CytoJournal monographs: First CMAS (CytoJournal Monograph/Atlas Series) on science of cell-block making, titled "CellBlockistry 101 (Text Book of Cell-blocking science)"

Proteomic analysis of small extracellular vesicles unique to cervical cancer

Background

Cervical cancer (CC) is the fourth most common cancer in females worldwide. Existing biomarkers for CC, such as squamous cell carcinoma antigens, show low specificity. Hence, a novel biomarker for the diagnosis of CC is required. Through proteomic analysis, this study aimed to distinguish between the small extracellular vesicle (sEV) protein profiles of healthy controls (HC) and CC sera and to identify potential sEV proteins that can serve as biomarkers for CC diagnosis.

Methods

The number and size distribution of sEVs in HC and CC sera were measured using nanoparticle tracking analysis. Differential ultracentrifugation combined with size-exclusion chromatography was used to isolate and purify sEVs. Liquid chromatography-tandem mass spectrometry was used to identify and compare the protein profiles between patients with CC and HC. Differentially expressed extracellular vesicle (EV) proteins were validated using The Cancer Genome Atlas database.

Results

The EV particle concentration in patients with CC was marginally higher than that in HC. Proteomic and functional protein analyses revealed a difference in the EV protein profiles between HC and CC and identified proteins that can serve as biomarkers for CC.

Conclusions

This study provides insights into the potential of sEVs as less invasive biomarkers for CC diagnosis. Validation with a well-designed cohort should be performed to determine the clinical diagnostic value of specific protein markers for CC.

Cell blocks in cytology: review of preparation methods, advantages, and limitations

Cell blocks are cytologic preparations that are processed as paraffin embedded blocks in a manner comparable to formalin-fixed paraffin-embedded tissue in surgical pathology. In addition to serving as an adjunct to other cytologic preparations for morphologic diagnosis, cell blocks play an increasingly important role as they yield tissue sections that can be utilized for ancillary testing such as immunohistochemical stains and molecular studies. While essentially universally viewed as playing a pivotal role in cytopathology practice, there are various factors that limit their use in practice and contribute to dissatisfaction with cell block quality. Cell block preparation, as opposed to tissue processing in surgical pathology, is more variable with many different protocols in use today. This review explores the most commonly used cell block preparation techniques currently in use with review of the unique advantages and limitations each method presents. The goal of this work is to serve as a resource that can aid in making more informed decisions about which cell block protocol may work best for individual laboratories.

The diagnostic value of add-on thyroid cell block in the evaluation of thyroid lesions

Objectives

Fine-needle aspiration (FNA) cytology plays a pivotal role in diagnosing thyroid nodules. Imaging assessment, followed by thyroid lesion sampling, is a widely applied clinical practice. Tissue fragments remnants are retrieved in cell-block providing an adjunct diagnostic tool for histopathology visualization and use of ancillary testing. This study aimed to evaluate whether the auxiliary application of cell-block adds to the diagnostic accuracy of the thyroid FNA.

Material and Methods

A total of 252 thyroid FNA cases between (2020 and 2021) were reviewed from patients aged 18-76. Of those, 150 cell-blocks were recovered and examined to assess their utility. Following categories were plotted during cell-blocks revision: (A) Inadequate material retrieved; (B) cell-block shows similar features along with their accompanying smears; and (C) value added to cytology diagnosis when using cell-block.

Results

The distribution of cell-blocks according to the aforementioned classification are as follows: A - non-diagnostic 63%, B - similar observation seen in both preparations 35%, and C - value added to the rendered diagnosis 2%. Hence, the use of cell-block improved cytology diagnosis in only 2% of total cases. Mostly were of immunostains application for diagnosis confirmation.

Conclusion

The non-diagnostic and atypical cytology cases have not been upgraded to a more meaningful category by the incorporation of cell-block performed with the routine non-enhancement random method. On the other hand, cell-blocks contributed generously toward immunostaining application in malignant scenarios.

PD-L1 immunohistochemical testing: A review with reference to cytology specimens

BACKGROUND

Immunotherapy based on disruption of the PD-1/PD-L1 axis is standard of care for many high stage malignancies including melanomas, non-small cell carcinomas of the lung, triple negative breast carcinomas, and squamous cell carcinomas of the head and neck. Eligibility for immunotherapy requires immunohistochemical assessment of PD-L1 expression. Currently, many high stage malignancies are diagnosed by cytology and cytologic material is the only specimen available for ancillary testing. Formal guidelines do not currently exist defining the optimal specimen type, antibody to be used or the best scoring system for cytologic material. Significant information has been published for PD-L1 testing of pulmonary specimens but much less data exists for the reproducibility, accuracy and best practices for material obtained from other body sites and types of malignancy.

METHODS

We searched the PubMed data base for manuscripts relating to PD-L1 testing of cytologic specimens. The search period was between 2016 and 2022. The search terms used were PD-L1, cytology, FNA, immunotherapy, immunohistochemistry, immunocytochemistry, cytology-histology correlation. Cross referencing techniques were used to screen for the most relevant manuscripts. The abstracts of these were then reviewed for final data collection and analysis.

RESULTS

A total of 86 studies were identified conforming to study relevancy. These were reviewed in their entirety by two authors (LJL, TZ) for extraction of data. The majority of studies involved pulmonary specimens (79) with three relating to PD-L1 testing of head and neck cytologic specimens and one each for PD-L1 testing of cytology specimens from melanomas, pancreas, pleural fluids, and triple negative breast carcinomas. While smears could be used, most studies found cell blocks optimal for testing.

SUMMARY

Currently, four drugs are approved for immunotherapy based on PD-L1 status. These drugs require specific antibody clones as well as scoring systems. Scoring systems and cut points vary with the type of neoplasm being treated. Cytology specimens from the lung, head and neck and melanomas can all be used for PD-L1 testing with good agreement with corresponding histology specimens.

Impact of cytopathology authors work: Comparative analysis based on Open-access cytopathology publications versus non-Open-access conventional publications

Objectives

Open access (OA) is based on a set of principles and a range of practices through which fruits of research are distributed online, free of cost, or other access barriers. According to the 2001 definition, OA publications are without barriers to copy or reuse with free access to readers. Some studies have reported higher rates of citation for OA publications. In this study, we analyzed the citation rates of OA and traditional nonOA (with or without free access) publications for authors publishing in the subspecialty of cytopathology during 2010-2015.

Material and Methods

We observed and compared citation patterns for authors who had published in both OA and traditional non-OA, peer-reviewed, scientific, cytopathology journals. Thirty authors were randomly selected with criteria of publishing a total of at least five cytopathology articles over 2010-2015. Number of citations per article (CPA) (during 2010-2015) for OA publications (in CytoJournal and Journal of Cytology) and non-OA publications (in Diagnostic Cytopathology, Cytopathology, Acta Cytologica, Journal of American of Cytopathology, and Indian Journal of Pathology and Microbiology) was collected and compared statistically using two-tailed Student's t-est. The data were collected manually through science citation analysis sites, mostly Google Scholar.

Results

Thirty authors published 579 cytopathology articles in OA and non-OA journals. Average CPA for OA publications was 26.64. This was 11.35 higher than the average CPA) of non-OA conventional with subscription cytopathology journals (74% increase) and 11.76 higher than the average CPA of conventional cytopathology non-OA journal articles with free access (79% increase). These differences were statistically significantly with P < 0.05.

Conclusion

We observed that the cytopathology publications in the OA journal attained a higher rate of CPA than the publications in the traditional non-OA journals in the field of cytopathology during 2010-2015.