The Identification of CELSR3 and Other Potential Cell Surface Targets in Neuroendocrine Prostate Cancer.

Although recent efforts have led to the development of highly effective androgen receptor (AR)-directed therapies for the treatment of advanced prostate cancer, a significant subset of patients will progress with resistant disease including AR-negative tumors that display neuroendocrine features [neuroendocrine prostate cancer (NEPC)]. On the basis of RNA sequencing (RNA-seq) data from a clinical cohort of tissue from benign prostate, locally advanced prostate cancer, metastatic castration-resistant prostate cancer and NEPC, we developed a multi-step bioinformatics pipeline to identify NEPC-specific, overexpressed gene transcripts that encode cell surface proteins. This included the identification of known NEPC surface protein CEACAM5 as well as other potentially targetable proteins (e.g., HMMR and CESLR3). We further showed that cadherin EGF LAG seven-pass G-type receptor 3 (CELSR3) knockdown results in reduced NEPC tumor cell proliferation and migration in vitro. We provide in vivo data including laser capture microdissection followed by RNA-seq data supporting a causal role of CELSR3 in the development and/or maintenance of the phenotype associated with NEPC. Finally, we provide initial data that suggests CELSR3 is a target for T-cell redirection therapeutics. Further work is now needed to fully evaluate the utility of targeting CELSR3 with T-cell redirection or other similar therapeutics as a potential new strategy for patients with NEPC. Significance: The development of effective treatment for patients with NEPC remains an unmet clinical need. We have identified specific surface proteins, including CELSR3, that may serve as novel biomarkers or therapeutic targets for NEPC.

Immunogenomic Landscape of Neuroendocrine Prostate Cancer.

PURPOSE: Patients with neuroendocrine prostate cancer (NEPC) are often managed with immunotherapy regimens extrapolated from small-cell lung cancer (SCLC). We sought to evaluate the tumor immune landscape of NEPC compared with other prostate cancer types and SCLC. EXPERIMENTAL DESIGN: In this retrospective study, a cohort of 170 patients with 230 RNA-sequencing and 104 matched whole-exome sequencing data were analyzed. Differences in immune and stromal constituents, frequency of genomic alterations, and associations with outcomes were evaluated. RESULTS: In our cohort, 36% of the prostate tumors were identified as CD8+ T-cell inflamed, whereas the remaining 64% were T-cell depleted. T-cell-inflamed tumors were enriched in anti-inflammatory M2 macrophages and exhausted T cells and associated with shorter overall survival relative to T-cell-depleted tumors (HR, 2.62; P < 0.05). Among all prostate cancer types in the cohort, NEPC was identified to be the most immune depleted, wherein only 9 out of the 36 total NEPC tumors were classified as T-cell inflamed. These inflamed NEPC cases were enriched in IFN gamma signaling and PD-1 signaling compared with other NEPC tumors. Comparison of NEPC with SCLC revealed that NEPC had poor immune content and less mutations compared with SCLC, but expression of checkpoint genes PD-L1 and CTLA-4 was comparable between NEPC and SCLC. CONCLUSIONS: NEPC is characterized by a relatively immune-depleted tumor immune microenvironment compared with other primary and metastatic prostate adenocarcinoma except in a minority of cases. These findings may inform development of immunotherapy strategies for patients with advanced prostate cancer.

GLI1 -Rearranged Enteric Tumor : Expanding the Spectrum of Gastrointestinal Neoplasms With GLI1 Gene Fusions.

GLI1 encodes a transcription factor that targets cell cycle regulators affecting stem cell proliferation. GLI1 gene fusions were initially described in pericytomas with a t[7;12] translocation and more recently in gastric plexiform fibromyxomas and gastroblastomas. This study describes the clinicopathologic, immunohistochemical, and molecular features of three intestinal-based neoplasms harboring GLI1 gene fusions. We studied three unique mesenchymal small bowel tumors. Paraffin embedded tumor tissues from these cases and 62 additional tumor samples that included a plexiform fibromyxoma were sequenced using a targeted RNAseq method to detect fusion events. The study patients included two women and one man who were 52, 80, and 22 years of age at the time of diagnosis. The tumors involved the submucosa and muscularis propria of the duodenum, jejunum, and ileum. All 3 tumors contained a proliferation of monotonous oval or spindle cells with scattered, somewhat dilated vessels. Two cases showed epithelioid structures such as glands, tubules, or nests. Immunohistochemical analysis revealed cytokeratin expression in the epithelioid components of both tumors displaying these features, and variable numbers of mesenchymal cells. Diffuse CD56 positivity was seen in the mesenchymal component of 2 tumors and desmin and smooth muscle actin staining in the other tumor. Immunostains for S-100 protein, DOG-1, and CD117 were negative in all cases. GLI1 fusions with different partner genes were detected in all tumors, and in the plexiform fibromyxoma, used as a control. Validation by fluorescence in situ hybridization was performed. None of the tumors have recurred or metastasize after surgery. We describe novel GLI1 fusions in 3 mesenchymal neoplasms of the small intestine, including 2 with biphenotypic features. Thus far, all cases have pursued indolent clinical courses. We propose the term " GLI1 -rearranged enteric tumor" to encompass this group of unique neoplasms of the small intestine that harbor GLI1 gene fusions and expand the spectrum of gastrointestinal neoplasms with these alterations.

Tumor-immune microenvironment revealed by Imaging Mass Cytometry in a metastatic sarcomatoid urothelial carcinoma with a prolonged response to pembrolizumab.

Sarcomatoid urothelial carcinoma (SUC) is a rare subtype of urothelial carcinoma (UC) that typically presents at an advanced stage compared to more common variants of UC. Locally advanced and metastatic UC have a poor long-term survival following progression on first-line platinum-based chemotherapy. Antibodies directed against the programmed cell death 1 protein (PD-1) or its ligand (PD-L1) are now approved to be used in these scenarios. The need for reliable biomarkers for treatment stratification is still under research. Here, we present a novel case report of the first Imaging Mass Cytometry (IMC) analysis done in SUC to investigate the immune cell repertoire and PD-L1 expression in a patient who presented with metastatic SUC and experienced a prolonged response to the anti-PD1 immune checkpoint inhibitor pembrolizumab after progression on first-line chemotherapy. This case report provides an important platform for translating these findings to a larger cohort of UC and UC variants.

Collision tumors revealed by prospectively assessing subtype-defining molecular alterations in 904 individual prostate cancer foci.

BACKGROUNDProstate cancer is multifocal with distinct molecular subtypes. The utility of genomic subtyping has been challenged due to inter- and intrafocal heterogeneity. We sought to characterize the subtype-defining molecular alterations of primary prostate cancer across all tumor foci within radical prostatectomy (RP) specimens and determine the prevalence of collision tumors.METHODSFrom the Early Detection Research Network cohort, we identified 333 prospectively collected RPs from 2010 to 2014 and assessed ETS-related gene (ERG), serine peptidase inhibitor Kazal type 1 (SPINK1), phosphatase and tensin homolog (PTEN), and speckle type BTB/POZ protein (SPOP) molecular status. We utilized dual ERG/SPINK1 immunohistochemistry and fluorescence in situ hybridization to confirm ERG rearrangements and characterize PTEN deletion, as well as high-resolution melting curve analysis and Sanger sequencing to determine SPOP mutation status.RESULTSBased on index focus alone, ERG, SPINK1, PTEN, and SPOP alterations were identified in 47.5%, 10.8%, 14.3%, and 5.1% of RP specimens, respectively. In 233 multifocal RPs with ERG/SPINK1 status in all foci, 139 (59.7%) had discordant molecular alterations between foci. Collision tumors, as defined by discrepant ERG/SPINK1 status within a single focus, were identified in 29 (9.4%) RP specimens.CONCLUSIONInterfocal molecular heterogeneity was identified in about 60% of multifocal RP specimens, and collision tumors were present in about 10%. We present this phenomenon as a model for the intrafocal heterogeneity observed in previous studies and propose that future genomic studies screen for collision tumors to better characterize molecular heterogeneity.FUNDINGEarly Detection Research Network US National Cancer Institute (NCI) 5U01 CA111275-09, Center for Translational Pathology at Weill Cornell Medicine (WCM) Department of Pathology and Laboratory Medicine, US NCI (WCM SPORE in Prostate Cancer, P50CA211024-01), R37CA215040, Damon Runyon Cancer Research Foundation, US MetLife Foundation Family Clinical Investigator Award, Norwegian Cancer Society (grant 208197), and South-Eastern Norway Regional Health Authority (grant 2019016 and 2020063).

Validation of a Circulating Tumor DNA-Based Next-Generation Sequencing Assay in a Cohort of Patients with Solid tumors: A Proposed Solution for Decentralized Plasma Testing.

BACKGROUND: Characterization of circulating tumor DNA (ctDNA) has been integrated into clinical practice. Although labs have standardized validation procedures to develop single locus tests, the efficacy of on-site plasma-based next-generation sequencing (NGS) assays still needs to be proved. MATERIALS AND METHODS: In this retrospective study, we profiled DNA from matched tissue and plasma samples from 75 patients with cancer. We applied an NGS test that detects clinically relevant alterations in 33 genes and microsatellite instability (MSI) to analyze plasma cell-free DNA (cfDNA). RESULTS: The concordance between alterations detected in both tissue and plasma samples was higher in patients with metastatic disease. The NGS test detected 77% of sequence alterations, amplifications, and fusions that were found in metastatic samples compared with 45% of those alterations found in the primary tumor samples (p = .00005). There was 87% agreement on MSI status between the NGS test and tumor tissue results. In three patients, MSI-high ctDNA correlated with response to immunotherapy. In addition, the NGS test revealed an FGFR2 amplification that was not detected in tumor tissue from a patient with metastatic gastric cancer, emphasizing the importance of profiling plasma samples in patients with advanced cancer. CONCLUSION: Our validation experience of a plasma-based NGS assay advances current knowledge about translating cfDNA testing into clinical practice and supports the application of plasma assays in the management of oncology patients with metastatic disease. With an in-house method that minimizes the need for invasive procedures, on-site cfDNA testing supplements tissue biopsy to guide precision therapy and is entitled to become a routine practice. IMPLICATIONS FOR PRACTICE: This study proposes a solution for decentralized liquid biopsy testing based on validation of a next-generation sequencing (NGS) test that detects four classes of genomic alterations in blood: sequence mutations (single nucleotide substitutions or insertions and deletions), fusions, amplifications, and microsatellite instability (MSI). Although there are reference labs that perform single-site comprehensive liquid biopsy testing, the targeted assay this study validated can be established locally in any lab with capacity to offer clinical molecular pathology assays. To the authors' knowledge, this is the first report that validates evaluating an on-site plasma-based NGS test that detects the MSI status along with common sequence alterations encountered in solid tumors.

The effects of calcitonin on post-orthodontic relapse in rats.

OBJECTIVES: To determine the effects of systematic calcitonin administration on post-orthodontic relapse in rat model. MATERIAL AND METHODS: This experimental animal model involved 36 male Wister rats. The maxillary right first molars were moved mesially, using a modified orthodontic appliance delivered 50 gm, for 14 days, retained for 4 days and left to relapse for 10 days. The study group was divided into three subgroups in which a single injection of calcitonin (20 IU/Kg), three injections of calcitonin (20 IU/Kg), each every other day, and normal saline were administered subcutaneously after orthodontic tooth movement has finished. The relapse ratio, histomorphometric analysis including osteoblasts, osteoclasts numbers and bone area and immunohistochemical analysis including the expression of receptor activator of nuclear factor kappa Β (RANK), receptor activator of nuclear factor kappa Β ligand (RANKL) and osteoprotegerin (OPG) were measured and assessed. RESULTS: The relapse ratio was significantly reduced in the three-dose calcitonin group (28%) compared to the single dose calcitonin group (34%) and the control group (46%). This was accompanied by a nonsignificant increase in osteoblasts number and bone area in three-dose calcitonin group and a nonsignificant reduction in osteoclast number. However, the immune histochemical expression of RANK, RANKL and OPG did not show statistically significant difference at the end of relapse period. CONCLUSIONS: Systemic administration of three doses of calcitonin may minimize the relapse ratio in experimentally moved rat molars.

Subgemmal Neurogenous Plaque: A Clinical and Pathologic Review With Comparison to Common Head and Neck Neural Tumors.

OBJECTIVE: In humans, subgemmal neurogenous plaques (SNPs) are normally found associated with taste buds. On histology, SNP may be mistaken for a neural neoplasm. The objective of this study was to correctly differentiate SNP among head and neck neural lesions and provide clinical and pathologic information that may assist in avoiding misdiagnosis. To our knowledge, this is the first study to provide an estimate of the degree of overdiagnoses of mucosal lesions in the head and neck mucosal area. STUDY DESIGN: Retrospective pathology and chart review. METHODS: All cases of head and neck mucosal neural lesions only in the mucosa of the oral cavity, oropharynx, or larynx from the pathology archives of a single urban tertiary care center between 3/2000 and 6/2017 were obtained. The pathologic and clinical data were reviewed. RESULTS: Twenty-six cases were identified: 9 neuromas, 9 neurofibromas, 2 ganglioneuromas and 6 cases of hyperplastic subepithelial nerve bundles. The mean greatest dimension of SNPs was 2.0 mm (range 1-3 mm) and most were subjacent to taste buds (13 cases). The 20 cases of SNP involved 15 women and 5 men. Their median age was 60 years (range 30-85 years). Clinical data were available in 19 cases. The most common presenting complaint was of a painless lesion (8 patients). CONCLUSIONS: This review confirmed the rarity of true neural neoplasms in the head and neck mucosa and estimates the risk of their over diagnosis given the possible diagnostic confusion with SNP.

Alternative lengthening of telomeres, ATRX loss and H3-K27M mutations in histologically defined pilocytic astrocytoma with anaplasia.

Anaplasia may be identified in a subset of tumors with a presumed pilocytic astrocytoma (PA) component or piloid features, which may be associated with aggressive behavior, but the biologic basis of this change remains unclear. Fifty-seven resections from 36 patients (23 M, 13 F, mean age 32 years, range 3-75) were included. A clinical diagnosis of NF1 was present in 8 (22%). Alternative lengthening of telomeres (ALT) was assessed by telomere-specific FISH and/or CISH. A combination of immunohistochemistry, DNA sequencing and FISH were used to study BRAF, ATRX, CDKN2A/p16, mutant IDH1 p.R132H and H3-K27M proteins. ALT was present in 25 (69%) cases and ATRX loss in 20 (57%), mostly in the expected association of ALT+/ATRX- (20/24, 83%) or ALT-/ATRX+ (11/11, 100%). BRAF duplication was present in 8 (of 26) (31%). H3-K27M was present in 5 of 32 (16%) cases, all with concurrent ATRX loss and ALT. ALT was also present in 9 (of 11) cases in the benign PA precursor, 7 of which also had ATRX loss in both the precursor and the anaplastic tumor. In a single pediatric case, ALT and ATRX loss developed in the anaplastic component only, and in another adult case, ALT was present in the PA-A component only, but ATRX was not tested. Features associated with worse prognosis included subtotal resection, adult vs. pediatric, presence of a PA precursor preceding a diagnosis of anaplasia, necrosis, presence of ALT and ATRX expression loss. ALT and ATRX loss, as well as alterations involving the MAPK pathway, are frequent in PA with anaplasia at the time of development of anaplasia or in their precursors. Additionally, a small subset of PA with anaplasia have H3-K27M mutations. These findings further support the concept that PA with anaplasia is a neoplasm with heterogeneous genetic features and alterations typical of both PA and diffuse gliomas.

Metastatic granular cell tumor to the breast diagnosed by fine needle aspiration cytology: A case report with review of the literature.

Granular cell tumors (GCT) are mesenchymal neoplasms of Schwann cell/neural origin. Malignant granular cell tumors (MGCTs) represent <1-2% of all GCT and defined as tumors demonstrating metastases or destructive local growth. Other clinical parameters suggestive of malignancy include rapid growth, size > 4 cm and necrosis. An apparently inconsistent set of histological features have been described in MGCT. Although the histologic parameters of a GCT are not always predictive of biologic behavior, the presence of atypical features may be indicative of an aggressive clinical behavior (recurrence and metastases). A preoperative estimate of features suggestive of malignancy is important for treatment and prognostication. Diagnosis and prognostication from preoperative fine needle aspiration (FNA) cytology is hampered by the fact that only a few case reports on cytologic features of malignant GCT have been published. We report a case of metastatic MGCT to breast and compare cytologic features to that of primary breast GCT and apocrine/histiocytoid variants of breast carcinoma.

Reactive histiocytic proliferation in the pleural fluid mimicking metastatic signet ring adenocarcinoma.

Reactive nodular and diffuse histiocytic proliferations of mesothelial and non-mesothelial lined sites have been sporadically reported in the literature. However, there is no cytologic literature describing this process. We report a case of reactive histiocytic proliferation mimicking a metastatic signet ring adenocarcinoma in pleural fluid from a 33-year-old white male. Ancillary studies such as immunohistochemistry should be used to elucidate the cell of origin and avoid diagnostic errors.

Hematologic Malignancies Discovered on Investigation of Breast Abnormalities.

OBJECTIVES: Hematological malignancies of the breast share a presentation similar to primary breast carcinomas but differ substantially in therapeutic approach and clinical outcomes. In this study, we investigate the frequency of hematological malignancies, their relative primary and secondary occurrences, and further characterize the distinct histopathologies of these malignancies with a special focus on lymphomas. To our knowledge this is one of the largest and most comprehensive studies of breast hematologic malignancies. METHODS: We conducted a retrospective review of our institution's pathology database for hematologic neoplasms diagnosed in breast tissue during a period of 22 years (1992-2014). Clinical characteristics, patient history, histologic subtype, and patient outcomes were analyzed. RESULTS: We identified 52 cases; 46 lymphomas, 4 plasmacytomas, and 2 myeloid sarcomas. The lymphoma cases were 15 diffuse large B-cell lymphomas (DLBCLs), 14 follicular lymphomas (FLs), 8 marginal zone lymphomas (MZLs), 2 anaplastic large T-cell lymphomas, 2 peripheral T-cell lymphomas-not otherwise specified, 1 each of small lymphocytic lymphoma, Burkitt lymphoma, mantle cell lymphoma, B-cell lymphoblastic lymphoma, and T-cell lymphoblastic lymphoma. In total, 30 cases were primary and 22 cases were secondary to the breast. Primary lymphomas accounted for 60% of lymphomas. Most FLs and almost all MZLs were primary. CONCLUSIONS: Primary hematological malignancies of the breast are more common than secondary: 58 % versus 42%. This finding is more evident in lymphomas: 63% versus 37%. The most common hematological malignancy in our study was DLBCL, followed by FL and MZL. Most FLs and almost all MZLs were primary. At the same time, the percentage of primary DLBCLs in our study is lower than the percentage reported in previous studies. We suggest that this could be the result of transformation from low-grade lymphomas. Although rare, hematological malignancies of the breast warrant a higher level of clinical suspicion as they present similarly to breast carcinomas but require a substantially different therapeutic approach.

Hereditary diffuse gastric cancer and lynch syndromes in a BRCA1/2 negative breast cancer patient.

INTRODUCTION: Genetic counseling and testing is recommended for women with a personal and/or family history of breast and other cancers (ovarian, pancreatic, male breast and others). Mutations in the BRCA1 and BRCA2 genes (BRCA1/2) are the most common causes of hereditary breast and ovarian cancer. Additional genetic counseling and testing with a multi-gene panel may be considered in breast cancer patients who tested negative for mutations in these two genes. In about 11% of BRCA1/2-negative patients, further genetic testing reveals pathogenic mutations in other high or moderate cancer risk genes. In 0.2% of cases, an individual may carry pathogenic mutations in more than one high penetrance gene (a double heterozygote). Finding one or more pathogenic mutations is important for cancer prevention in patients and/or their families. CASE PRESENTATION: Here we present a case of a breast cancer patient who did not have a pathogenic mutation in BRCA1/2 and had a family history of breast and stomach cancers. On an additional multi-gene panel testing, she was found to carry pathogenic mutations in the CDH1 and PMS2 genes, which cause Hereditary Diffuse Gastric Cancer and Lynch syndromes, respectively. To our knowledge, this is the first description of such a double heterozygote. DISCUSSION: Clinical manifestations, genetics, and management of both syndromes are reviewed, including prophylactic surgery and screening for unaffected family members. Management challenges for a mutation carrier with advanced breast cancer are discussed. Our case supports the clinical utility of additional multi-gene panel testing for breast cancer patients who do not have a pathogenic mutation in BRCA1/2 genes.

Prognostic Markers and Histologic Subtypes in Patients with Meningeal Carcinomatosis in Breast Cancer.

OBJECTIVE: Meningeal carcinomatosis (MC) is a rare complication in breast cancer patients. It is defined as a diffuse or multifocal leptomeningeal metastasis. STUDY DESIGN: From our institution database, we retrospectively studied 19 patients diagnosed with MC in the cerebrospinal fluid (CSF) in 1997-2015, in order to evaluate tumor prognostic markers, histologic subtypes, and clinical outcome. RESULTS: All patients were female, with a mean age of 53 years (range 36-75 years). The mean interval between diagnosis of breast carcinoma and MC was 28 months (range 6-62 months). The median survival from the time of diagnosis was 2 months (1-51 months). Sixteen cases (84%) were the ductal phenotype, 62% of which were of a high grade (grade 3), and 3 cases (16%) were lobular. Estrogen and progesterone receptors were positive on immunohistochemistry (IHC) in 53 and 33% of patients, respectively. HER2 IHC was positive (3+) in 20% of the cases; all were amplified by fluorescence in situ hybridization. The incidence of MC in triple-negative tumors was 40%. Twelve patients (63%) already had known metastasis at the time of diagnosis. CONCLUSIONS: Most cases of MC are high-grade ductal. MC is more common in triple-negative breast cancers. The outcome of these breast cancer patients with MC was poor. There was no survival difference according to age, histologic subtype, grade, or hormonal or HER2 status.

Spectrum of Clinicopathological Deviations in Long-Segment Hirschsprung Disease Compared With Short-Segment Hirschsprung Disease: A Single-Institution Study.

Hirschsprung disease (HSCR) is a congenital disorder characterized by intestinal aganglionosis leading to pseudoobstruction. The majority of cases are limited to the rectum or rectosigmoid (S-HSCR). A variably longer segment can be affected (L-HSCR), which may show many deviations from S-HSCR. We retrospectively reviewed 48 clinicopathologically confirmed total cases of HSCR at a single institution in a 21-year period to identify L-HSCR cases and determine their deviations from known features of S-HSCR. Eight L-HSCR cases were found where aganglionosis extended to the terminal ileum (7/8) or to the splenic flexure (1/8). L-HSCR lacked male preponderance and was in contrast more common in females (6/8). Associated anomalies included congenital heart disease (2) and neonatal hypothyroidism (1), previously underreported associations. The clinical diagnosis of L-HSCR was often delayed (average age at diagnosis 13 days) and the diagnosis was more often made operatively (5/8) rather than on rectal suction biopsy (3/8). Histologically, apart from aganglionosis, neural hyperplasia was either absent or focal, compounding the diagnostic difficulty. Although the number of cases in our study was limited due to the rarity of L-HSCR, this study still highlights the spectrum of deviations of L-HSCR from known clinicopathological features of S-HSCR.