Myoepithelial Tumors of Bone With EWSR1::PBX3 Fusion: A Spectrum From Benign to Malignant.

The EWSR1::PBX3 fusion gene, commonly associated with cutaneous syncytial myoepitheliomas, is also found in myoepithelial tumors (METs) of bone and soft tissue. These tumors typically demonstrate benign histology and favorable outcomes. This study examines 6 previously unreported intraosseous METs harboring the EWSR1::PBX3 fusion, focusing on their histopathologic characteristics, immunophenotype, clinical and radiographic profiles, and patient outcomes. The cohort comprised 5 men and 1 woman, aged 25 to 65 years (median age: 31 years), with tumors located in the proximal tibia (3 cases), distal radius (2 cases), and ilium (1 case) and sizes between 3.2 and 12.2 cm (median size: 3.9 cm). Imaging showed osteolytic lesions with varying degrees of cortical involvement and soft tissue extension in 3 cases. Histologically, 4 tumors showed mainly uniform oval-to-spindled cells in syncytial or fascicular arrangements within a collagenous matrix, displaying either bland nuclear features or mild atypia, and low to slightly elevated mitotic activity (≤1 per 10 high-power fields in 3 cases and 6 per 10 high-power fields in 1), classifying them as benign or atypical METs. In contrast, 2 tumors exhibited pronounced nuclear atypia with ovoid, spindled, epithelioid and round cells, hyperchromatic nuclei, inconspicuous nucleoli, increased N/C ratios, high mitotic rates (17 and 19 per 10 high-power fields), and extensive necrosis. Both tumors behaved aggressively-one patient underwent amputation after neoadjuvant chemotherapy and radiation, and the other died within 7 months with the disease still present. Immunohistochemically, the tumors consistently expressed epithelial membrane antigen and S100 but lacked keratin (AE1/AE3) expression. Our study demonstrated that bone METs with EWSR1::PBX3 fusions encompass a histologic continuum from benign to malignant, with benign/atypical METs mirroring their cutaneous analogs in morphology, and malignant variants distinguished by heterogeneous cytologic and architectural features, pronounced nuclear atypia, and high mitotic rates.

Myoepithelial carcinoma of the parotid gland with a novel CTCF::NCOA2 fusion.

We describe a case of a myoepithelial carcinoma of the superficial parotid gland in a 46-year-old male harboring a novel CTCF::NCOA2 gene fusion. To our knowledge, this novel gene fusion has not been described previously in myoepithelial carcinoma. A 46-year-old male patient presented with a mass involving the superficial left parotid gland with extension into the external auditory canal (EAC) and erosion of the conchal cartilage. Histologically, the neoplasm was composed of uniform spindled, epithelioid/ovoid cells arranged in cords and nests within hyalinized to myxoid stroma. On immunohistochemistry (IHC), the tumor cells demonstrated patchy and variable staining for low molecular weight cytokeratin (CAM5.2), pan-cytokeratin (OSCAR), and S-100. Overall, the morphological and immunohistochemical attributes supported a locally aggressive tumor of myoepithelial differentiation consistent with myoepithelial carcinoma. Molecular analysis using a custom 115-gene gene panel by targeted RNA sequencing, showed an in-frame CTCF::NCOA2 fusion. In addition to reporting this novel fusion in myoepithelial carcinoma, we also discuss relevant differential diagnosis, and provide a brief review of NCOA2 gene function in both normal and neoplastic contexts.

Similarities and Differences in the 2019 ISUP and GUPS Recommendations on Prostate Cancer Grading: A Guide for Practicing Pathologists.

Contemporary subspecialization of practice in prostate pathology has seen a transition to complex, nuanced reporting, where a growing number of histopathologic parameters may signal differences in patient management. In this context, the International Society of Urological Pathology (ISUP) and the Genitourinary Pathology Society (GUPS) both published proceedings papers on the grading of prostate cancer in 2019. Overall, the 2 prostate cancer grading manuscripts reached many of the same conclusions and recommendations. Yet, each consensus was conducted somewhat differently, and in a couple of key areas, each reached different conclusions and recommendations. Herein, sourced from the experience and viewpoints of members of both societies, we provide the practicing pathologist a summary of the shared recommendations, and of the discordances. It is anticipated that these 2 documents will inform future iterations of recommendations and guidelines for reporting prostate cancer by organizations such as the College of American Pathologists, the Royal College of Pathologists, and the European Society of Pathology, which will promote best practices for their respective constituents. Our goal is to provide the practicing pathologist a useful catalog of the main points of both, allowing each practitioner to make informed decisions and understand any divergent opinions as may arise between observers for individual cases.

Impact of margin status on survival after radical nephrectomy for renal cell carcinoma.

BACKGROUND: Data about the impact of surgical margin positivity on patient outcomes following radical nephrectomy (RN) for renal cell carcinoma (RCC) is limited. We evaluate the effect of positive surgical margins (PSMs) on relapse-free survival (RFS) and overall survival (OS.) METHODS: Clinicopathologic data of patients who underwent RN for RCC was analyzed based on margin status. χ2 and Student t test were used to compare groups. Cox regression analysis was used for the analysis. Kaplan-Meier method was used for survival curves. RESULTS: A total of 485 patients who underwent RN for RCC were analyzed. Most patients with T1/T2 stage had NSM. Most patients with T4 had PSM. T3 patients were split between the two groups. Analysis of the T3 group showed shorter RFS in the PSM group at 3 years (hazard ratio [HR]: 4.3, p = .01), and 5 years (HR: 4.3, p = .01.) OS analysis showed worse OS in PSM but not statistically significant. There was a significant association between PSM and laterality (p = .023) and histologic type (p = .025.) CONCLUSIONS: PSM was associated with shorter RFS after RN in T3 RCC patients. There was a trend towards worse OS in the PSM group, but it did not reach statistical significance. Laterality and histologic type were associated with surgical margin status.

What Do We Have to Know about PD-L1 Expression in Prostate Cancer? A Systematic Literature Review. Part 4: Experimental Treatments in Pre-Clinical Studies (Cell Lines and Mouse Models).

In prostate cancer (PC), the PD-1/PD-L1 axis regulates various signaling pathways and it is influenced by extracellular factors. Pre-clinical experimental studies investigating the effects of various treatments (alone or combined) may discover how to overcome the immunotherapy-resistance in PC-patients. We performed a systematic literature review (PRISMA guidelines) to delineate the landscape of pre-clinical studies (including cell lines and mouse models) that tested treatments with effects on PD-L1 signaling in PC. NF-kB, MEK, JAK, or STAT inhibitors on human/mouse, primary/metastatic PC-cell lines variably down-modulated PD-L1-expression, reducing chemoresistance and tumor cell migration. If PC-cells were co-cultured with NK, CD8+ T-cells or CAR-T cells, the immune cell cytotoxicity increased when PD-L1 was downregulated (opposite effects for PD-L1 upregulation). In mouse models, radiotherapy, CDK4/6-inhibitors, and RB deletion induced PD-L1-upregulation, causing PC-immune-evasion. Epigenetic drugs may reduce PD-L1 expression. In some PC experimental models, blocking only the PD-1/PD-L1 pathway had limited efficacy in reducing the tumor growth. Anti-tumor effects could be increased by combining the PD-1/PD-L1 blockade with other approaches (inhibitors of tyrosine kinase, PI3K/mTOR or JAK/STAT3 pathways, p300/CBP; anti-RANKL and/or anti-CTLA-4 antibodies; cytokines; nitroxoline; DNA/cell vaccines; radiotherapy/Radium-223).

What Do We Have to Know about PD-L1 Expression in Prostate Cancer? A Systematic Literature Review. Part 5: Epigenetic Regulation of PD-L1.

Epigenetic alterations (including DNA methylation or miRNAs) influence oncogene/oncosuppressor gene expression without changing the DNA sequence. Prostate cancer (PC) displays a complex genetic and epigenetic regulation of cell-growth pathways and tumor progression. We performed a systematic literature review (following PRISMA guidelines) focused on the epigenetic regulation of PD-L1 expression in PC. In PC cell lines, CpG island methylation of the CD274 promoter negatively regulated PD-L1 expression. Histone modifiers also influence the PD-L1 transcription rate: the deletion or silencing of the histone modifiers MLL3/MML1 can positively regulate PD-L1 expression. Epigenetic drugs (EDs) may be promising in reprogramming tumor cells, reversing epigenetic modifications, and cancer immune evasion. EDs promoting a chromatin-inactive transcriptional state (such as bromodomain or p300/CBP inhibitors) downregulated PD-L1, while EDs favoring a chromatin-active state (i.e., histone deacetylase inhibitors) increased PD-L1 expression. miRNAs can regulate PD-L1 at a post-transcriptional level. miR-195/miR-16 were negatively associated with PD-L1 expression and positively correlated to longer biochemical recurrence-free survival; they also enhanced the radiotherapy efficacy in PC cell lines. miR-197 and miR-200a-c positively correlated to PD-L1 mRNA levels and inversely correlated to the methylation of PD-L1 promoter in a large series. miR-570, miR-34a and miR-513 may also be involved in epigenetic regulation.

What Do We Have to Know about PD-L1 Expression in Prostate Cancer? A Systematic Literature Review. Part 3: PD-L1, Intracellular Signaling Pathways and Tumor Microenvironment.

The tumor microenvironment (TME) includes immune (T, B, NK, dendritic), stromal, mesenchymal, endothelial, adipocytic cells, extracellular matrix, and cytokines/chemokines/soluble factors regulating various intracellular signaling pathways (ISP) in tumor cells. TME influences the survival/progression of prostate cancer (PC), enabling tumor cell immune-evasion also through the activation of the PD-1/PD-L1 axis. We have performed a systematic literature review according to the PRISMA guidelines, to investigate how the PD-1/PD-L1 pathway is influenced by TME and ISPs. Tumor immune-escape mechanisms include suppression/exhaustion of tumor infiltrating cytotoxic T lymphocytes, inhibition of tumor suppressive NK cells, increase in immune-suppressive immune cells (regulatory T, M2 macrophagic, myeloid-derived suppressor, dendritic, stromal, and adipocytic cells). IFN-γ (the most investigated factor), TGF-ß, TNF-α, IL-6, IL-17, IL-15, IL-27, complement factor C5a, and other soluble molecules secreted by TME components (and sometimes increased in patients' serum), as well as and hypoxia, influenced the regulation of PD-L1. Experimental studies using human and mouse PC cell lines (derived from either androgen-sensitive or androgen-resistant tumors) revealed that the intracellular ERK/MEK, Akt-mTOR, NF-kB, WNT and JAK/STAT pathways were involved in PD-L1 upregulation in PC. Blocking the PD-1/PD-L1 signaling by using immunotherapy drugs can prevent tumor immune-escape, increasing the anti-tumor activity of immune cells.

Genital verruciform xanthoma: lessons from a contemporary multi-institutional series.

AIMS: Verruciform xanthoma (VX) is an uncommon lesion, seen in the oral mucosa and rarely occurring at cutaneous genital sites. Reports of exceptional VX presentations dominate the literature; herein, we assess the clinical and histological features of a cohort of routine, consecutive cases. METHODS AND RESULTS: Clinicopathological features of genital VXs from four academic centres were reviewed. A cohort of 25 lesions from 24 patients (22 male, two female; median age = 62 years), occurred on the scrotum (84%), penis (8%) and perineum/vulva (8%). VX was never suspected clinically; considerations ranged from fibroepithelial polyps to squamous cell carcinoma. Classic diagnostic criteria were present at least focally in each lesion, including verrucous architecture, prominent wedge-shaped parakeratosis extending between exophytic epidermal projections and neutrophils in the stratum corneum. Xanthomatous cells were present in all cases, but scattered to rare in 24%. CONCLUSIONS: Consecutive genital VXs reliably exhibited classic histopathological features, although the essential finding of xanthomatous cells may be scarce. Our comparison to meta-analyses of published cases found relatively fewer penile and vulvar examples. Additionally, the median age was older than in published series, which have emphasised syndromic associations.

Impact of 2013 ASCO/CAP HER2 reporting guidelines in breast cancer: An assessment study from Indian oncology centre that primarily performs HER2 IHC testing with special emphasis on IHC equivocal category.

The ASCO/CAP guidelines for HER2 reporting in breast cancer published in 2007 and were updated in 2013 to assure that the right patient receives the targeted therapy. The updated guidelines have lowered the threshold for HER2 positivity criteria and altered the equivocal category for both IHC and FISH. This first study from India addresses the impact of these updated guidelines in the various reporting categories at a tertiary care centre. We compared the trend of HER2 IHC reporting 1 year before (Period A) and 1 year after (Period B) the implementation of updated 2013 ASCO/CAP guidelines. All HER2 equivocal IHC cases of post 2013 guidelines were reclassified as per 2007 guidelines to detect additional number of cases that have been put into equivocal category. Reflex FISH correlation was also assessed to detect any additional cases eligible for anti HER2 therapy with implementation of these updated guidelines. With implementation of updated 2013 guidelines, there was significant decrease in the number of cases scored as 1+ (from 30.7% to 20.6%; P value: .0001) while significant increase in number of 2+ cases (from 20.2% to 27.3%; P value: .004). Post 2013 guidelines, 39% (64 cases) of tumors were additionally put into the equivocal category which would have been considered as negative (score 1+) as per 2007 guidelines. The reflex FISH testing in these equivocal cases resulted in detection of only 1.5% of additional cases eligible for anti HER2 therapy. With implementation of updated 2013 guidelines, there is no significant increase in HER2 positivity trend. However, there is appreciable increase in IHC equivocal cases which subsequently led to increased reflex FISH testing without significantly contributing to the detection of additional eligible cases for anti HER2 therapy, but resulted in delaying of definite HER2 status along with financial implications.

Morphological clues to the appropriate recognition of hereditary renal neoplasms.

An important emerging role of the surgical pathologist besides the traditional tasks of establishment of the diagnosis and documentation of prognostic and predictive factors, is to recognize the possibility of a hereditary condition in cases where the histology is suggestive for a familial cancer syndrome. In recent years, the knowledge regarding all of the above roles, including the role of recognition of familial cancer, has particularly expanded in renal neoplasms with the close scrutiny to morphology, molecular correlates and clinical features of the different sub-types of renal cell carcinoma. Awareness of these clinically distinctive sub-types and their associated histologic clues will prompt the pathologist for further immunohistochemical or molecular work up, to look for clinical information to support the suspected diagnosis of familial cancer, to alert managing physician/s to look for stigmata of history of familial cancer, which will permit triaging patients and their families for appropriate genetic counseling. This review provides a comprehensive review of the known sub-types of renal cell carcinoma that have a predilection to occur in the setting of hereditary disease; examples include renal cancers occurring in the background of von Hippel Lindau disease, hereditary leiomyomatosis and renal cell carcinoma syndrome, tuberous sclerosis, Birt Hogg Dube syndrome and succinate dehydrogenase deficiency. Herein we focus on diagnostic clues for renal tumors occurring in a non-pediatric setting that should prompt their correct recognition and reiterate the importance of the correct diagnosis.

Superficial dedifferentiated liposarcoma: A clinicopathologic study.

INTRODUCTION: Dedifferentiation occurs in approximately 10% of atypical lipomatous tumors/well-differentiated liposarcomas (ALT/WDLPS), primarily in retroperitoneal or deep-seated tumors, conferring metastatic potential. Superficial dedifferentiated liposarcoma (sDDLPS) is rare, and its progression and natural history are poorly documented. METHODS: We performed a 15-year retrospective review of our pathology database to identify cases of DDLPS in the skin or subcutaneous tissue. Diagnosis of primary sDDLPS required evidence of non-lipogenic sarcoma in the skin or subcutis, with concurrent ALT/WDLPS and/or MDM2 amplification. RESULTS: We identified 14 cases of DDLPS involving skin or subcutis: 7 primary sDDLPS and 7 secondary lesions (3 from recurrent deep DDLPS and 4 from metastasis). Primary sDDLPS cases (4 females, 3 males; median age: 74) mainly presented as undifferentiated spindle cell or pleomorphic sarcoma. Tumor grades were grade 2 (5 cases) and grade 3 (2 cases), with three cases also showing grade 1 areas. MDM2 amplification was confirmed in 6 sDDLPSs for which FISH was successfully performed. Follow-up available for 6 sDDLPS patients showed 2 local recurrences, treated with re-excision and radiation therapy, with all disease-free at last follow-up (5-126 months). Of the 7 secondary cases, 2 had ongoing disease after multiple recurrences, 1 was disease-free, and all 4 with cutaneous metastasis died of disease (follow-up range: 24-263 months). CONCLUSION: These findings emphasize the importance of distinguishing between primary sDDLPS and secondary lesions due to their distinct prognoses. Metastasis or superficial extensions from deep DDLP correlate with a considerably worse prognosis than those originating in superficial tissues.

Bilateral, multicenteric metanephric adenoma associated with Wilms' tumor in a child: a rare presentation with important diagnostic and therapeutic implications.

Metanephric adenoma is an uncommon benign renal tumor that occurs predominantly in adult females and rarely in children. On histomorphology it shows a resemblance to Wilms' tumor, nephrogenic rests and papillary renal cell carcinoma. Multifocality along with multicentricity has not been documented in English literature till date. From a diagnostic and therapeutic viewpoint, recognition of this entity is of the utmost importance, because it shows a favorable clinical outcome. We describe a rare case of bilateral, multicentric metanephric adenoma associated with triphasic Wilms' tumor (stage II) of the left kidney in a male child.

Urothelial Carcinoma: Divergent Differentiation and Morphologic Subtypes.

Urothelial carcinoma (UC) is known to encompass a wide spectrum of morphologic features and molecular alterations. Approximately 15% to 25% of invasive UC exhibits histomorphologic features in the form of "divergent differentiation" along other epithelial lineages, or different "subtypes" of urothelial or sarcomatoid differentiation. It is recommended that the percentage of divergent differentiation and or subtype(s) be reported whenever possible. Recent advances in molecular biology have led to a better understanding of the molecular underpinning of these morphologic variations. In this review, we highlight histologic characteristics of the divergent differentiation and subtypes recognized by the latest version of WHO classification, with updates on their molecular and clinical features.

Droplet Digital PCR (ddPCR) as a Novel Technology in Detecting CTNNB1 Mutations in Desmoid Fibromatosis.

Desmoid fibromatosis (DF) is a locally aggressive soft tissue neoplasm with frequent recurrences. DF is characterized by alterations in the Wnt/ß-catenin pathway, with the majority showing sporadic mutations in CTNNB1 , whereas others have germline mutations in APC . Immunohistochemical staining for ß-catenin is often difficult to interpret and can be negative in up to 30% of cases. Prior studies have shown that some DFs lacking nuclear expression of ß-catenin may carry activating CTNNB1 mutations. Droplet digital polymerase chain reaction (ddPCR) has been used effectively in detecting mutations in formalin-fixed, paraffin-embedded (FFPE) samples of various cancer types. In this study, we assess the diagnostic utility of ddPCR to detect CTNNB1 mutations in DF with ß-catenin expression on immunohistochemistry (IHC), as well as in diagnostically challenging cases. Of the 28 DFs with nuclear ß-catenin expression by IHC, 24 cases showed a CTNNB1 mutation by ddPCR using primers against the most common point mutations in CTNNB1 . The most frequent mutation was T41A (n=14; 50%), followed by S45F (n=8; 33%) and S45P (n=3;12%). We identified 8 additional (myo)fibroblastic lesions of uncertain classification, which were negative for nuclear ß-catenin expression by IHC. We detected CTNNB1 mutations in 3 unknown lesions, including S45F (n=2) and S45P (n=1). ddPCR is a sensitive, rapid and cost-efficient methodology to detect common CTNNB1 mutations in DF, especially in diagnostically challenging cases.

What Do We Have to Know about PD-L1 Expression in Prostate Cancer? A Systematic Literature Review (Part 6): Correlation of PD-L1 Expression with the Status of Mismatch Repair System, BRCA, PTEN, and Other Genes.

Pembrolizumab (anti-PD-1) is allowed in selected metastatic castration-resistant prostate cancer (PC) patients showing microsatellite instability/mismatch repair system deficiency (MSI-H/dMMR). BRCA1/2 loss-of-function is linked to hereditary PCs and homologous recombination DNA-repair system deficiency: poly-ADP-ribose-polymerase inhibitors can be administered to BRCA-mutated PC patients. Recently, docetaxel-refractory metastatic castration-resistant PC patients with BRCA1/2 or ATM somatic mutations had higher response rates to pembrolizumab. PTEN regulates cell cycle/proliferation/apoptosis through pathways including the AKT/mTOR, which upregulates PD-L1 expression in PC. Our systematic literature review (PRISMA guidelines) investigated the potential correlations between PD-L1 and MMR/MSI/BRCA/PTEN statuses in PC, discussing few other relevant genes. Excluding selection biases, 74/677 (11%) PCs showed dMMR/MSI; 8/67 (12%) of dMMR/MSI cases were PD-L1+. dMMR-PCs included ductal (3%) and acinar (14%) PCs (all cases tested for MSI were acinar-PCs). In total, 15/39 (39%) PCs harbored BRCA1/2 aberrations: limited data are available for PD-L1 expression in these patients. 13/137 (10%) PTEN- PCs were PD-L1+; 10/29 (35%) PD-L1+ PCs showed PTEN negativity. SPOP mutations may increase PD-L1 levels, while the potential correlation between PD-L1 and ERG expression in PC should be clarified. Further research should verify how the efficacy of PD-1 inhibitors in metastatic castration-resistant PCs is related to dMMR/MSI, DNA-damage repair genes defects, or PD-L1 expression.

SMARCA4 (BRG1) and SMARCB1 (INI1) expression in TTF-1 negative neuroendocrine carcinomas including merkel cell carcinoma.

SMARCA4 and SMARCB1 loss of function has been implicated in many different tumors. The objective of this study was to investigate the loss of BRG1 and INI1 expression in TTF-1 negative neuroendocrine carcinomas to see if they are analogous to small-cell carcinoma of the ovary, hypercalcemic type. The potential role of these tumor suppressor genes in high-grade neuroendocrine carcinoma largely remains unknown. Cases of previously diagnosed Small cell carcinoma (SmCC), Large cell neuroendocrine carcinoma (LCNEC) and Merkel cell carcinoma (MCC) were selected. Immunohistochemical expression patterns for BRG1 and INI1 were interpreted as: intact, hybrid and complete loss of nuclear staining. SmCC and LCNEC cases were divided as TTF-1 positive and TTF-1 negative subsets. One case of TTF-1 negative SmCC (lung) showed loss of SMARCA4(BRG1) expression. Amongst TTF-1 negative LCNEC, one case (lung) showed complete loss of SMARCA4(BRG1) and partial loss of SMARCB1(INI1) and one case (lymph node) had hybrid expression of SMARCA4(BRG1) with intact SMARCB1(INI1) expression. All TTF-1 positive cases and all MCC cases showed intact expression of SMARCA4(BRG1) and SMARCB1(INI1). Our study highlights that SMARCA4(BRG1) is deficient in a subset of NEC. Inactivation of SMARCA4 in a subset of TTF-1 negative neuroendocrine carcinomas especially of pulmonary site can be further studied for their therapeutic response to targeted therapy e.g. EZH2 inhibitors. In addition, our study is the first to show that BRG1 and INI1 expression are intact in MCC and hence the biology of MCC might be completely exclusive of these two tumor suppressor genes.

What Do We Have to Know about PD-L1 Expression in Prostate Cancer? A Systematic Literature Review. Part 7: PD-L1 Expression in Liquid Biopsy.

Liquid biopsy is an accessible, non-invasive diagnostic tool for advanced prostate cancer (PC) patients, potentially representing a real-time monitoring test for tumor evolution and response to treatment through the analysis of circulating tumor cells (CTCs) and exosomes. We performed a systematic literature review (PRISMA guidelines) to describe the current knowledge about PD-L1 expression in liquid biopsies of PC patients: 101/159 (64%) cases revealed a variable number of PD-L1+ CTCs. Outcome correlations should be investigated in larger series. Nuclear PD-L1 expression by CTCs was occasionally associated with worse prognosis. Treatment (abiraterone, enzalutamide, radiotherapy, checkpoint-inhibitors) influenced PD-L1+ CTC levels. Discordance in PD-L1 status was detected between primary vs. metastatic PC tissue biopsies and CTCs vs. corresponding tumor tissues. PD-L1 is also released by PC cells through soluble exosomes, which could inhibit the T cell function, causing immune evasion. PD-L1+ PC-CTC monitoring and genomic profiling may better characterize the ongoing aggressive PC forms compared to PD-L1 evaluation on primary tumor biopsies/prostatectomy specimens (sometimes sampled a long time before recurrence/progression). Myeloid-derived suppressor cells and dendritic cells (DCs), which may have immune-suppressive effects in tumor microenvironment, have been found in PC patients circulation, sometimes expressing PD-L1. Occasionally, their levels correlated to clinical outcome. Enzalutamide-progressing castration-resistant PC patients revealed increased PD-1+ T cells and circulating PD-L1/2+ DCs.

What Do We Have to Know about PD-L1 Expression in Prostate Cancer? A Systematic Literature Review. Part 2: Clinic-Pathologic Correlations.

Many studies have investigated the potential prognostic and predictive role of PD-L1 in prostatic carcinoma (PC). We performed a systematic literature review (PRISMA guidelines) to critically evaluate human tissue-based studies (immunohistochemistry, molecular analysis, etc.), experimental research (cell lines, mouse models), and clinical trials. Despite some controversial results and study limitations, PD-L1 expression by tumor cells may be related to clinic-pathologic features of adverse outcome, including advanced tumor stage (high pT, presence of lymph node, and distant metastases), positivity of surgical margins, high Grade Group, and castration resistance. Different PD-L1 positivity rates may be observed in matched primary PCs and various metastatic sites of the same patients. Over-fixation, type/duration of decalcification, and PD-L1 antibody clone may influence the immunohistochemical analysis of PD-L1 on bone metastases. PD-L1 seemed expressed more frequently by castration-resistant PCs (49%) as compared to hormone-sensitive PCs (17%). Some series found that PD-L1 positivity was associated with decreased time to castration resistance. Treatment with ipilimumab, cyclophosphamide/GVAX/degarelix, or degarelix alone may increase PD-L1 expression. Correlation of PD-L1 positivity with overall survival and outcomes related to tumor recurrence were rarely investigated; the few analyzed series produced conflicting results and sometimes showed limitations. Further studies are required. The testing and scoring of PD-L1 should be standardized.

What Do We Have to Know about PD-L1 Expression in Prostate Cancer? A Systematic Literature Review. Part 1: Focus on Immunohistochemical Results with Discussion of Pre-Analytical and Interpretation Variables.

Immunotherapy targeting the PD-1-PD-L1 axis yielded good results in treating different immunologically ''hot'' tumors. A phase II study revealed good therapeutic activity of pembrolizumab in selected prostatic carcinoma (PC)-patients. We performed a systematic literature review (PRISMA guidelines), which analyzes the immunohistochemical expression of PD-L1 in human PC samples and highlights the pre-analytical and interpretation variables. Interestingly, 29% acinar PCs, 7% ductal PCs, and 46% neuroendocrine carcinomas/tumors were PD-L1+ on immunohistochemistry. Different scoring methods or cut-off criteria were applied on variable specimen-types, evaluating tumors showing different clinic-pathologic features. The positivity rate of different PD-L1 antibody clones in tumor cells ranged from 3% (SP142) to 50% (ABM4E54), excluding the single case tested for RM-320. The most tested clone was E1L3N, followed by 22C3 (most used for pembrolizumab eligibility), SP263, SP142, and 28-8, which gave the positivity rates of 35%, 11-41% (depending on different scoring systems), 6%, 3%, and 15%, respectively. Other clones were tested in <200 cases. The PD-L1 positivity rate was usually higher in tumors than benign tissues. It was higher in non-tissue microarray specimens (41-50% vs. 15%), as PC cells frequently showed heterogenous or focal PD-L1-staining. PD-L1 was expressed by immune or stromal cells in 12% and 69% cases, respectively. Tumor heterogeneity, inter-institutional preanalytics, and inter-observer interpretation variability may account for result biases.

Follicular Lymphoma Diagnosed in Warthin Tumor: A Case Report and Review of the Literature.

Warthin tumor is one of the most common benign salivary gland tumors. It is unusual and difficult to diagnose follicular lymphoma within the lymphoid tissue of Warthin tumor. We present a rare case of a 69-year-old man with systemic follicular lymphoma initially diagnosed in a Warthin tumor. Lymphomas occurring within Warthin tumors are rare, however, follicular lymphoma is most commonly reported. Because these patients require further treatment depending on the stage of a disease, it is important for a pathologist to review the histology of Warthin tumors diligently to identify occult lymphomas.