Peter J. Chauvin

Metallothionein in testicular germ cell tumors and drug resistance: Clinical correlation

Background. Metallothioneins (MT) are endogenous metalloproteins involved in the homeostasis of essential metals and detoxification of toxic metals. Some recent experimental studies suggested tumor resistance to cisdiamminedichloroplatin may be associated with overexpression of MT in the tumor.

Palisaded encapsulated neuroma of oral mucosa

The palisaded encapsulated neuroma is a solitary, small peripheral nerve lesion that occurs primarily on the facial skin of middle-aged adults. We report a series of 13 cases of palisaded encapsulated neuroma occurring on oral mucosa. The lesions presented as solitary, firm, sessile, partly or completely encapsulated, 2 to 3 mm nodules in adults with a mean age of 51 years (median 55 years). Nine of the neuromas occurred on the hard palate; the remainder were found on the soft palate, lower lip mucosa, upper lip mucosa, and maxillary anterior alveolar ridge. None of the cases was associated with neurofibromatosis or multiple endocrine neoplasia syndrome type III. Microscopically, the tumors were characterized by a moderately cellular, fascicular proliferation of spindle cells that showed some areas of nuclear palisading, suggestive of schwannoma. Immunohistochemical stains revealed that the lesions were composed largely of S-100 protein-positive Schwann cells and variable numbers of peripheral nerve axons, which were identified by their positive neurofilament staining. The fibrous capsule of the lesions showed positive staining for epithelial membrane antigen, indicative of perineurium.

Invasion and migration of coordinated cell clusters in rhabdomyosarcoma and other head and neck tumors in a 3-D collagen matrix

EXPRESSION OF NM23-H1 AND NM23-H2 IN HUMAN EPITHELIOID SARCOMA CELL LINES OF DIFFERENT INVASIVE POTENTIAL IN VITRO T. Heymer, R. Engers, C.D. Gerharz, R. Krause-Paulus, N. EIBadawy, H.E. Gabbert Objective: Although epithelioid sarcoma is a very aggressive tumor with high metastatic potential in vivo, no investigations of metastasis associated molecules have been reported yet. Therefore, three clonal subpopulations (GRU-1A, GRU-1B, GRU-1C), derived from the same human epithelioid sarcoma cell line (GRU-1), were characterized with regard to their invasive potential in vitro and the expression of the two candidate metastasis suppressor genes nm23-H1 and nm23-H2. Methods: In vitro invasivaness was determined by the Matrigel invasion assay and by adhesion assays to laminin, fibronectin, collagen IV, hyaluronic acid and plastic. Nm23-H1 and nm23-H2 expression were investigated by RT-PCR and subsequent isoform specific oligonucleotide-hybridisation. Results: In the Matrigel invasion assay GRU-1A exhibited the highest invasive potential while GRU-1B and GRU-1C were significantly less invasive (GRU1A: 112_+12; GRU-1B: 12+_2; GRU1C: 23+_3 transmigrated tumor cells/counting area). Adhesion assays revealed major differences in the adhesive capacity for laminin (GRU-1A: 60_+7; GRU-1B: 18_+9; GRU-1C: 29_+ 7 adherent cells) and plastic (GRU-1A: 115-+1; GRU-1B: 106+_2; GRU-1C: 50 9 +5 adherent cells), while no significant differences could be detected for fibronectin, collagen IV and hyaluronic acid. These results were paralleled by differences in the expression of nm23-H1 and nm23-H2. While in the highly invasive cell line GRU-IA only nm23-H1 was detected, the cell lines of low invasive potential GRU-1B and GRU-1C both expressed nm23-H2. Furthermore, in GRU-1B also nm23-Hl was detected. Conclusions: In our tumor model the expression of nm23-H2 is inversely correlated with the invasive phenotype in vitro and the adhesive capacity to laminin. These results suggest a possibly inhibitory function of nm23-H2 in tumor invasion. Transfection experiments are under progress in order to examine a causative role of nm23-H2.