MMR deficiency in urothelial carcinoma of the bladder presents with temporal and spatial homogeneity throughout the tumor mass

Prognostic and predictive value of tertiary lymphoid structures in TURBT materials: Should it be seated in the routine pathological examination, and can it be used in deciding on the treatment method?

OBJECTIVE

This study aims to reveal the importance of tertiary lymphoid structures (TLS) in transurethral resection of bladder tumor (TURBT) materials with a practical and applicable method in which the effect of a certain threshold value on survival and treatment response can be implicated.

METHODS

TURBT materials that had not previously received any treatment (chemotherapy, radiotherapy, or immunotherapy) and were diagnosed for the first time at Mardin Training and Research Hospital between 2014 and 2022 were included in the study. The maximum TLS per 4× magnification field (field diameter: 4.5 mm) was recorded. Grouping and statistical analysis of the TLS number were performed using threshold values of "≥1", "≥2", and "≥3".

RESULTS

TLSs were more frequently found in high-grade tumors (P = 0.008) and showed a strong association with stage progression (P < 0.001). It was also significantly associated with many adverse histopathological parameters. Conversely, high TLS (≥1, ≥2, and ≥3) appeared to be associated with fewer recurrences (P = 0.032, P = 0.001, and P = 0.018, respectively), and cases with higher TLS showed longer recurrence-free survival (P = 0.089, P = 0.023, P = 0.037, respectively). TLS≥3 was found to be an independent parameter that was associated with favorable RFS (P = 0.019, HR = 0.401), and multifocality was found to be an independent risk factor for RFS (P = 0.023, HR = 2.302).

CONCLUSION

This study is the first to demonstrate the relationship between the presence and specific thresholds of TLS in TURBT materials with prognostic parameters. Including this information in the routine pathological examination of TURBT materials will allow a more accurate approach to treatment and follow-up, especially in patients with non-muscle invasive bladder cancer (NMIBC).

MSH2-Mutated Lynch Syndrome With 9 Synchronous Colon and Rectum Adenocarcinomas: An Extremely Rare Case Report

Synchronous colorectal carcinoma is having more than 1 primary carcinoma detected in a single patient at the same time or within 6 months of tumor diagnosis. Metachronous colorectal carcinoma is the presence of more than 1 primary carcinoma detected consecutively in a single person after a set time interval. Patients with Lynch syndrome and Muir-Torre syndrome (a subset of Lynch syndrome) inherit a germline mutation in 1 of the mismatch repair (MMR) genes. Patients with synchronous colorectal carcinoma have a higher proportion of MMR-mutated cancers than patients with solitary colorectal carcinoma. Most studies in the literature indicate that patients with synchronous colorectal cancers typically have only 2 carcinomas. However, there have been reports of a single patient having up to 6 synchronous carcinomas in the large intestine. This report discusses a patient with 9 simultaneous colorectal cancers at the initial diagnosis, along with a history of bladder cancer, sebaceous adenoma, and duodenal adenoma, associated with a germline mutS homolog 2 (MSH2) mutation. Additionally, the report explores various aspects of having synchronous colorectal cancers. More studies are needed to clarify the clinicopathologic and molecular landscape of these rare tumors and identify the best management and treatment strategies for these patients.

The Evolving Molecular Landscape and Actionable Alterations in Urologic Cancers

The genetic landscape of urologic cancers has evolved with the identification of actionable mutations that impact diagnosis, prognosis, and therapeutic strategies. This narrative review consolidates existing literature on genetic mutations across key urologic cancers, including bladder, renal, prostate, upper tract urothelial, testicular, and penile. The review highlights mutations in DNA damage repair genes, such as BRCA1/2 and PTEN, as well as pathway alterations like FGFR and PD-L1 overexpression. These mutations influence tumor behavior and therapeutic outcomes, emphasizing the need for precision oncology approaches. Molecular profiling, through tools like next-generation sequencing, has revolutionized patient care by enabling targeted treatment strategies, especially in cancers with distinct molecular subtypes such as luminal or basal bladder cancer and clear cell renal carcinoma. Emerging therapies, including FGFR inhibitors and immune checkpoint blockade, offer new treatment avenues, although resistance mechanisms remain a challenge. We also emphasize the importance of biomarker identification for personalized management, especially in metastatic settings where treatment intensification is often required. Future research is needed to further elucidate our understanding of the genetics affecting urologic cancers, which will help develop novel, individualized therapies to enhance oncologic outcomes.

The Evolving Landscape of Biomarkers for Immune Checkpoint Blockade in Genitourinary Cancers

In the past decade, immune checkpoint inhibitors (ICI) have been approved for treatment of genitourinary malignancies and have revolutionized the treatment landscape of these tumors. However, despite the remarkable success of these therapies in some GU malignancies, many patients' tumors do not respond to these therapies, and others may experience significant side effects, such as immune-related adverse events (iRAEs). Accordingly, biomarkers and improved prognostic tools are critically needed to help predict which patients will respond to ICI, predict and mitigate risk of developing immune-related adverse events, and inform personalized choice of therapy for each patient. Ongoing clinical and preclinical studies continue to provide an increasingly robust understanding of the mechanisms of the response to immunotherapy, which continue to inform biomarker development and validation. Herein, we provide a comprehensive review of biomarkers of the response to immunotherapy in GU tumors and their role in selection of therapy and disease monitoring.

Clinical features and oncological outcomes of bladder cancer microsatellite instability

OBJECTIVES

Excellent anticancer effect for solid tumors with microsatellite instability (MSI)-high by anti-PD-1 antibody has been reported. In this study, we investigated the clinical impact of MSI status in bladder cancer.

METHODS

This study included 205 Japanese patients who underwent transurethral resection for bladder cancer between 2005 and 2021. The prevalence rates of microsatellite stable (MSS), MSI-low (MSI-L), and MSI-high (MSI-H) were determined using molecular testing. We examined the association of MSI status (MSS versus MSI-L/H) with clinicopathological characteristics and oncological outcomes.

RESULTS

MSI-L/H tumors were associated with higher T-category in non-muscle invasive bladder cancer (NMIBC). Additionally, MSI-L/H tumors were associated with a higher risk of intravesical recurrence in NMIBC patients treated with intravesical bacillus Calmette-Guérin (BCG) but not with non-BCG therapy.

CONCLUSIONS

This study suggested that the MSI status might serve as a predictive marker for intravesical recurrence after BCG intravesical therapy in NMIBC and highlighted an unmet need for an alternative treatment in patients with MSI-L/H tumors.

Mismatch repair deficiency and microsatellite instability in urothelial carcinoma: a systematic review and meta-analysis

Background

Mismatch repair deficiency (dMMR) and microsatellite instability-high (MSI-H) occur in a subset of cancers and have been shown to confer sensitivity to immune checkpoint inhibition (ICI); however, there is a lack of prospective data in urothelial carcinoma (UC).

Methods and analysis

We performed a systematic review to estimate the prevalence of dMMR and MSI-H in UC, including survival and clinical outcomes. We searched for studies published up to 26 October 2022 in major scientific databases. We screened 1745 studies and included 110. Meta-analyses were performed if the extracted data were suitable.

Results

The pooled weighted prevalences of dMMR in bladder cancer (BC) and upper tract UC (UTUC) were 2.30% (95% CI 1.12% to 4.65%) and 8.95% (95% CI 6.81% to 11.67%), respectively. The pooled weighted prevalences of MSI-H in BC and UTUC were 2.11% (95% CI 0.82% to 5.31%) and 8.36% (95% CI 5.50% to 12.53%), respectively. Comparing localised versus metastatic disease, the pooled weighted prevalences for MSI-H in BC were 5.26% (95% CI 0.86% to 26.12%) and 0.86% (95% CI 0.59% to 1.25%), respectively; and in UTUC, they were 18.04% (95% CI 13.36% to 23.91%) and 4.96% (95% CI 2.72% to 8.86%), respectively. Cumulatively, the response rate in dMMR/MSI-H metastatic UC treated with an ICI was 22/34 (64.7%) compared with 1/9 (11.1%) with chemotherapy.

Conclusion

Both dMMR and MSI-H occur more frequently in UTUC than in BC. In UC, MSI-H occurs more frequently in localised disease than in metastatic disease. These biomarkers may predict sensitivity to ICI in metastatic UC and resistance to cisplatin-based chemotherapy.

Pan-keratin Immunostaining in Human Tumors: A Tissue Microarray Study of 15,940 Tumors

To evaluate the efficiency of pan-keratin immunostaining, tissue microarrays of 13,501 tumor samples from 121 different tumor types and subtypes as well as 608 samples of 76 different normal tissue types were analyzed by immunohistochemistry. In normal tissues, strong pan-keratin immunostaining was seen in epithelial cells. Staining intensity was lower in hepatocytes, islets of Langerhans, and pneumocytes but markedly reduced in the adrenal cortex. Pan-keratin was positive in ≥98% of samples in 62 (83%) of 75 epithelial tumor entities, including almost all adenocarcinomas, squamous cell and urothelial carcinomas. Only 17 of 121 tumor entities (13%) had a pan-keratin positivity rate between 25% and 98%, including tumors with mixed differentiation, endocrine/neuroendocrine tumors, renal cell carcinomas, adrenocortical tumors, and particularly poorly differentiated carcinoma subtypes. The 15 entities with pan-keratin positivity in 0.9%-25% were mostly of mesenchymal origin. Reduced/absent pan-keratin immunostaining was associated with high UICC stage (p = 0.0001), high Thoenes grade (p = 0.0183), high Fuhrman grade (p = 0.0049), advanced tumor stage (p < 0.0001) and lymph node metastasis (p = 0.0114) in clear cell renal cell carcinoma, advanced pT stage (p = 0.0007) in papillary renal cell carcinoma, and with advanced stage (p = 0.0023), high grade (p = 0.0005) as well as loss of ER and PR expression (each p < 0.0001) in invasive breast carcinoma of no special type (NST). In summary, pan-keratin can consistently be detected in the vast majority of epithelial tumors, although pan-keratin can be negative a fraction of renal cell, adrenocortical and neuroendocrine neoplasms. The data also link reduced pan-keratin immunostaining to unfavorable tumor phenotype in in epithelial neoplasms.

P63 and Ki-67 expression in radicular cyst

Objectives

The aim of the current study was to identify the expression of P63 and its relation to odontogenic epithelial cell proliferation, severity of the inflammatory infiltrate and size of radicular cysts (RCs).

Methods

In this retrospective cross-sectional study, 30 cases of paraffin-embedded RCs were randomly selected from the archive. P63 and Ki-67 expression was assessed by immunohistochemistry.

Results

Epithelial P63 expression was absent in four (13.3%), weak in 10 (33.3%), and moderate in 16 (53.3%) cases. In the connective tissue wall of RC, P63 expression was absent in two (6.7%) cases, weak in 24 (80.0%) cases, and moderate in four (13.3%) cases. Ki-67 was found to be weakly expressed in 12 (40.0%) cases, moderately expressed in 13 (43.3%), and strongly expressed in five (16.7%) cases. No correlation was found between Ki-67 expression in odontogenic epithelium and P63 expression in the odontogenic epithelium (rho = 0.110, p = .563) or fibrous capsule (rho = 0.160, p = .399). Nevertheless, we found a positive correlation between Ki-67 expression in the odontogenic epithelium and the size of the RC (rho = 0.450, p = .013). The inflammatory infiltrate was negatively correlated with P63 expression in the odontogenic epithelium (rho = -0.428, p = .018), and with the size of cysts (rho = -0.728, p < .001).

Conclusions

There is a high expression of P63 throughout the odontogenic epithelium and connective tissue capsule of the RC. P63 expression in the odontogenic epithelium is negatively correlated with the degree of the inflammatory infiltrate but not with epithelial cell proliferation or the size of the cyst.

Cross-species oncogenomics offers insight into human muscle-invasive bladder cancer

BACKGROUND

In humans, muscle-invasive bladder cancer (MIBC) is highly aggressive and associated with a poor prognosis. With a high mutation load and large number of altered genes, strategies to delineate key driver events are necessary. Dogs and cats develop urothelial carcinoma (UC) with histological and clinical similarities to human MIBC. Cattle that graze on bracken fern also develop UC, associated with exposure to the carcinogen ptaquiloside. These species may represent relevant animal models of spontaneous and carcinogen-induced UC that can provide insight into human MIBC.

RESULTS

Whole-exome sequencing of domestic canine (n = 87) and feline (n = 23) UC, and comparative analysis with human MIBC reveals a lower mutation rate in animal cases and the absence of APOBEC mutational signatures. A convergence of driver genes (ARID1A, KDM6A, TP53, FAT1, and NRAS) is discovered, along with common focally amplified and deleted genes involved in regulation of the cell cycle and chromatin remodelling. We identify mismatch repair deficiency in a subset of canine and feline UCs with biallelic inactivation of MSH2. Bovine UC (n = 8) is distinctly different; we identify novel mutational signatures which are recapitulated in vitro in human urinary bladder UC cells treated with bracken fern extracts or purified ptaquiloside.

CONCLUSION

Canine and feline urinary bladder UC represent relevant models of MIBC in humans, and cross-species analysis can identify evolutionarily conserved driver genes. We characterize mutational signatures in bovine UC associated with bracken fern and ptaquiloside exposure, a human-linked cancer exposure. Our work demonstrates the relevance of cross-species comparative analysis in understanding both human and animal UC.

High Homogeneity of Mesothelin Expression in Primary and Metastatic Ovarian Cancer

To study the extent of heterogeneity of mesothelin overexpression in primary ovarian cancers and their peritoneal and lymph node metastases, a tissue microarray (TMA) was constructed from multiple sites of 220 ovarian cancers and analyzed by immunohistochemistry. One tissue core each was taken from up to 18 different tumor blocks per cancer, resulting in a total of 2460 tissue spots from 423 tumor sites (188 primary cancers, 162 peritoneal carcinosis, and 73 lymph node metastases). Positive mesothelin expression was found in 2041 of the 2342 (87%) arrayed tissue spots and in 372 of the 392 (95%) tumor sites that were interpretable for mesothelin immunohistochemistry. Intratumoral heterogeneity was found in 23% of 168 primary cancer sites interpretable for mesothelin and decreased to 12% in 154 peritoneal carcinosis and to 6% in 71 lymph node metastases ( P <0.0001). Heterogeneity between the primary tumor and matched peritoneal carcinosis was found in 16% of 102 cancers with interpretable mesothelin results. In these cancers, the mesothelin status switched from positive in the primary tumor to negative in the peritoneal carcinosis (3 cancers) in or vice versa (2 cancers), or a mixture of positive and negative peritoneal carcinoses was found (11 cancers). No such switch was seen between the mesothelin-interpretable primary tumors and their nodal metastases of 59 cancers, and only 1 mesothelin-positive tumor had a mixture of positive and negative lymph node metastases. In conclusion, mesothelin expression is frequent and highly homogeneous in ovarian cancer.

WRN Is a Promising Synthetic Lethal Target for Cancers with Microsatellite Instability (MSI)

Microsatellite instability (MSI), a type of genetic hypermutability arising from impaired DNA mismatch repair (MMR), is observed in approximately 3% of all cancers. Preclinical work has identified the RecQ helicase WRN as a promising synthetic lethal target for patients with MSI cancers. WRN depletion substantially impairs the viability of MSI, but not microsatellite stable (MSS), cells. Experimental evidence suggests that this synthetic lethal phenotype is driven by numerous TA dinucleotide repeats that undergo expansion mutations in the setting of long-standing MMR deficiency. The lengthening of TA repeats increases their propensity to form secondary DNA structures that require WRN to resolve. In the absence of WRN helicase activity, these unresolved DNA secondary structures stall DNA replication forks and induce catastrophic DNA damage.

Immunohistochemical Study of Bladder Cancer Molecular Subtypes and Their Association with PD-L1 Expression

The significant heterogeneity in clinical outcomes among patients with bladder cancer has highlighted the existence of different biological subtypes of muscle-invasive bladder cancer (MIBC) and non-muscle-invasive bladder cancer (NMIBC). Meanwhile, immune checkpoint proteins and their interference with tumor-related immune-evasive strategies has led to the development of several immunotherapeutic drugs targeting programmed death-1 (PD-1) or programmed death ligand-1 (PD-L1). However, the lack of any known biomarker that could predict responses to immunotherapy has led to a more agnostic therapeutic approach. Here, we present a study conducted in 77 bladder cancer (BC) patients (n = 77), ranging from stages pTa to pT2. Tumor specimens were resected via transurethral resection of bladder tumor (TURBT) and consistuted of 24 low-grade (LG) and 53 high-grade (HG) tumors. Patients' tumors were then categorized into molecular subtypes, via immunohistochemistry (CK5/6 and GATA3). Furthermore, all tumor specimens were stained with anti-PD-L1 and demonstrated significant correlations with basal immunophenotype, stage pT2 and HG tumors. As such, we attempted to stratify patients into groups of likely-responders and likely-not-responders to immunotherapy with anti-PD-L1, based on their molecular phenotype. Finally, in acknowledging the fact that there is a universal lack of biomarkers associated with predicting BC response to immunotherapeutic drugs, we tested all tumors for deficiency of mismatch repair proteins (MMR).

Investigation of prognostic biomarkers in patients with urothelial carcinoma treated with platinum-based regimens

BACKGROUND

Bladder cancer (BC) is a heterogeneous malignancy with dismal outcome.

PATIENTS AND METHODS

Mutations in genes, altered or linked to platinum sensitivity in BC, were examined in 66 patients' tumors along with tumor infiltrating lymphocytes (TILs) density and MMR, PD-L1 and CD8 protein expression, as well as basal and luminal subtypes, defined by protein expression of markers, including CK5/6 and GATA3 or CK20, respectively.

RESULTS

41 tumors harbored mutations, mainly in TP53 (38%), ARID1A (17%) and the DNA damage response and repair (DDR) genes ERCC2 (17%) and BRCA2 (15%). Mutations in other DDR relevant genes were also present. Age showed unfavorable prognosis for overall survival (HR=1.07, P = 0.026); no benefit was seen for patients with TP53, ARID1A, ERCC2 or BRCA2 mutations or mutations in 1 or more DDR genes. PD-L1 status positively correlated with stromal (rho=0.46, P < 0.001) and intratumoral (rho=0.53, P < 0.001) CD8 expression or TILs (rho=0.29, P = 0.018); none associated with overall survival (OS). A statistically significant difference was observed between PD-L1 status and immunohistochemistry (IHC)‑based subtypes, with tumors classified as luminal (GATA3+ and/or CK20+ and CK5/6-) showing lower PD-L1 expression relative to basal (CK5/6+ and GATA3- and/or CK20-) (median value 0 vs. 2.5, P = 0.029). Concerning OS, no statistically significant difference was seen among patients with basal or luminal tumors.

CONCLUSION

No association was seen herein between DDR mutations, TILs, PD-L1, CD8 expression or IHC-based subtypes and patient survival; these observations warrant validation within a larger cohort.

Microsatellite Instability: From the Implementation of the Detection to a Prognostic and Predictive Role in Cancers

Microsatellite instability (MSI) has been identified in several tumors arising from either germline or somatic aberration. The presence of MSI in cancer predicts the sensitivity to immune checkpoint inhibitors (ICIs), particularly PD1/PD-L1 inhibitors. To date, the predictive role of MSI is currently used in the selection of colorectal cancer patients for immunotherapy; moreover, the expansion of clinical trials into other cancer types may elucidate the predictive value of MSI for non-colorectal tumors. In clinical practice, several assays are used for MSI testing, including immunohistochemistry (IHC), polymerase chain reaction (PCR) and next-generation sequencing (NGS). In this review, we provide an overview of MSI in various cancer types, highlighting its potential predictive/prognostic role and the clinical trials performed. Finally, we focus on the comparison data between the different assays used to detect MSI in clinical practice.

[Immunological biomarker research in uro-oncology-using the example of urothelial cancer]

The most common malignant tumor of the urinary tract system is urothelial carcinoma (UC). With the introduction of novel immunologic therapy options in both metastatic and localized settings, the exploration of immunologic biomarkers to predict potential treatment success has become a focus of clinical translational research. For example, expression levels of programmed cell death ligand 1 (PD-L1) in UC tumors can help clinicians decide which patients are more likely to respond to immuno-oncology therapies; in light of new approvals with mandated PD-L1 testing (e.g., adjuvant nivolumab therapy after radical cystectomy), harmonization of PD-L1 testing is becoming increasingly important. However, in addition to PD-L1 determination, broader potentially predictive biomarkers such as tumor mutational burden and immune signatures/phenotypes have been and continue to be investigated in clinical trials. This review will provide a streamlined overview of existing evidence and new developments in the field of urothelial carcinoma.

Morphological predictors for microsatellite instability in urothelial carcinoma

Introduction

Microsatellite instability occurs due to a series of mutations in the DNA pairing error repair (Mismatch repair; MMR) genes, which can affect germ cells as occurs in Lynch syndrome, whose patients are at high risk of developing multiple cancers. The loss of MMR protein is commonly determined by immunohistochemical studies. Although the relation between microsatellite instability and urothelial carcinomas has been widely studied, its evaluation is not currently performed in the analysis of urothelial carcinomas.

Methods

In this study, the microsatellite status of 139 urothelial carcinomas was analyzed and their clinicopathological characteristics were evaluated. We identified that 10.3% (13 patients) of urothelial carcinomas had loss of MMR protein expression (9 MLH1; 5 MSH2; 2 PMS2; 2 PSH6; n = 139).

Results

Results suggest that these tumors occur more frequently in males, are more frequently located in the bladder or ureters, and present a high tumor grade with a papillary histological pattern that does not infiltrate the lamina propria or, in the case of infiltrating tumors, that grows into perivesical tissues.

Conclusions

We identified patients with the aforementioned tumor characteristics as patients with a high probability of presenting loss of MMR protein expression, and consider that only these patients should undergo further immunohistochemical and molecular techniques for proper diagnosis. Therefore, we propose that the clinicopathological characteristics found in the present study could become possible markers to determine which cases should undergo additional tests.

Prognostic influence of microsatellite alterations of muscle-invasive bladder cancer treated with radical cystectomy

OBJECTIVE

To examine the prognostic effect of microsatellite instability (MSI) and loss of heterozygosity (LOH) on cancer-specific survival (CSS) in patients with muscle-invasive bladder cancer (MIBC).

PATIENTS AND METHODS

The liquid nitrogen-preserved specimens of 220 patients between March 2009 and December 2012 were analyzed for the presence of MSI and LOH in 12 loci (ACTBP2, D16S310, D16S476, D18S51, D4S243, D9S162, D9S171, D9S747, FGA, INF-α, MBP, MJD) using polymerase chain reaction. MSI was defined as MSI-stable, MSI-Low, or MSI-High if instability was detected in 0, 1, or 2 or more of the examined markers, respectively. The association between MSI-High and LOH and CSS was analyzed using uni- and multivariate analyses and the degree of agreement between tumor and urine samples were determined.

RESULTS

MSI were found in 1030 (39%) and 1148 (43.5%) in tumor and urine specimens, respectively (Kappa = 0.77). On the other hand, LOH was found in 163 (6.2%) of tumor tissues and 44 (1.7%) in urine specimens (Kappa = 0.34). Microsatellite alterations were significantly associated with worse CSS at 1- and 5-year in tumor tissue (95% and 83.7% vs. 65.8% and 3.5%, respectively; P < 0.001) and in urine sample (90% and 64% vs. 46.5% and 9.3%, respectively; P < 0.001). MSI and/or LOH was an independent predictor of CSS (HR: 9.8; 95%CI: 5.1-18.9; P < 0.001).

CONCLUSIONS

Microsatellite alterations were potentially an independent predictor of CSS in patients with MIBC. The agreement was good between tumor and urine MSI but weak for LOH.

Immunohistochemically detectable thyroglobulin expression in extrathyroidal cancer is 100% specific for thyroidal tumor origin

Thyroglobulin is a secreted 660 kDa glycoprotein produced by thyroid follicular cells used in diagnostic pathology to secure or exclude a thyroidal origin of metastases of unknown primary tumors. This study was performed to estimate specificity of thyroglobulin immunohistochemistry. 9974 tumor samples from 109 different tumor types and subtypes as well as 608 samples of 76 different normal tissue types were analyzed by immunohistochemistry in a tissue microarray format. Thyroglobulin was strongly expressed in all normal thyroid samples but not in any other normal tissues. Thyroglobulin immunostaining was detected in 99.1% of 106 thyroid adenomas, 98.1% of 364 papillary, 95.2% of 147 follicular, and 7.5% of 40 anaplastic thyroid cancers. Twelve of 15 thyroid samples that were thyroglobulin negative on TMAs showed at least a weak focal thyroglobulin positivity in corresponding large sections, suggesting higher sensitivity of large section analysis. Thyroglobulin positivity in one diffuse large B-cell lymphoma of the thyroid, one chondrosarcoma metastasis to the thyroid, and 42.4% of 92 medullary thyroid cancers was considered to be caused by diffusion of thyroidal colloid from destroyed or even intact adjacent follicles. Thyroglobulin positivity was, however, not seen in 6403 extrathyroidal tumors from 104 different tumor types and subtypes. Our data demonstrate a complete specificity of positive thyroglobulin immunostaining for thyroid origin in tumor tissues obtained from extrathyroidal locations. However, for all tumors located within the thyroid, false positivity can occur as a result of tissue contamination by thyroglobulin rich thyroid colloid from adjacent normal tissue.

Society for Immunotherapy of Cancer (SITC) clinical practice guideline on immunotherapy for the treatment of urothelial cancer

A number of immunotherapies have been developed and adopted for the treatment of urothelial cancer (encompassing cancers arising from the bladder, urethra, or renal pelvis). For these immunotherapies to positively impact patient outcomes, optimal selection of agents and treatment scheduling, especially in conjunction with existing treatment paradigms, is paramount. Immunotherapies also warrant specific and unique considerations regarding patient management, emphasizing both the prompt identification and treatment of potential toxicities. In order to address these issues, the Society for Immunotherapy of Cancer (SITC) convened a panel of experts in the field of immunotherapy for urothelial cancer. The expert panel developed this clinical practice guideline (CPG) to inform healthcare professionals on important aspects of immunotherapeutic treatment for urothelial cancer, including diagnostic testing, treatment planning, immune-related adverse events (irAEs), and patient quality of life (QOL) considerations. The evidence- and consensus-based recommendations in this CPG are intended to give guidance to cancer care providers treating patients with urothelial cancer.

Diagnostic and prognostic impact of cytokeratin 19 expression analysis in human tumors: a tissue microarray study of 13,172 tumors

To evaluate cytokeratin 19 (CK19) expression in normal and cancerous tissues, 15,977 samples from 122 tumor types and 608 samples of 76 normal tissue types were analyzed by immunohistochemistry (IHC). In normal tissues, CK19 expression occurred in epithelial cells of most glandular organs but was strictly limited to the basal cell layer of nonkeratinizing squamous epithelium and absent in the skin. CK19 expression in ≥90% of cases was seen in 34% of the tumor entities including the adenocarcinomas of the pancreas (99.4%), colorectum (99.8%), esophagus (98.7%), and stomach (97.7%), as well as breast cancer (90.0%-100%), high-grade serous (99.1%) or endometrioid (97.8%) ovarian cancer, and urothelial carcinoma (92.6%-100%). A low CK19 positivity rate (0.1-10%) was seen in 5 of 122 tumor entities including hepatocellular carcinoma and seminoma. A comparison of tumor versus normal tissue findings demonstrated that upregulation and downregulation of CK19 can occur in cancer and that both alterations can be linked to unfavorable phenotypes. CK19 downregulation was linked to high grade (p = 0.0017) and loss of estrogen receptor- and progesterone receptor-expression (p < 0.0001 each) in invasive breast carcinoma of no special type. CK19 upregulation was linked to nodal metastases in neuroendocrine tumors and papillary thyroid carcinomas (p < 0.05 each) and to poor grade in clear cell renal cell carcinoma (p < 0.05). CK19 upregulation was particularly common in squamous cell carcinomas. We concluded that CK19 IHC might separate primary liver cell carcinoma from liver metastases, seminoma from other testicular tumors, and helps in the detection of early neoplastic transformation in squamous epithelium.

Mismatch repair deficiency occurs very rarely in seminomas

Background

Dense tumor-associated lymphocyte infiltration is linked to mismatch repair (MMR) deficiency in colorectal and endometrial cancer. MMR deficiency is of high clinical importance as MMR deficient cancers tend to react favorably to treatment with immune checkpoint inhibitors. Strong lymphocytic infiltration is a morphological hallmark of seminomas. We thus asked whether seminomas may exhibit MMR deficiency at relevant frequency.

Methods

To screen for tumors with MMR deficiency, protein expression of MLH1, PMS2, MSH2, and MSH6 was analyzed by immunohistochemistry (IHC) on a tissue microarray (TMA) containing 574 seminomas.

Results

In total, 536 cases were evaluable resulting in 481 seminomas with unequivocally intact MMR protein expression. In 55 cancers, one or several IHC stains were equivocal and lacked detectable MMR protein in both tumor and stromal cells. Large section IHC analysis of all 55 equivocal cases demonstrated substantial staining issues due to improper fixation in 54 cases and identified one tumor with clear-cut MLH1 and PMS2 protein loss. This seminoma showed homogeneous loss of MLH1 and PMS2 in the entire tumor mass whereas minor adjacent foci of associated germ cell neoplasia in situ (GCNIS) were MMR intact. Polymerase chain reaction (PCR) analysis using the 5 microsatellite loci of the “Bethesda Panel” revealed instability in 1 of 4 interpretable loci (“MSI-low”) and additional instability of the complex tetra-penta repeat locus MYCL1 in this tumor.

Conclusions

In summary, one single seminoma with MMR deficiency, characterized by protein loss of MLH1 and PMS2, was identified among 536 interpretable seminomas (0.19%). MMR deficiency is not a relevant determinant of lymphocyte influx in seminoma.

Diagnostic and prognostic impact of cytokeratin 18 expression in human tumors: a tissue microarray study on 11,952 tumors

BACKGROUND

Cytokeratin 18 (CK18) is an intermediate filament protein of the cytokeratin acidic type I group and is primarily expressed in single-layered or "simple" epithelial tissues and carcinomas of different origin.

METHODS

To systematically determine CK18 expression in normal and cancerous tissues, 11,952 tumor samples from 115 different tumor types and subtypes (including carcinomas, mesenchymal and biphasic tumors) as well as 608 samples of 76 different normal tissue types were analyzed by immunohistochemistry in a tissue microarray format.

RESULTS

CK18 was expressed in normal epithelial cells of most organs but absent in normal squamous epithelium. At least an occasional weak CK18 positivity was seen in 90 of 115 (78.3%) tumor types. Wide-spread CK18 positivity was seen in 37 (31.9%) of tumor entities, including adenocarcinomas of the lung, prostate, colon and pancreas as well as ovarian cancer. Tumor categories with variable CK18 immunostaining included cancer types arising from CK18 positive precursor cells but show CK18 downregulation in a fraction of cases, tumor types arising from CK18 negative precursor cells occasionally exhibiting CK18 neo-expression, tumors derived from normal tissues with variable CK18 expression, and tumors with a mixed differentiation. CK18 downregulation was for example seen in renal cell cancers and breast cancers, whereas CK18 neo-expression was found in squamous cell carcinomas of various origins. Down-regulation of CK18 in invasive breast carcinomas of no special type and clear cell renal cell carcinomas (ccRCC) was related to adverse tumor features in both tumors (p ≤ 0.0001) and poor patient prognosis in ccRCC (p = 0.0088). Up-regulation of CK18 in squamous cell carcinomas was linked to high grade and lymph node metastasis (p < 0.05). In summary, CK18 is consistently expressed in various epithelial cancers, especially adenocarcinomas.

CONCLUSIONS

Down-regulation or loss of CK18 expression in cancers arising from CK18 positive tissues as well as CK18 neo-expression in cancers originating from CK18 negative tissues is linked to cancer progression and may reflect tumor dedifferentiation.

p63 expression in human tumors and normal tissues: a tissue microarray study on 10,200 tumors

Background

Tumor protein 63 (p63) is a transcription factor of the p53 gene family involved in differentiation of several tissues including squamous epithelium. p63 immunohistochemistry is broadly used for tumor classification but published data on its expression in cancer is conflicting.

Methods

To comprehensively catalogue p63 expression, tissue microarrays (TMAs) containing 12,620 tissue samples from 115 tumor entities and 76 normal tissue types were analyzed.

Results

p63 expression was seen in various normal tissues including squamous epithelium and urothelium. At least occasional weak p63 positivity could be detected in 61 (53%) of 115 different tumor types. The frequencies of p63 positivity was highest in squamous cell carcinomas irrespective of their origin (96–100%), thymic tumors (100%), urothelial carcinomas (81–100%), basal type tumors such as basal cell carcinomas (100%), and various salivary gland neoplasias (81–100%). As a rule, p63 was mostly expressed in cancers derived from p63 positive normal tissues and mostly not detectable in tumors derived from p63 negative cancers. However, exceptions from this rule occurred. A positive p63 immunostaining in cancers derived from p63 negative tissues was unrelated to aggressive phenotype in 422 pancreatic cancers, 160 endometrium cancers and 374 ovarian cancers and might be caused by aberrant squamous differentiation or represent stem cell properties. In 355 gastric cancers, aberrant p63 expression occurred in 4% and was linked to lymph node metastasis (p = 0.0208). Loss of p63 in urothelial carcinomas - derived from p63 positive urothelium - was significantly linked to advanced stage, high grade (p < 0.0001 each) and poor survival (p < 0.0001) and might reflect clinically relevant tumor dedifferentiation.

Conclusion

The high prevalence of p63 expression in specific tumor types makes p63 immunohistochemistry a suitable diagnostic tool. Loss of p63 expression might constitute a feature of aggressive cancers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40364-021-00260-5.