Elevated Proliferation Index Research Articles

TMOD-29. A MOUSE MODEL OF FGFR3-TACC3 UNCOVERS MECHANISMS OF GLIOMAGENESIS AND MAINTENANCE

Abstract Glioblastoma harboring Fibroblast Growth Factor Receptor 3 (FGFR3)-Transforming Acidic Coiled-Coil containing 3 (TACC-3) (FGFR3-TACC3) fusion is a distinct molecular subclass of tumors that can be targeted by FGFR kinase inhibitors. We generated a knock-in mouse in which the expression of FGFR3-TACC3 is doxycycline inducible and reversible. The tetO-FGFR3-TACC3-IRES-GFP cassette was placed into the Rosa26 locus and the FGFR3-TACC3 knock-in strain was intercrossed with GFAP-rtTA*M2 mice to trigger expression of the tetracycline transactivator (and the fusion gene) from the GFAP promoter. To recapitulate the genetic lesions that are more frequently associated with FGFR3-TACC3 in human glioblastoma, we also intercrossed the tetO-FGFR3-TACC3-IRES-GFP;GFAP-rtTA*M2 mice with TP53+/-or Ink4A+/-mouse strains. Both strains developed aggressive and infiltrating gliomas within 90 days after induction of FGFR3-TACC3 by doxycycline containing diet. Tumors occurred with a prevalence of ~50% and were found almost exclusively at two brain locations: the lateral septum and the neuro-epithelium adjacent to the fimbria of the hippocampus, thus recapitulating the restricted expression of endogenous FGFR3 in the ventral telencephalon and ganglionic eminence during development. The FGFR3-TACC3-positive glioma resembled human glioblastoma as they exhibited marked invasiveness and vascularization, elevated proliferative index and positivity for Nestin and GFAP. Rapid tumor progression caused appearance of neurological symptoms and death within few weeks. Doxycycline withdrawal from the diet of mice diagnosed with brain tumors by MRI resulted in rapid loss of FGFR3-TACC3 from glioma cells, marked inhibition of tumor growth with essentially complete glioma regression in some cases and recovery of general and neurological clinical symptoms. Our findings validate FGFR3-TACC3 as powerful oncogene that drives development of high-grade glioma from distinct areas of the brain. They also provide an accurate pre-clinical model in which glioma maintenance requires continuous expression of the fusion gene, thus supporting therapeutic targeting of the fusion protein in patients with FGFR3-TACC3-positive glioblastoma.

Elevated expression of mcl-1 inhibits apoptosis and predicts poor prognosis in patients with surgically resected non-small cell lung cancer

BackgroundMcl-1, an anti-apoptotic member of bcl-2 family, together with cleaved poly (ADC-ribose) polymerase (c-PARP) can serve as a marker of cell apoptosis. Previously we reported that treatment of Mnk inhibitor CGP57380 resulted in decreased Mcl-1 expression while increased c-PARP expression in non-small cell lung cancer (NSCLC) cells. In this study, we aimed to investigate association between Mcl-1 expression and clinicopathological features of NSCLC, and their correlation between Mcl-1 and both proliferation index (PI) and apoptotic index (AI) in NSCLC patients.MethodsTissue microarrays (TMA) including 350 cases of surgically resected NSCLC were utilize and stained with Mcl-1, Ki-67 and c-PARP antibodies, PI and AI were then evaluated, respectively.ResultsHigher Mcl-1 expression and PI were observed in NSCLC compared with non-cancerous lung tissues (non-CLT), while AI was significantly lower in lung adenocarcinoma (ADC) compared with non-CLT. Additionally, Mcl-1 expression in lung ADC was evidently higher than that of in lung squamous cell carcinoma (SCC). The elevated Mcl-1 expression was associated with PI, and inversely related to AI in NSCLC. NSCLC patients with elevated Mcl-1 expression and high PI, or with high Mcl-1 expression and low AI had remarkably shorter overall survival time than these patients with low Mcl-1 expression.ConclusionsElevated expression of Mcl-1 might be inversely proportional to disease progression of NSCLC patients by promoting cell proliferation and inhibiting apoptosis, and Mcl-1 might serve as novel biomarker of poor prognosis for NSCLC patients.

Stage IV lung carcinoids: spectrum and evolution of proliferation rate, focusing on variants with elevated proliferation indices

The spectrum and evolution of proliferation rates in stage IV lung carcinoids is poorly defined. In particular, there are limited data on the prevalence and characteristics of tumors exceeding the standard upper proliferative criteria—as defined largely based on early-stage carcinoids—in metastatic setting. Sixty-six patients with stage IV lung carcinoids were identified, and all evaluable samples (n = 132; mean 2 samples per patient) were analyzed for mitotic counts and Ki-67 rate. Clinicopathologic and genomic features associated with elevated proliferation rates (>10 mitoses per 2 mm2 and/or >20% hot-spot Ki-67), and evolution of proliferation rates in serial specimens were analyzed. We found that mitoses and/or Ki-67 exceeded the standard criteria in 35 of 132 (27%) samples, primarily (31/35 cases) at metastatic sites. Although neuroendocrine neoplasms with >10 mitoses per 2 mm2 are currently regarded as de facto neuroendocrine carcinomas, the notion that these cases are part of the spectrum of carcinoids was supported by (1) well-differentiated morphology, (2) conventional proliferation rates in other samples from same patient, (3) genetic characteristics, including the lack of RB1/TP53 alterations in all tested samples (n = 19), and (4) median overall survival of 2.7 years, compared to <1 year survival of stage IV neuroendocrine carcinomas in the historic cohorts. In patients with matched primary/metastatic specimens (48 pairs), escalation of mitoses or Ki-67 by ≥10 points was observed in 35% of metastatic samples; clonal relationship in one pair with marked proliferative progression was confirmed by next-generation sequencing. Notably, escalation of proliferation rate was documented in a subset of metastases arising from resected typical carcinoids, emphasizing that the diagnosis of typical carcinoid in primary tumor does not assure low proliferation rate at metastatic sites. In conclusion, stage IV lung carcinoids frequently exceed the standard proliferative criteria established for primary tumors, and commonly exhibit proliferative escalation at metastatic sites. Despite the overlap of proliferation rates, these tumors show fundamental morphologic, genomic and clinical differences from neuroendocrine carcinomas, and should be classified separately from those tumors. Awareness of the increased proliferative spectrum in metastatic carcinoids is critical for their accurate diagnosis. Further studies are warranted to explore the impact of proliferation indices on prognosis and therapeutic responses of patients with metastatic carcinoids.

THE ADDITION AT DAY 9 OF HD‐MTX TO THE (DA)‐EPOCH SCHEME WITH OR WITHOUT RITUXIMAB IS AN EFFECTIVE REGIMEN IN UNTREATED ADVANCED STAGE HIGH RISK LYMPHOMA: A FEASIBILITY STUDY

DA-EPOCH is an infusional regimen designed to improve the response rate in highly proliferative tumors by prolonging cell exposure to low concentrations of chemotherapeutic agents. It was demonstrated as effective regimen in both T and B cell high grade lymphomas with an elevated proliferative index. Moreover, the addition of Rituximab is currently the standard of care in any B cell lymphoma treatment strategy. Previous studies have shown that high dose methotrexate (HD-MTX) therapy is better than intrathecal MTX administration to prevent CNS relapse, but so far few data are available that explore the feasibility of combination therapy including HD-MTX and DA-EPOCH with or without Rituximab. Our pilot study reported the result of the above combination therapy in a series of high risk advanced stage lymphoma patients (pts). Five patients were enrolled in this feasibility study: 3 pts were affected by Diffuse Large B Cell Lymphoma (DLBCL) no GC type, 1 pt had a diagnosis of Primary Mediastinal Diffuse Large B Cell Lymphoma (PMDLBCL) and 1 pt had an ALK+ Anaplastic Large Cell Lymphoma (ALCL). All pts showed a stage IV disease with ³ 2 extranodal sites, high LDH level, a very high proliferation index evaluated by Ki67 (median 90%, range 60-100%) and intermediate/high IPI score (3). High risk of CNS relapse was present in all pts because of type of extranodal sites (gut, bone, liver, heart, mediastinum, pancreas) and for high proliferation rate. The combination therapy included classical DA-EPOCH-R scheme with exception of Rituximab in ALCL with the addition of high dose (3.5 g/m2) Methotrexate at day 9 after urine alkalinization and hydration. All patients were scheduled to receive a total of 6 courses of therapy including 4 courses of the classic DA-EPOCH scheme and 2 combined therapy cycles. G-CSF prophylaxis was administered to all patients starting on day +9 and day +12 in the case of DA-EPOCH or combination therapy, respectively. The aim of the study was to evaluate the impact of adding HD-MTX to DA-EPOCH on the time between DA-EPOCH- (R) cycles. Secondary endpoints were response rate, PFS, toxicity, and CNS relapse rate. After a total of 9 courses administered of combination therapy, no delay in DA-EPOCH-(R) schedule of 21 days was observed. All patients showed a very favorable toxicity profile with only G3 neutropenia without infectious complications and G2 hepatotoxicity with elevations in transaminases. Three out of 5 pts completed the treatment strategy obtaining a CR and are now in follow-up, while the others are still on treatment. No CNS relapse were observed. Our preliminary results showed the feasibility of the combination therapy DA-EPOCH-R/HD-MTX with satisfactory results on controlling very aggressive disease. However, only prospective trials can define the optimum scheduling of this regimen and the possibility to use as standard therapy in very aggressive lymphomas with high risk of CNS relapse. Keywords: DA-R-EPOCH; high-dose methotrexate; non-Hodgkin lymphoma (NHL).

Pituitary Adenoma in Pediatric and Adolescent Populations.

Pituitary adenomas are rare in children and adolescents and although mostly benign, they can sometimes be challenging to manage due to their locally invasive nature. In this study, we examined the clinicopathologic features of 42 pituitary adenomas in patients ≤21 years of age. The youngest patient was 8 years old (median age: 18 years), and the female-to-male ratio was 1.8:1. Five patients had recurrence after resection. There was no obvious difference between the recurrent rates in the typical (11.7%) and atypical adenomas (12.5%) based on the 2004 WHO classification. However, the recurrence rate was much higher in adenomas with an elevated proliferation index of ≥3% (20.8%) or with evidence of local invasion (18.2%). Adenomas with combination of an elevated proliferation index of ≥3% and imaging evidence of local invasion had the highest recurrence rate of 25%. In summary, pituitary adenomas are more frequent in adolescents as compared with children and are more common in girls. An elevated proliferation index of ≥3% and evidence of local invasion on imaging seem to correlate with a high probability of recurrence. Furthermore, we observe rarity of α-thalassemia/mental retardation syndrome X-linked (ATRX) protein loss (surrogate to ATRX mutation) in these tumors without any connotation on prognosis.

SAT-463 Familial X-Linked Acrogigantism: Postnatal Outcomes and Tumor Pathology in a Prenatally Diagnosed Infant and His Affected Mother

Background: X-linked acrogigantism (X-LAG), a condition of infant-onset acrogigantism marked by elevated levels of GH, IGF-1, and PRL, is extremely rare with 33 cases reported in the literature (1), including 7 total familial cases from 3 kindreds. Clinical Case: The patient’s mother, diagnosed with acrogigantism at 21 months of age, underwent pituitary tumor excision at 24 months with the expected subsequent hypopituitarism, diabetes insipidus, and seizure disorder. For over 30 years, stable GH, IGF-1, and PRL levels and serial MRI studies indicated no tumor recurrence. On pre-conception planning genetic studies, X-LAG was diagnosed: SNP microarray showed Xq26.3 microduplication. After conception at age 32, CVS with SNP microarray showed the same microduplication, confirming familial X-LAG in the male fetus (2,3). The infant experienced rapid interval growth between 5-6 months of age in conjunction with rising GH, IGF-1, and PRL levels and enlarging suprasellar pituitary mass, which continued to grow despite titration of bromocriptine started at 6 months. He underwent pituitary tumor resection at 15 months with development of the expected hypopituitarism requiring hormone replacement therapies. The pituitary adenoma resembles the mother’s pituitary adenoma, with tumor cells arranged in trabeculae and glandular structures. Many tumor cells in both cases express GH, PRL and Pit-1. The expression of other lineage-specific transcription factors (T-PIT, SF1) and Sox2 demonstrates the multipotentiality of X-LAG tumors, an observation not previously described. Both tumors showed an elevated Ki-67 proliferation index—5.6% (mother) and 8.5% (patient)—the highest reported in X-LAG (most are < 3%) (1). GH, IGF-1, and PRL levels fell precipitously and growth acceleration decreased, with WHO height Z-score decrease from 2.6 to 1.9 by 20 months of age. Conclusion: This is the first prenatally-diagnosed case of X-LAG. Prospective follow-up with close clinical evaluation provides insight into the natural history of X-LAG. Utilization of cell lineage-specific transcription factors and stem cell markers reveals unexpected complexity of X-LAG tumors.

Initial Results of a Phase II Study of Sequential Chemotherapy and Lenalidomide Followed By Rituximab and Lenalidomide Maintenance for Untreated Mantle Cell Lymphoma

Introduction: Cytarabine-containing induction chemotherapy followed by high dose therapy and autologous stem cell transplant (ASCT) is currently a standard treatment approach for younger patients with mantle cell lymphoma (MCL). This approach, however, may be associated with lesser efficacy in patients with high-risk disease biology (i.e. with elevated proliferative index, blastic morphology, or TP53 alteration). Older patients are treated with rituximab-based chemotherapy regimens without stem cell transplant. In this single-center prospective phase II study, we treated MCL patients, irrespective of their age, with immunochemotherapy combined with lenalidomide without ASCT to evaluate the safety and efficacy of this regimen.Methods: Treatment consisted of 3 parts: A) 4 cycles of lenalidomide (15mg orally days 1-14) and standard RCHOP chemotherapy in a 21-day cycle B) rituximab and high-dose cytarabine (RHIDAC) administered at a dose of 1,000-3,000 mg/m2 every 12 hours x 4 doses for a total of 2 cycles C) rituximab plus lenalidomide maintenance for 6 months. Eligible patients were untreated MCL, stage II-IV, KPS≥70%, and with adequate organ function. We enriched study enrollment for high risk patients, 31 of a total 47 patients, as defined by Ki-67 ≥30% and/or blastic/blastoid/pleomorphic morphologic subtype. PET/CT after each phase of treatment was completed and interpreted with the 5-point Deauville scale (negative=1-3). The primary endpoint of the study was to evaluate the 3-year progression free survival. Herein we are presenting preliminary data on the end-of-treatment (EOT) response rate and the toxicity of the regimen, including the interim and EOT PET data.Results: Interim data (as of June 1, 2018) for the first 45 of a planned 47 patients are presented here. Median age was 63 (range 30-79); 82% stage IV; MIPI low, intermediate and high risk were 31%, 31%, and 38%, respectively; 64% of patients had high-risk disease per our definition (28 patients with a Ki-67 ≥30% and 6 patients with blastic morphology).Of the 39 patients who completed Len-RCHOP induction, 85% were PET-negative and after RHIDAC, 95% of patients achieved a negative PET scan (Figure 1). Of the 26 patients who have completed Len-R maintenance, 92% were PET-negative, 8% PET-positive (Table 1). At EOT, 24 patients (92%) achieved a complete remission, 1 patient achieved a partial response, and 1 patient had progressive disease. Among the 24 patients who achieved a CR, the median follow-up is 9 months. Two relapses have occurred at 18 months and 25 months. The patients with a treatment failure (one PR at EOT, one progressive disease at EOT, and 2 relapses), occurred in patients either with a TP53 mutation (3/3 tested, 1 pending) or blastic morphology (3/4 patients). Overall the treatment program was well-tolerated and predominantly hematologic toxicities were observed, particularly during the RHIDAC phase consistent with past experience with this treatment regimen in MCL. During each phase (Len-RCHOP, RHIDAC, and Len-R maintenance), grade 3/4 neutropenia was observed at a rate of 13%, 52%, 16%, respectively; febrile neutropenia 1%, 4%, 0%, respectively; grade 3/4 anemia 11%, 32%, 1%, respectively; and grade 3/4 thrombocytopenia 8%, 75%, 2%, respectively. Comparing to our historical data in a cohort of 23 MCL patients (57% low risk), Len-RCHOP resulted in a higher PET-negative rate compared to RCHOP alone, 85% versus 65%, respectively.Conclusion: The addition of lenalidomide to RCHOP chemotherapy appeared to increase the rate of PET-negativity compared to historical results with RCHOP alone. Toxicity occurred as expected and was manageable. Early failures were observed in patients with TP53 mutation or blastic morphology. Although follow-up is limited, early results with this approach are promising. [Display omitted] DisclosuresKumar:Seattle Genetics: Research Funding; Abbvie Pharmaceuticals: Research Funding; Adaptive Biotechnologies: Research Funding; Pharmacyclics: Research Funding; Celgene: Consultancy, Honoraria, Research Funding. Zelenetz:Novartis/Sandoz: Consultancy; Amgen: Consultancy; Celgene: Consultancy; AstraZeneca: Consultancy; Abbvie: Research Funding; Gilead: Consultancy, Research Funding; Genentech/Roche: Consultancy, Research Funding. Hamlin:Portola: Consultancy. Matasar:Seattle Genetics: Honoraria. Moskowitz:Bristol Myers-Squibb: Consultancy, Research Funding; Takeda: Honoraria; Merck: Research Funding; Incyte: Research Funding; ADC Therapeutics: Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding. Straus:Bayer: Consultancy; Medical Crossfire: Speakers Bureau; DAVA Oncology: Consultancy, Honoraria; JUNO: Consultancy; Millenium (Takeda): Consultancy, Research Funding; Seattle Genetics: Consultancy; Onco Tracker: Consultancy; Roch China: Speakers Bureau; InPractice Elselvier: Consultancy; Memorial Sloan Kettering Cancer Center: Employment. Younes:BMS: Honoraria, Research Funding; Astra Zeneca: Research Funding; Genentech: Research Funding; Pharmacyclics: Research Funding; Celgene: Honoraria; Abbvie: Honoraria; Takeda: Honoraria; Roche: Honoraria, Research Funding; Novartis: Research Funding; Janssen: Honoraria, Research Funding; Merck: Honoraria; J&J: Research Funding; Curis: Research Funding; Incyte: Honoraria; Bayer: Honoraria; Sanofi: Honoraria; Seattle Genetics: Honoraria.

Immunohistochemical analysis and prognostic significance of PD-L1, PD-1, and CD8+ tumor-infiltrating lymphocytes in Ewing's sarcoma family of tumors (ESFT).

Ewing's sarcoma family of tumors (ESFT) are aggressive neoplasms with scant tumor-infiltrating lymphocytes. We analyzed the immunohistochemical (IHC) expression of PD-L1 and PD-1 and their prognostic significance in clinically localized neoplasms in a cohort of 370 ESFT. Slides prepared from tissue microarrays were stained for PD-L1, PD-1, and CD8. Membranous/cytoplasmic staining over 5% of tumor cells was regarded as positive for PD-L1 and PD-1. Prognostic analysis was done considering only clinically localized tumors (n = 217). PD-L1 expression was present in 19% of ESFT, while PD-1 was expressed in 26%. Forty-eight percent of tumors were negative and 12% were positive for both PD-L1 and PD-1. Metastatic tumors displayed higher expression of PD-L1 (p < 0.0001). Histological subtypes were not correlated with PD-L1 or PD-1 positivity. ESFT with elevated proliferation index (Ki-67) were associated with higher PD-L1 expression (p = 0.049). Regarding prognosis, no significant association was found between PD-L1 expression and progression-free survival (PFS) or overall survival (OS), whereas lack of PD-1 expression in tumor cells was correlated with both poor PFS (p = 0.02) and poor OS (p = 0.004). Tumor-infiltrating CD8(+) T lymphocytes were observed in 15.4% of ESFT with informative results (347 tumors). No correlation was found between tumor-infiltrating CD8(+) T lymphocytes and ESFT histological subtypes, tumor location, or PD-1 and PD-L1 expression, nor with PFS (p = 0.473) or OS (p = 0.087). PD-L1 expression was not significantly related to prognosis. PD-1 was expressed in 26% of ESFT tumor cells and may have prognostic and therapeutic implications. CD8 expression in tumor-infiltrating lymphocytes was not related to prognosis.

Gastroenteropancreatic neuroendocrine neoplasms: selected pathology review and molecular updates.

Gastroenteropancreatic (GEP) neuroendocrine neoplasms can be broadly separated into well- and poorly differentiated categories. Tumours within each category have similarities in morphology and immunophenotype, but vary in grade, behaviour, molecular signature and responses to therapy. The aetiology of these differences is multifactorial. Site of origin, mucosal milieu and hereditary influences are some of the currently known factors. Given these differences, staging and grading systems continue to evolve, and the most recent World Health Organization classification of pancreatic neuroendocrine neoplasms reflects this by introducing a grade 3 neuroendocrine tumour category for morphologically well-differentiated tumours with an elevated Ki-67 proliferation index and/or mitotic count. This review aims to highlight current classification guidelines with discussion of unique site-specific features of selected GEP neuroendocrine neoplasms and an emphasis on practical issues related to daily reporting.

Morphoproteomics, E6/E7 in-situ hybridization, and biomedical analytics define the etiopathogenesis of HPV-associated oropharyngeal carcinoma and provide targeted therapeutic options

BackgroundHuman papillomavirus (HPV) has been identified as an etiopathogenetic factor in oropharyngeal squamous cell carcinoma. The HPV E6 and E7 oncogenes are instrumental in promoting proliferation and blocking differentiation leading to tumorigenesis. Although surgical intervention can remove such tumors, the potential for an etiologic field effect with recurrent disease is real. A downstream effector of E7 oncoprotein, enhancer of zeste homolog 2 (EZH2), is known to promote proliferation and to pose a block in differentiation and in turn, could lead to HPV-induced malignant transformation. However, the EZH2 pathway is amenable to low toxicity therapies designed to promote differentiation to a more benign state and prevent recurrent disease by inhibiting the incorporation of HPV into the genome. This is the first study using clinical specimens to demonstrate EZH2 protein expression in oropharyngeal carcinoma (OPC).MethodsThe study included eight patients with oropharyngeal carcinoma, confirmed p16INK4a- positive by immunohistochemistry (IHC). The tissue expression of E6/E7 messenger RNA (mRNA) was measured by RNAscope® in-situ hybridization technology. Expression of EZH2, Ki-67, and mitotic indices were assessed by morphoproteomic analysis. Biomedical analytics expanded the results with data from Ingenuity Pathway Analysis (IPA) and KEGG databases to construct a molecular network pathway for further insights.ResultsExpression of E6 and E7 oncogenes in p16INK4a- positive oropharyngeal carcinoma was confirmed. EZH2 and its correlates, including elevated proliferation index (Ki-67) and mitotic progression were also present. Biomedical analytics validated the relationship between HPV- E6 and E7 and the expression of the EZH2 pathway.ConclusionThere is morphoproteomic and mRNA evidence of the association of p16INK4a-HPV infection with the E6 and E7 oncogenes and the expression of EZH2, Ki-67 and mitotic progression in oropharyngeal carcinoma. The molecular network biology was confirmed by biomedical analytics as consistent with published literature. This is significant because the biology lends itself to targeted therapeutic options using metformin, curcumin, celecoxib and sulforaphane as therapeutic strategies to prevent progression or recurrence of disease.

P2.04-036 Giant Primary Dedifferentiated Liposarcoma of the Anterior Mediastinum: An Extremely Rare Occurrence: Topic: Esophageal Cancer and Other Malignancies

To present an extremely rare case of giant primary dedifferentiated liposarcoma of the anterior mediastinum. A 70-year-old male presented for persistent dyspnea. Chest CT-scan showed a huge well-defined solid mass with a fatty tissue component in the anterosuperior mediastinum (Fig. 1A). The tumor caused a wide displacement of the right lung and mediastinal organs with no signs of invasion. PET-CT scan showed a unique uptake of the mediastinal mass (Suv max=4.6). A surgical resection was proposed. A right emi clamshell incision was performed. On exploration, a huge mass of the anterior mediastinum causing the compression of the right lung, pericardium and great vessels was observed; no sign of adjacent organs invasion was found. The tumor was radically resected and the patient was discharged uneventfully after 6 days. The patient denied any adjuvant therapy. No evidence of recurrence has been identified as of 16 months postoperatively. Macroscopically, the smooth, lobulated, well demarcated, yellowish-white mass weighed 2102g and measured 27×23×13cm (Fig. 1B). Microscopically, the tumor presented a dedifferentiated component characterized by spindle cells organized in a fascicular pattern with abundant stroma and necrosis (Fig. 1C) and a second component of lipoma-like well-differentiated liposarcoma (Fig. 1D). Figure 1E showed both components. The spindle cells displayed a moderate degree of nuclear atypia, with moderate to marked levels of pleomorphism and cellularity. The spindle cells resulted positive for desmin and SMA and had an elevated proliferative index (Ki67=50%) (Fig. 1F). Immunohistochemically, tumor cells of both components were positive for CDK4 (Fig. 1G) MDM2 (Fig. 1H) and negative for myoglobin, EMA, S-100. Given that, a final pathological diagnosis of primary dedifferentiated liposarcoma of the mediastinum was disclosed. Primary dedifferentiated liposarcoma of the mediastinum is extremely rare. Chemotherapy and radiotherapy seems to be ineffective; radical surgical resection represents the best therapeutic modality. A closed and long-term follow-up is required because of the high risk of recurrence.

Is there an Optimal Surgical Approach to Neuroendocrine Tumors of the Ampulla? A Single Institution Experience over 15 Years

Neuroendocrine tumors (NETs) of the ampulla of Vater are rare neoplasms accounting for a small fraction of gastroenteropancreatic NETs. The optimal surgical approach remains controversial. This study aimed to define the optimal approach in patients with ampullary NETs. Patients who underwent resection of ampullary NETs from 2000 to 2014 were analyzed. Fourteen patients with well-differentiated, nonfunctional NETs were identified. The mean age was 60 ± 15 years, and nine (64%) were male. The mean tumor size was 1.6 ± 0.9 cm and the majority (61%) had an advanced tumor-node-metastasis stage. Eight (57%) patients underwent pancreaticoduodenectomy (PD) and six (43%) underwent transduodenal ampullectomy (TA). Although the mean tumor size was similar (1.7 vs 1.5 cm), the majority (75 vs 20%) of PD patients demonstrated a trend toward more aggressive tumors, characterized by advance T stage in 25 vs 0 per cent, lymph node positivity in 88 vs 17 per cent, and elevated proliferative index (Ki-67) in 25 vs 0 per cent. Complete resection (R0) was achieved in all PD patients versus 75 per cent in TA patients. There was no difference in major complication rate (50 vs 33%). In the TA group, one (17%) patient recurred and two (33%) patients died, whereas only one (13%) patient died in the PD group and no patients recurred. In conclusion, ampullary tumors can be aggressive tumors characterized by high regional lymph node involvement. A transduodenal approach may provide an inadequate oncological resection and thus has the potential to understage ampullary NETs. In the era of increasing therapeutic options for gastroenteropancreatic NETs, accurate staging is crucial and appropriate oncologic resection via PD for ampullary NETs should be considered.

A Case Series Characterizing Pilomyxoid Astrocytomas in Childhood

The term pilomyxoid astrocytoma (PMA) was added to the World Health Organization Classification of Tumours of the central nervous system in 2007. Pilomyxoid tumors are grade II tumors, considered to be variants of pilocytic astrocytomas. We attempted to determine if positron emission tomography (PET), proliferative index (PI), and BRAF V600E mutation help better define PMAs. We report 5 patients' clinical and neuroimaging findings, pathology (PI), and outcome. Four of the 5 patients had PET scans. Three patients showed [18F]fluoro-deoxyglucose hypermetabolism. The PI was elevated in all 5 cases and the BRAF V600E mutation was found in 3 of the 3 patients tested. Our data suggest that PMAs are hypermetabolic on PET, have elevated PIs and BRAF V600E mutations, and behave aggressively.

RARE-23TWO CASES OF RARE INTRASPINAL POORLY DIFFERENTIATED NEUROENDOCRINE TUMOR WITH EXCELLENT RESPONSES TO RADIATION THERAPY

We describe two unusual cases of poorly differentiated neuroendocrine tumor of the spinal cord and leptomeninges. A 61-year-old woman developed rapidly progressive lower extremity paraparesis and sensory deficits. MRI revealed an intradural extramedullary mass levels arising from the conus extending from T12-S3, in multiple foramina, with extensive craniospinal leptomeningeal dissemination. Debulking revealed a poorly differentiated neoplasm characterized by nuclear molding and a high mitotic rate with immunohistochemical positivity for neuroendocrine markers (CD56, chromogranin, synaptophysin). Hematopoietic markers, keratin, GFAP, S100, and CD99/MIC2 were negative, and EWSR1 gene was intact by FISH. She received craniospinal irradiation of 39.6Gy in 22 fractions with a 5.4Gy boost followed by temozolomide. She remains clinically stable nineteen months since presentation, and MRI shows dramatic improvement with small remnants of enhancement at the cauda equina and thoracic thecal sac. The second case is a 65-year-old man with two months of progressive lower extremity paraparesis. He became non-ambulatory with a KPS of 40. MRI revealed an expansile intramedullary cervical cord lesion and diffuse neuroaxial leptomeningeal enhancement. Biopsy revealed a small round blue cell tumor with a markedly elevated proliferative index. Immunostaining showed diffuse positivity for CD56 and CD99/MIC2, while stains for CD45 and keratin were negative. EWSR1 and FUS genes were intact. He received craniospinal irradiation with a boost to bulky disease. His exam improved greatly and he was ambulatory four weeks after radiation with a KPS of 90. One year after radiation, he has little residual radiographic disease with an unchanged examination. For both cases, no alternative primary source was identified. Cauda equine paragangliomas have been the principal intraspinal neuroendocrine tumors described to date; we have been unable to identify other reports of primary intraspinal high grade poorly differentiated neuroendocrine tumors. Remarkably, despite extensive disease and poor performance status both our patients had excellent responses to radiation.

Hypothermia and Rewarming Induce Gene Expression and Multiplication of Cells in Healthy Rat Prostate Tissue

Prostate cancer has been extensively studied, but cellular stress responses in healthy prostate tissue are rarely investigated. Hypothermia is known to cause alterations in mRNA and protein expressions and stability. The aim of this study was to use normal rat prostate as a model in order to find out consequences of cold exposure and rewarming on the expressions of genes which are either members or functionally/structurally related to erythroblastic leukemia viral oncogene B (ErbB) signaling pathway. Relative mRNA expressions of amphiregulin (AMR), cyclin D1 (CyD1), cyclin-dependent kinase inhibitor 1A (p21), transmembrane form of the prostatic acid phosphatase (PAcP), thrombomodulin (TM) and heat shock transcription factor 1 (HSF1) in rat ventral prostate were quantified in mild (2 or 4.5 h at room temperature) and severe (2 or 4.5 h at +10°C) hypothermia and in rewarming after cold exposure (2 h at +10°C followed by 2 h at room temperature or 3 h at +28°C). AMR protein level, apoptotic Bcl-2 associated X protein to B-cell CLL/lymphoma 2 (Bax/Bcl-2) mRNA ratio and proliferative index Ki-67 were determined. 4.5-h mild hypothermia, 2-h severe hypothermia and rewarming increased expression of all these genes. Elevated proliferation index Ki-67 could be seen in 2-h severe hypothermia, and the proliferation index had its highest value in longer rewarming with totally recovered normal body temperature. Pro-apoptotic tendency could be seen in 2-h mild hypothermia while anti-apoptosis was predominant in 4.5-h mild hypothermia and in shorter rewarming with only partly recovered body temperature. Hypothermia and following rewarming promote the proliferation of cells in healthy rat prostate tissue possibly via ErbB signaling pathway.

Clinicopathological correlates of extrasellar growth patterns in pituitary adenomas

We reviewed clinical, imaging and histopathology details of 297 patients who underwent surgery for pituitary adenomas, with an equal distribution of functional and non-functioning tumors, to examine clinicopathological correlates of extrasellar growth. Knosp grades of 3 and 4 on MRI defined cavernous sinus invasion, Hardy grades of C and D defined significant suprasellar/subfrontal extension, and intraoperative evidence of tumor eroding through the clivus or sellar floor defined infrasellar invasion. Disease status at follow-up was known in 246 patients overall, including 35 patients who were evaluated for progression of residual disease on serial imaging. On univariate analysis, we found several statistically significant associations (p<0.05) including adenoma size with age, sex and tumor protein p53 reactivity; cavernous sinus invasion with size, non-functional status, increased mitotic activity, an elevated MIB-1 proliferation index and p53 reactivity; suprasellar/subfrontal extension with p53 reactivity; and infrasellar invasion with age and tumor size. When adjusting for confounders with logistic regression, several significant associations were evident including adenoma size with male sex and p53 reactivity; cavernous sinus invasion with size and elevated MIB-1 proliferation index; suprasellar/subfrontal extension with p53 reactivity; and infrasellar invasion with adenoma size alone. Patients with early progression of postoperative residual tumor were younger with a non-significant trend towards higher MIB-1 proliferation indices. Individual patterns of extrasellar growth in pituitary adenomas are associated with unique clinical and immunohistochemical profiles. Younger patients with elevated MIB-1 values are probably at high risk for early recurrence of non-functioning tumors. Definitions of atypia must be standardized before more robust assumptions about tumor biology can be established.

Pseudoxanthomatous salpingitis as an ex vivo model of fallopian tube serous carcinogenesis: a clinicopathologic study of 49 cases.

Iron is a well-documented carcinogen based on both animal models and observational studies in humans. There are limited published data on pseudoxanthomatous salpingitis, an uncommon condition characterized by the accumulation of histiocytes containing iron and iron-related compounds-lipofuscin and hemosiderin-in the lamina propria of the fallopian tube. The clinical and pathologic features of 49 consecutive cases were evaluated. The mean patient age was 53. A history of endometriosis was found in 20%, infertility in 17%, and tubal ligation in 7%. Thirteen (27%) had endometrial cancer and 2 patients had prior radiation therapy for cervical carcinoma. Histologic evidence of endometriosis other than tubal pigment deposition was identified in 65%, and in the fallopian tubes in 35%. Pigment deposition was unilateral in 65% and multifocal or diffuse in 80%. Plasma cells, eosinophils, and neutrophils were present in the tubal lamina propria in 57%, 18%, and 24%, respectively. Hydrosalpinx was present in 51%. An iron stain was positive in pseudoxanthoma cells lacking hemosiderin in 14 of 18 cases (78%). By immunohistochemistry, 2 of 22 cases displayed p53 signatures. The Ki67 proliferation index was elevated (>10%) in 11 of 22 cases, with a mean index of 32% in those cases. An elevated proliferation index did not correlate with inflammation. In summary, these findings characterize the clinical and pathologic features of pseudoxanthomatous salpingitis and confirm its close association with endometriosis, occasional association with radiation therapy, and the presence of iron in the histiocytes. In view of the evolving paradigm shift implicating the fallopian tubal epithelium as the site of origin of high-grade extrauterine serous carcinoma, the presence of iron and iron-related compounds in the fallopian tube provides an opportunity to study the early events in high-grade serous carcinogenesis in a setting characterized by a well-documented carcinogen in close anatomic proximity to the putative epithelium of origin.

Carcinogenic HPV infection in the cervical squamo-columnar junction.

Recent studies have suggested the involvement of a unique population of cells at the cervical squamo-columnar junction (SCJ) in the pathogenesis of early (squamous intraepithelial lesion or SIL) and advanced (squamous cell and adeno-carcinomas) cervical neoplasia. However, there is little evidence to date showing that SCJ cells harbour carcinogenic HPV or are instrumental in the initial phases of neoplasia. This study was designed to (1) determine if normal-appearing SCJ cells contained evidence of carcinogenic HPV infection and (2) trace their transition to early SIL. Sections of cervix from high-risk reproductive age women were selected and SCJ cells were analysed by using several techniques which increasingly implicated HPV infection: HPV DNA (genotyping and in situ hybridization)/RNA (PCR), immunostaining for HPV16 E2 (an early marker of HPV infection), p16(ink4), Ki67, and HPV L1 protein. In 22 cases with a history of SIL and no evidence of preneoplastic lesion in the excision specimen, HPV DNA was isolated from eight of ten with visible SCJ cells, six of which were HPV16/18 DNA-positive. In five of these latter cases, the SCJ cells were positive for p16(ink4) and/or HPV E2. Transcriptionally active HPV infection (E6/E7 mRNAs) was also detected in microdissected SCJ cells. Early squamous atypia associated with the SCJ cells demonstrated in addition diffuse p16(ink4) immunoreactivity, elevated proliferative index, and rare L1 antigen positivity. We present for the first time direct evidence that normal-appearing SCJ cells can be infected by carcinogenic HPV. They initially express HPV E2 and their progression to SIL is heralded by an expanding metaplastic progeny with increased proliferation and p16(ink4) expression. Whether certain SCJs are more vulnerable than others to carcinogenic HPV genotypes and what variables determine transition to high-grade SIL remain unresolved, but the common event appears to be a vulnerable cell at the SCJ.

P04.05 * HISTONE MUTATIONS IN CHILDHOOD AND YOUNG ADULT HIGH GRADE GLIOMA

BACKGROUND: High grade gliomas in children and young adults are clinically and genetically different from their adult counterparts. Recurrent mutations of the H3F3A gene coding for the H3.3 isoform of the H3 histone have recently been described. These mutations have been shown to be exclusive to high grade gliomas, and the majority occurs in the pediatric setting. OBSERVATION: We report on 2 cases of confirmed mutations of the H3F3A gene at the K27M site. The first patient was a young adult with a left cerebellar mass. Imaging and pathological analysis were typical of glioblastoma. The second patient was a 14-year old boy with a left thalamic lesion, rather circumscribed on MRI but with features of malignity on spectroscopy and perfusion. Pathologic analysis showed a heterogeneous tumor with regions in favor of ganglioglioma, and regions with marked anisokaryosis and rare mitoses, a slightly elevated proliferation index and high p53 positivity. Due to the presence of a histone mutation, the tumor was classified as a high grade glioma. DISCUSSION: Pathological analysis of pediatric tumors can be a challenge. Nowadays, molecular biology is an important tool to help us classify these tumors. In our first patient, the presence of a histone mutation confirmed the initial diagnosis. In the second patient however, the discovery of a histone mutation finally permitted us to classify this pathologically challenging tumor as a high grade glioma. CONCLUSION: When confronted with childhood or young adult brain tumors, it is important to search for histone mutations, since their presence can influence the final diagnosis.

Previously unrecognized pattern of central nervous system hemangiopericytoma with pseudoglandular spaces

Central nervous system hemangiopericytoma (HPC) is an uncommon extraaxial tumor with controversial terminology, histogenesis, and grading. Herein, we report a unique example in a 64-year-old woman with a 3.2 cm extra-axial right frontal lobe mass. Histologic sections showed an HPC with increased mitotic activity and elevated proliferation index, interspersed with gland-like spaces lined by epithelioid cells with apical blebs and filled with proteinaceous material. Both spindled and epithelioid cells expressed BCL-2, CD99, and nuclear STAT6, but were negative for CD34, AE1/AE3, CAM5.2, and epithelial membrane antigen. A diagnosis of anaplastic HPC with pseudoglandular spaces was rendered. To our knowledge, this is the first pathologically and molecularly well-documented example in the literature. This pattern has only been reported once in 1983 and is not widely known. Differential diagnosis included synovial sarcoma, anaplastic meningioma with epithelial metaplasia, malignant peripheral nerve sheath tumor, and metastatic carcinosarcoma. Accurate diagnosis depends on recognition of this pattern, along with appropriate immunohistochemical and molecular work-up.