Biomedical subjects

T Löning

Publications and source records attributed to T Löning.

At least 55 records · Page 3Linked to original sources

PubMed1999

Urokinase gene expression indicates early invasive growth in squamous cell lesions of the uterine cervix.

The plasminogen activating system plays a key role in the cascade of tumour-associated proteolysis leading to extracellular matrix degradation and stromal invasion. Changes in the expression of this system, consisting of urokinase- and tissue-type plasminogen activators (uPA and tPA, respectively), plasminogen activator inhibitors (PAI-1, PAI-2) and uPA receptor, have been associated with tumour aggressiveness in a variety of solid malignant tumours. This paper describes a study of squamous intraepithelial lesions (SILs, n=36), squamous cell carcinomas (SCCs, n=42), and normal mucosa (n=5) of the uterine cervix by in situ hybridization with (35)S-labelled RNA probes. uPA transcripts were absent from normal mucosa and non-invasive lesions, but present in atypical epithelial cells of all microinvasive carcinomas ( n=19) and in some of the more advanced invasive carcinomas (n=11). PAI-1 transcripts were found in stromal cells of most tissue samples with, however, significantly increased levels in invasive SCC compared with SIL, microinvasive SCC, and normal mucosa. uPA-positive invasive carcinomas often displayed additional PAI-1 expression by tumour cells. At variance with uPA, tPA transcripts were found in atypical epithelial cells of low- and high-grade SILs. In the majority of SCCs tested (27/29 cases), the HPV 16 E6/E7 oncogene and uPA transcription were correlated. uPA and PAI-1 expression indicates invasive growth when expressed by atypical epithelial cells of squamous cervical lesions. Moreover, the presence of uPA transcripts is indicative of early invasive growth. uPA and tPA seem to have different functions in the development of invasive properties in uterine cervical squamous epithelium.

Carcinoma, Squamous Cell↗

PubMed1999

[Tissue fragment diagnosis in gynecopathology].

Empirical knowledge, daily diagnostic efforts and scientific spirits are the prerequisites of theoretical and practical progress in gynecopathology. The current standards in this field have their root in the continuous interests of gynecologists educated and skilled in pathology. In Germany, however, there is no more the gynecologist, who is in charge for both the clinical and pathological diagnostic business. Also, it is no more a rule for gynecologists to pass through a fellowship in pathology during their specialization. This development leads to more distance between gynecology and pathology, which per se is a potential source of misunderstandings. One of the tasks of this introduction and subsequent articles is to describe controversial areas and to offer ways out of the conflicts. Yet, the master key for avoiding misunderstandings is the close interdisciplinary co-operation in the perioperative management of the patient.

Female↗

PubMed1999

[Guidelines for preparation of uterine surgical specimen].

Tumor classification, grading and staging of malignant tumors of the cervix and corpus uteri should be done according to the rules of the WHO fascicle of 1994 and the TNM manual of 1997, respectively. With these lines taking into account, the surgical pathology report will include the most important prognostic factors, which in part are also of therapeutic relevance, i.e. localization of the lesion, depth of invasion and distant tumor manifestation. Yet, gross inspection and preparation are the prerequisites of the quality of the histopathological statement. Accurate documentation of tumor extension, depth of invasion into the cervical stroma and/or the myometrium and distance to the resection lines at the vaginal cuff and the parametrium needs to be given in centimeters, first by eye, than controlled by histopathology. The tumor extension of cervical carcinomas should be given in three dimensions, including the depth of invasion into the cervical wall. It is also mandatory to document the number and size of lymph nodes with metastatic involvement compared to the total number of nodes which are discovered in parametral, pelvioperitoneal and paraaortal sites. Most of what has been outlined for the surgical pathology report of hysterectomy specimens is also pertinent to conisations, by whatever method these are performed (cold knife, laser or loop). For appropriate documentation of the localization of the lesion, horizontal expansion of the dysplastic lesion and recognition of microinvasion it is sufficient to dissect the conisation specimen clockwise and to cut the various paraffin blocks in serial sections.

Cervix Uteri↗

PubMed1999

[Molecular and clinical endocrinology of the endometrium].

The ovarian steroid hormones estradiol and progesterone exert their effect by interacting with their intracellular receptors, which, after ligand binding translocate to the nucleus and bind to the promoter regions of target genes. The consequence is a change in the transcription rate of the target genes, followed by a change in production of the corresponding proteins. Target genes of the sexual steroid hormones include cytokines and growth factors, among them CSF-1, TGF-beta and LIF. The rhythm and activity of steroidogenesis, receptor modulation and transcription are reflected by cycle-specific proliferation and differentiation processes in the endometrium. Quantitative and/or qualitative molecular endocrinology is of increasing interest for better definition of morphological changes, although, as yet, the pathological laboratory test is of much less practical consequence than a suspicious vaginal sonography. In spite of the high standard of ultrasound techniques, however, most cases with slightly increased endometrial thickness show histologically benign changes of the endometrium rather than endometrial precancer or cancer. This is especially true for perimenopausal women with no other clinical findings. Yet, the cancer risk is increased in women under tamoxifen therapy. Hence, as a rule, these cases, when endometrial thickness exceeds 5 mm, need a diagnostic biopsy or abrasio.

Biopsy↗

PubMed1999

[Algorithm of endometrial meta- and hyperplasia].

As to to their frequency and variety, endometrial meta- and hyperplasias are the most impressive examples of the growth and differentiation potential of the Muellerian system and the inductive power of steroid hormones and related inter- and intracellular factors. Characteristic steroid reactions are the glandular hyperplasias, ciliated and squamous cell metaplasias in the case of hyperestrogenism, and the mucinous and clear cell meta- and hyperplasias in the case of gestagen excess. In 1994, the WHO established a new classification of endometrial hyperplasias. This classification takes into account the profound differences in cancer risk, and accordingly demands a clearcut distinction between simple and complex (steroid sensitive, almost always reversible) hyperplasias without atypia, and simple and complex (partial steroid resistant and potential progressive) hyperplasias with atypia. The conclusion drawn from clinical experience is, that the atypical endometrial hyperplasia--and this alone--is the precancerous lesion of the ordinary endometroid carcinoma. In contrast, it is still not clear which biological significance accounts to all the complex squamous, mucinous, clear cell and ciliated cell meta- and hyperplasias. Yet, it is good pathological and clinical practice, to upgrade any metaplastic lesion with nuclear atypia, and to remove the uterus as it is done in almost all atypical endometrial hyperplasias.

Algorithms↗

PubMed1999

[Algorithm of clinical aspects and pathology of endometrial carcinoma].

The carcinoma of the endometrium is the most common malignancy seen in the female pelvic genital organs. Important risk factors are age and unopposed estrogen (both endogenous and exogenous). In comparison, the association of antiestrogens (e.g., tamoxifen) and endometrial cancer is rather small, as yet. Fortunately, survival is high because the majority of patients have in common the presence of a low grade, low stage carcinoma of the endometroid type which gives rise to vaginal bleeding and forces the patients to attend the gynecologist. Special screening studies (e.g. vaginal sonography) to evaluate the endometrium are not indicated in the asymptomatic patient without risk factors. Tumor type, grading, and--most importantly--the depth of myoinvasion and the extent of extrauterine disease are the prognostic indicators that allow differential treatment, and help to identify patients at high risk vs. low risk for recurrent disease. Investigations of growth fraction, ploidy, steroid receptors, K-ras or p53 may be a supplement for dissecting special subgroups, but do not influence the clinical regimen, as yet. Most patients with stage I cancer are cured by surgery alone. Patients successfully treated for endometrial cancer should enjoy the benefits of estrogen replacement therapy, since they do not bear a risk of increased recurrence of their disease. Radiation therapy will be given to patients with incomplete resection of pelvic disease and/or extensive lymphonodal involvement, especially paraaortal lymph node metastasis. As yet, there is no rationale for an adjuvant hormone-(gestagen-) or chemotherapy. An exception, however, is the (mostly palliative) treatment of recurrent disease.

Algorithms↗

PubMed1999

[Trophoblast lesions and trophoblast tumors].

The clinico-pathologic characteristics and the histological/immunohistological differential diagnosis of villous trophoblastic lesions (complete, partial, and invasive hydatiform moles), gestational choriocarcinoma and trophoblastic tumors and pseudotumors of the placental site (placental-site trophoblastic tumor, exaggerated placental site reaction, placental site nodule) are reviewed in context with aspects of cytogenetics, epidemiology and molecular pathogenesis.

Biomarkers, Tumor↗

PubMed1999

Human endogenous retrovirus (HERV)-K transcripts in gonadoblastomas and gonadoblastoma-derived germ cell tumours.

Gonadoblastomas are rare tumours of abnormal or dysgenetic gonads, often transforming to invasive seminomatous and nonseminomatous germ cell tumours (GCT). Because of the intimate association of noninvasive and invasive lesions, gonadoblastoma may provide clues as to the molecular pathogenesis of GCT. We studied the expression of the human endogenous retrovirus (HERV)-K gag gene in eight gonadoblastomas arising in phenotypically female patients, including two newborn girls. We also studied testicular biopsies with immature Sertoli cell nodules harbouring neoplastic germ cells, a lesion with morphological resemblance to gonadoblastoma. In five gonadoblastomas, invasive seminoma/dysgerminoma was noted, in two cases with formation of additional GCT components. HERV-K gag transcripts were found with moderate levels in gonocytes of all gonadoblastomas and in neoplastic germ cells in testicular Sertoli cell nodules. All invasive GCT except for teratomas displayed HERV-K transcripts. Thus, expression of HERV-K is induced during fetal or embryonal development and precedes invasive GCT formation. Although the specific role of HERV-K expression remains unknown, the findings place HERV-K expression in an appropriate time frame for it to have a role in the molecular pathogenesis of GCT and suggest a precursor-invasive tumour relationship for ovarian GCT equivalent to the more common carcinoma in situ of the testis and testicular GCT.

Adolescent↗

PubMed1999

P16/MTS1 and pRB expression in endometrial carcinomas.

p16MTS1/CDKN1 and the retinoblastoma protein Rb are both involved in negative regulation of G1/S progression in the mammalian cell cycle. Inactivation of one of these tumour suppressor genes is involved in many malignant tumours, and in some studies a negative correlation of p16 and Rb expression has been found. In order to study this interaction in endometrial carcinogenesis, we investigated 36 endometrial carcinomas, 11 cases of hyperplasia, 23 normal endometrial samples, and two uterine carcinoma cell lines by immunohistochemistry or RT-PCR. Rb was expressed in normal endometrial epithelium, hyperplasia, cell lines, and most carcinomas; negative immunostaining was only detected in 1 of 36 tumours. In contrast, p16 expression was weak in normal endometrium and increased in most cases of hyperplasia, but negative or minimally positive in 74% of the carcinomas and the Hec1B adenocarcinoma cell line, and there was no significant association with Rb immunostaining. Strikingly high p16 expression was found in foci of squamous metaplasia within hyperplastic or carcinomatous tissue. Deletion and mutation analysis of the p16 gene was performed in DNA from microdissected tumour samples and cell lines. No p16 deletion was found, and mutations were detected in only one tumour sample and Skut1B uterine mixed mesodermal tumour cells. Our data indicate that in spite of low or absent p16 expression, genetic alterations of the p16 and Rb tumour suppressor genes are rare in endometrial carcinogenesis.

Adult↗

PubMed1999

Strongly reduced expression of the cell cycle inhibitor p27 in endometrial neoplasia.

In the present study we investigated the expression of the cell cycle inhibitor p27 in endometrial neoplasia using immunohistochemistry with a p27-specific antibody. Expression of p27 in endometrial carcinomas was compared with expression in the normal endometrium throughout the cycle. Normal endometrial cells showed strong nuclear expression of p27. Expression was present throughout the cycle and was stronger during the secretory phase. We found strongly reduced or abolished expression of p27 in endometrial carcinoma (85.3% of cases). The 41 tumours analysed were classified according to p27 staining intensity and percentage of positive cells into the following categories of p27 expression: negative/very low (56.0%); low (29.3%); moderate (14.7%) and high (0.0%). All the p27-positive tumours were well-differentiated endometrioid carcinomas of malignancy grade G1. Comparison with the p53 status showed that all tumours with strong p53 expression had low/negative p27 staining, while those that were positive for p27 had negative/low p53 staining. Reduced or absent p27 levels were also observed by Western blot analysis both in tumour samples and in HEC-1B endometrial adenocarcinoma cells. It thus seems that p27 expression is essential for the control of normal endometrial proliferation, and reduced or absent p27 expression may be an important step in endometrial carcinogenesis.

Adenocarcinoma↗

PubMed1999

Matrix-metalloproteinases 1, 2, and 3 and their tissue inhibitors 1 and 2 in benign and malignant breast lesions: an in situ hybridization study.

Invasive growth requires degradation of extracellular matrix. Altered expression of matrix degrading enzymes may indicate an increased potential for invasive growth. We determined the expression patterns of matrix-metalloproteinases (MMP)-1, -2, and -3 and of the tissue inhibitors of metalloproteinases (TIMP)-1 and -2 by in situ hybridization with isotopically labeled RNA probes in normal breast tissue (n=6), fibrocystic disease (n=20), five cases of which contained radial scars, lobular carcinoma in situ (CLIS; n=5), ductal carcinoma in situ (DCIS; n=9) and invasive carcinomas (n=24). Only a few cells displayed MMP-1- and MMP-2-specific labeling in normal breast tissue and fibrocystic disease. Noninvasive ductal carcinomas showed elevated MMP-2 transcript levels in peritumor stromal cells in the absence of significant MMP-1 specific signals. In general, compared with adjacent normal breast tissue, a gradual increase of MMP-2 was found in noninvasive to invasive cancers. Invasive ductal and lobular carcinomas displayed co-expression of MMP-1 and MMP-2 by stromal cells, mainly of the invasion front, with high signal intensity particularly in high-grade invasive carcinomas. Tumor cells and peritumor stroma showed low MMP-3 transcript levels, especially in medullary carcinomas. TIMP-1 and -2 transcript levels were increased in invasive carcinomas correlating with the histological grade. These RNA expression patterns suggest an increased invasive potential in breast carcinomas even prior to histologically overt invasive growth.

Adenocarcinoma↗

PubMed1999

Relaxin-like factor (RLF): a new specific marker for Leydig cells in the ovary.

Relaxin-like factor (RLF), also known as the Leydig cell insulin-like factor (Ley-I-L), is a novel member of the insulin-IGF-relaxin family of hormones and growth factors that has recently been shown to be strongly expressed in testicular Leydig cells. Expression of the RLF peptide in the human ovary and in ovarian tumors has not been studied. In the present study, the expression of the RLF peptide in the human ovary was investigated by immunohistochemistry using a specific antibody raised against human RLF. By this method, RLF was found to be expressed in hilus (Leydig) cells and theca interna cells but absent in granulosa cells, ovarian stromal cells, and surface epithelium. RLF expression was also observed in the corpus luteum, although at a lower level than in theca cells. Thirty-seven sex cord-stromal tumors and five cases of hilar Leydig cell hyperplasia were also investigated for RLF expression. RLF was found to be strongly expressed in hilar Leydig cell hyperplasia and sex cord-stromal tumors with a component of Leydig or luteinized cells. Of the analyzed theca cell tumors, two displayed a diffuse staining pattern. As expected, RLF was not expressed in granulosa cell tumors. In conclusion, RLF appears to be a useful marker for Leydig cells in the human ovary and may be a diagnostic supplement in hyperplasias and tumors derived therefrom.

Biomarkers, Tumor↗

PubMed1998

p16/MTS1 inactivation in ovarian carcinomas: high frequency of reduced protein expression associated with hyper-methylation or mutation in endometrioid and mucinous tumors.

Inactivation of the tumor-suppressor gene p16 (MTS1/ CDKN2/INK4a) has been described in various human malignancies. Although p16 deletion has been found in various ovarian tumor cell lines, p16 inactivation by homozygous deletion or mutation has been reported only sporadically in primary ovarian carcinomas. In a comprehensive study, we analyzed p16 protein expression by immuno-histochemistry (IHC) on paraffin sections of 94 primary ovarian carcinomas of different histological subtype. Loss of expression was detected in 19 primary tumors (20%), mainly mucinous and endometrioid carcinomas. To reveal the cause of suppressed expression, we performed (i) analysis of homozygous deletions by comparative PCR after micro-dissection, (ii) mutation analysis by single-strand conformation polymorphism analysis and subsequent direct sequencing and (iii) methylation-specific PCR to determine the methylation status of 5'-CpG islands. Loss of or weak p16 expression was caused by hyper-methylation (12/19 IHC-negative cases), somatic mutation (10 tumors) or homozygous deletion (1 case). Aberrant p 16 results by one of these methods were detected in 71-79% of endometrioid and mucinous, but in only 10% of serous-papillary, carcinomas. Our data suggest that p16 inactivation is a typical feature of certain subtypes of ovarian carcinoma.

Adenocarcinoma, Mucinous↗

PubMed1998

[p53 mutations and HPV infections in squamous epithelial carcinomas of the head-neck region. Long-term follow-up].

Mutations of the p53 gene are the most commonly observed genetic alterations in malignant tumors and are often associated with a loss of the tumor suppressor function of the p53 protein. We have analyzed specimens of head and neck squamous cell carcinomas (HNSCC) from 110 patients for p53 gene mutations and 92 of them additionally for human papillomavirus (HPV) infection in order to evaluate the prognostic significance of these factors by comparison with clinical follow-up data. Using the method of polymerase chain reaction (PCR)/temperature gradient gel electrophoresis (TGGE), mutations within the exons 5 to 8 of the p53 gene were found in 48 tumors (44%). Sequencing revealed missense mutations in most cases (15/20). Frequency of p53 gene mutations was not related to the tumor stage, the grade of differentiation, the presence of lymph node metastases, or the smoking history of the patients. With the help of a highly sensitive PCR/hybridization assay, an infection with the high-risk HPV types 16 and 18 could be detected in 39/92 tumor specimens (42%). Follow-up data were obtained from 99 patients with a range of 2-112 months. No correlation of overall survival on the presence of p53 gene mutations or HPV infection could be observed. The absence of statistically significant correlations between p53 gene mutations and progressive disease, however, does not exclude its putative relevance in early phases of tumor development.

Adult↗

PubMed1998

No evidence of significant activity of the multidrug resistance gene product in primary human breast cancer.

BACKGROUND: The discovery of the multidrug resistance (MDR1) gene product P-glycoprotein (P-gp) has been widely seen as an important milestone in our understanding of the mechanisms underlying the clinical phenomenon of the emergence of resistant cells. MDR1 expression has been shown for numerous solid tumors and for virtually all hematologic malignancies. Nevertheless, results regarding MDR1/P-gp expression in human breast cancer have been controversial and the results of clinical trials on modulation of P-gp activity have not been encouraging. PATIENTS AND METHODS: MDR1/P-gp expression and the function of the P-gp pump were investigated in 61 tumor samples from patients with primary breast cancers by multiparameter analysis using MDR1-RT-PCR, immunohistochemistry with two MAbs (UIC2 and MRK16) and the rhodamine 123 (Rh123) efflux assay. The cellular composition of the tumor cell suspension was analyzed by using specific MAbs against the P-gp expressing lymphocyte subsets CD4, CD8 and CD56, as well as against the HER-2/neu gene product, which was used to identify breast carcinoma cells. RESULTS: UIC2 and MRK16 revealed a staining positivity in 72% and 75% of samples, respectively. A positive MDR1-RT-PCR signal was detected in 62% of the samples. Nevertheless, no correlation between immunohistochemistry and RT-PCR could be established. Furthermore, there was no correlation between HER-2/neu expression and MDR1-RT-PCR or P-gp immunohistochemical assays. A contamination by CD8+ and CD4+ lymphocytes was established in 100% and 84% of tumor cell suspensions, respectively. As assessed by the Rh123 efflux assay CD8+ and the CD4+ lymphocytes exhibited marked P-glycoprotein activity, whereas such activity was not detectable in a single instance for the breast carcinoma cells. In MDR1-RT-PCR positive samples, contamination by CD8 lymphocytes averaged 4.3%, while the contamination of CDS cells in the MDR1 mRNA-negative samples was only 2.4% (P = 0.007). This signal vanished after elimination of the lymphocyte subpopulations by T-cell rosetting. CONCLUSIONS: In primary breast cancer detection of MDR1 gene expression by means of RT-PCR or immunohistochemical assays is not indicative for the MDR phenotype, since there is no evidence of significant activity of the P-gp pump.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1998

Human endogenous retrovirus (HERV)-K transcripts in germ cell and trophoblastic tumours.

Prompted by the observation of retroviral particle formation in teratocarcinoma cell lines and the consistent finding of antibodies against Gag and Env proteins encoded by human endogenous retrovirus (HERV)-K genomes in the sera of patients with classical seminoma, we studied ovarian and testicular germ cell tumours, their precursor lesions, dysgenetic gonads, and trophoblast lesions for expression of HERV-K sequences by in situ hybridization using radioactive and non-radioactive probes. HERV-K transcripts were detected in all testicular and ovarian germ cell tumours with the exception of teratomas and spermatocytic seminomas. HERV-K expression was also common to testicular carcinoma in situ as well as gonocytes of dysgenetic gonads. Among gestational trophoblastic lesions, HERV-K expression was regularly found in choriocarcinomas, but not in molar lesions. The patterns of HERV-K expression suggest a common molecular pathogenesis of most germ cell tumour entities and malignant gestational trophoblastic disease. They furthermore support the concept of carcinoma in situ as a precursor lesion common to most testicular germ cell neoplasms. The detection of HERV-K gene products in body fluids and tissues may aid diagnosis and monitoring of germ cell tumours and related lesions.

Female↗

PubMed1998

p53 tumour suppressor gene mutations in benign prostatic hyperplasia and prostate cancer.

OBJECTIVES: To identify and analyse point mutations in p53 tumour suppressor gene (Tp53) in benign prostatic hyperplasia (BPH) by temperature gradient gel electrophoresis (TGGE) and sequence. MATERIALS AND METHODS: 141 tissue specimens (approx. 100 mg) after transurethral resection of the prostate (TURP), 12 specimens after needle biopsy. Control samples for genetic analysis were (a) 7 prostate tissues without any sign of BPH and malignancy and (b) 103 prostate cancer (PCa) tissues. DNA of the critical Tp53 exons 5-8 was amplified and run on horizontal polyacrylamide gels under defined temperature conditions (TGGE) to yield specific gel shifts and sets of homo- and heteroduplexes in case of mutation. Sequencing with a laser-fluorescent electrophoresis unit was done from re-amplified mutant and wild-type bands. RESULTS: TGGE screening of 153 BPH samples identified 29 specimens with Tp53 mutations (5 in exon 5, 11 in exon 6, 12 in exon 7, 3 in exon 8; 1 tissue sample showed mutations in 3 exons at a time). The computed mutation frequency was 19.0%. Two patients, with mutation in BPH tissue, developed PCa 2-3 years after TURP. One patient with mutation in BPH tissue developed bladder cancer. Of 118 patients with non-mutated DNA in BPH, none is known to have a urological cancer. The Tp53 mutation frequency in 103 PCa samples was 26.2%. Significant differences of mutation frequency between BPH and PCa were detected only in lower exon 5 mutation counts in BPH. CONCLUSION: Tp53 mutation in BPH tissue may be a tumour risk factor.

Adenocarcinoma↗

PubMed1998

Expression of the MCP-1 gene and the HPV 16 E6/E7 oncogenes in squamous cell carcinomas of the cervix uteri and metastases.

Monocyte chemoattractant protein 1 (MCP-1) plays an important role in the recruitment of monocytes in solid tumors. Previously, for cervical carcinoma cell lines an inverse correlation between the expression of the MCP-1 gene and the human papillomavirus (HPV) oncogenes E6/E7 was described. In this study paraffin-embedded biopsy specimens from 25 squamous cell carcinomas of the cervix uteri were analyzed for the expression of the MCP-1 gene and the HPV 16 E6/E7 oncogenes by RNA/RNA in situ hybridization. Similar to in vitro analyses, in our material a negative correlation between the transcription of these genes in tumor cells could be demonstrated in 19/25 cases, whereas in 6 cases both MCP-1 gene and HPV oncogene transcription could be detected. Interestingly, the same results regarding MCP-1 gene and HPV oncogene expression were observed in the majority of corresponding metastases. On the other hand, in stromal cells MCP-1-specific transcripts could be detected in all cases. In most of them intra- and/or peritumoral macrophages were observed. Our findings support the hypothesis that HPV oncoproteins are negative regulators of MCP-1 transcription.

Carcinoma, Squamous Cell↗