Somatic mutations in adrenocortical carcinoma with primary aldosteronism or hyperreninemic hyperaldosteronism

Several somatic mutations specific to aldosterone-producing adenomas (APAs) have been described. A small proportion of adrenocortical carcinomas (ACCs) are associated with hyperaldosteronism, either primary aldosteronism or hyperreninemic hyperaldosteronism. However, it is unknown whether they harbor mutations of the same spectrum as APAs. The objective of this study is to describe the clinical phenotype and molecular genotype of ACCs with hyperaldosteronism, particularly the analysis for common APA-associated genetic changes. Patients were identified by retrospective chart review at a specialized referral center and by positive staining for CYP11B2 of tissue microarrays. Twenty-five patients with ACC and hyperaldosteronism were initially identified by retrospective chart review, and tissue for further analysis was available on 13 tumors. Seven patients were identified by positive staining for CYP11B2 in a tissue microarray, of which two were already identified in the initial chart review. Therefore, a total number of 18 patients with a diagnosis of ACC and features of either primary aldosteronism or hyperreninemic hyperaldosteronism were therefore included in the final study. Mutational status for a select list of oncogenes, tumor suppressor genes and genes known to carry mutations in APAs were analyzed by next-generation sequencing. Review of clinical data suggested autonomous aldosterone production in the majority of cases, while for some cases, hyperreninemic hyperaldosteronism was the more likely mechanism. The mutational landscape of ACCs associated with hyperaldosteronism was not different from ACCs with a different hormonal phenotype. None of the ACCs harbored mutations of known APA-associated genes, suggesting an alternative mechanism conferring aldosterone production.

A five-CpG DNA methylation score to predict metastatic-lethal outcomes in men treated with radical prostatectomy for localized prostate cancer

BACKGROUND

Prognostic biomarkers for localized prostate cancer (PCa) could improve personalized medicine. Our group previously identified a panel of differentially methylated CpGs in primary tumor tissue that predict disease aggressiveness, and here we further validate these biomarkers.

METHODS

Pyrosequencing was used to assess CpG methylation of eight biomarkers previously identified using the HumanMethylation450 array; CpGs with strongly correlated (r >0.70) results were considered technically validated. Logistic regression incorporating the validated CpGs and Gleason sum was used to define and lock a final model to stratify men with metastatic-lethal versus non-recurrent PCa in a training dataset. Coefficients from the final model were then used to construct a DNA methylation score, which was evaluated by logistic regression and Receiver Operating Characteristic (ROC) curve analyses in an independent testing dataset.

RESULTS

Five CpGs were technically validated and all were retained (P < 0.05) in the final model. The 5-CpG and Gleason sum coefficients were used to calculate a methylation score, which was higher in men with metastatic-lethal progression (P = 6.8 × 10-6 ) in the testing dataset. For each unit increase in the score there was a four-fold increase in risk of metastatic-lethal events (odds ratio, OR = 4.0, 95%CI = 1.8-14.3). At 95% specificity, sensitivity was 74% for the score compared to 53% for Gleason sum alone. The score demonstrated better prediction performance (AUC = 0.91; pAUC = 0.037) compared to Gleason sum alone (AUC = 0.87; pAUC = 0.025).

CONCLUSIONS

The DNA methylation score improved upon Gleason sum for predicting metastatic-lethal progression and holds promise for risk stratification of men with aggressive tumors. This prognostic score warrants further evaluation as a tool for improving patient outcomes.

Solitary Fibrous Tumors of the Head and Neck: A Multi-Institutional Clinicopathologic Study

Solitary fibrous tumors (SFTs) of the head and neck are uncommon. Lesions previously diagnosed in the head and neck as hemangiopericytomas (HPCs), giant cell angiofibromas (GCAs), and orbital fibrous histiocytomas (OFHs) are now recognized as within the expanded spectrum of SFTs. To better understand the clinicopathologic profile of head and neck SFTs, we performed a multi-institutional study of 88 examples. There was no sex predilection (F:M ratio 1.2), and the median patient age was 52 years (range: 15 to above 89 y). The sinonasal tract and orbit were the most common sites involved (30% and 25%), followed by the oral cavity and salivary glands (15% and 14%). Original diagnoses included HPC (25%), SFT (67%), and OFH (6%), with 1 SFT and 1 OFH noted as showing GCA-like morphology. On review, the predominant histologic pattern was classic SFT-like in 53% and cellular (former HPC-like) in 47%; lipomatous differentiation (8%) and GCA-like pattern (7%) were less prevalent. Subsets demonstrated nuclear atypia (23%), epithelioid morphology (15%), or coagulative necrosis (6%). Infiltrative growth (49%) and osseous invasion (82%) were prevalent among evaluable cases. Of the 48 SFTs with follow-up (median: 43 mo), 19 showed recurrence (40%). Of these, 4 patients were alive with disease and 4 dead of disease. Size and mitotic rate were negative prognosticators using a joint prognostic proportional hazards regression model. Three patients experienced metastasis, to lungs, parotid, bone, and skull base, including one case showing overtly sarcomatous "dedifferentiation." As a group, SFTs present in a wide anatomic and morphologic spectrum in the head and neck. Only rare examples metastasize or cause death from disease. However, the fairly high local recurrence rate underscores their aggressive potential and highlights the importance of prospective recognition.

Phenotypic diversity of circulating tumour cells in patients with metastatic castration-resistant prostate cancer

OBJECTIVES

To use a non-biased assay for circulating tumour cells (CTCs) in patients with prostate cancer (PCa) in order to identify non-traditional CTC phenotypes potentially excluded by conventional detection methods that are reliant on antigen- and/or size-based enrichment.

PATIENTS AND METHODS

A total of 41 patients with metastatic castration-resistant PCa (mCRPC) and 20 healthy volunteers were analysed on the Epic CTC platform, via high-throughput imaging of DAPI expression and CD45/cytokeratin (CK) immunofluorescence (IF) on all circulating nucleated cells plated on glass slides. To confirm the PCa origin of CTCs, IF was used for androgen receptor (AR) expression and fluorescence in situ hybridization was used for PTEN and ERG assessment.

RESULTS

Traditional CTCs (CD45- /CK+ /morphologically distinct) were identified in all patients with mCRPC and we also identified CTC clusters and non-traditional CTCs in patients with mCRPC, including CK- and apoptotic CTCs. Small CTCs (≤white blood cell size) were identified in 98% of patients with mCRPC. Total, traditional and non-traditional CTCs were significantly increased in patients who were deceased vs alive after 18 months; however, only non-traditional CTCs were associated with overall survival. Traditional and total CTC counts according to the Epic platform in the mCRPC cohort were also significantly correlated with CTC counts according to the CellSearch system.

CONCLUSIONS

Heterogeneous non-traditional CTC populations are frequent in mCRPC and may provide additional prognostic or predictive information.

Frequent PD-L1 expression in primary and metastatic penile squamous cell carcinoma: potential opportunities for immunotherapeutic approaches

BACKGROUND

Despite aggressive multimodal therapy, locally advanced and/or metastatic penile squamous cell carcinoma (SqCC) is associated with significant morbidity and mortality, indicating a need for new therapeutic options. Given the emerging clinical utility of immunotherapeutics, we sought to assess the incidence and potential clinical significance of PD-L1 expression in penile SqCC.

PATIENTS AND METHODS

Using an anti-PD-L1 primary antibody (clone 5H1), immunohistochemistry was carried out on whole tumor sections from 37 patients with penile SqCC treated at our institution between 2005 and 2013. PD-L1-positive tumors were defined as those with membranous staining in ≥5% of tumor cells. Association between PD-L1 expression and clinicopathologic parameters was examined using Fisher's exact test. Correlation between PD-L1 expression in primary tumors and matched metastases was assessed using the Spearman rank correlation coefficient (ρ). The difference in cancer-specific mortality between PD-L1-positive and -negative groups was examined using the log-rank test.

RESULTS

Twenty-three (62.2%) of 37 primary tumors were positive for PD-L1 expression, and there was strong positive correlation of PD-L1 expression in primary and metastatic samples (ρ = 0.72; 0.032 < P < 0.036). Primary tumor PD-L1 expression was significantly associated with usual type histology (P = 0.040) and regional lymph node metastasis (P = 0.024), as well as decreased cancer-specific survival (P = 0.011).

CONCLUSIONS

The majority of primary penile SqCC tumors express PD-L1, which is associated with high-risk clinicopathologic features and poor clinical outcome. These data provide a rational basis for further investigation of anti-PD-1 and anti-PD-L1 immunotherapeutics in patients with advanced penile SqCC.

Genomic Profiling of Penile Squamous Cell Carcinoma Reveals New Opportunities for Targeted Therapy

Penile squamous cell carcinoma (PeSCCA) is a rare malignancy for which there are limited treatment options due to a poor understanding of the molecular alterations underlying disease development and progression. Therefore, we performed comprehensive, targeted next-generation sequencing to identify relevant somatic genomic alterations in a retrospective cohort of 60 fixed tumor samples from 43 PeSCCA cases (including 14 matched primary/metastasis pairs). We identified a median of two relevant somatic mutations and one high-level copy-number alteration per sample (range, 0-5 and 0-6, respectively). Expression of HPV and p16 was detectable in 12% and 28% of patients, respectively. Furthermore, advanced clinical stage, lack of p16 expression, and MYC and CCND1 amplifications were significantly associated with shorter time to progression or PeSCCA-specific survival. Notably, four cases harbored EGFR amplifications and one demonstrated CDK4 amplification, genes for which approved and investigational targeted therapies are available. Importantly, although paired primary tumors and lymph node metastases were largely homogeneous for relevant somatic mutations, we identified heterogeneous EGFR amplification in primary tumor/lymph node metastases in 4 of 14 cases, despite uniform EGFR protein overexpression. Likewise, activating HRAS mutations occurred in 8 of 43 cases. Taken together, we provide the first comprehensive molecular PeSCCA analysis, which offers new insight into potential precision medicine approaches for this disease, including strategies targeting EGFR.

Next-Generation Sequencing of Tubal Intraepithelial Carcinomas

IMPORTANCE

High-grade serous carcinoma (HGSC) is the most prevalent and lethal form of ovarian cancer. HGSCs frequently arise in the distal fallopian tubes rather than the ovary, developing from small precursor lesions called serous tubal intraepithelial carcinomas (TICs, or more specifically, STICs). While STICs have been reported to harbor TP53 mutations, detailed molecular characterizations of these lesions are lacking.

OBSERVATIONS

We performed targeted next-generation sequencing (NGS) on formalin-fixed, paraffin-embedded tissue from 4 women, 2 with HGSC and 2 with uterine endometrioid carcinoma (UEC) who were diagnosed as having synchronous STICs. We detected concordant mutations in both HGSCs with synchronous STICs, including TP53 mutations as well as assumed germline BRCA1/2 alterations, confirming a clonal association between these lesions. Next-generation sequencing confirmed the presence of a STIC clonally unrelated to 1 case of UEC, and NGS of the other tubal lesion diagnosed as a STIC unexpectedly supported the lesion as a micrometastasis from the associated UEC.

CONCLUSIONS AND RELEVANCE

We demonstrate that targeted NGS can identify genetic alterations in minute lesions, such as TICs, and confirm TP53 mutations as early driving events for HGSC. Next-generation sequencing also demonstrated unexpected associations between presumed STICs and synchronous carcinomas, providing evidence that some TICs are actually metastases rather than HGSC precursors.

Clonal evaluation of prostate cancer foci in biopsies with discontinuous tumor involvement by dual ERG/SPINK1 immunohistochemistry

The presence of two or more prostate cancer foci separated by intervening benign tissue in a single core is a well-recognized finding on prostate biopsy. Cancer involvement can be measured by including intervening benign tissue or only including the actual cancer involved area. Importantly, this parameter is a common enrollment criterion for active surveillance protocols. We hypothesized that spatially distinct prostate cancer foci in biopsies may arise from separate clones, impacting cancer involvement assessment. Hence, we used dual ERG/SPINK1 immunohistochemistry to determine the frequency of separate clones-when separate tumor foci showed discordant ERG and/or SPINK1 status-in discontinuously involved prostate biopsy cores from two academic institutions. In our cohort of 97 prostate biopsy cores with spatially discrete tumor foci (from 80 patients), discontinuous cancer involvement including intervening tissue ranged from 20 to 100% and Gleason scores ranged from 6 to 9. Twenty-four (25%) of 97 discontinuously involved cores harbored clonally distinct cancer foci by discordant ERG and/or SPINK1 expression status: 58% (14/24) had one ERG(+) focus, and one ERG(-)/SPINK1(-) focus; 29% (7/24) had one SPINK1(+) focus and one ERG(-)/SPINK1(-) focus; and 13% (3/24) had one ERG(+) focus and one SPINK1(+) focus. ERG and SPINK1 overexpression were mutually exclusive in all tumor foci. In summary, our results show that ~25% of discontinuously involved prostate biopsy cores showed tumor foci with discordant ERG/SPINK1 status, consistent with multiclonal disease. The relatively frequent presence of multiclonality in discontinuously involved prostate biopsy cores warrants studies on the potential clinical impact of clonality assessment, particularly in cases where tumor volume in a discontinuous core may impact active surveillance eligibility.

Development and validation of a scalable next-generation sequencing system for assessing relevant somatic variants in solid tumors

Next-generation sequencing (NGS) has enabled genome-wide personalized oncology efforts at centers and companies with the specialty expertise and infrastructure required to identify and prioritize actionable variants. Such approaches are not scalable, preventing widespread adoption. Likewise, most targeted NGS approaches fail to assess key relevant genomic alteration classes. To address these challenges, we predefined the catalog of relevant solid tumor somatic genome variants (gain-of-function or loss-of-function mutations, high-level copy number alterations, and gene fusions) through comprehensive bioinformatics analysis of >700,000 samples. To detect these variants, we developed the Oncomine Comprehensive Panel (OCP), an integrative NGS-based assay [compatible with < 20 ng of DNA/RNA from formalin-fixed paraffin-embedded (FFPE) tissues], coupled with an informatics pipeline to specifically identify relevant predefined variants and created a knowledge base of related potential treatments, current practice guidelines, and open clinical trials. We validated OCP using molecular standards and more than 300 FFPE tumor samples, achieving >95% accuracy for KRAS, epidermal growth factor receptor, and BRAF mutation detection as well as for ALK and TMPRSS2:ERG gene fusions. Associating positive variants with potential targeted treatments demonstrated that 6% to 42% of profiled samples (depending on cancer type) harbored alterations beyond routine molecular testing that were associated with approved or guideline-referenced therapies. As a translational research tool, OCP identified adaptive CTNNB1 amplifications/mutations in treated prostate cancers. Through predefining somatic variants in solid tumors and compiling associated potential treatment strategies, OCP represents a simplified, broadly applicable targeted NGS system with the potential to advance precision oncology efforts.

Abstract A1-43: Targeted amplicon-based next-generation sequencing of routine solid tumor specimens to detect clinically relevant somatic alterations

Background: Although precision medicine approaches have revolutionized oncology, widespread adoption requires robust, inexpensive approaches enabling the targeted assessment of all relevant alteration classes from routine tissue samples.

Methods: Here we interrogated &gt;7,000 cancer exomes and transcriptomes, along with &gt;30,000 array based cancer genomes to identify recurrent somatic alterations (mutations, copy number alterations [CNAs] and gene fusions) across solid tumors. From this analysis, we developed and validated an integrated multiplexed PCR based Ion Torrent next generation sequencing panel (Oncomine Cancer Research Panel [OCP]) targeting the actionable somatic cancer genome optimized for 20ng of formalin-fixed, paraffin-embedded (FFPE) tissue isolated DNA/RNA.

Results: We validated the OCP using FFPE cell line mixtures, as well as a prospective cohort of 104 FFPE tumor specimens sent for concurrent clinical molecular testing, with &gt;97% sensitivity and specificity for the presence/absence of KRAS, EGFR, BRAF and ALK point mutations, indels or gene fusions in this molecular testing cohort. We also applied the OCP to 100 lung cancers, identifying known and novel alterations, including ALK and ROS1 gene fusions. Lastly, applying the OCP to 116 prostate cancers, including 50 previously treated samples, we recapitulated known molecular subtypes, observed distinct profiles according to previous treatment and obtained 100% concordance for isoform specific TMPRSS2:ERG gene fusion detection compared to qPCR. Additionally, OCP profiling supports a novel molecular subtype of prostate cancer defined by IDH1 R132 hotspot mutations and informed on resistance mechanisms in a pre- and post-treatment sample pair. Importantly, 44%, 35% and 9% of patients in the molecular testing, lung and prostate cancer cohorts, respectively, harbored additional alterations (beyond routine molecular testing) associated with FDA approved or NCCN guideline referenced therapies.

Conclusions: Through analysis of both DNA and RNA to assess the actionable somatic cancer genome, the validated OCP panel may have utility in both clinical and research settings.

Citation Format: Daniel H. Hovelson, Andrew S. McDaniel, Bryan Johnson, Andi K. Cani, Kate Rhodes, Paul D. Williams, Chia-Jen Liu, Santhoshi Bandla, Catherine S. Grasso, Michael J. Quist, Seth Sadis, Daniel R. Rhodes, Scott A. Tomlins. Targeted amplicon-based next-generation sequencing of routine solid tumor specimens to detect clinically relevant somatic alterations. [abstract]. In: Proceedings of the AACR Special Conference on Translation of the Cancer Genome; Feb 7-9, 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 1):Abstract nr A1-43.

A subset of solitary fibrous tumors express nuclear PAX8 and PAX2: a potential diagnostic pitfall

Solitary fibrous tumor (SFT), a mesenchymal neoplasm with widespread anatomic distribution, can be diagnostically challenging in limited samples. We recently encountered an aspirate of a pancreatic mass, incorrectly interpreted as metastatic renal cell carcinoma based on strong PAX8 expression by immunohistochemistry (IHC). After resection, morphologic features with additional IHC (CD34 positivity) correctly identified this lesion as a SFT. PAX8 and PAX2 are commonly used as renal tumor markers; however, no series has investigated PAX8 or PAX2 expression in SFT. IHC for PAX8 and PAX2 was performed on 41 SFTs (biopsy and resections) from varying sites. Eight were histologically malignant and eight were recurrences of previous resections. PAX8 staining was observed at least focally in 26.8% (11 of 41) SFT cases; additionally, PAX2 was positive in 12.2% (5 of 41 cases) of SFTs. For PAX8 and PAX2 positive cases 45.6% and 40%, respectively, showed diffuse expression. No correlation was found between PAX8/PAX2 positivity and age, tumor size, site, malignancy, or recurrence. In conclusion, a substantial minority of SFTs express PAX8 and PAX2 via IHC. This presents a diagnostic pitfall when evaluating possible metastases from the kidney, particularly when primary tumors show sarcomatoid or spindle cell morphologies.

Integrative molecular profiling of routine clinical prostate cancer specimens

BACKGROUND

Comprehensive molecular profiling led to the recognition of multiple prostate cancer (PCa) molecular subtypes and driving alterations, but translating these findings to clinical practice is challenging.

PATIENTS AND METHODS

We developed a formalin-fixed paraffin-embedded (FFPE) tissue compatible integrative assay for PCa molecular subtyping and interrogation of relevant genetic/transcriptomic alterations (MiPC). We applied MiPC, which combines capture-based next generation sequencing and quantitative reverse transcription PCR (qRT-PCR), to 53 FFPE PCa specimens representing cases not well represented in frozen tissue cohorts, including 8 paired primary tumor and lymph node metastases. Results were validated using multiplexed PCR based NGS and Sanger sequencing.

RESULTS

We identified known and novel potential driving, somatic mutations and copy number alterations, including a novel BRAF T599_V600insHT mutation and CYP11B2 amplification in a patient treated with ketoconazole (a potent CYP11B2 inhibitor). qRT-PCR integration enabled comprehensive molecular subtyping and provided complementary information, such as androgen receptor (AR) target gene module assessment in advanced cases and SPINK1 over-expression. MiPC identified highly concordant profiles for all 8 tumor/lymph node metastasis pairs, consistent with limited heterogeneity amongst driving events. MiPC and exome sequencing were performed on separately isolated conventional acinar PCa and prostatic small cell carcinoma (SCC) components from the same FFPE resection specimen to enable direct comparison of histologically distinct components. While both components showed TMPRSS2:ERG fusions, the SCC component exclusively harbored complete TP53 inactivation (frameshift variant and copy loss) and two CREBBP mutations.

CONCLUSIONS

Our results demonstrate the feasibility of integrative profiling of routine PCa specimens, which may have utility for understanding disease biology and enabling personalized medicine applications.

Tumor evolution and progression in multifocal and paired non-invasive/invasive urothelial carcinoma

Although multifocal tumors and non-invasive/invasive components are commonly encountered in surgical pathology, their genetic relationship is often poorly characterized. We used next-generation sequencing (NGS) to characterize somatic alterations in a patient with five spatially distinct, high-grade papillary urothelial carcinomas (UCs), with one tumor harboring an underlying invasive component. NGS of 409 cancer-related genes was performed on DNA isolated from formalin-fixed paraffin-embedded (FFPE) blocks representing each papillary tumor (n = 5), the invasive component of one tumor, and matched normal tissue. We identified nine unique non-synonymous somatic mutations across the six UC samples, including five present in each carcinoma sample, consistent with clonal origin and limited intertumoral heterogeneity. Copy number and loss of heterogeneity (LOH) profiles were similar in all six carcinomas; however, the invasive carcinoma component uniquely showed focal CDKN2A loss and chromosome 9 LOH and did not harbor gains of chromosomes 5p or X that were present in the other tumor samples. Phylogenetic analysis supported the invasive component arising from a shared progenitor prior to the outgrowth of cells in the non-invasive tumors. Results were extended to three additional cases of upper tract UC with paired non-invasive/invasive components, which identified driving alterations exclusive to both non-invasive and invasive components. Lastly, we performed targeted RNA sequencing (RNAseq) using a custom bladder cancer panel, which confirmed gene expression signature differences between paired non-invasive/invasive components. The results and approaches presented here may be useful in understanding the clonal relationships in multifocal cancers or paired non-invasive/invasive components from routine FFPE specimens.

Next-Gen Sequencing Exposes Frequent MED12 Mutations and Actionable Therapeutic Targets in Phyllodes Tumors

Phyllodes tumors are rare fibroepithelial tumors with variable clinical behavior accounting for a small subset of all breast neoplasms, yet little is known about the genetic alterations that drive tumor initiation and/or progression. Here, targeted next-generation sequencing (NGS) was used to identify somatic alterations in formalin-fixed paraffin-embedded (FFPE) patient specimens from malignant, borderline, and benign cases. NGS revealed mutations in mediator complex subunit 12 (MED12) affecting the G44 hotspot residue in the majority (67%) of cases spanning all three histologic grades. In addition, loss-of-function mutations in p53 (TP53) as well as deleterious mutations in the tumor suppressors retinoblastoma (RB1) and neurofibromin 1 (NF1) were identified exclusively in malignant tumors. High-level copy-number alterations (CNA) were nearly exclusively confined to malignant tumors, including potentially clinically actionable gene amplifications in IGF1R and EGFR. Taken together, this study defines the genomic landscape underlying phyllodes tumor development, suggests potential molecular correlates to histologic grade, expands the spectrum of human tumors with frequent recurrent MED12 mutations, and identifies IGF1R and EGFR as potential therapeutic targets in malignant cases.

IMPLICATIONS

Integrated genomic sequencing and mutational profiling provides insight into the molecular origin of phyllodes tumors and indicates potential druggable targets in malignant disease. Visual Overview: http://mcr.aacrjournals.org/content/early/2015/04/02/1541-7786.MCR-14-0578/F1.large.jpg.

HRAS mutations are frequent in inverted urothelial neoplasms

Inverted urothelial papilloma (IUP) is an uncommon neoplasm of the urinary bladder with distinct morphologic features. Studies regarding the role of human papillomavirus (HPV) in the etiology of IUP have provided conflicting evidence of HPV infection. In addition, little is known regarding the molecular alterations present in IUP or other urothelial neoplasms, which might demonstrate inverted growth pattern like low-grade or high-grade urothelial carcinoma (UCA). Here, we evaluated for the presence of common driving somatic mutations and HPV within a cohort of IUPs, (n = 7) noninvasive low-grade papillary UCAs with inverted growth pattern (n = 5), and noninvasive high-grade papillary UCAs with inverted growth pattern (n = 8). HPV was not detected in any case of IUP or inverted UCA by either in situ hybridization or by polymerase chain reaction. Next-generation sequencing identified recurrent mutations in HRAS (Q61R) in 3 of 5 IUPs, described for the first time in this neoplasm. Additional mutations of Ras pathway members were detected including HRAS, KRAS, and BRAF. The presence of Ras pathway member mutations at a relatively high rate suggests this pathway may contribute to pathogenesis of inverted urothelial neoplasms. In addition, we did not find any evidence supporting a role for HPV in the etiology of IUP.

An immunohistochemical panel for reliable differentiation of salivary duct carcinoma and mucoepidermoid carcinoma

Salivary duct carcinoma is a highly aggressive salivary gland malignancy that may be misdiagnosed as high-grade mucoepidermoid carcinoma. We utilized tissue microarrays with 78 examples of mucoepidermoid carcinoma and 47 salivary duct carcinomas to evaluate the utility of an immunohistochemical panel consisting of androgen receptor, Her2/neu, p63, and cytokeratin 5/6 in distinguishing these entities. Among all cases in the cohorts, androgen receptor was highly specific for salivary duct carcinoma, while cytokeratin 5/6 and p63 were specific for mucoepidermoid carcinoma. While the rate of unequivocal Her2/neu overexpression among the salivary duct carcinomas was low (8.9 %), discrimination of salivary duct carcinoma was enhanced when this marker was used in combination with androgen receptor due to profound sensitivity. The immunohistochemical panel was particularly efficacious at distinguishing the problematic subset of high-grade mucoepidermoid carcinomas from salivary duct carcinoma. Utilization of this set of immunohistochemical markers allows reliable differentiation of salivary duct and mucoepidermoid carcinoma, a distinction with important prognostic and therapeutic implications.