Gian Luigi Taddei

hERG1 channels are overexpressed in glioblastoma multiforme and modulate VEGF secretion in glioblastoma cell lines

Recent studies have led to considerable advancement in our understanding of the molecular mechanisms that underlie the relentless cell growth and invasiveness of human gliomas. Partial understanding of these mechanisms has (1) improved the classification for gliomas, by identifying prognostic subgroups, and (2) pointed to novel potential therapeutic targets. Some classes of ion channels have turned out to be involved in the pathogenesis and malignancy of gliomas. We studied the expression and properties of K+ channels in primary cultures obtained from surgical specimens: human ether a gò-gò related (hERG)1 voltage-dependent K+ channels, which have been found to be overexpressed in various human cancers, and human ether a gò-gò-like 2 channels, that share many of hERG1s biophysical features. The expression pattern of these two channels was compared to that of the classical inward rectifying K+ channels, IRK, that are widely expressed in astrocytic cells and classically considered a marker of astrocytic differentiation. In our study, hERG1 was found to be specifically overexpressed in high-grade astrocytomas, that is, glioblastoma multiforme (GBM). In addition, we present evidence that, in GBM cell lines, hERG1 channel activity actively contributes to malignancy by promoting vascular endothelial growth factor secretion, thus stimulating the neoangiogenesis typical of high-grade gliomas. Our data provide important confirmation for studies proposing the hERG1 channel as a molecular marker of tumour progression and a possible target for novel anticancer therapies.

Extracolonic polyps in familial polyposis coli and Gardner's syndrome

Endoscopy and biopsy of the upper gastrointestinal tract and terminal ileum were performed in 24 patients with familial polyposis or Gardners syndrome in order to further define the incidence of extracolonic adenomatous polyps. Polyps, usually multiple and small in size, were detected in the gastric fundus (12.5 percent), antrum (29.1 percent), duodenum (66.6 percent), and terminal ileum (41.7 percent). Histology showed hyperplasia of the fundic glands and cystic dilatation in the polyps of gastric fundus, and adenomas in several cases of antral (three patients) or duodenal polyps (14 patients). Polyps of the terminal ileum were either adenomas (five patients) or lymphoid aggregates. Patients with stigmata of Gardners syndrome, desmoids or mesenteric fibromatosis presented a major incidence of adenomas in the duodenum, but not in other parts of the digestive tract investigated. Subsequent checkup after an average of 33 months in ten patients revealed an increase of lesions only in the duodenum in two patients. These findings confirm that adenomatous polyps are not limited to the colon and rectum, as previously believed, but can affect the whole gastrointestinal tract. Periodic surveillance of mucosa seems to be indicated, especially for the duodenum, since degeneration of adenomas into carcinoma is possible

Genetic and expression profiles of cerebellar liponeurocytomas

Cerebellar liponeurocytoma, a rare, newly identified CNS neoplasm of adults, is characterized by advanced neuronal/neurocytic and focal lipomatous differentiation, low proliferative potential and a favorable clinical prognosis. Despite the different age distribution and benign biological behavior, the cerebellar liponeurocytoma shares several features with the cerebellar medulloblastoma, which may include an origin from the periventricular matrix of the fourth ventricle or the external granular layer of the cerebellum. To establish the genetic profile of cerebellar liponeurocytomas, we have formed an international consortium and collected tumor samples from 20 patients. DNA sequencing revealed TP53 missense mutations in 4 (20%) of 20 cerebellar liponeurocytomas, a frequency higher than in medulloblastomas. There was no case with PTCH, APC, or β‐catenin mutations, each of which may be present in subsets of medulloblastomas. Isochromosome 17q, a genetic hallmark of classic medulloblastomas, was not observed in any of the cases investigated by FISH analysis. cDNA array analyses were carried out on 4 cerebellar liponeurocytomas, 4 central neurocytomas, and 4 classic medulloblastomas. Cluster analysis of the cDNA expression data of 1176 genes grouped cerebellar liponeurocytomas close to central neurocytomas, but distinct from medulloblastomas. These results suggest cerebellar liponeurocytoma as a distinct tumor entity that is genetically different from medulloblastoma. Furthermore, the cDNA expression array data suggest a relationship to central neurocytomas, but the presence of TP53 mutations, which are absent in central neurocytomas, suggests that their genetic pathways are different.

c-Kit Expression in Patients with Uterine Leiomyosarcomas: A Potential Alternative Therapeutic Treatment

Purpose: Uterine leiomyosarcomas are rare tumors characterized by their resistance to chemotherapy and radiation treatment. Surgery is the primary method of treatment, but for patients with unresectable disease, alternate therapeutic options are clearly warranted. According to initial observations of c-KIT expression, correlation with a bad prognosis, and the successful therapeutic possibility of STI571 in gastrointestinal stromal tumors, the data have encouraged us to study c-KIT expression in these tumors. Experimental Design: We analyzed the expression of c-KIT and genetic assessment of exon 11 of c-kit gene in 32 uterine leiomyosarcomas. Results: In 17 cases (53.1%), we observed a c-KIT expression in tumor cells. Of the 17 patients with distinct c-KIT-positive immunoreactivity, eight had I or II stage disease and nine had III or IV stage disease. Molecular genetic analysis of exon 11, analyzed by direct DNA sequencing, was performed for all of the c-KIT-positive uterine leiomyosarcomas. No mutations were found. Conclusion: The conventional chemotherapy in leiomyosarcomas appears to be ineffective for patients with metastatic or unresectable disease, and the management of these patients poses a special problem. In these women, new therapeutic strategies are warranted. The treatment with STI571 in leiomyosarcoma patients might be hypothesized, because uterine leiomyosarcomas also express c-KIT.

Utility of CDX-2 in distinguishing between primary and secondary (intestinal) mucinous ovarian carcinoma: an immunohistochemical comparison of 43 cases.

Primary and secondary mucinous tumors can involve the ovaries and have similar histologic appearances. The differential diagnosis is important for surgical and chemotherapeutic treatment and for the prognosis, but often it is extremely difficult. This article discusses an immunohistochemical panel that includes carcinoembryonic antigen (CEA), cytokeratin (CK) 7, CK20, CA125, CA19.9, and a new marker, CDX-2, for the distinction between primary ovarian mucinous carcinomas and metastatic (intestinal) ovarian tumors. Forty-three cases representing primary and secondary ovarian tumors were considered and consisted of 14 primary mucinous ovarian carcinomas (PMOCs) and 29 secondary (intestinal) ovarian tumors (SI-OTs). Fisher exact test was performed to evaluate the reliability of the respective antibodies to discriminate between PMOCs and SIOTs. CDX-2 was diffusely positive in all SIOTs and was expressed focally in 3 cases (21.42%) of PMOCs. CK7 was diffusely positive in 13 cases (44.82%) of SIOTs and in 13 cases (92.85%) of PMOCs. CK20 was diffusely positive in 17 cases (58.62%) of SIOTs and in 6 cases (42.85%) of PMOCs. CEA was diffusely positive in 28 cases (96.55%) of SIOTs and in 12 cases (85.71%) of PMOCs. CA19.9 was positive in all SIOTs and in 12 cases (85.71%) of PMOCs. CA125 was positive in 3 cases (10.34%) of SIOTs and in 4 cases (28.57%) of PMOCs. CK7 and especially CDX-2, a specific and sensitive marker, can aid pathologists in making a differential diagnosis (P = 0.003 and P < 0.0005, respectively), whereas CEA, CK20, CA125, and CA19.9 markers are not high enough to distinguish between primary and secondary mucinous ovarian tumors.

Subependymal giant cell astrocytoma (SEGA): Is it an astrocytoma? Morphological, immunohistochemical and ultrastructural study.

Subependymal giant‐cell astrocytoma (SEGA) is a rare intra‐ventricular low‐grade tumor which frequently occurs as a manifestation of tuberous sclerosis complex. The histogenesis of SEGA is controversial and its astrocytic nature has been doubted. First studies suggested the astrocytic nature of SEGA while several recent reports demonstrate its glio‐neuronal nature. In spite of this, in the recently revised WHO classification of the CNS tumors, SEGA has been still included in the group of astrocytomas. We studied nine tuberous sclerosis complex‐associated SEGAs. Patients were 1–18 years old. Eight patients (89%) had a solitary lesion located in the lateral ventricle close to of the head of the caudate nucleus, the remaining patient (11%) had two tumors, one located close to the head of the left caudate nucleus and the other in the central part of the right lateral ventricle. Histologically, tumors were composed of three types of cells: spindle, gemistocytic and ganglion‐like. Four tumors (44%) had a prominent vascularization and three (33%) showed an angiocentric pattern. Calcifications were observed in six cases (66%). By immunohistochemistry, the majority of the tumors were GFAP‐ (9; 100%), neurofilament‐ (8, 89%), neuron‐specific enolase‐ (9, 100%), and synaptophysin‐ (8; 89%) positive. Ultrastructural studies were performed on four cases. In all four there were glial cell processes filled with intermediate filaments. In one case dense core putative neurosecretory granules were appreciable. Our results emphasize the glio‐neuronal nature of SEGA. We suggest moving it into the group of mixed glio‐neuronal tumors under the denomination of subependymal giant cell tumor.

Correlation of Epidermal Growth Factor Receptor Expression with Tumor Microdensity Vessels and with Vascular Endothelial Growth Factor Expression in Ovarian Carcinoma

We analyzed in advanced ovarian serous G3 carcinoma the correlation between epidermal growth factor receptor (EGFR) overexpression and tumor angiogenesis and their relation with clinical outcome. Microvessel density (MVD) and vascular endothelial growth factor (VEGF) were statistically correlated with disease-free interval and death from disease both in univariate and multivariate analyses while EGFR expression was not correlated with clinical outcome. MVD was significantly associated with progression of disease during chemotherapy while VEGF and EGFR expression were not correlated with responsiveness to chemotherapy (Fisher’s exact test). VEGF expression was correlated with MVD (Fisher’s exact test). EGFR showed a trend to correlation with MVD. Further studies focusing on the use of angiogenesis inhibitors in addition to EGFR inhibitors on ovarian carcinoma cells may produce therapeutic strategies in the selection of tailored therapies in ovarian cancer patients.

Papillary glioneuronal tumor radiologically mimicking a cavernous hemangioma with hemorrhagic onset

Papillary glioneuronal tumor is a recently identified low‐grade brain neoplasm classified as variant of ganglioglioma. Its salient morphological characteristics are the presence of pseudopapillary structures composed of blood vessels, often hyalinized, lined by uniform small astrocytes and a proliferation of neurocytic cells, eventually admixed with ganglioid and ganglion cells. We present a case of papillary glioneuronal tumor occurring in a 15‐year‐old female with an unusual hemorrhagic onset. The clinical, morphological and immunohistochemical features are discussed and the published literature is reviewed. This article proposes that papillary glioneuronal tumor should be included in the differential diagnosis of patients with tumoral related brain hemorrhage.

Primary cervical adenocarcinoma with intestinal differentiation and colonic carcinoma metastatic to cervix: an investigation using Cdx-2 and a limited immunohistochemical panel.

CONTEXT Cdx-2 is expressed in normal colonic epithelia and in most colorectal adenocarcinomas. No data exist on Cdx-2 expression in primary cervical adenocarcinoma with colonic differentiation. OBJECTIVE To ascertain the utility of Cdx-2 and a limited immunohistochemical panel in differentiating between primary cervical adenocarcinoma with intestinal differentiation and secondary (colonic) cervical adenocarcinoma, which call for different surgical and chemotherapeutic treatment protocols. DESIGN We examined cervical tract adenocarcinomas in women with previously negative medical histories for neoplastic disease and in women with colonic carcinoma. An immunohistochemical panel consisting of cytokeratin 7, cytokeratin 20, carcinoembryonic antigen, and a new marker, Cdx-2, was evaluated in all cases. The clinical data, the morphologic features, and the immunohistochemical staining patterns were compared. RESULTS Of the tumors diagnosed as metastatic intestinal adenocarcinoma of the cervix, based on clinical data and hematoxylin-eosin-stained sections, all were Cdx-2 positive, whereas Cdx-2 was not expressed in any of our cases of primary cervical adenocarcinoma with colonic differentiation. Carcinoembryonic antigen was expressed both in primary cervical tumor and in secondary (intestinal) cervical adenocarcinoma. Cytokeratin 20 was not expressed in our cases of cervical adenocarcinoma, and it was not expressed in 7.15% of cervical metastases from intestinal carcinoma. Immunostaining with cytokeratin 7 was positive in cervical adenocarcinoma, but was negative in secondary (intestinal) cervical adenocarcinoma. CONCLUSIONS Our immunohistochemical analysis shows that Cdx-2 has good specificity and would be a good marker to use in a limited panel of immunohistochemical markers, such as cytokeratin 7, cytokeratin 20, and carcinoembryonic antigen, to distinguish primary cervical adenocarcinoma from intestinal metastases to the cervix.

Embryonal tumor with abundant neuropil and true rosettes: morphological, immunohistochemical, ultrastructural and molecular study of a case showing features of medulloepithelioma and areas of mesenchymal and epithelial differentiation.

Embryonal tumors are a group of malignant neoplasms that most commonly affect the pediatric population. Embryonal tumor with abundant neuropil and true rosettes is a recently recognized rare tumor. It is composed of neurocytes and undifferentiated neuroepithelial cells arranged in clusters, cords and several types of rosettes in a prominent neuropil‐rich background. We describe a new case of this tumor. The patient, a 24‐month‐old female infant, was referred to the Meyer Childrens Hospital with a history of right brachio‐crural deficit associated with occasional episodes of headache and vomiting. Computed tomography scan and MRI revealed a large bihemispheric mass. The patient underwent two consecutive surgeries. The resultant surgical resection of the tumor was macroscopically complete. The postoperative period was uneventful. On light microscopy the tumor showed a composite morphology: embryonal tumor with abundant neuropil and true rosettes (specimen from the first surgery); medulloepithelioma with mesenchymal and epithelial areas (specimen from the second surgery). The immunohistochemistry evidenced the heterogeneous (neuronal, mesenchymal and epithelial) immunoprofile of tumoral cells. By real‐time polymerase chain reaction (RT‐PCR), the PTEN gene expression in the tumor was lower than in the five non‐neoplastic brain tissues used as control. Mutation analysis did not show any variation in INI‐1 and PTEN sequence while P53 analysis showed the presence of homozygote P72R variation. Fluorescent in situ hybridization analysis showed polysomy of chromosome 2 while amplification of N‐MYC was not detected. Owing to the rarity of embryonal tumor with abundant neuropil and true rosettes, each new case should be recorded to produce a better clinical, pathological and molecular characterization of this lesion.