Antonella Marzullo

Expression of Met protein in thyroid tumours

Met protein is a transmembrane 190 kD heterodimer with tyrosine kinase activity, encoded by c‐MET oncogene. It serves as a high affinity receptor for hepatocyte growth factor (HGF)/scatter factor (SF), a cytokine which stimulates cell proliferation, motility, and invasion. Expression of Met protein was investigated in 116 thyroid tumours using an anti‐Met mouse monoclonal antibody (DQ‐13) active on paraffin‐embedded material. Reactivity for DQ‐13 was observed in 77 per cent of papillary carcinomas, in 70 per cent of Hürthle cell tumours, and rarely in other tumours. The staining was either uniformly present throughout the tumour or limited to nests of infiltrating tumour cells. In some Hürthle cell tumours, prominent accumulation of the protein was observed in the Golgi area. Reactivity for Met protein was decreased or absent in poorly differentiated tumours and was not influenced by tumour size, presence of lymph node metastases, or age of the patient. Immunostaining for Ki‐67 revealed that cytoplasmic accumulation of Met protein was not associated with enhanced proliferation of tumour cells. Overexpression of Met protein in thyroid papillary carcinoma may result in increased motility of tumour cells, which in turn may account for intraglandular multifocal dissemination and early lymph node metastasis.

Increased expression of Met protein is associated with up-regulation of hypoxia inducible factor-1 (HIF-1) in tumour cells in papillary carcinoma of the thyroid

Met protein, the high affinity receptor for hepatocyte growth factor (HGF), was highly expressed by the tumour cells of 64 well‐differentiated papillary carcinomas of the thyroid. The p145 mature form and the p170 precursor form of the protein were both isolated from the tumours. Enhanced expression of Met protein was associated with a 9.5 ± 5‐fold increase in MET RNA transcript levels, suggesting increased transcription of the gene. In the same tumours, the levels of RNA transcripts for hypoxia inducible factor‐1 (HIF‐1), a potent stimulator of met gene transcription, were 4.5 ± 3‐fold higher than those present in the surrounding normal thyroid tissues. HIF‐1 is generally induced by hypoxia. Histological features suggestive of a hypoxia were observed in 37 of 50 tumours and included coagulative necrosis, psammoma bodies, cystic changes, intratumoural haemorrhage, and hyalinization of the fibrous stroma. Immunostaining for Met protein was particularly intense in some cells located at the tumour periphery which were characterized by an invasive phenotype. Microdissection of tumour cell nests from the invading front revealed that the levels of RNA transcripts for MET/HIF were higher than in the centre of the tumour in four of nine cases. Taken together, the findings of this study suggest that HIF‐1, perhaps driven by hypoxia, may be one of the factors leading to the increased transcription of met gene in papillary carcinoma and that this event is often more pronounced at the tumour periphery. Copyright

Hepatocyte growth factor (HGF) stimulates tumour invasiveness in papillary carcinoma of the thyroid

The present study has investigated the functional role of the Met receptor in primary cultures of 20 papillary carcinomas and of normal thyroid cells obtained from the same patients. Normal and tumour cells grew as adherent cells, formed a confluent monolayer after 10–20 days, had epithelial morphology, and were immunoreactive for cytokeratin, vimentin, and thyroglobulin. The potential effect of hepatocyte growth factor (HGF) on cell invasiveness was investigated in Boyden chambers, using a nucleopore filter coated with Matrigel as the barrier and HGF as the chemoattractant. Tumour cells of five out of seven cases of papillary carcinoma were more responsive to HGF than the corresponding normal cells in terms of the number of migrated cells per mm2. Involvement of the Met receptor in the HGF‐induced migratory response was suggested by the observation that the agonistic anti‐Met monoclonal antibody (MAb) DO‐24 was equally effective. HGF did not affect the proliferative activity of thyroid cells. Under the same experimental conditions, 10 per cent fetal bovine serum (FBS) induced a two‐fold increase in [3H]thymidine incorporation into normal cells and tumour cells. These findings are consistent with the possibility that HGF plays a crucial role in determining the invasiveness of tumour cells in papillary carcinoma of the thyroid. Copyright

Expression of EDA/EDB isoforms of fibronectin in papillary carcinoma of the thyroid

Cellular fibronectins containing the extracellular domain A or B (EDA and EDB) are particularly abundant in fetal and neoplastic tissues. The presence of EDA and EDB was investigated in 28 cases of papillary carcinoma of the thyroid using IST‐9 and BC‐1 monoclonal antibodies. Immunostaining for EDA and EDB was detected in tumour stroma, in tumour basement membranes, and in tumour blood vessels. EDA was present in 27 of the 28 cases, in 20 of which more than 75 per cent of the tumour stroma was stained. Immunostaining for EDB was detected in 23 of the 28 cases and was less pronounced than that for EDA, being present in less than 25 per cent of the tumour stroma in most cases. Reactivity for EDA/EDB was not observed in the adjacent normal thyroid in any of the cases investigated. In a group of 20 non‐papillary tumours, immunostaining for EDA was present in the stroma of three follicular carcinomas (one minimally and two widely invasive), one medullary carcinoma, and 5 of 16 follicular adenomas; expression of EDB was more restricted, being present in only the two cases of widely invasive follicular carcinoma. The presence of EDA and EDB was not correlated with the extent of fibrosis or the degree of tumour cell differentiation. Immunoreactivity was already present in microcarcinomas. These observations raise the possibility that the production of oncofetal fibronectins is an important step in papillary carcinoma tumourigenesis, perhaps facilitating adhesion and spreading of tumour cells. Copyright

Detection and molecular characterisation of thyroid cancer precursor lesions in a specific subset of Hashimoto's thyroiditis.

Hashimotos thyroiditis (HT) represents the most common cause of hypothyroidism and nonendemic goiter, but its clinical and pathological heterogeneity opens the question if this disease should be more properly considered as a spectrum of different thyroid conditions rather than as a single nosological entity. In this study, we analysed 133 cases of HT for the expression of galectin-3, a lectin molecule involved in malignant transformation, apoptosis and cell cycle control. An unexpected expression of galectin-3 was demonstrated in a subset of HT together with the presence of HBME-1, c-met and cyclin-D1 that are also involved in malignant transformation and deregulated cell growth. Furthermore, a loss of allelic heterozygosity in a specific cancer-related chromosomal region was demonstrated in some HT harbouring galectin-3-positive follicular cells, by using laser capture microdissection. On the basis of the morphological and molecular findings we identified four subsets of HT: (a) HT with classic features of chronic autoimmune thyroiditis; (b) HT associated to hyperplastic/adenomatous lesions; (c) HT harbouring thyroid cancer precursors; (d) HT associated to unequivocal thyroid microcarcinomas. Our findings provide a well-substantiated morphological and molecular demonstration that HT may include a spectrum of different thyroid conditions ranging from chronic autoimmune thyroiditis to thyroiditis triggered by specific immune-response to cancer-related antigens.

GIANT ABDOMINOPELVIC EPITHELIOID ANGIOMYOLIPOMA ASSOCIATED WITH TUBEROUS SCLEROSIS: REPORT OF A CASE

Tuberous sclerosis is a hereditary autosomal-dominant disease characterized by hamartomas that can develop in any organ. We report herein the case of a 34-year-old female with tuberous sclerosis and a huge abdominopelvic mass that started growing quickly 2 years after its diagnosis. The patient had undergone several previous operations for hydrocephalus and cerebral tubers, and a nephrectomy for right renal angiomyolipoma. On admission, she was in poor general health with renal failure, severe anemia, and weight loss. A laparotomy revealed that the tumor occupied the pelvis, the lower and part of the upper abdomen, and was hypervascularized, with an extremely irregular surface covered in nodules, vegetations, and areas of hemorrhagic necrosis. The development of the mass and the impossibility of recognizing the internal genital organs led us to assume that the formation had originated from these. Frozen-section examination indicated an undifferentiated tumor that had not been completely resected. Her postoperative course was complicated by bronchopneumonia and progressive renal failure. The patient died 10 days after surgery due to cardio-respiratory failure. A histological diagnosis of epithelioid angiomyolipoma was confirmed. Although it is presently impossible to determine whether angiomyolipoma with predominant epithelioid cells is more aggressive than typical angiomyolipoma, it definitively demonstrated local aggressive behavior in this patient.

Bone marrow involvement at onset of Hodgkin's disease.

Bilateral trephine bone marrow biopsies of 370 patients with Hodgkins disease first seen at the Institute of Hematology, University of Rome, between 1970 and 1981, revealed tumor involvement of the bone marrow in 18 cases. The histologic type was mixed cellularity in 7 cases, lymphocytic depletion in 4 cases, nodular sclerosis in 4 cases, and lymphocytic prevalence in 1 case. Anemia with less than 10 g/dl of hemoglobin was observed in 5 patients; white blood cells were less than 4.0 × 109/liter in 2 patients; platelets were less than 12.0 × 109/liter in 1 case; a pancytopenic condition was observed in only 1 case. B symptoms were present in 14 of the 18 patients. All patients who underwent laparosplenectomy presented spleen involvement, 4 also had liver involvement. All patients were treated with chemotherapy; MOPP regimen was employed in 11 cases, ABVD in 5 patients, and PROVECIP in 1 case. Of the 13 patients evaluable for therapeutic response, 11 achieved complete remission, with a median actuarial relapse-free survival of 15 months. The actuarial survival curve showed that 50% of all patients are projected alive at 47 months with a follow-up ranging from 1 to 109 months.

Unusual metastasis of gastrointestinal stromal tumor misdiagnosed as anaplastic thyroid carcinoma

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumorsof thedigestive tract. Almost allGISTs express theKIT protein (CD 117), the product of the c-KIT protoncogene that is a transmembrane receptor for the stem cell factor (SCF or KIT ligand) with a tyrosine kinase domain. The tumorigenesis of GISTs involves mutations in the cKIT protoncogene, resulting in ligand-independent

Involvement of the bone marrow by non-Hodgkin's lymphomas: incidence, histology and pathologic correlations.

The Lukes and Collins system of classification was applied to 151 cases of non-Hodgkins lymphoma who had bone marrow biopsies taken immediately after histologic diagnosis. Incidence and histologic pattern of bone marrow involvement at the time of initial diagnosis were determined for each subtype of lymphoma. Thirty-three patients (21.8 %) had bone marrow involvement. The frequency of bone marrow involvement was high for undefined and convoluted lymphocyte lymphomas (66.6 %) and low to intermediate for follicular centre cell (20.3 %) and small lymphocyte lymphomas (20.0 %). Within the FCC lymphomas the non-cleaved cell type had a higher incidence of marrow involvement than the cleaved cell type (41.6 % vs 8.9 %). The follicular and diffuse histologic patterns in the diagnostic node did influence the incidence of marrow invasion in the non-cleaved cell type (75 % vs 25 %). A low incidence of marrow involvement was observed for the immunoblastic lymphomas (14.2 %); evidence of marrow infiltration was never observed in patients with true histiocytic lymphoma.

Thyroid C-cell hyperplasia in an adolescent with neurofibromatosis type 1.

Background: Subjects with neurofibromatosis type 1 (NF1) show an increased risk of endocrine tumors, especially pheochromocytoma, whereas thyroid C-cell hyperplasia (CCH) and medullary thyroid carcinoma (MTC) are very rare events described only in adult patients. Method: A case of CCH diagnosed in a 14-year-old girl affected with NF1 is reported. Calcitonin serum level after pentagastin was elevated (286 pg/ml). Genetic testing was performed in order to rule out mutations in the RET proto-oncogene. Result: No germline mutation previously reported in MEN2 was detected. Multifocal and bilateral CCH was demonstrated by immunohistochemistry. Conclusion: It is suggested that in such a genetic background of high risk for malignancy, CCH could be considered as an extremely rare condition likely preceding MTC.