Integrative clinical genomics of advanced prostate cancer.

Toward development of a precision medicine framework for metastatic, castration-resistant prostate cancer (mCRPC), we established a multi-institutional clinical sequencing infrastructure to conduct prospective whole-exome and transcriptome sequencing of bone or soft tissue tumor biopsies from a cohort of 150 mCRPC affected individuals. Aberrations of AR, ETS genes, TP53, and PTEN were frequent (40%-60% of cases), with TP53 and AR alterations enriched in mCRPC compared to primary prostate cancer. We identified new genomic alterations in PIK3CA/B, R-spondin, BRAF/RAF1, APC, ß-catenin, and ZBTB16/PLZF. Moreover, aberrations of BRCA2, BRCA1, and ATM were observed at substantially higher frequencies (19.3% overall) compared to those in primary prostate cancers. 89% of affected individuals harbored a clinically actionable aberration, including 62.7% with aberrations in AR, 65% in other cancer-related genes, and 8% with actionable pathogenic germline alterations. This cohort study provides clinically actionable information that could impact treatment decisions for these affected individuals.

Organoid cultures derived from patients with advanced prostate cancer.

The lack of in vitro prostate cancer models that recapitulate the diversity of human prostate cancer has hampered progress in understanding disease pathogenesis and therapy response. Using a 3D organoid system, we report success in long-term culture of prostate cancer from biopsy specimens and circulating tumor cells. The first seven fully characterized organoid lines recapitulate the molecular diversity of prostate cancer subtypes, including TMPRSS2-ERG fusion, SPOP mutation, SPINK1 overexpression, and CHD1 loss. Whole-exome sequencing shows a low mutational burden, consistent with genomics studies, but with mutations in FOXA1 and PIK3R1, as well as in DNA repair and chromatin modifier pathways that have been reported in advanced disease. Loss of p53 and RB tumor suppressor pathway function are the most common feature shared across the organoid lines. The methodology described here should enable the generation of a large repertoire of patient-derived prostate cancer lines amenable to genetic and pharmacologic studies.

Single-cell analysis of treatment-resistant prostate cancer: Implications of cell state changes for cell surface antigen-targeted therapies.

Targeting cell surface molecules using radioligand and antibody-based therapies has yielded considerable success across cancers. However, it remains unclear how the expression of putative lineage markers, particularly cell surface molecules, varies in the process of lineage plasticity, wherein tumor cells alter their identity and acquire new oncogenic properties. A notable example of lineage plasticity is the transformation of prostate adenocarcinoma (PRAD) to neuroendocrine prostate cancer (NEPC)-a growing resistance mechanism that results in the loss of responsiveness to androgen blockade and portends dismal patient survival. To understand how lineage markers vary across the evolution of lineage plasticity in prostate cancer, we applied single-cell analyses to 21 human prostate tumor biopsies and two genetically engineered mouse models, together with tissue microarray analysis on 131 tumor samples. Not only did we observe a higher degree of phenotypic heterogeneity in castrate-resistant PRAD and NEPC than previously anticipated but also found that the expression of molecules targeted therapeutically, namely PSMA, STEAP1, STEAP2, TROP2, CEACAM5, and DLL3, varied within a subset of gene-regulatory networks (GRNs). We also noted that NEPC and small cell lung cancer subtypes shared a set of GRNs, indicative of conserved biologic pathways that may be exploited therapeutically across tumor types. While this extreme level of transcriptional heterogeneity, particularly in cell surface marker expression, may mitigate the durability of clinical responses to current and future antigen-directed therapies, its delineation may yield signatures for patient selection in clinical trials, potentially across distinct cancer types.

L1 Cell Adhesion Molecule (L1CAM) Expression and Molecular Alterations Distinguish Low-Grade Oncocytic Tumor From Eosinophilic Chromophobe Renal Cell Carcinoma.

Renal low-grade oncocytic tumor (LOT) is a recently recognized renal cell neoplasm designated within the "other oncocytic tumors" category in the 2022 World Health Organization classification system. Although the clinicopathologic, immunohistochemical, and molecular features reported for LOT have been largely consistent, the data are relatively limited. The morphologic overlap between LOT and other low-grade oncocytic neoplasms, particularly eosinophilic chromophobe renal cell carcinoma (E-chRCC), remains a controversial area in renal tumor classification. To address this uncertainty, we characterized and compared large cohorts of LOT (n = 67) and E-chRCC (n = 69) and revealed notable differences between the 2 entities. Clinically, LOT predominantly affected women, whereas E-chRCC showed a male predilection. Histologically, although almost all LOTs were dominated by a small-nested pattern, E-chRCC mainly showed solid and tubular architectures. Molecular analysis revealed that 87% of LOT cases harbored mutations in the tuberous sclerosis complex (TSC)-mTOR complex 1 (mTORC1) pathway, most frequently in MTOR and RHEB genes; a subset of LOT cases had chromosomal 7 and 19q gains. In contrast, E-chRCC lacked mTORC1 mutations, and 60% of cases displayed chromosomal losses characteristic of chRCC. We also explored the cell of origin for LOT and identified L1 cell adhesion molecule (L1CAM), a collecting duct and connecting tubule principal cell marker, as a highly sensitive and specific ancillary test for differentiating LOT from E-chRCC. This distinctive L1CAM immunohistochemical labeling suggests the principal cells as the cell of origin for LOT, unlike the intercalated cell origin of E-chRCC and oncocytoma. The ultrastructural analysis of LOT showed normal-appearing mitochondria and intracytoplasmic lumina with microvilli, different from what has been described for chRCC. Our study further supports LOT as a unique entity with a benign clinical course. Based on the likely cell of origin and its clinicopathologic characteristics, we propose that changing the nomenclature of LOT to "Oncocytic Principal Cell Adenoma of the Kidney" may be a better way to define and describe this entity.

Differential NEUROD1, ASCL1, and POU2F3 Expression Defines Molecular Subsets of Bladder Small Cell/Neuroendocrine Carcinoma with Prognostic Implications.

Small cell carcinomas (SMC) of the lung are now molecularly classified based on the expression of transcriptional regulators (NEUROD1, ASCL1, POU2F3, YAP1) and DLL3, which has emerged as an investigational therapeutic target. PLCG2 has been shown to identify a distinct subpopulation of lung SMC with stem cell-like and pro-metastasis features and poor prognosis. We analyzed the expression of these novel neuroendocrine markers and their association with traditional neuroendocrine markers and patient outcomes in a cohort of bladder neuroendocrine carcinoma (NEC) consisting of 103 SMC and 19 large cell neuroendocrine carcinomas (LCNEC) assembled in tissue microarrays. Co-expression patterns were assessed and integrated with detailed clinical annotation including overall (OS) and recurrence free survival (RFS) and response to neoadjuvant/adjuvant chemotherapy. We identified five distinct molecular subtypes in bladder SMC based on expression of ASCL1, NEUROD1 and POU2F3: ASCL1+/NEUROD1- (n=33; 34%), ASCL1-/NEUROD1+ (n=21; 21%), ASCL1+/NEUROD1+ (n=17; 17%), POU2F3+ (n=22, 22%), and ASCL1-/NEUROD1-/POU2F3- (n=5, 5%). POU2F3+ tumors were mutually exclusive with those expressing ASCL1 and NEUROD1 and exhibited lower expression of traditional neuroendocrine markers. PLCG2 expression was noted in 33 tumors (32%) and was highly correlated with POU2F3 expression (p < 0.001). DLL3 expression was high in both SMC (n=72, 82%) and LCNEC (n=11, 85%). YAP1 expression was enriched in non- neuroendocrine components and negatively correlated with all neuroendocrine markers. In patients without metastatic disease who underwent radical cystectomy, PLCG2+ or POU2F3+ tumors had shorter RFS and OS (p<0.05), but their expression was not associated with metastasis status or response to neoadjuvant/adjuvant chemotherapy. In conclusion, NEC of the bladder can be divided into distinct molecular subtypes based on the expression of ASCL1, NEUROD1 and POU2F3. POU2F3 expressing tumors represent an ASCL1/NEUROD1-negative subset of bladder NEC characterized by lower expression of traditional neuroendocrine markers. Marker expression patterns were similar in SMC and LCNEC. Expression of PLCG2 and POU2F3 was associated with shorter recurrence-free and overall survival. DLL3 was expressed at high levels in both SMC and LCNEC of the bladder, nominating it as a potential therapeutic target.

Treatment-related Neuroendocrine Prostate Carcinoma-Diagnostic and Molecular Correlates.

Treatment-related neuroendocrine prostate cancer is a distinctive category of prostate cancer that arises after intensive suppression of the androgen receptor by next-generation therapeutic inhibition of androgen receptor signaling. The biological processes that set in motion the series of events resulting in transformation of adenocarcinoma to neuroendocrine carcinoma include genomic (loss of tumor suppressors TP53 and RB1, amplification of oncogenes N-MYC and Aurora Kinase A, dysregulation of transcription factors SOX2, achaete-scute-homolog 1, and others) as well as epigenomic (DNA methylation, EZH2 overexpression, and others). Pathologic diagnosis is key to effective therapy for this disease, and this is aided by localizing metastatic lesions for biopsy using radioligand imaging in the appropriate clinical context. As our understanding of biology evolves, there has been increased morphologic recognition and characterization of tumor phenotypes that are present in this advanced post-treatment setting. New and promising biomarkers (delta-like ligand 3 and others) have been discovered, which opens up novel therapeutic avenues including immunotherapy and antibody-drug conjugates for this lethal disease with currently limited treatment options.

Novel Androgen Receptor Splice Variant 7 in Gynecologic Tumors.

Androgen receptor splicing variant 7 (AR-V7) is a truncated variant of the AR mRNA that may be a predictive biomarker for AR-targeted therapy. AR-V7 has been described in prostate, breast, salivary duct, and hepatocellular carcinomas as well as mammary and extra-mammary Paget disease. We report 2 gynecologic cancers occurring in the lower uterine segment and ovary and both harboring AR-V7 by targeted RNA sequencing. The uterine tumor was an undifferentiated carcinoma consisting of epithelioid cells and focally spindled cells arranged in sheets, nests, and cords associated with brisk mitotic activity and tumor necrosis. The ovarian tumor consisted of glands with cribriform and solid architecture and uniform cytologic atypia. ER and PR were positive in the ovarian tumor and negative in the uterine tumor. Both were positive for AR and negative for HER2, GATA3, and NKX3.1. DNA methylation profiling showed epigenetic similarity of the AR-V7-positive gynecologic cancers to AR-V7-positive breast cancers rather than to prostate cancers. AR-V7 may underpin rare gynecologic carcinomas with undifferentiated histology or cribriform growth reminiscent of prostatic adenocarcinoma and breast invasive ductal carcinoma.

Ganglioneuroblastoma intermixed: Clinicopathological implications of diagnosis at presentation and genomic correlations.

BACKGROUND: Ganglioneuroblastoma intermixed (GNBI) is classified as "favorable" histology by International Neuroblastoma Pathology Classification system. However, the International Neuroblastoma Risk Group (INRG) stratifies patients using wider clinicopathological and cytogenetic/molecular parameters. While the diagnosis of GNBI is typically made on resected tumor, it may sometimes be rendered on initial biopsy. We studied GNBI noted at diagnosis to evaluate its correlation with INRG staging and other clinicopathological and molecular features. METHODS: In this retrospective study, clinical, radiological, pathological, cytogenetic, and molecular information from patients with GNBI at diagnosis seen between 1995 and 2021 was analyzed. INRG staging was performed. RESULTS: Of the 15,827 neuroblastoma specimens, GNBI was noted in 237 patients. Of these, 53 had the initial pathological diagnosis of GNBI; median follow-up 3.5 (range: 0.2-14) years. Disease was locoregional in 41 (77%, 16 stage L1 and 25 L2); none relapsed. Twelve (23%) had metastatic disease at presentation; six (50%) relapsed, and two died of disease. MYCN was amplified in two metastatic tumors. Six of 31 (19%) tumors tested had recurrent cytogenetic abnormalities and nonrecurrent somatic gene mutations in 10/23 (43%). The presence of any adverse molecular/cytogenetic findings was associated with metastatic disease (p < .05). For patients with localized GNBI undergoing both biopsy and resection, GNBI was diagnosed in both in 17/19 (90%). CONCLUSIONS: Localized GNBI at diagnosis has excellent long-term clinical outcome even without cytotoxic therapy. For localized GNBI, a biopsy sample is adequate to make the diagnosis. When associated with metastasis at diagnosis, prognosis is poorer, possibly due to associated adverse biological features.

Comparative genomics of primary prostate cancer and paired metastases: insights from 12 molecular case studies.

Primary prostate cancer (PCa) can show marked molecular heterogeneity. However, systematic analyses comparing primary PCa and matched metastases in individual patients are lacking. We aimed to address the molecular aspects of metastatic progression while accounting for the heterogeneity of primary PCa. In this pilot study, we collected 12 radical prostatectomy (RP) specimens from men who subsequently developed metastatic castration-resistant prostate cancer (mCRPC). We used histomorphology (Gleason grade, focus size, stage) and immunohistochemistry (IHC) (ERG and p53) to identify independent tumors and/or distinct subclones of primary PCa. We then compared molecular profiles of these primary PCa areas to matched metastatic samples using whole-exome sequencing (WES) and amplicon-based DNA and RNA sequencing. Based on combined pathology and molecular analysis, seven (58%) RP specimens harbored monoclonal and topographically continuous disease, albeit with some degree of intratumor heterogeneity; four (33%) specimens showed true multifocal disease; and one displayed monoclonal disease with discontinuous topography. Early (truncal) events in primary PCa included SPOP p.F133V (one patient), BRAF p.K601E (one patient), and TMPRSS2:ETS rearrangements (eight patients). Activating AR alterations were seen in nine (75%) mCRPC patients, but not in matched primary PCa. Hotspot TP53 mutations, found in metastases from three patients, were readily present in matched primary disease. Alterations in genes encoding epigenetic modifiers were observed in several patients (either shared between primary foci and metastases or in metastatic samples only). WES-based phylogenetic reconstruction and/or clonality scores were consistent with the index focus designated by pathology review in six out of nine (67%) cases. The three instances of discordance pertained to monoclonal, topographically continuous tumors, which would have been considered as unique disease in routine practice. Overall, our results emphasize pathologic and molecular heterogeneity of primary PCa, and suggest that comprehensive IHC-assisted pathology review and genomic analysis are highly concordant in nominating the 'index' primary PCa area. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Papillary renal cell carcinoma: a single institutional study of 199 cases addressing classification, clinicopathologic and molecular features, and treatment outcome.

The morphologic spectrum of type 1 papillary renal cell carcinoma (PRCC) is not well-defined, since a significant proportion of cases have mixed type 1 and 2 histology. We analyzed 199 cases of PRCC with any (even if focal) type 1 features, with a median follow-up of 12 years, to identify clinicopathological features associated with outcome. Ninety-five tumors (48%) of the cohort contained some type 2 component (median amount: 25%; IQR: 10%, 70%). As a group they showed high rates of progression-free (PFS) and cancer-specific survival (CSS). Tumor size, mitotic rate, lymphovascular invasion, sarcomatoid differentiation, sheet-like architecture, and lack of tumor circumscription were significantly associated with CSS (p ≤ 0.015) on univariate analysis. While predominant WHO/ISUP nucleolar grade was associated with PFS (p = 0.013) and CSS (p = 0.030), the presence of non-predominant (<50%) nucleolar grade did not show association with outcome (p = 0.7). PFS and CSS showed no significant association with the presence or the amount of type 2 morphology. We compared the molecular alterations in paired type 1 and type 2 areas in a subset of 22 cases with mixed type 1 and 2 features and identified 12 recurrently mutated genes including TERT, ARID1A, KDM6A, KMT2D, NFE2L2, MET, APC, and TP53. Among 78 detected somatic mutations, 61 (78%) were shared between the paired type 1 and type 2 areas. Copy number alterations, including chromosome 7 and 17 gains, were similar between type 1 and 2 areas. These findings support that type 2 features in a PRCC with mixed histology represent either morphologic variance or clonal evolution. Our study underscores the notion that PRCC with any classic type 1 regions is best considered as type 1 PRCC and assigned the appropriate WHO/ISUP nucleolar grade. It provides additional evidence that type 2 PRCC as a separate category should be re-assessed and likely needs to be abandoned.

Neuroendocrine differentiation in the setting of prostatic carcinoma: contemporary assessment of a consecutive series.

AIM: Clinicopathologic characterisation of a contemporary series of neuroendocrine (NE) differentiation in the setting of prostatic carcinoma (PCa) was examined. METHODS AND RESULTS: We reviewed institutional databases for in-house cases with a history of PCa and histopathologic evidence of NE differentiation during the disease course. In all, 79 cases were identified: 32 primary and 47 metastases. Metastatic lesions were in liver (n = 15), lymph node (n = 9), bone (n = 6), lung (n = 3), brain (n = 1), and other sites (n = 13). In all, 63 of 76 (82%) cases with NE differentiation and available history were posttherapy: six postradiation therapy (RT), 24 post- androgen-deprivation therapy (ADT), and 33 post-RT + ADT. Morphologic assessment (n = 79): (i) 23 pure small-cell/high-grade NE carcinoma (HGNEC): 20/23 metastatic; (ii) 10 combined high-grade PCa and small-cell/HGNEC: 9/10 primary; (iii) 15 PCa with diffuse NE immunohistochemistry (IHC) marker positivity/differentiation, associated with nested to sheet-like growth of cells with abundant cytoplasm and prominent nucleoli, yet diffuse positivity for at least one prostatic and one NE IHC marker: all metastatic; (iv) 11 PCa with patchy NE differentiation, displaying more than single-cell positivity for NE IHC: five primary / six metastatic; (v) nine PCa with focal NE marker positive cells: four primary / five metastatic; (vi) 11 PCa with 'Paneth cell-like' change: all primary. CONCLUSIONS: In this contemporary series, the majority of NE differentiation in the setting of PCa was seen posttherapy. We highlight the tendencies of small-cell/HGNEC and PCa with diffuse NE differentiation by IHC to occur in metastatic settings, while morphologically combined high-grade PCa + small-cell/HGNEC and 'Paneth cell-like' change occur in primary disease.

Clinical utility of subclassifying positive surgical margins at radical prostatectomy.

OBJECTIVE: To determine whether subclassification of positive surgical margins (PSMs) increases predictive ability for biochemical recurrence (BCR) and aids clinical decision-making in patients undergoing radical prostatectomy. PATIENTS AND METHODS: We studied 2147 patients with pT2 and pT3a prostate cancer with detailed surgical margin parameters and BCR status. We compared a base model, a linear predictor calculated from the Memorial Sloan Kettering Cancer Center postoperative nomogram (prostate-specific antigen, pathological tumour grade and stage), with the addition of surgical margin status to five additional models (base model plus surgical margin subclassifications) to evaluate enhancement in predictive accuracy. Decision curve analysis (DCA) was performed to determine the clinical utility of parameters that enhanced predictive accuracy. RESULTS: Among 2147 men, 205 had PSMs, and 231 developed BCR. Discrimination for the base model with addition of surgical margin status was high (c-index = 0.801) and not meaningfully improved by adding surgical margin subclassification in the full cohort. In analyses considering only men with PSMs (N = 55 with BCR), adding surgical margin subclassification to the base model increased discrimination for total length of all PSMs - alone or with maximum Gleason grade at the margin (c-index improvement = 0.717 to 0.752 and 0.753, respectively). DCA demonstrated a modest benefit to clinical utility with the addition of these parameters. CONCLUSIONS: Specific subclassification parameters add predictive accuracy for BCR and may aid clinical utility in decision-making for patients with PSMs. These findings may be useful for patient counselling and future adjuvant therapy trial design.

Genomic correlates of clinical outcome in advanced prostate cancer.

Heterogeneity in the genomic landscape of metastatic prostate cancer has become apparent through several comprehensive profiling efforts, but little is known about the impact of this heterogeneity on clinical outcome. Here, we report comprehensive genomic and transcriptomic analysis of 429 patients with metastatic castration-resistant prostate cancer (mCRPC) linked with longitudinal clinical outcomes, integrating findings from whole-exome, transcriptome, and histologic analysis. For 128 patients treated with a first-line next-generation androgen receptor signaling inhibitor (ARSI; abiraterone or enzalutamide), we examined the association of 18 recurrent DNA- and RNA-based genomic alterations, including androgen receptor (AR) variant expression, AR transcriptional output, and neuroendocrine expression signatures, with clinical outcomes. Of these, only RB1 alteration was significantly associated with poor survival, whereas alterations in RB1, AR, and TP53 were associated with shorter time on treatment with an ARSI. This large analysis integrating mCRPC genomics with histology and clinical outcomes identifies RB1 genomic alteration as a potent predictor of poor outcome, and is a community resource for further interrogation of clinical and molecular associations.

Adverse histology, homozygous loss of CDKN2A/B, and complex genomic alterations in locally advanced/metastatic renal mucinous tubular and spindle cell carcinoma.

Mucinous tubular and spindle cell carcinoma (MTSCC) is a rare subtype of renal cell carcinoma with characteristic histologic features and chromosomal alterations. Although typically indolent, a small subset of cases has been reported to exhibit aggressive clinical behavior. We retrospectively identified 33 patients with MTSCC, consisting of 10 cases of locally advanced/metastatic MTSCC (pT3 or N1 or M1) and 23 kidney-confined MTSCC (pT1/T2) without disease recurrence or progression. Utilizing a single-nucleotide polymorphism array and a targeted next-generation sequencing platform, we examined genome-wide molecular alterations in 24 cases, including 11 available samples from 8 patients with locally advanced/metastatic MTSCC. Ten patients with locally advanced/metastatic MTSCC were 8 females (80%) and 2 males (20%). At nephrectomy, 7 of these 10 cases (70%) were pT3 or pN1 while the remaining 3 (30%) were pT1/T2. Eight patients (80%) developed metastases and common sites included lymph node (4, 40%), bone (4, 40%), and retroperitoneum (3, 30%). Four patients died of disease (40%) during follow-up. Locally advanced/metastatic MTSCCs shared typical MTSCC genomic profiles with loss of chromosomes 1, 4, 6, 8, 9, 13, 14, 15, and 22, while some exhibited additional complex genomic alterations, most frequently a relative gain of 1q (7/8). Homozygous loss of CDKN2A/B was observed in 3 (38%) locally advanced/metastatic MTSCCs. Tumor necrosis, solid nested/sheet pattern, irregular trabecular/single-file infiltration in a desmoplastic stroma, lymphovascular space invasion, and increased mitotic activity were associated with locally advanced/metastatic MTSCCs (all p < 0.05). Our findings reveal that MTSCCs with aggressive clinical behavior have progressed through clonal evolution; CDKN2A/B deletion and additional complex genomic abnormalities may contribute to this process. Recognizing the morphologic presentation of high-grade MTSCC and evaluating adverse histologic features seen in these tumors can help establish a definitive diagnosis and stratify patients for treatment and prognostication.

PTEN Loss with ERG Negative Status is Associated with Lethal Disease after Radical Prostatectomy.

PURPOSE: Few groups have investigated the combined effects of PTEN loss and ERG expression on the outcomes of metastasis of or death from prostate cancer in surgically treated patients. We examined the association of PTEN/ERG status with lethal prostate cancer in patients treated with radical prostatectomy. MATERIALS AND METHODS: Included in analysis were 791 patients with clinically localized prostate cancer treated with radical prostatectomy at a single institution. Genetically validated immunohistochemistry assays for PTEN and ERG were performed on tissue microarrays. Multivariable Cox proportional hazard models were used to assess the association of PTEN/ERG status with lethal prostate cancer (defined as metastasis or prostate cancer specific death), adjusting for patient age, race, pathological grade and stage, and surgical margin status. RESULTS: Median followup in the cohort was 12.8 years. Of 791 cases 203 (25%) demonstrated PTEN loss and 330 of 776 (43%) were ERG positive. On multivariable analysis PTEN loss (HR 1.9, 95% CI 1.2-3.0, p=0.012) but not ERG expression (HR 0.6, 95% CI 0.4-1.1, p=0.11) was associated with an increased risk of lethal prostate cancer. The association of PTEN loss with lethal disease only remained among men with ERG negative tumors (HR 2.3, 95% CI 1.3-4.1, p=0.005) and not ERG positive tumors (HR 1.1, 95% CI 0.6-2.1, p=0.81). CONCLUSIONS: PTEN loss is associated with an increased risk of lethal prostate cancer after radical prostatectomy and this risk is most pronounced in the subgroup of patients with ERG negative tumors. This work corroborates the use of PTEN and ERG status for risk stratification in surgically treated patients.

Predicting malignancy in patients with adrenal tumors using 18 F-FDG-PET/CT SUVmax.

BACKGROUND AND OBJECTIVES: 18 F-fluorodeoxyglucose positron emission tomography/computed tomography (18 F-FDG-PET/CT) parameters may help distinguish malignant from benign adrenal tumors, but few have been externally validated or determined based on definitive pathological confirmation. We determined and validated a threshold for 18 F-FDG-PET/CT maximum standard uptake value (SUVmax) in patients who underwent adrenalectomy for a nonfunctional tumor. METHODS: Database review identified patients with 18 F-FDG-PET/CT images available (training cohort), or only SUVmax values (validation cohort). Discriminative accuracy was assessed by area under the curve (AUC), and the optimal cutoff value estimated by maximally selected Wilcoxon rank statistics. RESULTS: Of identified patients (n = 171), 86 had adrenal metastases, 20 adrenal cortical carcinoma, and 27 adrenal cortical adenoma. In the training cohort (n = 96), SUVmax was significantly higher in malignant versus benign tumors (median 8.3 vs. 3.0, p < .001), with an AUC of 0.857. Tumor size did not differ. The optimal cutoff SUVmax was 4.6 (p < .01). In the validation cohort (n = 75), this cutoff had a sensitivity of 75% and specificity 55%. CONCLUSIONS: 18 F-FDG-PET/CT SUVmax was associated with malignancy. Validation indicated that SUVmax ≥ 4.6 was suggestive of malignancy, while lower values did not reliably predict benign tumor.

Genomic landscape of inverted urothelial papilloma and urothelial papilloma of the bladder.

Inverted urothelial papilloma (IUP) and urothelial papilloma (UP) are rare urothelial neoplasms that typically follow a benign clinical course. Oncogenic mutations in FGFR3, HRAS, and the TERT promoter have been reported in these entities but no comprehensive molecular analysis has been performed. We sought to characterize the genomic landscape of IUP and UP using whole-exome and targeted next-generation sequencing. In IUP, 10 of 11 tumors harbored oncogenic hotspot mutations in HRAS and the remaining tumor had an oncogenic KRAS mutation. None of the IUP tumors harbored TERT promoter or FGFR3 mutations. In UP, 8 of 11 tumors had oncogenic KRAS mutations and two had oncogenic HRAS mutations. One UP tumor had oncogenic mutations in FGFR3, PIK3CA, and the TERT promoter, and arose in a patient with recurrent non-invasive papillary urothelial carcinomas. In contrast to urothelial carcinoma, the APOBEC mutational signature was not present in any IUP and UP tumors, and oncogenic alterations in chromatin remodeling genes were uncommon in both IUP and UP. The current study suggests that IUP and UP are driven primarily by RAS pathway activation and lack the more common genomic features of urothelial cancers. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Distinctive mechanisms underlie the loss of SMARCB1 protein expression in renal medullary carcinoma: morphologic and molecular analysis of 20 cases.

Renal medullary carcinoma is a rare but highly aggressive type of renal cancer occurring in patients with sickle cell trait or rarely with other hemoglobinopathies. Loss of SMARCB1 protein expression, a core subunit of the switch/sucrose nonfermentable (SWI/SNF) chromatin remodeling complex, has emerged as a key diagnostic feature of these tumors. However, the molecular mechanism underlying this loss remains unclear. We retrospectively identified 20 patients diagnosed with renal medullary carcinoma at two institutions from 1996 to 2017. All patients were confirmed to have sickle cell trait, and all tumors exhibited a loss of SMARCB1 protein expression by immunohistochemistry. The status of SMARCB1 locus was examined by fluorescence in situ hybridization (FISH) using 3-color probes, and somatic alterations were detected by targeted next-generation sequencing platforms. FISH analysis of all 20 cases revealed 11 (55%) with concurrent hemizygous loss and translocation of SMARCB1, 6 (30%) with homozygous loss of SMARCB1, and 3 (15%) without structural or copy number alterations of SMARCB1 despite protein loss. Targeted sequencing revealed a pathogenic somatic mutation of SMARCB1 in one of these 3 cases that were negative by FISH. Tumors in the 3 subsets with different FISH findings largely exhibited similar clinicopathologic features, however, homozygous SMARCB1 deletion was found to show a significant association with the solid growth pattern, whereas tumors dominated by reticular/cribriform growth were enriched for SMARCB1 translocation. Taken together, we demonstrate that different molecular mechanisms underlie the loss of SMARCB1 expression in renal medullary carcinoma. Biallelic inactivation of SMARCB1 occurs in a large majority of cases either via concurrent hemizygous loss and translocation disrupting SMARCB1 or by homozygous loss.

Tubulocystic renal cell carcinoma: a distinct clinicopathologic entity with a characteristic genomic profile.

Tubulocystic renal cell carcinoma, a unique tumor, was recently included as a new entity in the World Health Organization classification of renal tumors. It has variably been reported to be related to other renal cell carcinomas, including papillary renal cell carcinoma, fumarate hydratase-deficient carcinoma, and others, likely because many such carcinomas may show variable amounts of tubulocystic architecture. The published data characterizing the molecular features of these tumors are inconsistent. We studied nine "pure" tubulocystic renal cell carcinomas, as defined by International Society of Urologic Pathologists (ISUP) and World Health Organization (WHO), by targeted next-generation sequencing, and fluorescence in situ hybridization for X and Y chromosomes, to investigate if these show any unique characteristics or any overlap with known mutational/molecular profiles or copy number alterations in other subtypes of renal cell carcinoma. All nine tubulocystic carcinomas demonstrated combined losses at chromosome 9 and gains at chromosome 17, as well as, loss of chromosome Y (in 5/5). None of the tumors showed mutational profiles characteristic of other renal neoplasms, including those seen in fumarate hydratase-deficient renal cell carcinoma. Recurrent mutations in chromatin-modifying genes, KMT2C and KDM5C, were detected in two of nine tumors. Thus, tubulocystic renal cell carcinoma, if defined strictly, at the clinical and pathologic level, demonstrates genomic features distinct from other subtypes of renal cell carcinoma. These findings support the contention that tubulocystic renal cell carcinoma should be diagnosed only using strict morphological criteria and only when presenting in a "pure" form; presence of variable papillary, poorly differentiated, or other architectural patterns most likely do not belong to the category of tubulocystic renal cell carcinoma.