Evaluation of double immunocytochemical staining for CK20 and P53 as a potential adjunct to cytology for urothelial cancer diagnosis

Principles of Analytic Validation of Immunohistochemical Assays: Guideline Update

CONTEXT.—

In 2014, the College of American Pathologists developed an evidence-based guideline to address analytic validation of immunohistochemical assays. Fourteen recommendations were offered. Per the National Academy of Medicine standards for developing trustworthy guidelines, guidelines should be updated when new evidence suggests modifications.

OBJECTIVE.—

To assess evidence published since the release of the original guideline and develop updated evidence-based recommendations.

DESIGN.—

The College of American Pathologists convened an expert panel to perform a systematic review of the literature and update the original guideline recommendations using the Grading of Recommendations Assessment, Development and Evaluation approach.

RESULTS.—

Two strong recommendations, 1 conditional recommendation, and 12 good practice statements are offered in this updated guideline. They address analytic validation or verification of predictive and nonpredictive assays, and recommended revalidation procedures following changes in assay conditions.

CONCLUSIONS.—

While many of the original guideline statements remain similar, new recommendations address analytic validation of assays with distinct scoring systems, such as programmed death receptor-1 and analytic verification of US Food and Drug Administration approved/cleared assays; more specific guidance is offered for validating immunohistochemistry performed on cytology specimens.

The Role of Novel Bladder Cancer Diagnostic and Surveillance Biomarkers-What Should a Urologist Really Know?

The aim of this review is to analyze and describe the current landscape of bladder cancer diagnostic and surveillance biomarkers. We researched the literature from 2016 to November 2021 to find the most promising new molecules and divided them into seven different subgroups based on their function and location in the cell. Although cystoscopy and cytology are still the gold standard for diagnosis and surveillance when it comes to bladder cancer (BCa), their cost is quite a burden for national health systems worldwide. Currently, the research is focused on finding a biomarker that has high negative predictive value (NPV) and can exclude with a certainty the presence of the tumor, considering missing it could be disastrous for the patient. Every subgroup has its own advantages and disadvantages; for example, protein biomarkers cost less than genomic ones, but on the other hand, they seem to be less precise. We tried to simplify this complicated topic as much as possible in order to make it comprehensible to doctors and urologists that are not as familiar with it, as well as encourage them to actively participate in ongoing research.

The Paris system classification for urinary cytology in patients under bacillus Calmette-Guerin treatment

BACKGROUND

The role of urinary cytology as a diagnostic test for the detection and surveillance of urothelial cancer is crucial. Intravesical bacillus Calmette-Guerin (BCG) is the appropriate therapeutic strategy for patients with high-grade urothelial carcinoma (HGCU) or in situ carcinoma. We investigate how applicable is the Paris System for reporting urinary cytology (TPS) and how accurate is urinary cytology, in patients who undergo intravesical BCG instillations.

METHODS

Our study contains urine samples from patients during the period January 1, 2017 to December 31, 2019. The inclusion criteria were patients with history of urothelial bladder carcinoma who had been treated with intravesical BCG instillation and cytology was followed by histology. We report our results and estimate the risk of high-grade malignancy (ROHM) for each TPS category and cytology accuracy.

RESULTS

Four hundred thirty-eight samples corresponding to 146 patients fulfilled the criteria to be included in the study. There were 2 inadequate, 118 negative for high-grade urothelial carcinoma (NHGUC), 14 atypical urothelial cells (AUC), 6 suspicious for high-grade urothelial carcinoma (SHGUC), and 6 cases HGUC. Corresponding histology assessment has shown that the ROHM amounted to 0 for inadequate, 3.4% for NHGUC, 57% for AUC, 100% for SHGUC and HGUC. Sensitivity was 50%, specificity 100%, PPV 100%, NPV 91%, and accuracy 91.7%, considering inadequate, NHGUC and AUC as negative and SHGUC and HGUC as positive result. However, considering AUC a positive result, the accuracy parameters were different; sensitivity 83.3%, specificity 95%, PPV 76.9%, NPV 96.67%, and accuracy 93%.

CONCLUSION

The Paris system for reporting urinary cytology can be safely applied to patients during follow-up after BCG intravesical administration.

p53 expression in repair/reactive renal tubular cells: A potential pitfall leading to a false-positive diagnosis of urine cytology

Background

p53 immunostaining is routinely used as a surrogate marker for TP53 mutational status. In urine cytology, p53 immunocytochemistry is reportedly useful in detecting urothelial carcinoma cells as well as in improving the detection sensitivity and specificity. However, to the best of our knowledge, p53 expression in repair/reactive renal tubular cells (RRTCs) from urine cytologic specimens has not been assessed to date.

Methods

We evaluated the immunoexpression of p53 and homogentisate 1,2‐dioxygenase (HGD) antibody, a renal tubular cells marker, in RRTCs using voided urine and renal biopsy samples from 80 patients who were histologically diagnosed with glomerular disease.

Results

Repair/reactive renal tubular cells were detected in 68 (68/80, 85%) samples at a mean count of 141.1 cells per sample (range, 5–4220). Immunocytochemical analysis found p53‐positive RRTCs in all the samples (68/68, 100%) with an average p53 positivity rate of RRTCs per sample at 47.7% (range, 3.8%–96.5%). Of the 68 p53‐positive RRTC samples, 38 (55.9%) included cells that were HGD positive for cytoplasm. Similarly, renal biopsy analysis revealed p53‐positive RRTCs in all the specimens (68/68, 100%). All 68 (100%) cases showed RRTCs that were positive for both p53 and HGD.

Conclusion

To avoid false positives of p53 immunocytochemistry, cytologists must consider the fact that RRTCs from patients with glomerular disease are positive for p53.

An institutional experience evaluating hTERT immunostaining in 100 consecutive ThinPrep urine specimens

INTRODUCTION

Studies have shown that expression of human telomerase reverse transcriptase (hTERT) in mature urothelial cells indicates an increased risk of urothelial carcinoma. We evaluated the utility of immunocytochemistry with a commercially available anti-hTERT antibody (SCD-A7) in 100 consecutive urine cytology specimens using ThinPrep processing.

MATERIALS AND METHODS

ThinPrep slides prepared from 100 consecutive urine specimens were stained using anti-hTERT antibody (SCD-A7) after staining optimization had been successfully completed. Patient demographics, cytology diagnoses, histologic follow-up data, and anti-hTERT staining results were recorded.

RESULTS

The cytology diagnoses included 7 cases of high-grade urothelial carcinoma (HGUC), 2 cases suspicious for HGUC (SHGUC), 24 cases of atypical urothelial cells (AUCs), and 67 cases negative for HGUC (NHGUC). Of 92 samples, 68 (74%) were positive and 24 (26%) were negative for anti-hTERT staining. Although 31 of 32 specimens (97%) with a diagnosis of AUCs and greater showed positive staining, 37 of 60 NHGUC cases (62%) were also positive for anti-hTERT. Although the HGUC and suspicious for HGUC cases were more likely to show strong staining (6 of 9; 67%), 7 AUC (32%) and 8 NHGUC (22%) cases also demonstrated strong staining. Eight samples (8%) were unsatisfactory for interpretation. Anti-hTERT staining of nonurothelial cells was seen in 77 of 92 samples (84%).

CONCLUSIONS

Interpretation of anti-hTERT immunocytochemical staining of ThinPrep material is challenging owing to obscuring of nonurothelial cell staining and difficulty discerning individual urothelial cell cytomorphology when the cells are stained. The significance of the large number of anti-hTERT-positive but cytology-negative cases in our study is uncertain.

Unbiased enrichment of urine exfoliated cells on nanostructured substrates for sensitive detection of urothelial tumor cells

Background

Early detection of urothelial carcinoma (UC) by noninvasive diagnostic methods with high accuracy is still underscored. This study aimed to develop a noninvasive assay incorporating both enrichment of urine exfoliated cells and immunoassays for UC detection.

Methods

Polystyrene dishes were exposed to oxygen plasma and modified with 3‐aminopropyltriethoxysilane to prepare amine‐functionalized nanostructured substrates (NS). Performance characterization of NS was evaluated by atomic force microscope and X‐ray photoelectron spectroscopy. Urine exfoliated cells were captured by NS and then immunostained to detect urinary tumor cells (UTCs), which was called UTC assay. The receiver operating characteristic (ROC) curve, area under ROC curve (AUC), and Youden index were used to find the cutoff value of UTC assay. ROC analysis and McNemar test were used to compare the diagnostic accuracy of UTC assay with cytology. Kappa test was used to analyze the agreement of UTC assay and cytology with pathological diagnosis.

Results

Nanostructured substrates had good cell binding yields of nucleated cells and tumor cells. CK20⁺CD45⁻CD11b⁻ cells were considered as UTCs. UTC number ≥ 1 per sample could be considered as a positive result. By AUC and Kappa analysis, UTC assay showed good performance in UC detection. McNemar test demonstrated that UTC assay had a superior sensitivity even in low‐grade subgroup and a similar specificity compared to cytology in UC diagnosis.

Conclusions

Nanostructured substrates could be used to enrich the exfoliated cells from urine samples. UTC assay with NS has the potential to play a role in UC detection. The value of this assay still needs additional validation by large, multi‐center studies.

Cytokeratin 20/p53 dual immunocytochemistry for improving the diagnostic accuracy of urine liquid-based cytology in the detection of urothelial neoplasm: A retrospective study

Backgrounds:

Dual immunocytochemistry (DIC) with cytokeratin (CK) 20 and p53 in liquid-based cytology is a tool for improving the accuracy of urine cytology (UC). This study was conducted to compare the diagnostic accuracy of UC alone with that of UC combined with CK20/p53 DIC.

Methods:

We retrieved urine samples collected between January 2015 and March 2016 stored in PreservCyt®solution that were from cases categorized as malignant, highly suspicious, suspicious, and atypical and that were matched with a subsequent biopsy. We re-prepared 63 samples of 28 patients for DIC and blindly evaluated 63 pairs of original Papanicolaou smears and DIC.

Results:

Of the 63 samples, 11 could not be analyzed because of the low number of atypical urothelial cells, and the results of the remaining 52 samples were as follows: 34 positive and 18 negative. The positive predictive value of DIC was 100%, and the negative predictive value was 78%. Fifteen DIC-positive cases, histologically proven as malignant were originally diagnosed as highly suspicious (4), suspicious (8), and atypical (3), which were strongly suggestive of “urothelial carcinoma”. Four negative cases, histologically confirmed as non-neoplastic cases, were filtered from false positivity.

Conclusions:

Despite the small sample size, this study demonstrated the diagnostic utility, high sensitivity, and positive predictive value of CK20/p53 DIC, especially in cases with a small number of single malignant cells or cellular clusters of reactive atypical urothelial cells. Thus, CK20/p53 DIC can be used for improving diagnostic accuracy of UC, either as an ancillary method to cytology or as a part of a potential future diagnostic panel to improve patient diagnosis and management.

Double staining: diagnostic utility in non-small cell lung carcinoma in the era of tissue conservation

INTRODUCTION

In an era of precision medicine distinguishing pulmonary squamous cell carcinoma (SQCC) from adenocarcinoma (ADC) is vital for treatment. Immunohistochemical (IHC) staining for p40, p63 and Cytokeratin 5 (CK5) are useful for SQCC, while TTF-1 and Napsin-A can be used for confirming ADC. Fine needle aspiration (FNA) cell blocks (CB) have limited tissue, hence, double IHC staining is helpful for tissue conservation for molecular analysis.

MATERIALS AND METHODS

Thirty six confirmed lung SQCC and 45 ADC CB were selected for IHC. Double staining was performed with p40/CK5 and p63/CK5 on all SQCC, and with TTF-1/Napsin-A on all ADC. Results were positive if at least 5% of malignant cells were immunoreactive for the antigen.

RESULTS

P40/CK5 had (92%) sensitivity, (100%) specificity, (100%) positive predictive value (PPV), (91%) negative predictive value (NPV) and an overall diagnostic accuracy of (96%). By contrast, P63/CK5 double stains showed (92%) sensitivity, (80%) specificity, (85%) PPV, (89%) NPV and (86%) overall diagnostic accuracy, respectively. TTF-1/Napsin A staining for ADC showed a sensitivity of 80%, specificity of 96%, PPV of 97%, NPV of 71% and accuracy of 85%.

CONCLUSION

P40/CK5 double stain has higher specificity, PPV, NPV, and overall accuracy than P63/CK5 double stain in the diagnosis of lung SQCC. TTF-1/Napsin-A double staining is a valuable marker with high specificity, PPV, and diagnostic accuracy in diagnosing lung ADC. The usage of P40/CK5 and TTF-1/Napsin-A as a panel can be recommended for characterizing non-small cell carcinoma (NSCC) of the lung and for conserving tissue for molecular testing.