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The pathologist forms a very important part of the clinical team in the management of pediatric intra-abdominal masses in giving a rapid, accurate diagnosis for these potentially curable tumors. Fine-needle aspiration cytology (FNAC) is an invaluable tool in this regard when interpreted with clinicoradiologic parameters. With this in mind, we decided to evaluate the role of FNAC in pediatric abdominal masses in our institution. A total of 83 of 105 FNAC accessioned in the pathology department over 5 years (2003-2007) were studied. These included only cases where a diagnosis could be offered on cytology. Detailed clinicoradiological features were obtained from hospital records. Cytomorphological features examined included cellularity, architectural pattern, background, key cellular details. Immunocytochemistry were done where necessary. Lesions diagnosed on FNAC included Wilms' tumor (19), lymphoma (10), neuroblastoma (6), hepatoblastoma (5), PNET (5), rhabdomyosarcoma (2), DSRCT (2), germ cell tumor (6), and miscellaneous tumors (7). Definite diagnosis could be offered on cytomorphology in 74.7% (62) cases, while in 25.3% (21) cases only a diagnosis of round cell tumor could be offered. Concordance with final histopathology and biochemical parameters was subsequently obtained in 79/83 (95.5%) of cases. A clinically relevant classification is possible on FNAC in pediatric abdominal tumors when interpreted with clinicoradiologic parameters. This obviates the need for a more time-consuming biopsy procedure in critical situations and in stage II nephroblastoma where it is contraindicated.

Vascular endothelial growth factor (VEGF) and the vascular endothelial growth factor receptors (VEGFRs) regulate the development of hemogenic mesoderm. Oxygen concentration-mediated activation of hypoxia-inducible factor targets such as VEGF may serve as the molecular link between the microenvironment and mesoderm-derived blood and endothelial cell specification. We used controlled-oxygen microenvironments to manipulate the generation of hemogenic mesoderm and its derivatives from embryonic stem cells. Our studies revealed a novel role for soluble VEGFR1 (sFlt-1) in modulating hemogenic mesoderm fate between hematopoietic and endothelial cells. Parallel measurements of VEGF and VEGFRs demonstrated that sFlt-1 regulates VEGFR2 (Flk-1) activation in both a developmental-stage-dependent and oxygen-dependent manner. Early transient Flk-1 signaling occurred in hypoxia because of low levels of sFlt-1 and high levels of VEGF, yielding VEGF-dependent generation of hemogenic mesoderm. Sustained (or delayed) Flk-1 activation preferentially yielded hemogenic mesoderm-derived endothelial cells. In contrast, delayed (sFlt-1-mediated) inhibition of Flk-1 signaling resulted in hemogenic mesoderm-derived blood progenitor cells. Ex vivo analyses of primary mouse embryo-derived cells and analysis of transgenic mice secreting a Flt-1-Fc fusion protein (Fc, the region of an antibody which is constant and binds to receptors) support a hypothesis whereby microenvironmentally regulated blood and endothelial tissue specification is enabled by the temporally variant control of the levels of Flk-1 activation. Disclosure of potential conflicts of interest is found at the end of this article.

The distinction between metastasis from a colorectal adenocarcinoma into the ovary and an ovarian adenocarcinoma is vital, but challenging at times, due to overlapping morphological features. Similarly, a distinction between an ovarian metastasis into the colorectum and a colorectal adenocarcinoma, although rare; is important and can be daunting. We report an analysis of 20 cases of ovarian involvement by metastatic colorectal adenocarcinomas and colorectal involvement by metastatic ovarian adenocarcinomas, including the value of differential expression of cytokeratins 7 & 20 by immunohistochemistry (IHC), in these cases. Nine cases (45%) were identified as colorectal adenocarcinomas metastatic to the ovary. On biopsy, all these cases showed a 'garland-like' tumor necrosis, with desmoplasia and predominantly exhibited a tubuloalveolar pattern (67% cases). On IHC, all 8 of 9 such cases, where staining for cytokeratin 20 was performed, displayed strong positivity and 7 cases, where staining for carcinoembryogenic antigen (CEA) was performed, revealed positivity for this marker (100%). Other 11 cases (55%) were ovarian adenocarcinomas, metastatic to the colorectum. These showed metachronous presentations, with the ovarian tumor preceding the colorectal tumor deposits. Morphologically, psammomatous calcification was noted in 73% of these cases, whereas 'garland-like' necrosis was absent in all. The chief morphological subtype was serous papillary cystadenocarcinoma (55% cases). On IHC, CK7 and CA 125 were positive in all 6 of 11 such cases, whereas CK 20 was negative in all these cases. In cases of complex presentations like an ovarian involvement by a metastatic colorectal adenocarcinoma and vice-versa, certain clinicopathological features are useful. Differential expression of CK 7 and CK20 is vital in resolving these dilemmas. CK20 positivity and CK7 negativity is associated with a colorectal adenocarcinoma. Markers like CEA and CA-125 have an added value.

Follicular dendritic cell sarcomas are rare neoplasms arising from the accessory cells of the lymph nodes, the follicular dendritic cells. They commonly occur in the lymph nodes, but have also been reported at extranodal sites (especially the tonsil). At both sites, there is usually a proliferation of spindled to ovoid cells, mimicking a mesenchymal tumor. Herein, we report a tonsillar tumor in a 50-year-old man, which was composed exclusively of large polygonal cells and numerous osteoclastic giant cells that resembled a giant cell carcinoma. The true nature of the tumor was revealed after an array of immunohistochemical stains. The patient is well 4 years after tonsillectomy.

Introduction: The most common histotype representing 90% of ovarian cancer cases is High Grade Serous Carcinoma. In a previous publication we found C/EBP-δ to be significantly increased in fallopian tube epithelial in BRCA1 mutation carriers and specifically in the luteal phase of the menstrual cycle, by transcription and protein expression. C/EBP-δ represents a master regulator of gene transcription primarily through STAT3 activation in many tumor types. C/EBP-δ is commonly induced by stress and is associated with increased DNA damage. Additionally, studies in breast cancer showed that C/EBP-δ could interact with FANCD2, which is involved in DNA repair along with BRCA1 and BRCA2. C/EBP-δ plays a dichotomous role in tumor suppression and promotion, which is tissue specific. We therefore studied the 1) differential expression of C/EBP-δ in serous carcinoma 2) expression of C/EBP-δ in precursor lesions (STIC) and 3) modeled the effect of over-expression of C/EBP-δ in an in vitro fallopian tube cell culture model. Methods: The study protocol for collection of tissue and clinical information for all patients was approved by the UHN REB. Tissue microarrays containing the different histotypes were used to validate immunohistochemical protein expression. Fallopian tubes with lesions classified as STIC using published diagnostic criteria, were selected (n=15) from women undergoing surgery for HGSC. FTE Cells were propagated on collagen IV coated plates in MCDB105/M199 media supplemented with BPE, EGF, insulin and hydrocortisone. Cells were immortalized via double infection with a lentiviral dominant negative TP53 vector and retroviruses with E7 and hTERT. Statistical analysis was performed using ANOVA (p Results/Conclusion: C/EBP-δ is down-regulated in over 60% of HGSC analyzed, an observation which is also histotype specific as LGSC tumors show high expression levels (p Citation Format: Sophia HL George, Ramlogan Sowamber, Patricia Shaw. The role of BRCA and CEBPD in serous ovarian cancer carcinogenesis [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr POSTER-BIOL-1312.

Background: Recently described precursors of high-grade serous carcinoma (HGSC), the p53 signature, a latent precursor, and Serous Tubal Intraepithelial Carcinoma (STIC), a pre-malignant precursor, occur most frequently at the distal and fimbriated end of the fallopian tube (FTE). In 3 previous reports, we have demonstrated that the FTE of BRCA1 mutation carriers, at genetic risk of HGSC, have altered signaling pathways compared to controls. Ovarian production of ROS is released after the LH surge to induce ovulation. Reactive oxygen species (ROS) have been implicated in serous carcinogenesis. The objective of this study is to compare the transcriptome profiles of normal fimbria (high-risk epithelia prone to transformation) FTE and normal ampulla (low-risk epithelia) FTE which may lead to understanding the distal end of the fallopian tube as the preferential anatomic location of the fallopian to tube for cellular transformation. Method: Snap-frozen matched fimbria and ampulla tissues were controlled for age and ovarian cycle status. Cases included 12 luteal phase and 12 follicular phase women at no known risk for ovarian cancer. Laser capture microscopy was used to microdissect FTE cells, using 7-10 sections per case. Total RNA was isolated, RNA extracted and cDNA amplified. The expression profiles were generated using Affymetrix Human Genome HTA-2.0 Array. Results: Using gene level differential expression analysis with the Affymetrix Expression Console software, we performed unsupervised hierarchical clustering analysis with all 24 samples. We used a fold change of < -2 or > 2 and ANOVA p-value < 0.05 as a cut-off criteria for selecting genes. The cases clustered predominantly by ovarian cycle status rather than by their differences in anatomical origin or their matched pair. There were 427 genes differentially expressed amongst the 4 groups– Fim-Luteal, Fim-Follicular, FT-Luteal and FT-Follicular. Independent of ovarian cycle status, very few differences (35 genes– SALL1, ME1– higher in the ampulla; GSTA1, GSTA2, SERPINA3-higher in the fimbria– genes involved in metabolic pathways) were observed between the ampulla and fimbria FTE. Conclusions: The epithelia of the anatomically high-risk fallopian tube– the fimbria, show few differences in gene expression profiles compared to the lower risk portion– the ampulla. Expression differences predominantly are in response to the hormonal milieu, post-ovulation with an antioxidant program The increased anatomic risk of the fimbria is likely due to effects of the microenvironment, such as repeated exposure to follicular fluid at ovulation (higher ROS) and antioxidant genes and their interaction with DNA repair genes (like TP53), rather than intrinsic differences of the FTE in the two sites. Citation Format: Sophia H. George, Anca Milea, Noor Hera Salman, Patricia Ann Shaw. Differential transcription profile of epithelia in fimbria versus the ampulla of the fallopian tube. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2080. doi:10.1158/1538-7445.AM2015-2080

Epithelial ovarian cancer is a heterogeneous group of diseases with multiple histotypes which can be broadly divided into a dualistic model based on morphological, molecular genetic, and clinical features. The most common and aggressive of all EOC, accounting for 90% of deaths, is High Grade Serous Carcinoma (HGSC). It is characterized by a genetically unstable, rapidly growing phenotype, is diagnosed at advanced stage with poorly defined cancer precursors compared to the more indolent Low Grade Serous Carcinoma (LGSC). Reproductive hormone receptor status (estrogen/ progesterone receptor) may be an important indicator of response to anti-hormonal therapy in ovarian cancer. There have been few reports detailing the expression of ER in HGSC, LGSC and the normal fallopian tube epithelium, the likely cell of origin of both histotypes. We hypothesize that some ER mediated signaling is maintained despite the loss of progesterone receptor in HGSC compared to the LGSC. Methodology: Snap-frozen tissues (43 HGSC and 18 LGSC) were selected from the UHN Biobank. We used our previously published gene expression profiles to generate a candidate gene list, which was chosen based on the presence of known estrogen responsive elements. They were validated by qPCR and immunohistochemistry on HGSC and LGSC tissue microarrays. Human fallopian tube epithelial cell lines were treated with estradiol at 50nm to determine ‘normal’ ER response. An ER positive cancer cell line (SKOV3) was used to determine the cellular response to candidate genes. IHC was scored using automated image analysis. Statistical analysis was performed using ANOVA and Fisher's Exact Test. Results: 35/43 (81%) of HGSC were ER+/PR- whilst 9/27 of LGSC were ER+/PR- and 18/27 ER+/PR+. Gene expression analysis of ER+ HGSC and ER- HGSC revealed 881 genes with more than a 2-FC in gene expression including 202 genes with known or putative estrogen responsive elements. They are involved in immune response, locomotion, metanephrous development and cellular adhesion. We compared genes that were differentially expressed between normal fallopian tube cells obtained during pre- or post-ovulation (93 genes). 42 ‘FTE-normal’ genes were differentially expressed between ER- versus ER+ HGSC. We selected 5 genes to validate by qPCR and IHC, based on gene ontology and known associations to cancer pathways. Conclusions: These results show that HGSC is predominantly an ER+/ PR- cancer (80%) while LGSC is predominantly an ER positive/ PR positive cancer (66%). Our data also indicate that some ER signalling is maintained in the absence of the progesterone receptor and ER+ HGSC are transcriptionally different from ER- HGSC although, there is no distinct clinical benefit between these two groups. ER is still able to transcriptionally activate a subset of known ER target genes and this information should provide further insight into the use of hormone receptors as indicators of anti-hormone therapy in ovarian cancer. Citation Format: Sophia Hl George, Anca Milea, Ramlogan Sowamber, Danielle Toccalino, Patricia A. Shaw. The role of estrogen receptor signalling in serous ovarian cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4765. doi:10.1158/1538-7445.AM2013-4765

Background: LKB1 is a ubiquitously expressed serine/threonine protein kinase recently ranked sixteenth on the list of top cancer genes. Inactivating germ-line mutations in LKB1 gene on chromosome 19p13.3 found in 60–70% of patients with Peutz-Jeghers syndrome (PJS), leading to increased risk of developing cancers of epithelial origin. Loss of LKB1 protein with underlying LKB1 gene methylation previously found in high-grade breast carcinoma – low expression associated with shorter relapse-free survival. Heterozygous mutations of LKB1 and p53 genes cooperate in the acceleration of tumorigenesis in mice. High-grade serous ovarian cancer (HGSC) is rarely diagnosed at an early and potentially curable stage, effective early detection and preventative strategies are few. In a previously published microarray study, we observed that LKB1 mRNA was significantly lower in Fallopian tube cancers and HGSC. Recently the discovery of occult invasive and intraepithelial tubal carcinomas in BRCA1 mutation carriers, who are at high risk of serous cancer, undergoing prophylactic surgery has focused attention on the fallopian tube epithelium as the cell of origin and has led to the reporting of putative serous cancer precursor lesions. We therefore, sought to determine the expression of LKB1 in different histological subtypes of ovarian cancer and in early lesions; and the effect of loss of LKB1 on fallopian tube epithelial cells in vitro. Methodology: Archived sections of ovarian tumors were reviewed, paraffin blocks selected, and tissue microarrays created using triplicate 0.6 mm cores. The major histological types included were: high grade serous (n=201), non-serous (n=87), and low grade (micropapillary) (n=12) carcinomas, serous tumors of low malignant potential (n=26) and STICS (n=15). Immunohistochemistry for LKB1 protein (Santa Cruz mouse mAb sc-32245) was performed using standard techniques. Percentage of tumor cells with positive cytoplasmic staining (0–3), staining intensity (0–3) and histoscores were determined by viewing digitalized images with Aperio ImageScope software. A combined score of > 4 was considered positive. Fishers exact test with 95% confidence intervals was used to determine the significance of results. Fallopian tube epithelial cells were established from freshly digested tissue and infected with shRNA targeting LKB1. In vitro assays to determine proliferation and malignant transformation were used. Results: Loss of cytoplasmic LKB1 protein expression is more frequently observed in sporadic and hereditary high-grade serous carcinomas compared to other histological types, including low-grade serous carcinoma and serous tumors of low malignant potential. LKB1 may be exclusively involved in the high-grade serous oncogenic pathway and not in the development of low-grade serous carcinoma. Loss of LKB1 in early lesions was observed in 15/15 cases and indicates a role for in sporadic HGSC tumorigenesis in corporation with previously identified oncogenes. The frequency of LKB1 loss in high-grade tumors (67–69%) is similar to frequency of p53 mutations previously observed (70%). Citation Information: Cancer Prev Res 2011;4(10 Suppl):A11.

The Rb pathway functions as a cell cycle checkpoint and deregulation of its components, commonly found in malignancies, causes progression from G1 to S phase, promoting cellular proliferation. Because of Rb's central role in checkpoint regulation, abrogation of the pathway can occur through multiple non-redundant mechanisms including Rb loss, hypermethylation or mutation, and CCND1 or CCNE amplification. Emerging evidence shows that tumour types can often be distinguished by particular alterations in one member of the pathway suggesting that different mechanisms of Rb abrogation may regulate tumour behaviour. We hypothesize that Rb pathway deregulation is frequent in HGSC, the most common and most aggressive histotype of ovarian cancer, and that the mechanism of Rb pathway deregulation identifies clinically distinct subgroups of HGSC. Micro-dissected epithelium from HGSC and normal FTE samples were analyzed for differential gene expression using the Affymetrix U133 Plus 2.0 gene-chips, and expression values for p53, p21, p27, p16, CCND1, CCNE and Rb genes determined. Protein expression was assessed by immunohistochemistry (IHC) on tissue microarrays composed of ovarian/tubal carcinomas inclusive of the major histotypes. Digitized stained slides were quantified using automated image analysis and correlated with clinico-pathologic variables including outcome. Rb loss of heterozygosity (LOH) was tested by an Rb diagnostics protocol involving D13S153 and RB1.2 polymorphic marker analyses using PCR amplification, followed by comparisons of the tumour and its corresponding normal sample by MicroGene Clipper sequencers. Gene expression analysis showed statistically significant over-expression of p53, CCNE E2F1/3 and p16 and down-regulation of p21 and CCND1 in HGSC compared to normal fallopian tube epithelium (p HGSC is characterized by both genetic and protein abrogation in the Rb pathway. Additionally, we observed differences in the mechanism of this G1/S checkpoint inactivation amongst HGSC patient samples which may represent important biological/clinical differences amongst sub-groups of serous cancer patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 333. doi:10.1158/1538-7445.AM2011-333

Background: High-grade serous ovarian cancer is rarely diagnosed at an early and potentially curable stage, effective early detection and preventative strategies are few. Recently the discovery of occult invasive and intraepithelial tubal carcinomas in BRCA1 mutation carriers, who are at high risk of serous cancer, undergoing prophylactic surgery has focused attention on the fallopian tube epithelium as the cell of origin and has led to the reporting of putative serous cancer precursor lesions. However, little is known of the early molecular events of serous oncogenesis, or why cancers in BRCA 1 mutation carriers are found preferentially in tissues which are responsive to reproductive hormones. We hypothesize that molecular alterations are present in morphologically normal tubal epithelium from BRCA1 heterozygotes, and that these changes may reflect the earliest alterations in serous carcinogenesis and may be markers of increased cancer risk as well as targets for risk reduction. To identify cancer predisposition candidate genes of high-risk fallopian tube epithelium, we compared gene expression profiles of microdissected tubal epithelium from BRCA1 mutation carriers, control women and patients with HGSC. Methodology: Snap-frozen tissues were selected from the UHN Biobank; control and BRCA cases controlled for age, ovarian cycle status at surgery, and hormone therapy. Cases included 12 BRCA1 mutation carriers and 12 control women, undergoing salpingo-oophorectomy for reasons other than adnexal malignancy or family history, 15 HGSC and 8 contralateral normal tubes. Epithelium was microdissected in all cases using laser capture, RNA extracted and cDNA amplified. The gene expression profiles were generated using Affymetrix Human Genome U133 Plus 2.0 Array. Candidate genes were validated by qPCR and IHC on 2 fallopian tube TMAs. IHC was scored using Spectrum. Statistical analysis was performed using ANOVA (p Results: We focused the microarray analyses on identifying differential expression between BRCA1 heterozygotes and controls. Comparisons between FTE-nonBRCA and FTE-BRCA, resulted in 440 probe sets with more than 2-FC in gene expression. We selected 5 genes to validate by qPCR and IHC, based on gene ontology and known associations to cancer pathways. Conclusions: These results show that histological normal fallopian tube epithelium from BRCA1 heterozygotes have altered gene expression and these differences are most pronounced in the post-ovulatory phase of the ovarian cycle in pre-menopausal women, suggesting that factors associated with the luteal phase are implicated in the increased risk of HGSC in BRCA1 mutation carriers. We also show that genes involved in inflammation pathways are up-regulated in mutation carriers and that these genetic signatures are maintained in HGSC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2835. doi:10.1158/1538-7445.AM2011-2835