Marcello Gambacorta

EML4-ALK Rearrangement in Non-Small Cell Lung Cancer and Non-Tumor Lung Tissues

A fusion gene, echinoderm microtubule associated protein like 4-anaplastic lymphoma kinase (EML4-ALK), with transforming activity has recently been identified in a subset of non-small cell lung cancer (NSCLC), but its pathogenetic, diagnostic, and therapeutic roles remain unclear. Both frequency and type of EML4-ALK transcripts were investigated by reverse transcription PCR in 120 frozen NSCLC specimens from Italy and Spain; non-neoplastic lung tissues taken far from the tumor were used as controls. In cases carrying the fusion transcript, we determined EML4-ALK gene and protein levels using fluorescence in situ hybridization, Western blotting, and immunoprecipitation. We also analyzed ALK protein levels in paraffin samples from 662 NSCLC specimens, including the 120 cases investigated in the molecular studies. EML4-ALK transcripts (variants 1 and 3) were detected in 9 of 120 NSCLC samples but were not specific for NSCLC since they were also found in non-cancerous lung tissues taken far from the tumor. Notably, no transcripts were detected in matching tumor samples from these patients. Fluorescence in situ hybridization analysis of cases expressing EML4-ALK transcripts showed that only a minority of cells harbored the EML4-ALK gene. None of these cases was found to express the EML4-ALK protein as examined by immunohistochemistry, Western blotting, and immunoprecipitation. The EML4-ALK transcript cannot be regarded as a specific diagnostic tool for NSCLC. Our results show therefore that the causal role and value of EML4-ALK as a therapeutic target remain to be defined.

Abdominopelvic Sarcoma of Perivascular Epithelioid Cells. Report of Four Cases in Young Women, One with Tuberous Sclerosis

The perivascular epithelioid cell has been proposed to be the unifying proliferating cell type in a number of lesions such as angiomyolipoma, lymphangiomyomatosis, clear cell “sugar” tumor and renal capsuloma. With the exception of rare examples of angiomyolipoma, they are non-metastasizing. We report four examples of a new member of this family of perivascular epithelioid cell neoplasms that occur in abdominopelvic location and show metastatic properties. The patients, all women, were aged 19 to 41 years (mean, 32), and presented with a tumor mass involving the serosa of the ileum, uterus or pelvic cavity. Morphologically, the tumors were composed of sheets of large polygonal cells with glycogen-rich clear or eosinophilic cytoplasm and moderately pleomorphic nuclei, traversed by a delicate vasculature, mimicking clear cell carcinoma. There were areas of coagulative necrosis and occasional mitotic figures. Intracytoplasmic brown pigment was present in two cases. Spindly cells, smooth muscle and fat were absent. Lymphovascular invasion was present in all, lymph node metastasis was documented in two and metastasis to the ovary was present in one case. Two patients developed widespread metastatic disease after 10 and 28 months from diagnosis. One patient showed the clinical signs of tuberous sclerosis. In spite of the epithelial-like appearance, the tumor cells were negative for epithelial markers but were strongly positive with the melanogenesis-related marker HMB45. Another melanogenesis marker (MART-1) was positive in two cases. Other markers including S-100 protein, vimentin, muscle-specific actin, desmin and chromogranin A were negative. Thus, these tumors are not readily classifiable in the existing schema of known entities, and show overlapping morpho-phenotypic features of clear cell “sugar” tumor of the lung and epithelioid angiomyolipoma. We consider them as sarcomas composed of a pure population of uncommitted perivascular epithelioid cell, that lack modulation toward smooth muscle or adipose cells.

Glial fibrillary acidic protein immunoreactivity in normal and diseased human breast

Immunostaining for glial fibrillary acidic protein (GFAP) identifies a minor subpopulation of immunoreactive myoepithelial cells in the normal resting human breast. The GFAP-immunoreactive cells also express a panel of myoepithelial cell markers, including cytokeratin 14 (CK 14), vimentin, smooth-muscle-specific actin isoforms, nerve growth factor receptor (NGFR) and common acute lymphoblastic leukaemia antigen (CALLA). The percentage of GFAP-immunoreactive myoepithelial cells is greatly increased in various neoplastic and non-neoplastic diseases of the breast, being highest in adenomyoepitheliomas. Furthermore, in all the instances of fibroadenoma, phyllodes tumour, epitheliosis and gynaecomastia, a variable number of epithelial cells also acquires immunoreactivity for GFAP, vimentin, CK 14, NGFR and, to a lesser extent, for CALLA. Conversely, GFAP immunoreactivity has never been encountered in the malignant cells of the different types of breast carcinoma. These findings suggest that the expression of GFAP might be a (possibly transient) feature of proliferating epithelial and myoepithelial cells in breast diseases other than carcinomas.

IRTA1 is selectively expressed in nodal and extranodal marginal zone lymphomas

Falini B, Agostinelli C, Bigerna B, Pucciarini A, Pacini R, Tabarrini A, Falcinelli F, Piccioli M, Paulli M, Gambacorta M, Ponzoni M, Tiacci E, Ascani S, Martelli M P, Dalla Favera R, Stein H & Pileri S A 
(2012) Histopathology 61, 930–941

Coexpression of cytokeratins and vimentin in common epithelial tumours of the ovary: An immunocytochemical study of eighty-three cases

An immunocytochemical investigation has been performed on 83 common epithelial tumours of the ovary, to ascertain their capability of expressing vimentin in addition to cytokeratins. Our results demonstrate that vimentin coexpression is related to the tumour histotype and -to a lesser extent- to the degree of differentiation of malignant variants. Indeed, most serous tumours (80%), some endometrioid adenocarcinomas, and all the clear cell carcinomas investigated exhibited a variable number of neoplastic cells co-synthesizing the two distinct intermediate filament (IF) proteins, whereas only one of 29 mucinous tumours and none of the Brenner tumours displayed vimentin-immunoreactive cells. Moreover, in serous and endometrioid carcinomas, the expression of vimentin was related to the degree of tumour differentiation, being consistently identifiable in the better differentiated cases. The immunocytochemical findings of a parallel investigation on IF expression in the ovarian coelomic epithelium and in the müllerian-derived epithelia of the female genital tract allowed us to ascertain that ovarian epithelial tumours (with the possible exception of poorly differentiated carcinomas) maintain the pattern of IF expression typical of the normal epithelia. This investigation emphasizes the usefulness of IF typing as a tool for the more precise characterization of the origin and differentiation of human neoplasms.

Desmoplastic versus classic medulloblastoma : comparison of DNA content, histopathology and differentiation

A microfluorometric analysis was performed to analyse the DNA content of 42 medulloblastomas (MBs) and to seek correlations, if any existed, between the DNA distribution and ploidy values, neoplasm types (i.e. classic vs desmoplastic), histological features of aggressiveness, and immunocytochemical features indicating glial and/or neuronal differentiation. Thirty-one cases were classified as classic and 11 cases as desmoplastic MBs. Ten of 11 desmoplastic MBs had a near-diploid main mode and the remaining 1 case had a near-tetraploid main mode. Moreover, 10 of 11 (90%) cases showed a “monomodal” DNA distribution diagram. All these cases showed a uniform histology. In contrast, classic MBs represented a heterogeneous group of neoplasms. Twenty-two cases were near-diploid, 5 cases were near-tetraploid and 3 cases were near-triploid. The histogram type distribution showed a similar heterogeneity. Twelve of 31 (39%) cases had a monomodal histogram, 12 (39%) cases had a bimodal diagram and 7 (22%) cases a complex DNA distribution. There was a statistically significant difference (P<0.001) in terms of prevalence of DNA monomodal histograms between classic and desmoplastic MBs. Significant correlations were not observed among classic MBs between histological features of aggresiveness, type and degree of differentiation and DNA distribution. The present study indicates that desmoplastic MBs represent a homogeneous group of neoplasms in terms of histology and DNA distribution. In contrast, classic MBs are lesions with different degrees of histologically apparent aggressiveness and a complex DNA distribution.

Coexpression of cytokeratins and vimentin in normal and diseased thyroid glands. Lack of diagnostic utility of vimentin immunostaining.

We documented the coexpression of cytokeratins and vimentin in epithelial cells of the thyroid gland in 100 samples examined from 65 patients. These included normal, inflammatory, and neoplastic tissues that were routinely fixed in formalin and embedded in paraffin. The number of epithelial cells coexpressing the two intermediate filament proteins as well as the subcellular compartmentalization of vimentin immunoreactivity did not correlate with the various conditions of the thyroid gland. Therefore, we conclude that the immunolocalization of vimentin does not represent a useful adjunct tool for the histopathological diagnosis of thyroid diseases.