Use Of Immunohistochemistry Research Articles

Unique Molecular Alteration of Lobular Breast Cancer: Association with Pathological Classification, Tumor Biology and Behavior, and Clinical Management

Invasive lobular carcinoma (ILC), accounting for up to 15% of diagnosed breast cancers, has garnered significant attention due to the loss of the epithelial cell–cell adhesion molecule E-cadherin. This loss contributes to its distinct biological, morphological, and clinical characteristics compared to non-lobular breast cancers. The use of immunohistochemistry (IHC) for E-cadherin and/or the associated cadherin–catenin complex, such as p120-catenin and beta-catenin, in morphologically equivocal cases, has been increasingly adopted in pathology practice. This approach has substantially improved diagnostic accuracy, interobserver reproducibility, and the identification of new morphologic variants of ILC. ILCs exhibit unique tumor biology, which presents considerable challenges in clinical management, especially in preoperative imaging evaluation, surgical management, and neoadjuvant treatment. Recent advances in translational and clinical research have enhanced our understanding of ILC and have spurred the development of new clinical trials specifically targeting these cancers. This review highlights recent progress in various aspects of ILC, including its unique molecular alteration, pathological classification and diagnostic approach, tumor biology and behavior, key clinical management challenges, and ongoing clinical trials, as well as the role of artificial intelligence in diagnosing ILC radiologically and pathologically. The goal of this review is to provide an updated understanding of the tumor biology, clinical manifestations, and molecular landscape of ILC and to help refine current tumor classification and diagnosis, subsequently improving management strategies and overall outcomes for lobular carcinoma patients.

The Role of Immunohistochemistry for AMACR/p504s and p63 in Distinguishing Prostate Cancer from Benign Prostate Tissue Samples in Botswana.

Prostate cancer (CaP) is the most common malignancy and the second leading cause of cancer-related deaths among men in Botswana. Currently, diagnosing CaP relies on examining prostate biopsy samples, which can be challenging due to benign mimics. This study aims to evaluate the potential of Alpha-methyl acyl-CoA racemase (AMACR/p504s) and p63, as diagnostic markers for CaP. This may potentially validate the use of immunohistochemistry for detecting CaP in Botswana, where it is not routinely utilized. The study included 69 samples, comprising 5 prostatic chip specimens, 50 core biopsies, and 14 radical prostatectomy specimens. These cases were reviewed and categorized into CaP (49 cases) and benign prostatic hyperplasia (BPH) (20 cases). Immunohistochemistry was performed using AMACR/p504s and p63 immunohistochemical stains. The study found that AMACR/p504s had a sensitivity of 96% and a specificity of 95%, while p63had a sensitivity and specificity of 100%. PSA levels showed significant positive correlation with AMACR/p504s expression (P < 0.00001). In this study, we have demonstrated the diagnostic utility of AMACR/p504s and p63 due to their high sensitivity and specificity in detecting CaP in Botswana, where these biomarkers are not yet widely used. Furthermore, utilizing these markers in conjunction with other diagnostic tools, such as PSA levels and morphological evaluation, could improve the diagnostic accuracy, especially in challenging cases where histopathological examination alone may be inconclusive.

The limited use of immunohistochemistry for the diagnosis of low-grade myofibroblastic sarcoma

The limited use of immunohistochemistry for the diagnosis of low-grade myofibroblastic sarcoma

Renal collapse: A window into an underlying high-grade hematological malignancy – A case report

Kidney disease is prevalent in patients with hematologic malignancies, particularly multiple myeloma (MM) and acute leukemias. These conditions can directly infiltrate the kidneys or disrupt renal function through metabolic and immunological mechanisms. Renal failure is a significant complication, often the second leading cause of mortality in MM patients. Over 50% of multiple myeloma patients experience renal impairment, commonly identified as "myeloma kidney." Occasionally, blastoid morphology of some plasma cells can lead to diagnostic confusion, necessitating the use of immunohistochemistry to distinguish plasma cell leukemia (PCL) from other types of leukemias and lymphomas. Accurate diagnosis of renal disease can also reveal underlying hematologic malignancies, as demonstrated in our case where a kidney biopsy diagnosed a high-grade malignancy, facilitating timely and correct management.

CXCR2 expression is associated with prostate-specific membrane antigen expression in hepatocellular carcinoma: reappraisal of tumor microenvironment and angiogenesis.

Angiogenesis is a critical component of neoplastic progression, and inflammatory cells within the tumor microenvironment contribute to neoangiogenesis. Prostate-specific membrane antigen (PSMA)is expressedin the neovasculature of various solid tumors, including hepatocellular carcinoma (HCC). Also, CXCR2 + inflammatory cells, including CD15 + neutrophils, play crucial roles in HCC progression.We evaluated the associations between PSMA expression and CXCR2 + inflammatory cells in HCC by immunohistochemistry (IHC). CXCR2 expression and its correlation with PSMA, the PSMA/CD34 ratio, immune markers (CD3, CD15, CD68, and CD163), clinical parameters, and oncologic outcomes were evaluated in 76HCC and background benign liver tissue. PSMA and the PSMA/CD34 ratioshowed a positive correlationwith intratumoralCXCR2,but not with intratumoral CD15. Intratumoral CXCR2 + cell count was positively associated with intratumoral CD3, CD15, CD68, and CD163 expression levels. In the benign compartment, CXCR2 was significantly associated with CD15. Metabolic dysfunction-associated steatotic liver disease (MASLD) risk factors and cirrhosis had an opposite effect on CXCR2 + cell count in benign liver tissue. Higher CD15 + cell count in the benign liver was associated with decreased overall survival (OS) and recurrence-free survival (RFS). In HCC, intratumoral CXCR2 + cell count is associated with PSMA expression. Intratumoral and benign compartments had different CXCR2 + inflammatory cell makeup. The immune microenvironment of HCC appears to differ depending on underlying risk factors. Further investigations are warranted to elucidate PSMA biology and assess the potential utility of CXCR2 IHC in PSMA-targeted theranostics.

Validation of Various Pan‐ApoE and Isoform‐Specific ApoE Antibodies

AbstractBackgroundApolipoprotein E (ApoE) exists in three protein isoforms: E2, E3, and E4, which differ by only one or two amino acids. These slight differences profoundly effect protein structure and function, allowing each isoform to differentially impact Alzheimer’s Disease (AD) risk. Relative to the most common E3 isoform, E4 dramatically increases risk, while E2 confers a substantial decrease in risk. The close similarity between protein isoforms makes it difficult to develop isoform‐specific antibodies that are reliable and selective. Here, we aim to validate and optimize a number of common, commercially available ApoE antibodies to determine isoform specificity.MethodControl samples included plasma and brain collected from APOE knockout (KO), homozygous E2, E3 and E4 humanized APOE (hAPOE) mice, and human plasma from all 6 possible APOE genotypes. Western blotting was used on plasma and brain homogenates to determine isoform specificity of E2, E3, or E4 antibodies. Commercial antibodies tested included pan‐ApoE antibodies from Cell Signaling Technologies (CST) and Abcam, ApoE4 antibodies from Novus and CST, ApoE2 antibodies from CST, and ApoE3 antibodies from Abcam and Novus. Additionally, pan‐ApoE antibodies were kindly gifted to us by collaborators (Drs. Lammich and Haass, LMU) and tested. Antibodies were also tested for use in immunohistochemistry (IHC) using hAPOE and APOE KO mouse brain sections (30 uM).ResultDespite the ApoE3 antibodies being marketed as isoform‐specific, they did not show efficacy in either application. Commercial pan‐ApoE antibodies were outperformed by the LMU antibodies, but still showed efficacy. When used for western blotting, the CST ApoE4 and ApoE2 antibodies showed clear isoform specificity in hAPOE mouse and human samples. While none of the isoform‐specific antibodies passed controls for IHC purposes, multiple pan‐ApoE antibodies were variably effective for staining of brain tissue.ConclusionThese data identify several isoform‐specific ApoE antibodies that are reliable and selective across multiple sample types and applications; albeit some display higher affinity for one application over another. Overall, we hope these results will provide AD researchers with important resources that are crucial for visualizing and quantifying ApoE isoform distribution in heterozygote individuals and across a number of AD models, systems, and studies.

Consenso de expertos multidisciplinario para la calidad diagnóstica y uso de biomarcadores en cáncer de pulmón. Asociación Colombiana de Patología (ASOCOLPAT). 2023

Introduction: Lung cancer is the third cause of cancer worldwide of 2,200,000 and a mortality of approximately 35%. Diagnosis by a multidisciplinary team has become the most effective tool for early treatment. This is linked to the use of immunohistochemistry and immunomarkers that in the last decade have allowed us to strengthen the diagnosis and have involved target-directed therapies. Objective: To define by common agreement of experts, considerations for diagnostic quality and the use of biomarkers in lung cancer in Colombia. Methods: A formal consensus of experts, mixed type (Delphi/Nominal), was carried out with the participation of oncopathologists, pathologists, pulmonologists and chest surgeons by ASOCOLPAT. A group of questions and answers were graded, which were discussed in a nominal session. The information was consolidated in Excel and analyzed in STATA 14. Results: 12 questions and answers were structured and rated, addressing the following aspects: pathological diagnosis of lung cancer, description of the clinical centers, and some administrative and logistical issues in each region of Colombia. Conclusions: The consensus of experts defined 12 considerations by common agreement, for guidance in the pathological diagnosis of lung cancer, hoping to homogenize both medical and administrative aspects in order to generate an effective result and timely treatment.

Consenso de expertos multidisciplinario para la calidad diagnóstica y uso de biomarcadores en cáncer de pulmón. Asociación Colombiana de Patología (ASOCOLPAT). 2023

Introduction: Lung cancer is the third cause of cancer worldwide of 2,200,000 and a mortality of approximately 35%. Diagnosis by a multidisciplinary team has become the most effective tool for early treatment. This is linked to the use of immunohistochemistry and immunomarkers that in the last decade have allowed us to strengthen the diagnosis and have involved target-directed therapies. Objective: To define by common agreement of experts, considerations for diagnostic quality and the use of biomarkers in lung cancer in Colombia. Methods: A formal consensus of experts, mixed type (Delphi/Nominal), was carried out with the participation of oncopathologists, pathologists, pulmonologists and chest surgeons by ASOCOLPAT. A group of questions and answers were graded, which were discussed in a nominal session. The information was consolidated in Excel and analyzed in STATA 14. Results: 12 questions and answers were structured and rated, addressing the following aspects: pathological diagnosis of lung cancer, description of the clinical centers, and some administrative and logistical issues in each region of Colombia. Conclusions: The consensus of experts defined 12 considerations by common agreement, for guidance in the pathological diagnosis of lung cancer, hoping to homogenize both medical and administrative aspects in order to generate an effective result and timely treatment.

PAX6 is a useful marker for pancreatic origin of neuroendocrine neoplasms: A tissue microarray study evaluating more than 19,000 tumors from 150 different tumor types

PAX6 immunohistochemistry (IHC) was proposed as a tool to identify a pancreatic origin of neuroendocrine neoplasms (NENs). To evaluate the diagnostic utility of PAX6 IHC, a tissue microarray containing 19,214 samples from 150 tumor types was analyzed. Data on progesterone receptor (PR) and glutamate decarboxylase 2 (GAD2) expression were available from previous studies. PAX6 staining occurred in 2.6% of 17,224 analyzable tumors and 60 tumor categories showed PAX6 positivity in at least one case. The highest rates of PAX6 positivity occurred in pancreatic (42.9-70.8%) and other NENs (up to 50.0%), testicular tumors (up to 58.3%), basal cell carcinomas of the skin (51.9%), squamous cell carcinomas of different organs (1.5-11.8%), and in gynecological tumors (up to 30%). For detection of pancreatic origin of NENs, sensitivity was highest for PAX6 (68.7%) followed by GAD2 (62.6%) and PR (52.5%) while specificity was highest for GAD2 (95.2%), followed by PR (91.3%), and PAX6 (91.1%). Of the analyzed combinations, the highest sensitivity (53.8%) and specificity (100%) was found for PAX6/GAD2, although combinations of PAX6/PR (49.5%/99.3%), PR/GAD2 (40.7%/98.9%), and PAX6/PR/GAD2 (40.6%/100%) did also result in high specificity. Only 14% of the 118 NENs with negativity for all three antibodies were of pancreatic origin. It is concluded that PAX6 IHC is useful to identify a pancreatic origin in case of NEN metastases of unknown origin. The combination with GAD2 and PR further increase the diagnostic performance of PAX6 and results in a >98% specificity in case of positivity for at least 2 of these markers.

Gene Expression Profiling of the Peritumoral Immune Cell Infiltrate of Penile Squamous Cell Carcinomas.

Penile carcinomas are rare tumors in Europe and need further investigations due to their inferior prognosis in late tumor stages. The presence of disparate immune cell infiltrates was observed in these tumors, which were subsequently demonstrated to give rise to divergent tumor prognoses. The objective was to further characterize this immune cell infiltrate with the use of immunohistochemistry and RNA expression. A total of twelve well-characterized cases of penile squamous cell carcinomas with known infection status by human papillomavirus (HPV) and p16 status were assessed. The cases were classified according to their morphological characteristics, including those exhibiting a pronounced peritumoral immune cell infiltrate and those with less peritumoral immune cell infiltration. The generation of RNA expression data was conducted using the nCounter® PanCancer Immune Profiling Panel. Computational models were employed to calculate the proportions of immune cells. To corroborate the findings, an immunohistochemical analysis was conducted using antibodies against CD20, CD3, CD4, CD8, MUM1, CD68, and CD117. Our cases were clustered according to the immune cell infiltrate detected via histology in a group with less immune cell infiltrate density and in a group with increased immune cell infiltrate density. Generally, all immune cells showed an increased amount in the group with pronounced immune cell infiltrate density. The clusters were found to relate to cell functions, the complement system, cytotoxicity, pathogen defense, regulation, and T-cell functions. In cases exhibiting a pronounced immune cell infiltrate, the top three genes that exhibited the greatest upregulation were GZMA, MICB, and GNLY. No relationship to HPV infection status was demonstrated. Immunohistochemistry validated the data gained via RNA expression and showed a correlation with EPIC and Cibersort. The clustering of cases based on immune cell infiltrate density revealed significant distinctions between groups with lower and higher immune cell infiltrate density. The group with increased immune cel infiltrate density showed a greater abundance of immune cells, aligning with key functions like cytotoxicity, pathogen defense, and T-cell regulation. Among these cases, the genes GZMA, MICB, and GNLY were significantly upregulated, suggesting their involvement in an increased immune response. The role of HPV infection status in our cases with regard to the peritumoral immune cell infiltrate remains inconclusive.

A Comprehensive Review of TRPS1 as a Diagnostic Immunohistochemical Marker for Primary Breast Carcinoma: Latest Insights and Diagnostic Pitfalls.

Immunohistochemical expression of TRPS1 (trichorhinophalangeal syndrome type 1) protein is usually used by pathologists to confirm breast origin for triple-negative breast cancers (TNBC) or metastatic carcinomas of unknown primary. However, recent studies have reported TRPS1 expression in a variety of non-breast lesions. This review aims to provide a comprehensive evaluation of TRPS1 expression across various tumor types, highlighting both its diagnostic utility and potential pitfalls that may arise in clinical practice. A thorough search of the PubMed database on TRPS1 immunoexpression in tumor pathology was conducted. While the gene itself has been known for several decades, most studies regarding its use in immunohistochemistry emerged in the late 2010s. Particular emphasis was placed on case reports and cohort studies that examined the implications of TRPS1 expression in non-breast tissues, as well as variations in the results between commercially available TRPS1 clones, which may influence the staining intensity and specificity. TRPS1 demonstrated a strong diagnostic utility in identifying primary breast lesions, particularly in TNBC cases. However, its expression in a growing number of non-breast cancers, such as lung adenocarcinoma, prostate adenocarcinoma, urothelial carcinoma, ovarian high-grade serous carcinoma, and endometrial adenocarcinoma, as well as up to 96% of synovial sarcomas with SS18-SSX fusion, emphasizes the need for caution when interpreting TRPS1 positivity and suggests a multi-marker approach in order to increase the diagnostic accuracy. While TRPS1 remains a highly sensible immunohistochemical marker for confirming breast primary lesions, pathologists should be aware of its low specificity and incorporate complementary diagnostic methods in order to ensure accurate clinical management. Further research should focus on elucidating the molecular pathways regulating TRPS1 expression in various tumor types, which may better define its clinical utility.

Comprehensive Analysis of Receptor Status, Histopathological Classifications (B1-B5), and Cumulative Histological Dimensions in Breast Cancer: Predictors of Malignancy and Diagnostic Implications.

Breast cancer has become one of the most serious and widespread public health concerns globally, affecting an increasing number of women-and, in rare cases, men-across the world. It is the most common cancer among women across all countries. In this study, we aimed to evaluate the influence of demographic factors, medical and reproductive history, diagnostic techniques, and hormone receptor status on the development and progression of breast cancer. A total of 687 female patients from Romania underwent standard breast examination techniques, including clinical breast examination, mammography, ultrasonography, and, ultimately, breast biopsy. Statistical analysis was performed using the R programming language and RStudio software. The study included a comparative analysis and a prediction analysis for malignancy and tumor size (cumulative histological dimension) through logistic and linear regression models. The comparative analysis identified several variables associated with malignancy: older age (p < 0.001), non-vulnerability (p = 0.04), no daily physical activity (p = 0.002), no re-biopsy (p < 0.001), immunohistochemistry use (p < 0.001), use of larger gauge needles (p < 0.001), ultrasound-guided biopsy (p < 0.001), and vacuum biopsy (p < 0.001). The hormone receptor statuses-estrogen receptor (ER), progesterone receptor (PR), and androgen receptor (AR)-showed statistically significant differences in distribution across breast cancer B classifications. Logistic regression analysis identified ER, PR, and age as significant predictors of malignancy. Linear regression analysis revealed histopathological results, living environment, geographical region, vulnerability, prior breast examination, and the number of histological fragments as significant predictors of cumulative histological dimension. Our predictive models demonstrate the impact of demographic factors, medical history, diagnostic techniques, and hormone receptor status on breast cancer development and progression, accounting for a significant portion of the variance in malignancy and cumulative histological dimension.

Prognostic and predictive significance of p53 and ATRX in neuroendocrine neoplasms of GIT and pancreas and their utility as an adjunct to accurate diagnosis-An eight-year retrospective study.

Neuroendocrine neoplasms of gastrointestinal tract (GIT)and pancreas are heterogenous tumors. World Health Organization (WHO)2019 classification introduced Grade (G)3 neuroendocrine tumor (NET) distinct from neuroendocrine carcinoma (NEC), based on molecular differences and to triage the patients for appropriate therapy. This distinction largely relies on morphology, which can be challenging at times. Genomic profiling has revealed TP53andRB1mutations in NECs, while death domain-associated protein 6 (DAXX) and alpha-thalassemia/mental retardation X-linked (ATRX),in G3NET. Their role as biological markers in differentiating these entities and their significance as prognostic markers are not yet established. This study aims at analyzing the diagnostic and prognostic role of p53 and ATRX in neuroendocrine neoplasms of GIT and pancreas. A single-centre, eight-year retrospective study of neuroendocrine neoplasm of GIT and pancreas comprised G2NET, G3NET and NEC. Tumor slides were stained by immunohistochemistry for p53 and ATRX. Strong nuclear staining of > 50% of tumor cells for p53 was considered mutated. Nuclear staining of ATRX in < 5% of tumor cells was considered ATRX loss. Expression of p53 and ATRX was analyzed and correlated with tumor grades and patient survival. Fifty-five patients with gastro-entero-pancreatic neuroendocrine neoplasm were studied, comprising G2NET (58%), G3NET (16%) and NEC (26%). Median age of diagnosis was 59years with male predominance. The pancreas was the most common site followed by the small bowel. NEC showed lower survival compared to G3 and G2NET. Mutated p53 immunohistochemical expression was more frequent among NEC than G3NET. Patients with mutated p53 had significantly lower survival irrespective of the grade (p = 0.001). There was no association of ATRX loss with grade or survival. G3NETs are genetically different from NECs. Use of immunohistochemistry for p53 in addition to histomorphology may facilitate accurate categorization of NEC and G3NET. Mutated p53 may also be used as an independent prognostic marker in neuroendocrine tumors of GIT and pancreas.

Quel bilan anatomo-pathologique ?

The WHO classification of lung tumours on which pathologists base their diagnosis was revised in 2015 on the basis of an international consensus established in 2011 between clinicians, radiologists and pathologists. This resulted in a histo-molecular and prognostic classification of adenocarcinomas. The use of immunohistochemistry for the classification of poorly differentiated non-small cell carcinomas and a new classification adapted to small specimens were defined. These concepts are still relevant today, as the management of small specimens is a key point in the collaboration between the sampling physician and the pathologist.This classification was revised in 2021 and remains broadly the same except for the appearance of new entities: SMARCA4-defident undifferentiated thoracic tumour; bron-chiolar adenoma / muconodular ciliated papillar tumour. Although rare, these lesions have histopathological, clinical and/or molecular appearances that merit their presence as new entities.For invasive adenocarcinomas, the 5 architectural patterns are maintained but the IASLC proposes a grading system which has shown a prognostic impact for early stages.Some clarifications regarding the diagnosis of neuroendocrine tumours/carcinomas were provided.Regarding pleural pathology, mesothelioma in situ is defined and characterised. 1877-1203/© 2024 SPLF. Published by Elsevier Masson SAS. All rights reserved.

Acceptance of emerging renal oncocytic neoplasms: a survey of urologic pathologists

Oncocytic renal neoplasms are a major source of diagnostic challenge in genitourinary pathology; however, they are typically nonaggressive in general, raising the question of whether distinguishing different subtypes, including emerging entities, is necessary. Emerging entities recently described include eosinophilic solid and cystic renal cell carcinoma (ESC RCC), low-grade oncocytic tumor (LOT), eosinophilic vacuolated tumor (EVT), and papillary renal neoplasm with reverse polarity (PRNRP). A survey was shared among 65 urologic pathologists using SurveyMonkey.com (Survey Monkey, Santa Clara, CA, USA). De-identified and anonymized respondent data were analyzed. Sixty-three participants completed the survey and contributed to the study. Participants were from Asia (n = 21; 35%), North America (n = 31; 52%), Europe (n = 6; 10%), and Australia (n = 2; 3%). Half encounter oncocytic renal neoplasms that are difficult to classify monthly or more frequently. Most (70%) indicated that there is enough evidence to consider ESC RCC as a distinct entity now, whereas there was less certainty for LOT (27%), EVT (29%), and PRNRP (37%). However, when combining the responses for sufficient evidence currently and likely in the future, LOT and EVT yielded > 70% and > 60% for PRNRP. Most (60%) would not render an outright diagnosis of oncocytoma on needle core biopsy. There was a dichotomy in the routine use of immunohistochemistry (IHC) in the evaluation of oncocytoma (yes = 52%; no = 48%). The most utilized IHC markers included keratin 7 and 20, KIT, AMACR, PAX8, CA9, melan A, succinate dehydrogenase (SDH)B, and fumarate hydratase (FH). Genetic techniques used included TSC1/TSC2/MTOR (67%) or TFE3 (74%) genes and pathways; however, the majority reported using these very rarely. Only 40% have encountered low-grade oncocytic renal neoplasms that are deficient for FH. Increasing experience with the spectrum of oncocytic renal neoplasms will likely yield further insights into the most appropriate work-up, classification, and clinical management for these entities.

Cowper Glands Identified in Prostate and Urethral Specimens: A Comprehensive Immunohistochemical Characterization and Potential Diagnostic Pitfall.

Cowper glands recognition remains one of the key histoanatomic benign mimics of prostatic adenocarcinoma. In most instances, these can be identified based on the dimorphic population of lobulated acini and duct(s). However, in the prostate biopsy setting with incomplete/distorted cores, this may not be immediately apparent and may warrant use of immunohistochemistry to argue against prostatic adenocarcinoma. Although immunohistochemical pitfalls in Cowper glands have been described, to our knowledge a comprehensive evaluation of both traditional and purportedly prostate-specific novel markers in Cowper glands has not been previously performed. Herein, we studied the clinicopathological and immunohistochemical features of 21 male patients (age range 39-81 years; mean = 63 years), including 15 prostate biopsies (7 of which also had prostate cancer in the same specimen set and 2 of which had both prostate cancer and Cowper glands in the same biopsy core). Immunohistochemistry showed the following results in Cowper glands: 100% positive for NKX3.1, 100% positive (basal cells) for both high molecular weight keratin and p63, 57% positive for PSAP, 25% positive for PSMA, 5% positive for AMACR, and 0% positive for PSA. In conclusion, for specimens lacking appreciable dimorphic morphology, caution should be rendered when using prostate-specific markers (PSA, PSAP, PSMA, and NKX3.1) as these can show considerable staining in Cowper glands and be a pitfall. Instead, findings from this cohort indicate relying on basal markers (high molecular weight keratin/p63; either individually or in a "cocktail" approach) and PSA are most useful in distinguishing Cowper glands (retained basal cell markers staining) from prostatic adenocarcinoma.

Discordant ALK Status in Non-Small Cell Lung Carcinoma: A Detailed Reevaluation Comparing IHC, FISH, and NGS Analyses.

ALK detection was performed on 2813 EGFR-unmutated NSCLC cases by simultaneous use of immunohistochemistry (VENTANA® anti-ALK D5F3, Roche Molecular Systems, Inc., Rotkreuz, Switzerland) and fluorescence in situ hybridization with the ALK break apart and the ALK/EML4 fusion probe (ZytoVision, Bremerhaven, Germany). A total of 33 cases were positive discordant (FISH-positive, IHC-negative) and 17 cases were negative discordant (FISH-negative, IHC-positive). This study's aim was to reevaluate the methods used and compare discordant samples to positive concordant samples in order to ellucidate the differences. FISH signal variants were examined and compared. Positive discordant cases featured one pattern of ALK rearrangement in 41.4%, two patterns in 48.3%, and three patterns in 10.3% of analysed samples, with a higher variability of detected patterns and a higher number of ALK copy gains. Positive concordant cases displayed one pattern of rearrangement in 82%, two patterns in 17.8%, and three patterns in 0.6% of analysed samples. The association between number of patterns and concordance/discordance was statistically significant (p < 0.05). Eleven positive discordant and two negative concordant cases underwent NGS analysis, which resulted in identification of ALK fusion in one positive discordant and two negative discordant cases. Positive protein expression regardless of FISH result correlated more with a positive NGS result compared to samples with a positive FISH result with negative protein expression. FISH analysis was able to detect atypical or heterogenous patterns of rearrangement in a proportion of cases with negative protein expression, which may be associated with more extensive genetic alterations rather than true ALK rearrangement.

Quality Assurance in Immunocytochemistry: A Review and Practical Considerations.

Cytological samples play a critical role in diagnosing advanced-stage tumors and those arising in difficult-to-reach anatomical sites such as the pancreatobiliary tract, lung, thyroid, suprarenal, pelvis, and others such as salivary glands. These samples are often the only available material for accurate diagnosis and for performing ancillary studies, such as immunocytochemistry (ICC) or the detection of molecular biomarkers. While the use of immunohistochemistry is well established and standardized on formalin-fixed-paraffin-embedded histological tissue, in cytological samples, it presents unique challenges. Methods used for obtaining and processing these specimens are complex and are not standardized among laboratories. Moreover, there is also diversity in the types of cytological samples potentially suitable for ICC. This review explores the current landscape of ICC practices in European and North American laboratories, highlighting variability in methods and the need for standardization to ensure reliable results and reproducibility of ICC on cytological specimens.

Retinoic acid receptor-related orphan receptor alpha and synthetic RORα agonist against invasion and metastasis in tongue squamous cell carcinoma

Retinoic acid receptor-related orphan receptor alpha (RORα), an essential tumor suppressor in a range of human malignancies, is classified as a member of the orphan nuclear receptor family. The most prevalent form of oral cancer, tongue squamous cell carcinoma (TSCC) is characterized by its severe malignancy and unfavorable prognosis. However, the extent to which its tumorigenesis mechanisms are associated with RORα expression levels is still not fully understood. The objective of this study was to examine the molecular mechanisms by which RORα is involved in TSCC. Through the use of immunohistochemistry (IHC), it was discovered that the expression level of RORα was significantly downregulated in TSCC tissues when compared to adjacent normal tissues in this study. To further investigate the role of RORα in TSCC, we activated the expression of RORα in human TSCC cell line (SCC9 cells) by transfecting RORα cDNA and using the selective RORα agonist SR1078. The results show that RORα can significantly inhibit the invasion, migration, proliferation, and adhesion of TSCC cells and induce cell apoptosis. In addition, xenograft models confirmed the conclusion that stable activation or treatment with SR1078 to increase RORα content significantly inhibited tumor growth and development. Taken together, this study provides solid evidence for the inhibitory role of RORα in the progression of TSCC. In addition, the preliminary application results of SR1078 in TSCC show that SR1078 is expected to be a potential therapeutic medication for TSCC. These findings provide innovative perspectives on the development of potential biomarkers and agents for TSCC therapy. The objective is to introduce novel strategy and alternatives for the prevention and treatment of TSCC.

Mohs for Melanoma: A Review of MART-1 Frozen Section Interpretation.

Mohs surgery for melanoma has been performed for many decades, but advances in the use of immunohistochemistry with frozen sections during Mohs surgery have allowed for more accurate, reliable, and efficient margin assessment with improved local control of the disease. To describe the use of MART-1 in treating melanoma with Mohs surgery and serve as a primer for the Mohs surgeon adding melanoma cases to their repertoire. Review of the literature and discussion of experience with Mohs for melanoma. Practical approach and pitfalls when assessing margins using MART-1 immunohistochemistry during Mohs surgery for the treatment of melanoma. Mohs for melanoma is an expanding field-education of Mohs surgeons and increasing the practice of this technique has the potential to improve patient outcomes.