling index

OBJECTIVE

To determine whether follicular lymphoma (FL) can be graded on fine needle aspiration (FNA) biopsies by determining the percentage of centroblasts in the neoplastic follicles on the smears.

STUDY DESIGN

Eighty-nine cases of histologically confirmed cases of FL, including 31 grade 1, 46 grade 2 and 12 grade 3, were evaluated. Proliferative index (PI) by DNA image analysis (DIA) and Ki-67 labeling index (LI) were obtained on all cases. A minimum of 200 cells were counted per case (range, 200-800 cells) at 40x magnification, and the number of large cells (centroblasts) was expressed as a percentage of the total number of cells counted within the follicles.

RESULTS

The percentage of centroblasts in the follicular aggregates was 9.7 +/- 2.9% in grade 1 FLs, 24.7 +/- 5.6% in grade 2 and 48.4 +/- 7.5% in grade 3. These differences were significant (P < .05). DNA image analysis of PI and Ki-67 LI differed significantly between grade 1 FLs and grade 2 and 3 FLs (P < .05), but there were no significant differences between grade 2 and 3 FLs.

CONCLUSION

Determining the percentage of centroblasts in the follicular aggregates on FNA specimens is a good method of grading FLs. Using the percentage of centroblasts per follicular structure, FL grades 1, 2 and 3 were adequately distinguished. PI by DIA and Ki-67 LI clearly distinguished FL grade 1 from FL grades 2 and 3; however, it did not clearly distinguish between grades 2 and 3.

Detection of DNA methylation. Potential applications to diagnostic cytopathology

Inactivation of tumor suppressor genes is often the result of genetic mutations or deletions. However, another mechanism for silencing genes involves DNA methylation. In this setting, a methyl group is added to cytosine residues within the gene promoter region; that prevents transcription. Tumors usually contain multiple genes that have been silenced by methylation, unlike normal tissues, in which gene methylation events are less common. The list of genes methylated in a given tumor is often referred to as a gene methylation profile. Gene methylation profiles may be almost unique for each type of tumor. Methylation-specific polymerase chain reaction is a sensitive technique that can detect gene methylation in cytologic samples. Application of this technique to cytologic cancer screening tests may increase their sensitivity. Also, the introduction of novel chemotherapeutic drugs that target DNA methylation may utilize gene methylation assays on fine needle aspiration biopsies of tumors.

[Sharper diagnostic tool the future promise of laser-assisted microdissection]

The paper describes the use of laser-assisted microdissection to retrieve microscopically defined cell populations including single cells from tissue sections for subsequent analysis of genomic DNA and mRNA. A general background is given on the techniques available and requirements for PCR based on minute templates. Different pre-PCR approaches are briefly described and possibilities and limitations of using archival material compared to fresh frozen tissue are discussed. In the article we give one example on how we have used the PALM laser microscopy system in combination with a nested, multiplex PCR system to analyze single normal keratinocytes as well as tumor cells from a case of basal cell cancer. We found that p53 mutations are common in normal, chronically sun-exposed skin. Widespread yet common mutations in the p53 gene that were unrelated to immunoreactivity for the p53 antibody were found in tumor cells. In addition there were rare mutations in occasional tumor cells that apparently did not result in selective growth advantage. Perspectives for the future are presented and the potential of laser assisted microdissection is highlighted within the fields of cancer research, developmental studies as well as studies of inflammatory and degenerative diseases. The combination of a method that allows careful selection of defined cells with powerful micro array based techniques, provides a setting with potential to uncover pathogenic mechanisms for large variety of human diseases.

[Increasing importance of cytological diagnostics in the Netherlands]

Cytological diagnosis has important practical clinical value, as shown by the observation that 54% of all diagnostic activities in pathology laboratories consist of cytological investigations. New impulses are, however, required to ensure ongoing developments. For example, from a scientific point of view, there appears to be little evidence-based information. A shift from case reports to systematic evaluation and from descriptive to prescriptive research is needed. The discipline of cytological diagnostics requires greater academic interest, and better guidance and structuring.

Tissue engineering of urinary organs

Tissue engineering can serve as an alternative treatment for a malfunctioning or lost organ. Isolated and expanded cells adhere to a temporary scaffold, proliferate, and secrete their own extracellular matrices (ECM) replacing the biodegrading scaffold. The genitourinary system, composed of the kidney, ureter, bladder, urethra, and genital organs, is exposed to a variety of possible injury sites from the time of fetal development. All the urinary organs are mainly composed of smooth muscle and uroepithelial cells and which may be approached by tissue engineering techniques. A large number of materials, including naturally-derived and synthetic polymers have been utilized to fabricate prostheses for the genitourinary system. Usually, whenever there is a lack of native urologic tissue, reconstruction is considered with native non-urologic tissue, such as, gastrointestinal segments, or skin or mucosa from multiple body sites. Engineering tissues using selective cell transplantation may provide a means to create functional new genitourinary tissues. This review concerns urinary tissues reconstructed with bladder uroepithelial cells and smooth muscle cells (SMCs) implanted on biodegradable polymer matrices.

[Cervical screening--its essence and quality-control methodology in cytology laboratories]

The essence and importance of the quality control in the activity of the cytological laboratories, fulfilling the 1st step of the cervical screening are discussed. The methodology is presented, as well as the possibilities of the different kinds of internal and external control and the place of the introduced in the practice of the developed countries automated analyzing systems are under consideration.

Atomic force microscopy in histology and cytology

This review briefly introduces the principles of the atomic force microscope (AFM) and shows our own results of AFM application to biological samples. The AFM, invented in 1986, is an instrument that traces the surface topography of the sample with a sharp probe while monitoring the interaction forces working between the probe and sample surface. Thus, the AFM provides three-dimensional surface images of the sample with high resolution. The advantage of the AFM for biologists is that AFM can visualize non-conductive materials in a non-vacuous (i.e., air or liquid) environment. AFM images of the plasmid DNA are comparable to those by transmission electron microscopy using a rotary shadowing technique, and have the advantage of examining directly the molecule without staining nor coating. The surface structure of human metaphase chromosomes and mouse collagen fibrils demonstrated in air by the non-contact mode AFM is comparable to that obtained by scanning electron microscopy. Quantitative information on the heights of structures is further obtainable from the AFM images. Embedment-free thin tissue-sections are useful for observing intracellular structures by AFM. The present review also shows AFM images of living cultured cells which have been collected in a contact mode in liquid. This technique afforded us three-dimensional observation of the cellular movement with high resolution. Although there are some innate limitations for AFM imaging, the AFM has great potential for providing valuable new information in histology and cytology.

Image cytometry: current applications and future trends

Image cytometry has numerous clinical and research applications and is particularly useful in anatomic pathology for the study of malignant lesions. Modern image systems encompass morphometry, densitometry, neural networks, and expert systems. Rapid advances in technology and the development of user-friendly systems have provided pathologists with an alternative to flow cytometry, particularly useful in the evaluation of small or hypocellular specimens. The most common current application of image cytometry is for DNA analysis, followed by quantitation of immunohistochemical staining. Newer uses under active investigation include development of expert systems that may act as diagnostic consultants in the future. Beyond DNA analysis, image cytometry holds great promise for improved tumor classification, for screening and surveillance in high-risk populations, and as a tool to improve diagnostic ability. This article discusses types of image analysis systems, specimen preparation, data acquisition, current applications in specific organ sites, and possible future applications.

Flow cytometric applications in cytopathology

Flow cytometric (FCM) methodology represents a powerful analytical tool for screening and detecting abnormal and malignant cells, for subclassifying malignancies beyond conventional morphologic type and grade and for transcending light microscopic features by providing more biologically meaningful information. This paper reviews the historical background leading to the development of the FCM methodology and instrumentation that is presently being used for cytopathologic (and histopathologic) diagnosis, tumor subclassification and identification of aggressive cancers. Emphasis is placed on human carcinomas, with reference to hematologic malignancies when appropriate. Examples of FCM DNA content and cytokinetic techniques are described for the various cytologic sampling methods. The advantages, limitations and future prospects for the application of flow cytometric techniques in cytopathology are discussed.

Flow cytometry in cytopathology. Overview and perspectives

The future applications of flow cytometry (FCM) are briefly discussed. Whereas the early goals of its clinical applications were cancer diagnosis and classification, it has now become apparent that FCM can more successfully provide information on a variety of cell constituents of crucial importance in the evaluation of tumor prognosis and treatment sensitivity. It is suggested that (1) the data being provided by FCM will probably lead to a more clinically relevant classification of tumors, based more on the biochemical/molecular markers of individual cells and an assessment of tumor heterogeneity and less on classical cell morphology and tumor progression, and (2) FCM seems likely to become established as a routine methodology in cytopathology.

Aspiration cytology in Sweden: The Karolinska Group

The method of aspiration biopsy cytology began to receive international attention after publications, innovations, and courses originating at the Karalinska Hospital in Sweden. Sixteen Franzen, Josef Zajieek, Pier Esposti, and Torsten Lowhagen were prime movers of this clinical and scientific development. The history of their arrival at the Karolinska and their seminal contributions is reviewed.

Stereological methods in cell biology: where are we--where are we going?

The current state of the art in morphometric cell biology is reviewed by looking at the developmental state of stereological methods, and at the approaches used to arrive at quantitative structure-function correlation. Stereological methods have reached a fairly advanced level of sophistication since mathematical stereology has been developed as a branch of geometric probability theory. The application of these methods in cell biology lags behind, both quantitatively and qualitatively. Among the strategies used in exploiting stereological methods in cell biology the physiological approach (where a change is induced experimentally and its effect on the cells is followed by biochemical and morphometric methods) ranks highest and is still valid. More analytical approaches, such as combining stereology and biochemistry in cell fraction studies, are fraught with difficulties. In considering future developments of stereological methods, the emphasis will have to be 1) on developing procedures for eliminating biases such as section thickness or resolution effects, and 2) on increasing the efficiency of the methods by better sampling rules and improved instrumentation. The future trends in morphometric cell biology might best be served by exploiting the potentials of histochemistry and stereology by combining them with a view to 1) establishing procedures for cell-specific sampling and 2) developing methods towards "molecular morphometry" on the basis of immunocytochemical labeling.