Reet Koomägi
German Cancer Research Center
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Featured researches published by Reet Koomägi.
International Journal of Cancer | 1998
Reet Koomägi; Manfred Volm
Tissue factor (TF) is the physiological initiator of blood coagulation. It has been suggested that TF also regulates tumor growth and angiogenesis. We therefore used immunohistochemistry to analyze the expression of TF and angiogenesis in non‐small‐cell lung carcinomas of 191 patients. A significant association was found between TF expression and microvessel density (MVD): TF‐negative carcinomas more frequently exhibited low MVD. Additionally, a significant relationship between TF expression and the expression of vascular endothelial growth factor (VEGF) was discovered. TF was also compared with the resistance of the carcinomas to doxorubicin, as measured in vitro: TF‐negative tumors were more frequently resistant to doxorubicin than were TF‐positive tumors. Kaplan‐Meier survival analysis revealed that survival times were longer in patients with TF‐negative tumors than in patients with TF‐positive tumors. These data suggest that TF functions as an additional angiogenic factor that could be used as a new prognostic and predictive factor for non‐small‐cell lung carcinomas. Int. J. Cancer (Pred. Oncol.) 79:19–22, 1998.© 1998 Wiley‐Liss, Inc.
International Journal of Cancer | 1999
Reet Koomägi; Manfred Volm
In order to examine whether or not the expression of the apoptosis‐related receptor Fas (CD‐95/APO‐1) and its ligand (FasL) has relevance for patient survival, immunohistochemistry was used to analyze the proteins of both factors in 164 non‐small cell lung carcinomas. Patients with Fas‐positive tumors exhibited significantly longer survival times than patients with Fas‐negative carcinomas. In contrast, FasL did not significantly influence patient survival time. A multivariate analysis of clinical and biological factors indicated that lymph node status and Fas expression were significant prognostic factors. Carcinoma patients who were negative for both Fas and FasL had a significantly higher incidence of lymph node involvement than did carcinoma patients who were positive for Fas and FasL. Carcinomas that were positive for Fas and FasL demonstrated a greater sensitivity to doxorubicin in vitro. Int. J. Cancer (Pred. Oncol.) 84:239–243, 1999.
European Journal of Cancer | 1997
Manfred Volm; Reet Koomägi; Jürgen Mattern; G. Stammler
Tumour specimens of 206 patients with untreated non-small cell lung carcinomas (NSCLC) were analysed immunohistochemically for the expression of the basic fibroblast growth factor (bFGF) and for its receptor (FGFR-1, Flg). Seventy of the tumours showed weak expression, 109 moderate and 27 high expression of bFGF. Thirty-eight tumours had low expression of FGFR-1, 116 had moderate and 52 cases high expression. Patients with high FGFR-1 expression had significantly shorter survival times than patients with weak or moderate expressions (P < 0.05), but there was no significant correlation between bFGF expression and patient survival. The results of the multivariate analysis demonstrated that FGFR-1 in the presence of stage is not an independent prognostic factor.
International Journal of Cancer | 1997
Manfred Volm; Reet Koomägi; G. Stammler; Werner Rittgen; Felix Zintl; Axel Sauerbrey
Immunohistochemistry was used to analyze samples of 40 newly diagnosed childhood acute lymphoblastic leukemias (ALL) for their expression of cyclins (D1, E, A), cyclin‐dependent kinases (cdk2, cdk4) and tumor‐suppressor genes (pRb, p16INK4A), in order to discover whether or not the expression of these various proteins may be of prognostic relevance for the survival of children with ALL. Patients with ALL who were strongly positive for cyclin D1 had a lower probability of remaining in first continuous remission than ALL patients who were negative or weakly positive for this trait. There was also a significant correlation between expression of cyclin D1 and frequency of recurrence. For cyclin E and cyclin A, in contrast, there was no difference in the duration of relapse‐free‐intervals or the frequency of recurrence in patients. Children with cdk4‐positive ALL had a lower probability of remaining in first continuous remission than children with cdk4‐negative ALL. No prognostic relevance was found for cdk2. Patients with ALL who expressed pRb had a higher probability and patients who expressed p16 a lower probability of remaining in first continuous remission, but the results were not statistically significant. This investigation demonstrated that cyclin D1 and cdk4 were the most important prognostic factors for children with ALL, and that the combination of them showed the strongest prognostic relevance. Int. J. Cancer 74:508–512, 1997.
Cancer Letters | 1996
Reet Koomägi; G. Stammler; C. Manegold; Jürgen Mattern; Manfred Volm
Twenty tumoral and peritumoral tissues from patients with lung cancer were analyzed immunohistochemically for the drug resistance-related proteins P-glycoprotein (P-170), topoisomerase II (Topo-II), glutathione S-transferase-pi (GST-pi), metallothionein (MT), heat shock protein-70 (HSP-70) and the putative regulators of resistance (ErbB1, Fos and Jun). Protein expression of Topo-II, GST-pi, MT, HSP-70, ErbB1, Fos and Jun was elevated in tumor tissue in comparison to normal tissue. The different expression of the proteins between tumoral and normal tissues was statistically significant for Topo-II (P = 0.05), MT (P = 0.03), and HSP-70 (P = 0.01), whereas ErbB1 showed a borderline significance. The expression of the proteins was frequently increased in smokers in comparison to non-smokers. In general, the increase of the proteins of smokers corresponded in tumoral and non-tumoral tissue. Different expression was only found with MT and HSP-70 which were higher in tissues of smokers.
International Journal of Cancer | 1998
Manfred Volm; Reet Koomägi; Werner Rittgen
In the search for new risk factors at the molecular and cellular levels, clinical data [lymph‐node involvement (LN) and stage] were used and 104 squamous‐cell lung carcinomas were analyzed by immuno‐histochemistry for expression of cyclin D1, cyclin A, cdk2, cdk4, RB, and E2F1. The results of the univariate analysis of all 8 factors showed that cyclin A and cdk2 gave the best prognostic information, while no prognostic value could be found associated with cyclin D1, cdk4, RB and E2F1. The subsequent multivariate analysis of all possible combinations of the important factors showed that the pairs LN/cyclin A, LN/cdk2 and cyclin A/cdk2, and the triplet LN/cyclin A/cdk2 yielded the best prognostic information. It was essentially better than the information given by a single factor. Int. J. Cancer (Pred. Oncol.) 79:294–299, 1998.© 1998 Wiley‐Liss, Inc.
Anti-Cancer Drugs | 1997
Manfred Volm; Gerd Stammler; Zintl F; Reet Koomägi; Sauerbrey A
Thirty-eight children with initial and 25 children with relapsed lymphoblastic leukemia (ALL) were analyzed for the expression of LRP (lung resistance protein or p110 major vault protein) using immunocytochemistry. LRP expression was found in 18 of 38 (47%) children with initial ALL and in 17 of 25 (68%) children with relapsed ALL. Children with initial ALL and without LRP expression had significantly longer relapsefree intervals than patients with LRP expression
Lung Cancer | 2002
Jürgen Mattern; Reet Koomägi; Manfred Volm
Non-small cell lung cancer (NSCLC) is a malignant tumor with poor prognosis. Although the prognostic variables determining short-term survival have been well described, relatively little attention has been paid to factors associated with long-term survival. In search of these factors we studied the expression of several molecular markers in NSCLC. Only tumor samples of patients with squamous cell carcinomas and stage III tumors with a postoperative survival of at least 5 years and those of patients who died within 2 years after resection were selected for this study. The expression of several parameters including oncogene and suppressor gene products, proliferative, apoptotic, angiogenic and resistance-related factors were investigated and the differences in these two extreme populations were determined by the Wilcoxon rank sum test. Factors involved in proliferation (ras, fos, erbB-1, jun, cyclin A) were downregulated whereas factors involved in apoptosis (p53, bcl-2, CD95) were upregulated in the long survival group. Direct measurement of parameters of proliferation (cell cycle analysis by flow cytometry, PCNA index) revealed a lower proliferative activity in tumors of the long survivors compared to short survivors. In conclusion, tumors of the long survival group are characterized by a downregulation of factors involved in proliferation and an upregulation of factors involved in apoptosis. These tumors may grow more slowly and this may influence long-term survival of patients with NSCLC.
Clinical & Experimental Metastasis | 2002
Manfred Volm; Reet Koomägi; Jürgen Mattern; Thomas Efferth
The purpose of this investigation was to evaluate firstly whether different protein expression patterns exist in primary squamous cell lung carcinomas of patients with and without lymph node involvement and secondly, whether or not different patterns exist in tumours with positive lymph nodes. For this reason, formalin-fixed, paraffin-embedded specimens from 130 patients with squamous cell lung carcinomas were analyzed by immunohistochemistry. In a first step, proteins were selected which showed a relationship to lymph node involvement. The expression of JUN, ERBB2, MYC, cyclin D, PCNA, bFGF, VEGF and Hsp70 proteins revealed a positive correlation to lymph node involvement. In contrast, caspase-3, Fas ligand, Fas/CD95, and PAI showed an inverse correlation to lymph node involvement. In a second step, these parameters were further analyzed by hierarchical cluster analyses. The resulting clusters were correlated to patients with or without lymph node involvement. The data show that different protein expression patterns exist between primary squamous cell lung carcinomas with and without lymph node involvement and within carcinomas with lymph node involvement. The data suggest that various metastasis profiles exist.
Clinical & Experimental Metastasis | 1996
Manfred Volm; Reet Koomägi; Manfred Kaufmann; Jürgen Mattern; Gerd Stammler
Relationships between the incidence of metastatic spread and microvessel density, expression of proto-oncogene products, or expression of resistance-related proteins were investigated in human ovarian carcinomas by immunohistochemistry. Ovarian carcinomas with a high microvessel density showed a significantly increased formation of metastases (P=0.005). Tumors with positive immunoreactivity of c-jun and c-myc products had a higher metastatic spread; however, these results were not statistically significant. A marginally significant correlation existed between the expression of erbB1 (EGFR) and metastatic spread (P=0.05). No significant relationship was found between the expression of the resistance-related proteins P-glycoprotein or glutathione S-transferase-π and the incidence of metastases. Furthermore, no correlation was detected between expression of the heat shock protein 70 and the occurrence of metastases.