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R Parwaresch

Publications and source records attributed to R Parwaresch.

At least 91 records · Page 5Linked to original sources
PubMed1998

[Significance of differential nuclear expression of Ki-67 in adult soft tissue sarcomas].

As many other nuclear markers, e.g. steroid receptors, Ki-67 epitopes are differentially expressed in tumour cell nuclei. It is unclear whether this phenomenon represents tumour cell heterogeneity, different stages of the cell-cycle or a biological phenomenon with prognostic impact. We analysed 104 primary adult soft tissue sarcomas (ASTS), formalin-fixed, paraffin-embedded, by APAAP and LSAB immunohistochemistry, epitope retrieval technique and 2 anti-Ki-67 antibodies (MIB-1 and Ki-S-5). Expression was evaluated by 4 indexes/1000 tumour cells: a) A-index: sum of all (weak, moderate and strong stained) Ki-67-nuclei, b) the weighed R-index: sum of all strong stained Ki-67+ nuclei x3, moderate stained nuclei x2 and weak stained nuclei x1, c) ID1-index: sum of all strong stained Ki-67+ nuclei, and d) ID2-index: sum of all strong and moderate stained Ki-67+ nuclei. Prognostic impact was analysed by Kaplan-Meier and logrank statistics with respect to overall survival. Quantitative Ki-67 expression did not vary significantly if determined by MIB-1 or Ki-S-5. The A-index turned out to be the strongest prognostic parameter within the whole group of ASTS as well as within each single sarcoma type investigated. Significant (p < 0.05) correlations between A-index and overall survival existed in LMS, LPS, MFH, SS, while a trend to significance (p = 0.06) was observed in MPNST. Quantitative evaluation of all three differential expression levels is necessary to obtain the most comprehensive prognostic informations of proliferation markers in ASTS.

Adult↗
PubMed1998

The immunohistochemical marker Ki-S2: cell cycle kinetics and tissue distribution of a novel proliferation-specific antigen.

The monoclonal antibody Ki-S2 binds to a recently characterized proliferation-specific protein, p100. To assess its distribution pattern under physiologic and pathologic conditions, we performed immunohistochemical analyses on an exhaustive spectrum of normal tissues, 624 miscellaneous solid cancers, and 95 hematologic malignancies, and compared the results with Ki-67 immunostaining on consecutive sections. In addition, Ki-S2 expression was related to the DNA content by dual parameter flow cytometric analysis in parallel with Ki-67 labeling using a human cancer cell line. Immunoreactivity was enhanced at the G1/S transition and persisted through G2 and M phase. After adequate antigen retrieval, the antibody was found to yield identical results on fresh and formalin-fixed, paraffin-embedded material. The antibody specifically labeled actively proliferating cells, which constitute a subset of the population recognized by Ki-67. In normal human tissues, Ki-S2 immunolabeling hardly ever exceeded 40% of the Ki-67+ cell fraction. Immunoreactive scores of the two antibodies exhibited a linear correlation, but statistically significant differences in the ratio of Ki-S2-positive to Ki-67-positive cells were nevertheless observed between different tissue types. In contrast, the ratio of Ki-S2 and Ki-67 immunoreactive scores varied widely in neoplastic cells and tissues, occasionally attaining a ratio of almost 1:1. This suggests that loss of growth regulatory mechanisms in malignant cells might result in an extreme reduction of the G1 phase fraction and thus in a significantly shorter doubling time. Therefore, antibody Ki-S2 is likely to allow a more precise evaluation of the cell fraction that will complete a division cycle and a more confident appraisal of the malignancy potential of a neoplastic process.

Antibodies, Monoclonal↗
PubMed1997

p100: a novel proliferation-associated nuclear protein specifically restricted to cell cycle phases S, G2, and M.

By immunization with nuclear lysates of L428 cells, we raised a monoclonal mouse antibody, Ki-S2 (IgG1). In Western blots, this antibody recognizes a nuclear antigen with an apparent molecular mass of 100 kD, termed p100. Protein sequencing of p100 showed that this is a hitherto unknown protein. Immunohistochemical examination of cryostat and paraffin sections of nearly all human tissue types and neoplasms showed that p100 was exclusively expressed in the nuclei of a fraction of proliferating cells. Cell sorting and fluorescence-activated cell sorting analysis of stimulated peripheral blood mononuclear cells showed that p100 was exclusively expressed in proliferating cells from the transition G1/S until the end of cytokinesis. During mitosis, this protein is strictly associated with the spindle pole and with the mitotic spindle, whereas during S and G2, p100 is diffusely distributed throughout the cell nucleus. Immediately after completion of cytokinesis, p100 was rapidly degraded. In L428 cells, p100 is phosphorylated at least during mitosis. It has a turnover time of about 1 hour. Studies on routinely processed paraffin sections of specimens of malignant lymphoma, benign and malignant nevocellular tumors, and breast cancer showed that in all cases less than 40% of the Ki-67-positive growth fraction expressed p100. Thus, p100 might prove to be a more reliable measure of cellular proliferation and one that is more closely correlated to cancer prognosis, beyond its general biologic relevance as a cell cycle protein.

Animals↗
PubMed1997

Molecular basis of artifacts in the detection of telomerase activity and a modified primer for a more robust 'TRAP' assay.

Human somatic cells have essentially no telomerase activity. Telomerase is linked to tumor genesis and is a valuable marker for malignant growth. Extreme paucity of the enzyme neccessitated development of a PCR-based assay, 'telomeric repeat amplification protocol' (TRAP). Unfortunately, this method is not without difficulties. Amplification products are not related to the size of the amplified telomerase products. Furthermore, false positive results can occur, and careful control of reaction conditions is crucial. We analyzed in detail the molecular basis of artifacts. Based on these data, reverse PCR primer was changed and both problems in the TRAP assay were eliminated.

Artifacts↗
PubMed1997

Proliferation marker Ki-S5 as a diagnostic tool in melanocytic lesions.

BACKGROUND: A discrimination between benign and malignant melanocytic lesions is not always possible by conventional histology. OBJECTIVE: Our purpose was to determine the proliferative activity in various types of melanocytic neoplasms and to appraise its value as a diagnostic adjunct. METHODS: The growth fraction was assessed immunohistochemically in 398 melanocytic lesions by means of the monoclonal antibody Ki-S5 directed to the Ki-67 antigen. In this way, a cut-off level was defined and applied to 112 lesions of equivocal histology. The revised diagnoses were correlated to the clinical courses. RESULTS: Common nevi, Spitz nevi, and melanomas exhibited significantly different proliferation indices and distinctive distribution patterns of cycling cells. In agreement, malignancy diagnosed on the basis of a growth fraction greater than 5% was confirmed by disease progression in 68% of our cases with uncertain diagnosis. CONCLUSION: Determination of the proliferative activity in melanocytic lesions may usefully complement conventional histology to improve diagnostic accuracy.

Antibodies, Monoclonal↗
PubMed1997

Immunophenotyping of dermal spindle cell tumors: diagnostic value of monocyte marker Ki-M1p and histogenetic considerations.

Various studies have reported the utility of anti-CD34 staining in the differential diagnosis of dermal spindle-cell tumors. To investigate whether monoclonal antibody Ki-M1p might add practical diagnostic information, we examined a total of 120 cutaneous spindle cell neoplasms using a panel of markers. Anti-CD34 antibody QBEnd/10 consistently stained dermatofibrosarcomas, Kaposi's sarcomas, neurofibromas, and, to a lesser extent, hemangiopericytomas. A positive reaction was also found in > 18% of the dermatofibromas. Ki-M1p staining showed an intense immunoreaction in all dermatofibromas, whereas no reactivity was observed in dermatofibrosarcomas. In addition, a subset of cells was labeled in atypical fibroxanthomas and Kaposi's sarcomas. Neurofibromas, spindle-cell hemangioendotheliomas, and hemangiopericytomas were negative. Dermatofibrosarcomas and atypical fibroxanthomas also moderately expressed smooth muscle-specific actin. Immunohistochemically, a discrimination between dermatofibrosarcomas and neurofibromas was possible only by means of an antibody against the nerve growth factor receptor. We conclude that the combination of several antibodies, in particular anti-CD34 and Ki-M1p, may improve the accuracy of diagnostic immunohistochemistry in the field of cutaneous spindle cell tumors. We speculate that dermatofibroma is primarily a macrophage-rich inflammatory lesion in which cytokine secretion induces a secondary proliferation of fibroblasts, whereas dermatofibrosarcoma is likely to issue from primitive dermal cells of uncertain origin.

Antibodies, Monoclonal↗
PubMed1997

Detection of human topoisomerase II alpha in cell lines and tissues: characterization of five novel monoclonal antibodies.

We report five novel monoclonal antibodies (Ki-S1, Ki-S4, Ki-S6, Ki-S7, and Ki-S8) reactive with a proliferation-related nuclear antigen. In immunoprecipitation and Western blot experiments using crude nuclear extracts, they recognized a protein of 170 kD that, after proteolytic digestion of the immunoprecipitate and sequencing of the resulting peptides, was identified as the alpha-isoform of human topoisomerase II. This was confirmed by testing the antibodies on a highly purified enzyme preparation. Crossreactivity with topoisomerase II beta was ruled out by testing the antibodies on crude extracts from yeast cells expressing the beta-isoform exclusively. The antibodies bind the antigen with different affinities and at different epitopes, apparently located within the carboxyl third of the enzyme. All five antibodies are suitable for archival material after adequate antigen retrieval, thereby enabling retrospective studies. This report illustrates the tissue and subcellular distribution of the antigen through the cell cycle by immunohistochemistry and confocal fluorescence microscopy. The antibodies will be useful tools in further analysis of morphological and functional aspects of topoisomerase II and may serve diagnostic purposes, as well as providing prognostic information in tumor pathology.

Antibodies, Monoclonal↗
PubMed1997

Prognostic significance of the proliferative activity in neuroblastoma.

The prognostic significance of the immunohistochemically assessed growth fraction in neuroblastomas was determined in relation to tumor grade and tumor stage. A total of 101 cases of neuroblastoma were examined with the monoclonal antibodies PC10 against proliferating cell nuclear antigen (PCNA) and Ki-S5 against the Ki-67 protein. Patients were followed for a mean time of 4.8 years. Expression of both PC10 and Ki-S5 was found to be significantly linked to tumor grade and tumor stage. Prognostically favorable stage IVs was associated with low PCNA and Ki-S5 levels. For ganglioneuroblastoma, significant differences were found between the diffuse and the composite type. In univariate analysis of stage III and IV tumors, Ki-S5 and PCNA scores were significantly correlated with disease-free survival (P < 0.0015), allowing definition of a subset of cases with favorable outcome. As to Shimada's group with poor prognosis, significant differences in the clinical course were found for low and high Ki-S5 scores (P = 0.036) but not for PCNA. In multivariate analysis, only patient age, Shimada's grade, and Ki-S5 scores achieved prognostic significance. We conclude that proliferation marker Ki-S5 may provide substantial prognostic information and might become a useful adjunct for predicting the clinical courses of neuroblastoma.

Adolescent↗
PubMed1997

Detection of rare RNA sequences by single-enzyme in situ reverse transcription-polymerase chain reaction. High-resolution analyses of interleukin-6 mRNA in paraffin sections of lymph nodes.

To study the distribution pattern of interleukin-6 (IL-6)-producing cells in normal human lymph nodes, we applied the in situ reverse transcription-polymerase chain reaction technique. We describe a new modification of this technique for monitoring small amounts of specific nucleotide sequences in conventional paraffin sections. This technique differs in at least two respects from those described earlier. The two decisive steps are: 1) the reverse transcription of mRNA and the subsequent amplification of cDNA by polymerase chain reaction are performed by a new single enzyme capable of both reaction types in one and the same medium without buffer exchange; and 2) for the specific detection of the amplified cDNA, a modified version of the primed in situ labeling technique was used. The technique, carried out on normal human lymph nodes, traces a low load of IL-6 mRNA in fibroblasts, endothelial cells, and a minor population of T lymphocytes in the pulp region. High levels of expression were encountered in about 20% of perisinusoidal pulp macrophages. In addition, moderate activity was detectable in sinus lining cells. Because no major activity was found in the germinal centers of the lymphoid B follicles and in the T zone, it is suggested that the plasma cell differentiation ensuing from primary and secondary B-cell immunization is mainly effected by the sinus lining cells as well as perifollicular and perisinusoidal pulp macrophages capable of producing high amounts of IL-6.

Humans↗
PubMed1997

Prognostic relevance of a novel proliferation marker, Ki-S11, for soft-tissue sarcoma. A multivariate study.

In 132 soft-tissue sarcomas and 52 benign soft-tissue tumors, cellular proliferation was examined by immunohistochemistry using monoclonal antibodies Ki-S11 (Ki-67 antigen) and Ki-S1 (topoisomerase II alpha) and by flow cytometric analysis of the S-phase fraction (SPF). Malignant tumors were graded histologically according to the Fédération Nationale des Centres de Lutte Contre le Cancer (FNCLCC) system. Patient age, sex, tumor location, histological type, and DNA ploidy were considered as additional prognostic variables. Consistent immunoreactivity was seen in approximately 95% of the cases, and determination of SPF was possible in approximately 60% Ki-S11 and Ki-S1 immunolabeling indices correlated in a linear manner. All proliferation parameters yielded significant differences between benign and malignant tumors. Ki-S11 and Ki-S1 immunoreactive scores also co-varied significantly with SPF, mitotic count, and histopathological grade. In univariate analysis, immunohistochemical proliferation indices, histopathological grade, mitotic count, and SPF were predictive of overall survival and the development of metastases. In multivariate analysis, immunolabeling scores of proliferation markers, grade, and SPF emerged as independent predictors of global survival and systemic progression. We conclude that the immunohistochemical assessment of proliferation, being more readily performable and more easily assessable than the equally relevant S phase fraction, may add appreciable information to the current prognostic models for soft-tissue sarcoma.

Adolescent↗
PubMed1997

Primary lymphoma of the stomach: three-year results of a prospective multicenter study. The German Multicenter Study Group on GI-NHL.

BACKGROUND: In October 1992, an ongoing prospective study on primary gastrointestinal (GI) lymphoma was initiated to evaluate histological features, sites of involvement, and management. PATIENTS AND METHODS: Until May 1996, 352 patients were enrolled, with 279 being evaluable for clinical features (208 patients presented with primary gastric lymphoma). Standardized diagnostic workup included central histologic review and endoscopic and radiologic evaluation of the complete GI tract. Primary surgery or conservative management depended on the physician's decision, followed by radiotherapy with or without chemotherapy. Treatment outcome is evaluable in 122 patients with gastric lymphoma. RESULTS: In 279 evaluable patients, the distribution of NHL was as follows: stomach 74.6%, small bowel 8.6%, ileocoecal region 6.5%, multilocal GI involvement 6.8%. In gastric lymphoma, low-grade NHLs accounted for 39%. Of the remaining high-grade NHLs, 36.1% showed simultaneous low-grade components, thus being also of MALT origin. Of 208 patients with gastric NHL, 71.1% were classified as stage I and II1. CCR rate in stomach lymphoma is significantly higher compared to those of the small bowel, whereas involvement of multiple GI organs has the worst prognosis. So far only 7 patients with gastric NHL in stages I and II presented with progressive disease or relapse. Over all stages there seems to be no difference in therapeutic outcome in surgically or conservatively treated patients. Even after R0-resection in limited stages patients appear to have no better outcome. CONCLUSION: The value of surgery in treatment of primary gastric lymphoma--as favored by most authors--should be reexamined.

Adult↗
PubMed1997

Sinus-lining cells of the lymph nodes recognized as a dendritic cell type by the new monoclonal antibody Ki-M9.

In the immunobiological characterization of lymph node cells, sinus-lining cells (SLCs) have been given little attention mainly due to the difficulties in their recognition. Ki-M9 is a new monoclonal antibody (MAb) selected for its unique capability to visualize SLCs in human lymph nodes. The details were established by light and electron microscopy and immunoprecipitation of the corresponding biosynthetically labeled antigen. Ki-M9 recognizes a 70-kd protein localized on the surface membrane of SLCs. In the lymphoid tissue, a mild reactivity was exclusively encountered on follicular dendritic reticulum cells in the germinal centers of secondary lymphoid follicles. In other organs, some squamous epithelial and myoepithelial cells were recognized by this antibody. Immunomonitoring of SLCs on light and electron microscopic levels revealed their dendritic morphology, lack of phagosomes, and their close association with type IV collagen fibers. Considering the occurrence of typical dendritic SLCs on the front line of antigen flood, we propose that SLCs be investigated for a possible antigen-binding property.

Animals↗
PubMed1997

A case of atypical myelodysplastic syndrome with micromegakaryocytes, normal platelet count, and t(3;12)(q21;p13) with inv(3)(q21q26).

A 49-year-old woman patient with atypical myelodysplastic syndrome (MDS) showing a der(3)t(3;12)(q21;p13), and der(12)t(3;12)(q21;p13)inv(3)(q21q26) as an acquired chromosomal abnormality in the bone marrow is described. The chromosomal breakpoints of the presented complex aberration with combination of the inv(3)(q21q26) and t(3;12)(q21;p13) were defined by fluorescence in situ hybridization (FISH) with yeast artificial chromosomes (YACs). The inv(3) is a relatively frequent chromosomal rearrangement in patients with myeloid malignancies and dysmegakaryopoiesis and t(3;12)(q26;p13) has also been reported as a recurrent abnormality in MDS and in blast crisis of chronic myelogenous leukemia (CML). Whereas the t(3;12), inv(3), and t(3;3) are associated with a very poor prognosis, our patient surprisingly had a mild clinical course.

Chromosome Banding↗
PubMed1996

Precast commercial polyacrylamide gels for separation of DNA amplificates by temperature gradient gel electrophoresis: application to clonality analysis of lymphomas.

The third complementary determining region (CDR-III) of the rearranged immunoglobulin heavy chain (IgH) genes represents a unique marker for a lymphocyte and its clonal descendants and can be amplified by the polymerase chain reaction (PCR) technique. This approach has markedly enhanced the sensitivity for detection of clonal lymphocyte populations in patients with malignant B-lymphoid neoplasias. To monitor minimal residual disease (MRD) in tissue specimens during or after antineoplastic treatment, the problem of detecting the presence of a few clonal (malignant) lymphocytes in coexistence with a majority of polyclonal lymphocytes has to be addressed. Semi-nested PCR amplification of CDR-III rearrangements from specimen infiltrated by tumor cells generates clonal signals in front of a polyclonal background, and therefore high resolution electrophoretic techniques for separation of DNA fragments are required. Temperature gradient gel electrophoresis (TGGE) resolving DNA homo- and heteroduplexes according to their thermal stability has been successfully applied for this purpose using special electrophoretic equipment. We describe an adjustment to this technique by using a commercially available precast 0.5 mm thick polyacrylamide gel and by changing a standard horizontal electrophoretic device into a TGGE device. By this means we screened patients with B-cell lymphoma undergoing high-dosage radiochemotherapy followed by autologous transplantation for continuous presence of clonal (tumor-specific) CDR-III rearrangements. Specimens from blood and bone marrow were collected on diagnosis as well as before and after autologous transplantation. In addition, the autograft (bone marrow or peripheral blood hematopoietic stem cells) was analyzed. Tumor cells were easily detected in the transplants and in specimens collected during follow-up examinations. The clinical value of these findings remains unclear as yet because the number of cases investigated was small and the follow-up time is still too short. However, we conclude that the technique of combining the sensitivity of PCR with the specificity of high resolution TGGE is easy to use, making it possible to handle, in a clinical routine, a great number of samples within a short time in order to monitor MRD in patients with B-cell neoplasias.

Cell Transplantation↗
PubMed1996

Proliferative activity of the endometrium throughout the menstrual cycle in infertile women with and without endometriosis.

OBJECTIVE: To assess whether changes in endometrial proliferation in patients with endometriosis contribute to ectopic endometrial implantation. DESIGN: Endometrial biopsies from patients with endometriosis were stained immunohistochemically and compared with endometrium of a control group (n = 111). The newly developed monoclonal antibody Ki-S3 was used as a marker of cellular proliferation in surface and glandular epithelia and in stromal cells. SETTING: Female Infertility Clinic, Research Centre of Obstetrics, Gynecology, and Perinatology, Moscow, Russia, and Institute of Pathology, Christian-Albrechts-University, Kiel, Germany. PATIENTS: One hundred thirty-nine women with endometriosis and 111 women without endometriosis, all being infertile. INTERVENTION: Collecting endometrial samples during diagnostic and therapeutic laparoscopy. MAIN OUTCOME MEASURE: Number of proliferating cells in endometrial stroma, glandular, and surface epithelia. RESULTS: Endometrial proliferation showed a characteristic cyclic dependency with greatest activity in the follicular phase. Although epithelial proliferation ceased completely during the luteal phase, the number of proliferating cells in the stroma increased again toward the end of the menstrual cycle after its maximum at ovulation. No significant differences could be found between both investigated groups. CONCLUSIONS: Endometriosis is not due to an altered proliferative activity in eutopic endometrium. Proliferating stromal cells at the end of the menstrual cycle may reflect increasing numbers of immunocompetent cells. Endometrium of patients with endometriosis reveals almost the same cyclical changes as endometrium of patients without endometriosis does. Further attention to cells and cell-mediated reactions in the extrauterine milieu is required to elucidate the pathogenesis of endometriosis.

Adult↗
PubMed1996

Diagnosis of Castleman's disease by identification of an immunophenotypically aberrant population of mantle zone B lymphocytes in paraffin-embedded lymph node biopsies.

Castleman's disease (CD) is characterized by lymph node enlargement due to hyperplasia of abnormal lymphoid follicles and paracortical lymphocytic hyaline vascular (HV) stroma or plasmacytosis (PC). The lymphoid follicles in CD show involuted germinal centers and prominent mantle zone lymphocytes. Ninety-seven cases clinically suspected to be CD were analyzed according to conventional histologic criteria established by Castleman and Keller for diagnosis. Twenty-two cases were excluded as nonspecific hyperplasia (12); Hodgkin's and non-Hodgkin's lymphoma (9); and multiple myeloma involving lymph node paracortex (1). The 75 remaining cases, consisting of 51 cases of CD and 24 with altered follicles or paracortex suggestive of CD, were further analyzed immunohistologically for changes in follicular dendritic reticulum cells (FDRC) using the monoclonal antibody Ki-M4p, for germinal center proliferation with Ki-S5, for mantle zone immunophenotype with Ki-B3 and Ki-B5, for paracortical plasmacytoid monocytes with Ki-M1p, and for plasma cell clonality by applying antibodies to kappa and lambda immunoglobulin light chains. Lymph nodes showing nonspecific follicular and paracortical hyperplasia were included as controls. Hyaline vascular CD and plasma cell CD showed enlarged, polyploid FDRC with prominent nucleoli, decreased germinal center proliferation, and mantle zone populations of immunophenotypically aberrant, Ki-B3-negative B lymphocytes. Thirty-seven percent of hyaline vascular CD and plasma cell CD contained plasmacytoid monocytes, and 15% showed interstitial areas of lambda predominant plasma cells. Plasmacytoid monocytes were common in hyaline vascular CD but rare in plasma cell CD. Cases suspected to be CD that demonstrated a mantle zone population of Ki-B3-negative B lymphocytes had clinical finding of POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal paraprotein, and skin changes or sclerotic bone lesions) syndrome and were reclassified as hyaline vascular CD, plasma cell CD, and mantle zone CD with an aberrant mantle zone immunophenotype only (lacking follicular center and paracortical histologic or immunohistologic abnormalities). Immunohistochemistry was valuable for identification of dysplastic FDRC, decreased germinal center proliferation, and plasmacytoid monocytes. In addition, immunohistochemistry was essential for detection of plasma cell clonality, an aberrant mantle zone immunophenotype, and mantle-zone-restricted CD that was devoid of diagnostic alterations of germinal center or paracortex.

Antibodies, Monoclonal↗
PubMed1996

Monoclonal antibodies Ki-S3 and Ki-S5 yield new data on the 'Ki-67' proteins.

The monoclonal antibody (mab) Ki-67 has been used for about 10 years, mainly in tissue sections, to monitor proliferating cells, but so far only very little is known about the proteins it recognizes. The new mabs Ki-S3 and Ki-S5 detect proliferating cells in frozen and paraffin-embedded tissues. They recognize proteins with the same molecular mass as Ki-67 in Western blot and for the first time also in immunoprecipitation experiments. With these mabs we were able to enrich and purify the Ki-67 proteins. Protein sequencing of four peptides of the digested proteins corresponded to the cDNA-deduced amino acid sequence already published for the Ki-67 proteins. Since we were able to immunoprecipitate the Ki-67 proteins, we performed various immunoprecipitation experiments to obtain more information about the nature of these proteins. After radiolabelling L428 cells with [35S]-methionine we were able to immunoprecipitate the Ki-67 proteins after only 5 min of labelling time. In turnover experiments the Ki-67 proteins could not be detected 3 h after the end of labelling. These data indicate a half-life of the Ki-67 proteins of about 90 min. Labelling experiments with [32P]-orthophosphate revealed that the Ki-67 proteins are phosphorylated. After dephosphorylation was blocked with okadaic acid or cell growth was arrested by means of Colcemid, the phosphorylation of the Ki-67 proteins was greatly increased, indicating that the Ki-67 proteins are phosphorylated via serine and threonine, and that the phosphorylation of the Ki-67 proteins increases in cycling cells. Labelling experiments with [3H]-mannose and [3H]-glucose revealed that the protein is weakly N-glycosylated.

Amino Acid Sequence↗