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Biomedical subjects

G Niehans

Publications and source records attributed to G Niehans.

8 recordsLinked to original sources
PubMed2000

Adhesion of aspirated tumor cells to extracellular matrix proteins: a new methodology utilizing fine-needle aspiration.

BACKGROUND: Cell adhesion molecules mediate the interactions of cells with other cells and with extracellular matrix components. Such interactions may be important in the development of tumor invasion and metastasis. This article describes a new approach to the evaluation of tumor cell-matrix interactions by utilizing fine-needle aspiration of resected tumors. METHODS: Fine-needle aspiration was performed on 15 fresh surgical specimens of various types of carcinomas. After partial purification by isotonic Percoll centrifugation, tumor cell adhesion to collagen Type IV, laminin, and fibronectin was evaluated by counting cytologically malignant cells adhering to matrix-coated plastic substrates. Frozen tissue sections of the corresponding tumors were studied simultaneously for immunohistochemical expression of alpha-2, alpha-3, alpha-4, and alpha-5 integrin subunit expression. Results of the immunohistochemical staining then were compared with the adhesion data for particular tumors. RESULTS: In general, the majority of the tumors exhibited little or no adhesion to collagen or laminin, but several tumors showed marked adhesion to fibronectin. Striking differences were noted between some tumors of the same histologic subtype. Competitive inhibition studies performed with two of the tumors (a large cell carcinoma and a renal cell carcinoma) showed decreased adhesion to fibronectin in the presence of anti-alpha-5, suggesting at least a partial role for the alpha-5-beta 1 fibronectin receptor in mediating the adhesion of these tumors to fibronectin. All the tumors examined exhibited strong immunohistochemical expression of the alpha-2 and alpha-3 integrin subunits, and all were negative for alpha-4. Three of the tumors showed weak expression of alpha-5, two of which (a squamous cell carcinoma and a renal cell carcinoma) were the tumors that showed the greatest adhesion to fibronectin. CONCLUSIONS: Quantitative adhesion data can be obtained using cell suspensions prepared from fine-needle aspirates, and there are marked differences in adhesive properties between particular tumors. Although two of the tumors showed a correlation between adhesion to fibronectin and immunohistochemical expression of the alpha-5 integrin subunit, matrix adhesion does not necessarily correlate with immunohistochemical expression of adhesion molecule receptors. In the future, this methodology potentially could be of value in determining which patients may benefit from therapies aimed at modifying tumor cell-matrix interactions.

Biopsy, Needle↗
PubMed1999

Correlation of CD44S expression in renal clear cell carcinomas with subsequent tumor progression or recurrence.

BACKGROUND: Recent reports have shown altered expression of CD44 in renal cell carcinomas. However, to the authors' knowledge there are no data correlating CD44 expression in renal cell carcinomas with subsequent tumor progression or recurrence, nor is there information about the presence of particular splice variants of CD44 in these tumors. METHODS: The authors examined the immunohistochemical expression of CD44S, the standard isoform of CD44, in renal cell carcinomas from 43 patients using 2 different monoclonal antibodies, Mab2137 and Hermes-3. In addition, they stained the renal cell carcinomas with antibodies to 2 splice variants of CD44, CD44v3 and CD44v6. RESULTS: Increased staining of renal clear cell carcinomas with Mab2137 was observed in high grade versus low grade tumors (45% vs. 0%, P = 0.013), whereas increased staining of clear cell carcinomas with Hermes-3 was noted in high stage versus low stage tumors (40% vs. 0%, P = 0.006). Few tumors stained with antibodies to CD44v3. Although increased expression of the splice variant CD44v6 was noted in papillary versus clear cell carcinomas, and increased staining of papillary carcinomas with Mab2137 and with antibodies to CD44v6 was noted for low stage versus high stage tumors, these differences did not achieve statistical significance. Clinical follow-up of at least 43 months was available for 26 patients. Six of these patients (five with clear cell carcinoma and one with papillary carcinoma) developed progressive or recurrent disease. The primary tumors from all 5 patients with progressive or recurrent clear cell carcinoma showed staining with Mab2137, whereas the primary tumors from only 2 of the 15 patients with at least 43 months follow-up and no evidence of progressive or recurrent clear cell carcinoma (13%) showed staining with Mab2137 (P = 0.001). Alternatively, 5 of 7 clear cell carcinomas (71%) that stained with Mab2137 were from patients who subsequently developed recurrence or progression, compared with 0 of 13 clear cell carcinomas that did not stain. Similar findings were not observed for papillary carcinomas, which appeared to be biologically distinct from clear cell carcinomas. CONCLUSIONS: CD44S staining with Mab2137 correlates with progression or recurrence of clear cell renal cell carcinoma. CD44S may, therefore, play a pathogenetic role in tumor progression.

Adult↗
PubMed1999

Subcellular immunolocalization of protein kinase CK2 in normal and carcinoma cells.

CK2 is a messenger-independent protein serine/threonine kinase that has been implicated in cell growth and proliferation. Our recent analysis of squamous cell carcinomas of the head and neck (SCCHN) revealed a significant elevation in CK2 activity in these tumor cells relative to normal mucosa of the upper aerodigestive tract and suggested a correlation with aggressive tumor behavior and poor clinical outcome. In order to further define the distribution of CK2 in these tissues, we have examined the immunohistochemical staining pattern of surgical specimens of both SCCHN tumors and normal upper aerodigestive tract mucosa using a monoclonal antibody directed against the catalytic subunit CK2-alpha of the kinase, and have compared these data with the subcellular distribution of CK2 activity in these same tissues. These measurements showed that CK2 is predominantly localized to the nuclei of the tumor cells, which agreed closely with the immunohistochemical staining pattern of CK2-alpha in tumor cells. The chiefly nuclear distribution of CK2-alpha immunostaining found consistently in SCCHN tumor cells and tumor-infiltrating lymphocytes contrasted with a relatively more predominant cytosolic staining pattern exhibited by various cellular constituents of normal oropharyngeal mucosa. The immunostaining pattern of CK2-alpha revealed that staining was observed in the cells stained for the proliferation-marker Ki-67; however, strong distinct immunostaining for CK2-alpha was also observed in large numbers of other cells in these same tumors, suggesting that CK2 elevation in these tumors is not a reflection of proliferative activity alone, but may also relate to the pathobiological behavior of the tumor.

Carcinoma, Squamous Cell↗
PubMed1997

Germline and somatic mutations in the tyrosine kinase domain of the MET proto-oncogene in papillary renal carcinomas.

Hereditary papillary renal carcinoma (HPRC) is a recently recognized form of inherited kidney cancer characterized by a predisposition to develop multiple, bilateral papillary renal tumours. The pattern of inheritance of HPRC is consistent with autosomal dominant transmission with reduced penetrance. HPRC is histologically and genetically distinct from two other causes of inherited renal carcinoma, von Hippel-Lindau disease (VHL) and the chromosome translocation (3;8). Malignant papillary renal carcinomas are characterized by trisomy of chromosomes 7, 16 and 17, and in men, by loss of the Y chromosome. Inherited and sporadic clear cell renal carcinomas are characterized by inactivation of both copies of the VHL gene by mutation, and/or by hypermethylation. We found that the HPRC gene was located at chromosome 7q31.1-34 in a 27-centimorgan (cM) interval between D7S496 and D7S1837. We identified missense mutations located in the tyrosine kinase domain of the MET gene in the germline of affected members of HPRC families and in a subset of sporadic papillary renal carcinomas. Three mutations in the MET gene are located in codons that are homologous to those in c-kit and RET, proto-oncogenes that are targets of naturally-occurring mutations. The results suggest that missense mutations located in the MET proto-oncogene lead to constitutive activation of the MET protein and papillary renal carcinomas.

Adult↗
PubMed1996

Immunohistochemical staining for markers of future neoplastic progression in the larynx.

We performed a retrospective, longitudinal study to determine whether abnormalities in immunohistochemical staining for the epidermal growth factor receptor (EGFR), p53, or cyclin D1 occur before the development of laryngeal carcinoma. Staining was performed on 63 paraffin-embedded biopsies from 18 patients who subsequently developed carcinoma in situ (CIS) or invasive carcinoma of the larynx. These were compared to 71 biopsies from 20 patients who did not develop CIS/cancer (minimum follow-up period, 4 years). Also studied were the 34 biopsies containing CIS and/or carcinoma from those patients who progressed and 22 biopsies obtained concurrently. The two patient groups did not differ significantly in terms of tobacco and alcohol use. Distinct patterns of staining correlated with malignant progression. These included EGFR staining of two thirds or more of the epithelium thickness, a linear basal p53 staining pattern, and strong (3+) staining for cyclin D1 (P < 0.01 for each). These staining patterns also correlated with increasing atypia. In our study population, linear basal staining for p53 and strong staining for cyclin D1 had higher specificity for progression than did EGFR overexpression, which was also seen in association with inflammation and chronic irritation. Marked site-to-site variation was seen in the immunohistochemical staining and in the degree of atypia, suggesting that multiple biopsies are necessary to properly assess risk. These immunohistochemical staining patterns may be clinically useful to predict patients at risk for neoplastic progression.

Adult↗
PubMed1990

Epidermoid cyst (monodermal teratoma) of the testis.

We report 14 patients with epidermoid cyst of the testis (monodermal teratoma). In 7 patients (5 treated within the last 5 years) the mass was excised and adjacent testicular tissue was biopsied. Seven patients underwent radical inguinal orchiectomy. Carcinoma in situ was not detected in any testicular tissue examined. There was no evidence of tumour recurrence in any patient after a mean follow-up of 10 years. Ultrasonographic appearance was not specific for a diagnosis of epidermoid cyst and exploratory surgery was required in all cases. Excision of the tumour and biopsy of adjacent testicular tissue to determine the presence or absence of carcinoma in situ is adequate treatment for this rare testicular neoplasm.

Adult↗
PubMed1987

Intermediate trophoblast in germ cell neoplasms.

One-hundred-twenty-four germ cell tumors and 11 gestational choriocarcinomas were assessed immunohistochemically for the presence of the following placental markers: human chorionic gonadotrophin, human placental lactogen, and pregnancy-specific beta-1 glycoprotein, and for the expression of cytokeratin. A total of 40 cases contained syncytial trophoblastic cells, large mononuclear cells, or both. These cases included all gestational choriocarcinomas and choriocarcinomatous foci in 11 mixed germ cell tumors, 14 embryonal carcinomas, and four seminomas. Syncytial trophoblastic cells reactive for cytokeratin were identified in all choriocarcinomas, 12 embryonal carcinomas, and two seminomas. Human placental lactogen-reactive syncytial trophoblastic cells were observed in nine gestational choriocarcinomas, 10 choriocarcinomatous foci in mixed germ cell tumors, four embryonal carcinomas, and one seminoma. Pregnancy-specific beta-1 glycoprotein-reactive syncytial trophoblastic cells were seen in 10 gestational choriocarcinomas, all choriocarcinomatous foci in mixed germ cell tumors, 11 embryonal carcinomas, and one seminoma. Cytotrophoblasts, as expected, were identified only in choriocarcinomas. Cytokeratin-reactive cytotrophoblast was seen in all gestational choriocarcinomas and 10 choriocarcinomatous foci in mixed germ cell tumors. Human chorionic gonadotrophin-reactive cytotrophoblast was observed in two gestational choriocarcinomas and three choriocarcinomatous foci in mixed germ cell tumors. Cytotrophoblast was uniformly nonreactive for human placental lactogen and pregnancy-specific beta-1 glycoprotein. Cytokeratin-reactive large mononuclear cells were observed in 10 gestational choriocarcinomas, all choriocarcinomatous foci in mixed germ cell tumors, five embryonal carcinomas, and three seminomas. Human placental lactogen-reactive large mononuclear cells were identified in nine gestational choriocarcinomas, seven choriocarcinomatous foci in mixed germ cell tumors, one embryonal carcinoma, and one seminoma. Pregnancy-specific beta-1 glycoprotein-reactive large mononuclear cells were present in 10 gestational choriocarcinomas, 10 choriocarcinomatous foci in mixed germ cell tumors, two embryonal carcinomas, and two seminomas. Because of morphologic and immunohistochemical similarities of large mononuclear cells with intermediate trophoblast of the normal placenta and gestational trophoblastic neoplasms, we propose that the large mononuclear cells in gonadal and extragonadal germ cell neoplasms are equivalent to the intermediate trophoblast.

Choriocarcinoma↗