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M H Therkildsen

Publications and source records attributed to M H Therkildsen.

At least 19 recordsLinked to original sources
PubMed1999

Expression of polypeptide GalNAc-transferases in stratified epithelia and squamous cell carcinomas: immunohistological evaluation using monoclonal antibodies to three members of the GalNAc-transferase family.

Mucin-type O-glycosylation is initiated by a large family of UDP-GalNAc: polypeptide N -acetyl-galactosaminyltransferases (GalNAc-transferases). Individual GalNAc-transferases appear to have different functions and Northern analysis indicates that they are differently expressed in different organs. This suggests that O-glycosylation may vary with the repertoire of GalNAc-transferases expressed in a given cell. In order to study the repertoire of GalNAc-transferases in situ in tissues and changes in tumors, we have generated a panel of monoclonal antibodies (MAbs) with well defined specificity for human GalNAc-T1, -T2, and -T3. Application of this panel of novel antibodies revealed that GalNAc- transferases are differentially expressed in different cell lines, in spermatozoa, and in oral mucosa and carcinomas. For example, GalNAc-T1 and -T2 but not -T3 were highly expressed in WI38 cells, and GalNAc-T3 but not GalNAc-T1 or -T2 was expressed in spermatozoa. The expression patterns in normal oral mucosa were found to vary with cell differentiation, and for GalNAc-T2 and -T3 this was reflected in oral squamous cell carcinomas. The expression pattern of GalNAc-T1 was on the other hand changed in tumors to either total loss or expression in cytological poorly differentiated tumor cells, where the normal undifferentiated cells lacked expression. These results demonstrate that the repertoire of GalNAc-transferases is different in different cell types and vary with cellular differentiation, and malignant transformation. The implication of this is not yet fully understood, but it suggests that specific changes in sites of O-glycosylation of proteins may occur as a result of changes in the repertoire of GalNAc-transferases.

Animals↗
PubMed1998

Salivary gland carcinomas: prognostic significance of simple mucin-type carbohydrate antigens.

The prognosis of salivary gland carcinomas is difficult to assess. Simple mucin-type carbohydrates (T and sialosyl-T antigens, Tn and sialosyl-Tn antigens) have been shown to be of value in predicting prognosis for carcinomas in other locations. We studied the prognostic significance of the expression of these structures in a retrospective study of 133 patients with salivary gland carcinomas, using immunohistochemistry and a panel of well-defined monoclonal antibodies (MAbs) on formalin-fixed paraffin-embedded tissues. Sialosyl-Tn, T and sialosyl-T antigens were not correlated with prognosis. Univariate analyses showed no overall difference in survival or locoregional control between patients with Tn-positive and patients with Tn-negative tumours, but indicated that expression of the Tn antigen was associated with early locoregional recurrences and deaths. Tn was, however, not an independent prognostic factor by multivariate regression analysis.

Adult↗
PubMed1998

Salivary gland carcinomas--prognostic factors.

A retrospective study of factors of prognostic significance for clinical course and survival was performed using uni- and multivariate analyses in 251 patients with primary salivary gland carcinoma admitted during the period 1958-1992. Univariate analyses indicated that site of primary tumour, histology, clinical stage, presence of node metastases at primary diagnosis, and status of surgical margins were important prognostic factors for cause-specific survival, locoregional control and distant metastases. Multivariate analyses confirmed that histology was important for both locoregional control and cause-specific survival, whereas primary site was only of importance for locoregional control. Presence of node metastases at diagnosis was more important for locoregional control than clinical stage, whereas clinical stage was the most important factor for cause-specific survival. Status of surgical margins was of major importance for both cause-specific survival and locoregional control. Radiotherapy in addition to surgery improved locoregional control only, whereas survival was not affected.

Adolescent↗
PubMed1998

Can alterations in integrin and laminin-5 expression be used as markers of malignancy?

Development of squamous cell carcinomas (SCCs) involves alterations in the adhesive interactions in the epithelium and invasion through the basement membrane. Therefore, changes in the expression of receptors and ligands involved in cell-cell and cell-matrix adhesion may be essential for the transformation of a premalignant into a malignant lesion. The aim of this study was to examine if expression of specific cell adhesion molecules can be used as markers of malignant development. By immunohistochemistry, we examined the expression pattern of integrins alpha2beta1, alpha3beta1, alpha6beta4 and laminin-5 in biopsies from SCCs (n=18), premalignant lesions (leukoplakias, n=21) and non-premalignant tissue with chronic inflammation (n=11). In poorly differentiated SCCs, patchy loss of alpha3beta1, alpha6beta4 and laminin-5 expression was pronounced at the invasion front, whereas there was a tendency to increased expression of alpha2beta1. Analogous to the SCCs, biopsies from the leukoplakias and the non-premalignant inflammatory tissue showed alterations of the expression of alpha3beta1 and alpha6beta4 in the basal cell layers and of laminin-5. However, a characteristic finding in biopsies from leukoplakias was loss of alpha2beta1 and alpha3beta1 in the suprabasal cells. There was no unequivocal expression of the adhesion molecules distinguishing between inflammatory tissue, premalignant, and malignant lesions.

Adult↗
PubMed1997

Loss of a novel mucin-like epithelial glycoprotein in oral and cervical squamous cell carcinomas.

Stratified squamous epithelia of oral and cervical mucosa express high levels of simple mucin-type O-linked carbohydrates, and these are known to undergo structural changes in relation to epithelial differentiation and neoplastic transformation. O-glycans in these epithelia are associated with the cell membrane, but the identity of the carrier molecule(s) remains largely unknown. We report here the identification of a membrane-bound M(r) 200,000-250,000 glycoprotein (gp230) that is expressed in stratified squamous epithelia of the oral cavity. Western blot analysis identified gp230 as a major carrier of simple-mucin type carbohydrate antigens in buccal nonkeratinized mucosal epithelium, suggesting that it may represent a mucin-like molecule. A monoclonal antibody PANH4 defining a protein epitope of gp230 was generated. The PANH4 epitope was localized by immunohistology to suprabasal cell layers of buccal epithelium and was also found in larynx, esophagus, vagina, and exocervix, but not in epidermis. Data showed that gp230 was distinct from MUC1 or CD44. It is interesting that in most cases gp230 was not expressed in squamous cell carcinomas of buccal and cervical mucosa. A few moderately differentiated carcinomas, mainly from cervix, expressed the gp230 epitope. The results suggest that a membrane-bound mucin-like molecule, gp230, is associated with the differentiated phenotype of normal mucosal stratified squamous epithelia and that expression of gp230 generally is lost in severe oral epithelial dysplasia and squamous cell carcinomas of oral and cervical mucosa.

Adult↗
PubMed1997

Identification of a major human high molecular weight salivary mucin (MG1) as tracheobronchial mucin MUC5B.

Human saliva contains high and low molecular weight mucin glycoproteins, that are distinct. Recently the gene encoding low molecular weight salivary mucin was cloned and designated MUC7, whereas the primary structure of high molecular weight salivary mucin is unclear. Furthermore, the expression patterns of high and low molecular weight salivary mucins in salivary glands have been debated. We have previously generated monoclonal antibodies specific for the peptide cores of salivary mucins. In the present study a monoclonal antibody specific for high molecular weight salivary mucin was used to screen a human salivary gland cDNA library. A single clone, SAL1, was identified and found to be encoded by tracheobronchial mucin gene MUC5B. A previously reported partial cDNA sequence from salivary mucin was linked to SAL1/MUC5B by genomic cloning and reverse transcriptase-polymerase chain reaction. Northern analysis of salivary gland RNA probed with SAL1 suggested that MUC5B was highly expressed in salivary glands. In situ hybridization was performed with a SAL1/MUC5B probe and a MUC7 probe. All mucous cells from the submandibular, sublingual, palatine, and labial glands labeled with the MUC5B probe, while serous cells labeled with the MUC7 probe. These findings were in accordance with our previous immunohistological results of the cellular localizations of salivary mucins. The results suggest that MUC5B is identical to or a major fraction of high molecular weight salivary mucin, and that MUC5B is expressed in all mucous cells of salivary glands. In contrast MUC7 is expressed in serous cells of salivary glands except the parotid glands.

Amino Acid Sequence↗
PubMed1997

Observer variability in histological malignancy grading of adenoid cystic carcinomas.

The value of malignancy grading of adenoid cystic carcinomas (ACC) is controversial. Some studies have shown that tumours with a solid growth component have a rapid fatal course, compared to tumours without a solid growth component, in which recurrences develop even many years after initial treatment. Other studies have failed to correlate growth patterns with clinical course. No universally accepted grading system exists and no reproducibility studies of the existing grading systems have been performed. The aim of this study was to examine the reproducibility of grading based on semi-quantitative assessment of the solid growth pattern in ACC. Two different grading systems were assessed by 3 observers on a material of 59 ACC. Interobserver agreement was evaluated using the kappa statistic. The reproducibility of grading was poor, except for the category "solid component constituting 50% or more of the tumour" (kappa = 0.52). It is concluded that quantitative methods are necessary if grading is to be used in prognostic evaluation of ACC. The rarity of the tumours, however, combined with difficulties in diagnosis will impede such investigations unless multicentre studies are undertaken.

Carcinoma, Adenoid Cystic↗
PubMed1996

Differential expression of human high-molecular-weight salivary mucin (MG1) and low-molecular-weight salivary mucin (MG2).

Two distinct mucin components of saliva, MG1 and MG2, have been identified based on chemical composition and molecular weights (high and low, respectively) in saliva. With the aim of characterizing the expression pattern of salivary mucins, we have prepared monoclonal antibodies (MAbs) directed against the peptide core of MG1 and against a synthetic peptide derived from the MG2 (MUC7) sequence. MAb PANH2 raised against partially deglycosylated MG1 stained a high-molecular-weight smear in Western blots of partially purified MG1. PANH2 binding was increased by deglycosylation with trifluoromethanesulfonic acid as well as with subsequent periodate treatment, and was eliminated by pronase treatment, strongly suggesting that MAb PANH2 was directed to a peptide epitope of MG1. MAb PANH3 raised against a synthetic peptide derived from the MG2 (MUC7) sequence reacted with the native molecule and stained a narrow smear of ca. 200,000 to 210,000 in Western blots of concentrated saliva and a lower-molecular-weight smear of trifluoromethanesulfonic-acid-treated MG2. Immunohistology on frozen sections of human salivary glands showed that MAb PANH2 selectively labeled mucous cells, whereas MAb PANH3 labeled subpopulations of serous cells. Double-direct immunofluorescence staining with PANH2 and PANH3 demonstrated that the staining patterns were non-overlapping. The development of these antibody probes will facilitate studies of mucin expression in diseases of salivary glands.

Adult↗
PubMed1995

The Thomsen-Friedenreich (T) simple mucin-type carbohydrate antigen in salivary gland carcinomas.

The simple mucin-type T (Thomsen-Friedenreich) antigen is a marker of carcinomas, and has been related to aggressiveness of malignant tumours. We studied the expression of T, sialosyl-T, A and H blood group antigens in salivary gland carcinomas. The aim was to study whether the tumours, based on the expression of these structures, could be divided into new diagnostic groups that may later show prognostic significance. Formalin fixed paraffin-embedded tissue sections from 77 salivary gland carcinomas of different histological types were studied using immunohistology and monoclonal antibodies (MAbs). Fresh frozen tissue was examined in 30 of the cases. Frozen sections were superior to paraffin sections in demonstrating T and H antigens. Aberrant glycosylation with accumulation of T (in cytoplasm) and sialosyl-T antigens (in cytoplasm, membrane and mucin) was found in all tumour types except acinic cell carcinomas. In carcinomas in pleomorphic adenomas (CinPA) the effect of fixation was minimal and T antigen location was different. In carcinomas with myoepithelial cell (MEC) participation, the MECs had retained a normal glycosylation pattern. H antigen was expressed in all tumour types, except acinic cell carcinomas and CinPA. A antigen was expressed in all tumour types from blood group A patients, except in CinPA. The expression of T, sialosyl-T, H and A antigens in relation to differentiation grade varied with tumour type in poorly differentiated areas. High and moderate differentiated areas were always stained, whereas poorly differentiated areas in some tumour types expressed T and sialosyl-T antigens and others did not. The accumulation versus lack of expression of the investigated structures in poorly differentiated areas of the tumours may be of prognostic significance.

ABO Blood-Group System↗
PubMed1995

A sensitive enzyme-linked immunosorbent assay used for quantitation of epidermal growth factor receptor protein in head and neck carcinomas: evaluation, interpretations and limitations.

The EGF receptor is a transmembrane glycoprotein exerting mitogenic effects on epithelial cells. The purpose of the present study was to develop a sensitive enzyme-linked immunosorbent assay (ELISA) for determination of the epidermal growth factor receptor (EGFR) protein to examine whether the receptor was overexpressed in head and neck squamous cell carcinomas compared with the normal counterpart, and to establish whether clinicopathological correlations were present by investigating a broad spectrum of parameters (tumour size, clinical stage, positive lymph nodes, tumour site, histological grade, keratinisation, preoperative irradiation and clinical outcome). The assay employs two commercially available monoclonal antibodies, both detecting protein epitopes. The material comprises 60 head and neck carcinomas, corresponding normal tissue and normal oral mucosa from healthy individuals. The study demonstrates significantly higher receptor levels in tumours compared with normal tissue (P < 0.002) and a range in tumours and normal tissues of 0.4-10.5 and 0.1-4.3 nmol g-1 membrane protein respectively. Quantitation of receptors in normal mucosa emphasises the importance of using the patients' corresponding normal tissue, because using the patients' mucosa resulted in 83% overexpression, while using normal mucosa from healthy individuals only demonstrated overexpression in 50% of cases. No significant clinicopathological correlations could be established, although the mean values for EGFR increased with tumour size and advanced clinical stage. Furthermore, the prognostic value concerning disease-free survival, recurrence and the time interval for recurrence were investigated but no significance could be demonstrated. In conclusion, the investigation supports the theory of overexpression of EGFR protein as a common motif for malignant epithelial tumours, but limitations in interpretations are demonstrated and discussed further.

Adult↗
PubMed1995

Observer variability in the histologic assessment of oral premalignant lesions.

Histopathologic examination of oral leukoplakias has a major impact on the assessment of prognosis and treatment planning. We investigated the extent of agreement in grading epithelial dysplasia between pathologists with the same or different educational backgrounds. Two general pathologists and two oral pathologists were each given 100 sections of oral leukoplakia to grade from no dysplasia to carcinoma in-situ. The interobserver agreement rates were in the range of 49% to 69%. The calculated kappa values were in the range of 27% to 45%, showing poor to moderate agreement between the pathologists. When comparing the kappa values between the two pairs of pathologists with the same education, these values did not diverge from the general level of kappa values, indicating that the interobserver variability was due to individual differences rather than to educational background.

Clinical Competence↗
PubMed1994

Simple mucin-type carbohydrate antigens (T, Tn and sialosyl-Tn) in mucoepidermoid carcinoma of the salivary glands.

Thirty-two cases of mucoepidermoid carcinoma of the salivary glands were studied in order to characterize the expression of simple mucin-type carbohydrate antigens T, Tn and sialosyl-Tn and to evaluate its implication for tumour histogenesis. Monoclonal antibodies of known specificity were used on formalin-fixed, paraffin-embedded tissue, and the expression of these antigens was studied in each of the three cell types (mucous, intermediate and squamous) as well as in the secretory content of neoplastic lumina. Aberrant glycosylation of simple-mucin type antigens was found in all cell types, as compared with that of normal excretory duct cells of the salivary glands. The more 'primitive' antigens Tn and sialosyl-Tn were present in a high percentage of epidermoid and intermediate cells. Mucous cells and the intraluminal secretory content also expressed Tn in 57.7% of the cases. This contrasts with the absence of secretion of these simple mucin type carbohydrates by normal salivary gland cells. Mucin-producing cells did not express T antigen but only sialosyl-T, in contrast to 57.1% and 56.3% respectively of the epidermoid and intermediate cell types. T and sialosyl-T were also found in the secretory products of the neoplastic lumina in 11.5% and 53.6% of the cases, respectively. The distinctive glycosylation pattern between mucin-producing cells on the one hand and intermediate and squamous cells on the other does not contradict the common origin of the three cell types from the reserve cell of the salivary excretory duct, but favours the proposition that intermediate cells constitute a step in the differentiation pathway of epidermoid, but not of mucin-producing, cells.

Adolescent↗
PubMed1994

Simple mucin-type carbohydrate antigens in major salivary glands.

Simple mucin-type carbohydrate antigens Tn, sialosyl-Tn and T are often markers of neoplastic transformation and have very limited expression in normal tissues. We performed an immunohistological study of simple mucin-type carbohydrate antigens, including H and A variants, with well-defined monoclonal antibodies (MAb) on frozen and paraffin-embedded normal salivary gland tissue from 22 parotid, 14 submandibular, six sublingual, and 13 labial glands to elucidate the simple mucin-type glycosylation pattern in relation to cyto- and histodifferentiation. The investigated carbohydrate structures were predominantly observed in the cell cytoplasm, most often in the supranuclear area, suggesting localization to the Golgi region, whereas ductal contents were unstained. Mucous acinar cells expressed Tn, sialosyl-Tn, and H and A antigens, regardless of glandular location. Serous acinar cells, on the other hand, expressed A, H, and inconstantly sialosyl-T, Tn, and sialosyl-Tn antigens in major salivary glands, whereas serous cells of minor (labial) salivary glands expressed H exclusively, Tn and sialosyl-T antigens inconstantly, but never sialosyl-Tn and A antigens. The difference may be related to a more simple cytodifferentiation of serous cells of minor (labial) salivary glands as compared with major salivary glands. Duct cells in major salivary glands expressed A, H, and inconstantly T, sialosyl-T, and Tn antigens, whereas minor (labial) salivary glands ducts exclusively expressed H, T and sialosyl-T antigens, differences that may be related to dissimilarities in the duct system. Myoepithelial cells and basal cells exclusively expressed T and sialosyl-T antigens, which may prove useful in studies of salivary gland tumors, since these cells are known to play a key role in the histological characteristics of some salivary gland tumors. The results indicate a similar glycosylation pattern in the different major salivary glands, whereas minor (labial) salivary gland differ slightly in serous and duct cells. The limited and exclusive intracellular expression of the immature Tn, sialosyl-Tn, and T antigens indicates that these structures may be of value as markers of salivary gland tumors.

Antibodies, Monoclonal↗
PubMed1994

Oncofetal fibronectins in oral carcinomas: correlation of two different types.

Different isoforms of fibronectin are derived from a single gene by alternative processing of the primary RNA transcript or by posttranslational modifications. We have previously demonstrated that an oncofetal fibronectin (FN) isoform derived by O-glycosylation is highly associated with malignancy in breast and oral tumors. Another oncofetal FN isoform containing the ED-B sequence is derived by alternative splicing, and FN containing ED-B has been found to be a stromal marker of malignancies in various tissues. Here we report a comparative study by immunohistology of the distribution of the ED-B-containing isoform and the oncofetal FN isoform derived by O-glycosylation, in oral squamous cell carcinomas, premalignant lesions, and normal oral mucosa. A selective expression of the ED-B-containing isoform was demonstrated in close relation to the invading carcinoma (38/38), whereas there was virtually no staining in submucosa underlying premalignant lesions (1/11) and normal epithelium (0/5). The ED-B-containing FN showed close co-distribution and staining pattern with the oncofetal isoform derived by O-glycosylation. These results demonstrate that accumulation of FN adjacent to oral carcinomas includes both the ED-B-containing isoform and the isoform derived by O-glycosylation. Although both the change in primary structure and glycosylation of FN create conformational and immunologically detectable changes, the functional consequences in association with invasive carcinoma are poorly understood at present. Diagnostic implications especially of borderline lesions as well as evaluation of tumor aggressiveness may, however, be important.

Aged↗
PubMed1993

Simple mucin-type Tn and sialosyl-Tn carbohydrate antigens in salivary gland carcinomas.

BACKGROUND: Neoplastic transformation is associated frequently with changes in the glycosylation process. Simple mucin-type glycosylation in cancer cells has been found to be characterized by incomplete synthesis with precursor accumulation, leading to the exposure of the structures Tn and sialosyl-Tn, which are normally cryptic in human cells and secretions, including saliva and salivary glands. METHODS: Paraffin sections from 50 salivary gland carcinomas of different histologic types were investigated with immunohistologic studies and a panel of monoclonal antibodies with well-defined specificity for Tn and sialosyl-Tn. RESULTS: Tn and sialosyl-Tn antigens were expressed in the cytoplasm of glandular differentiated cells; in the luminal membranes and mucinous content of the glandular differentiated areas in almost all mucoepidermoid carcinomas and adenocarcinomas; and in carcinoma in pleomorphic adenoma, when the malignant component was an adenocarcinoma. In contrast, acinic cell carcinomas and adenoid cystic carcinomas expressed only minimal amounts of Tn and sialosyl-Tn, and the staining was seen only in relation to the luminal membrane and mucin of a few glandular structures. CONCLUSIONS: Mucin-type Tn and sialosyl-Tn may be regarded as markers of a glandular differentiation pattern in salivary gland carcinomas. The cellular location of the antigen-antibody complex indicates that they are synthesized and secreted from the tumor cells into saliva or serum.

Adenocarcinoma↗
PubMed1993

Immunoreactive transforming growth factor alpha and epidermal growth factor in oral squamous cell carcinomas.

Forty oral squamous cell carcinomas have been investigated immunohistochemically for the presence of transforming growth factor alpha (TGF-alpha) and epidermal growth factor (EGF). The same cases were recently characterized for the expression of EGF-receptors. TGF-alpha was detected with a monoclonal mouse antibody and EGF with polyclonal rabbit antiserum. Thirty-five of the tumours were positive for TGF-alpha and 26 of the tumours for EGF. None of the poorly differentiated tumours was positive for EGF, but they all were for TGF-alpha. In sections including normal differentiated oral mucosa, the cells above the basal cell layer were positive for both TGF-alpha and EGF. The same staining pattern was observed in oral mucosa obtained from healthy persons. In moderately to well differentiated carcinomas, the immunoreactivity was mainly confined to the cytologically more differentiated cells, thus paralleling the situation observed in the normal differentiated oral mucosa. In four cases, material was available from both a primary tumour and a metastasis. Three of these were positive for TGF-alpha and EGF with the same staining pattern as that of the primary tumours. This investigation together with our previous results confirms the existence of TGF-alpha, EGF, and EGF-receptors in the majority of oral squamous cell carcinomas and their metastases.

Carcinoma, Squamous Cell↗