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Dive into the research topics where Peter Kenemans is active.

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Featured researches published by Peter Kenemans.


British Journal of Cancer | 1994

Differences in MHC and TAP-1 expression in cervical cancer lymph node metastases as compared with the primary tumours.

F. V. Cromme; P. F. J. Van Bommel; J. M. M. Walboomers; Maarten P.W. Gallee; P. L. Stern; Peter Kenemans; Theo J.M. Helmerhorst; M. J. Stukart; Chris J. L. M. Meijer

In previous studies we have shown down-regulation of class I major histocompatibility complex (MHC) expression in a significant proportion of primary cervical carcinomas, which was found to be strongly correlated with loss of expression of the transporter associated with antigen presentation (TAP). By contrast, class II MHC expression was frequently up-regulated on neoplastic keratinocytes in these malignancies. In order to investigate whether these changes are associated with biological behaviour of the tumours, 20 cervical carcinomas were analyzed for MHC (HLA-A, HLA-B/C, HLA-DR) and TAP-1 expression in the primary tumours and in lymph node metastases by immunohistochemistry. The results showed a significant increase in the prevalence of HLA-A and HLA-B/C down-regulation in metastasised neoplastic cells as compared with the primary tumour (P = 0.01). In all cases this was accompanied by loss of TAP-1 expression. Up-regulated HLA-DR expression was found exclusively in primary tumours and was absent in the corresponding metastases (P = 0.002). These data are consistent with the hypothesis that loss of TAP-1 and the consequent down-regulation of class I MHC expression provides a selective advantage for neoplastic cervical cells during metastasis. Furthermore, the lack of class II MHC expression in metastasised cells either reflects a different local lymphokine production or indicates that these cells may have escaped CD4+ cytotoxic T-lymphocyte (CTL)-mediated killing.


Gynecologic Oncology | 2003

Laparoscopic detection of sentinel lymph nodes followed by lymph node dissection in patients with early stage cervical cancer.

Marrije R. Buist; Rik Pijpers; Arthur van Lingen; Paul J. van Diest; Jan Dijkstra; Peter Kenemans; René H.M. Verheijen

OBJECTIVE The purpose of this study was to investigate the feasibility of sentinel node detection through laparoscopy in patients with early cervical cancer. Furthermore, the results of laparoscopic pelvic lymph node dissection were studied, validated by subsequent laparotomy. METHODS Twenty-five patients with early stage cervical cancer who planned to undergo a radical hysterectomy and pelvic lymph node dissection received an intracervical injection of technetium-99m colloidal albumin as well as blue dye. With a laparoscopic gamma probe and with visual detection of blue nodes, the sentinel nodes were identified and separately removed via laparoscopy. If frozen sections of the sentinel nodes were negative, a laparoscopic pelvic lymph node dissection, followed by radical hysterectomy via laparotomy, was performed. If the sentinel nodes showed malignant cells on frozen section, only a laparoscopic lymph node dissection was performed. RESULTS One or more sentinel nodes could be detected via laparoscopy in 25/25 patients (100%). A sentinel node was found bilaterally in 22/25 patients (88%). Histological positive nodes were detected in 10/25 patients (40%). One patient (11%) had two false negative sentinel nodes in the obturator fossa, whereas a positive lymph node was found in the parametrium removed together with the primary tumor. In seven patients (28%), the planned laparotomy and radical hysterectomy were abandoned because of a positive sentinel node. Bulky lymph nodes were removed through laparotomy in one patient, and in six patients only laparoscopic lymph node dissection and transposition of the ovaries were performed. These patients were treated with chemoradiation. In two patients, a micrometastasis in the sentinel node was demonstrated after surgery. Ninety-two percent of all lymph nodes was retrieved via laparoscopy, confirmed by laparotomy. Detection and removal of the sentinel nodes took 55 +/- 17 min. Together with the complete pelvic lymph node dissection, the procedure lasted 200 +/- 53 min. CONCLUSION Laparoscopic removal of sentinel nodes in cervical cancer is a feasible technique. If radical hysterectomy is aborted in the case of positive lymph nodes, sentinel node detection via laparoscopy, followed by laparoscopic lymph node dissection, prevents potentially harmful and unnecessary surgery.


Gynecologic Oncology | 1988

An initial analysis of preoperative serum CA 125 levels in patients with early stage ovarian carcinoma

Vincent R. Zurawski; Robert C. Knapp; Nina Einhorn; Peter Kenemans; Rodrigue Mortel; Kazuo Ohmi; Robert C. Bast; Roy E. Ritts; George D. Malkasian

Preoperative serum CA 125 levels were determined for 36 patients with Stage I and II ovarian carcinoma. Levels ranged from 9 to 1962 U/ml with a mean of 216 U/ml. In Stage I patients, CA 125 levels averaged 133 U/ml and in Stage II patients 382 U/ml. Nine of 24 Stage I (38%) and 9 of 12 Stage II patients (75%) had CA 125 levels in excess of 65 U/ml in a population somewhat overrepresented in mucinous tumors. Patients with non-mucinous neoplasms had CA 125 elevations more often--in 75% of the cases--than those with mucinous tumors. A larger study will be required to more precisely estimate the fraction of early stage patients with elevated preoperative serum CA 125 levels; however, this investigation demonstrates an assay sensitivity minimally adequate to initiate a pilot evaluation of serum CA 125 levels in a population at risk for ovarian carcinoma.


American Journal of Obstetrics and Gynecology | 1996

Serum tumor marker immunoassays in gynecologic oncology: Establishment of reference values

G.G. Bon; Peter Kenemans; Rob A. Verstraeten; Gerard J. van Kamp; Jo Hilgers

OBJECTIVE Our purpose was to establish reference values for six monoclonal antibody-based serum immunoassays applied in patients with carcinoma of the female genital tract. STUDY DESIGN Sera from 938 healthy women (median age 48.0 years, range 37 to 76 years) were assayed for levels of CA 125, CA 15.3 (two methods), CA M29, CA M26, and mucin-like cancer antigen (MCA). RESULTS Reference values, defined as those including 95% of healthy controls, were in women with unknown menopausal status as follows: CA 125, 37 U/ml; CA 15.3 (Centocor), 33 U/ml; CA 15.3 (Boehringer Mannheim), 28 U/ml; CA M26, 83 U/ml; CA M29, 13 U/ml; and MCA, 19 U/ml. Postmenopausal values were significantly lower for CA 125 and CA M26 and significantly higher for CA M29 and CA 15.3 (both methods). MCA serum levels were age independent. CONCLUSION Reference values found were not in accord with those generally applied in gynecologic oncology. In addition, serum levels were influenced significantly by menopausal status (except with MCA).


The American Journal of Surgical Pathology | 2001

Prospective multicenter evaluation of the morphometric D-score for prediction of the outcome of endometrial hyperplasias

Jan P. A. Baak; Anne Ørbo; Paul J. van Diest; Mehdi Jiwa; Peter C. de Bruin; Marc Broeckaert; Wim Snijders; P. Jan Boodt; Guus Fons; Curt W. Burger; R.H.M. Verheijen; Paul W. H. Houben; Peter Kenemans

Prospective multicenter evaluation of the WHO classification and the morphometric D-score to predict endometrial hyperplasia cancer progression. In 132 endometrial hyperplasias WHO classification was performed by two experienced gynecologic pathologists. The D-score was assessed blindly by technicians in a routine diagnostic setting. Development of endometrial carcinoma during a 1–10-year follow-up was used as the end point. Eleven of 132 patients (8%), 10 of 61 (16%) atypical hyperplasias, and 1 of 71 (1%) nonatypical hyperplasias developed cancer. Twenty-six curettings had a D-score ≤0 (“unfavorable” or endometrial intraepithelial neoplasia) of which 10 (38%) developed cancer. None of the 86 cases with a D-score >1 (“favorable”) and one of the 20 (5%) cases with 0 < D-score ≤1 (“uncertain”) developed cancer. Sensitivity of the D-score was 100%, specificity 82%, the positive and negative predictive values were 38% and 100%, respectively. These values are similar to those in three prior retrospective D-score studies but higher than the WHO values (which are 91%, 58%, 16%, and 99%, respectively). The D-score in endometrial hyperplasias is a more sensitive and specific marker for cancer prediction than the WHO classification, can be assessed in a routine clinical setting on standard hematoxylin and eosin sections (15–30 minutes per case), and is highly reproducible and cost-effective (U.S.


Tumor Biology | 1998

An Enzyme-Linked Immunosorbent Assay for the Measurement of Circulating Antibodies to Polymorphic Epithelial Mucin (MUC1)

Silvia von Mensdorff-Pouilly; Maia M. Gourevitch; Peter Kenemans; Albert A. Verstraeten; Gerard J. van Kamp; Astrid Kok; Kees van Uffelen; Frank G.M. Snijdewint; Marinus A. Paul; Sybren Meijer; J. Hilgers

50 per case).


Menopause | 2005

Effect of a combination of isoflavones and Actaea racemosa Linnaeus on climacteric symptoms in healthy symptomatic perimenopausal women: a 12-week randomized, placebo-controlled, double-blind study.

Marieke O. Verhoeven; Marius J. van der Mooren; Peter H.M. van de Weijer; Peter J. E. Verdegem; Leontine M. J. Van Der Burgt; Peter Kenemans

Introduction: About one-third of breast and ovarian carcinoma patients have circulating antibodies reactive with polymorphic epithelial mucin (MUC1), either free or bound to immune complexes. While the presence of these immune complexes has prognostic significance in breast cancer patients, the significance of free MUC1 antibodies is less clear. The objective of this study was to develop a reliable assay for the accurate determination of circulating free antibodies to MUC1. Material and Methods: We developed an enzyme-linked immunosorbent assay (ELISA) (PEM.CIg) employing a 60 mer peptide (a triple tandem repeat sequence of the MUC1 peptide core) conjugated to bovine serum albumin and peroxidase-labeled antihuman immunoglobulin G or M antibodies. The assay was standardized and its analytical performance evaluated. A total of 492 serum samples were obtained from 40 healthy men, from 201 healthy women (including 55 women without a history of pregnancy and 45 pregnant women), and (before primary treatment) from 62 benign breast tumor patients and 190 breast cancer patients. MUC1 serum levels were determined with commercial CA 15-3 tests. Results: Circulating antibodies to MUC1 are present both in healthy subjects and in breast cancer patients. The within- and between-assay coefficients of variation were, respectively, 2 and 12% for the IgG determinations and 1.2 and 3% for the IgM determinations. Correlation coefficients for serially diluted serum samples ranged from 0.9998 to 0.9920 for IgG and from 0.9996 to 0.9818 for IgM determinations. The reactivity of serum samples was partially blocked by the addition of various MUC1 peptides and by MUC1 mucin. The inhibiting effect of modified 60 mer peptides suggests the presence of antibodies directed to more than one epitope. Conclusions: The PEM. CIg assay is a reliable ELISA for measuring free MUC1 antibodies in serum. We are in the process of relating the results obtained in the breast cancer group to disease outcome to evaluate its prognostic significance. In addition, the assay may become a useful tool for vaccine therapy monitoring.


Acta Oncologica | 1995

Experience with hormonal therapy in advanced epithelial ovarian cancer

Nine van der Vange; Stefano Greggi; Curt W. Burger; Peter Kenemans; Jan B. Vermorken

Objective:To investigate the effects of a novel dietary supplement containing soy isoflavones and Actaea racemosa Linnaeus (formerly called Cimicifuga racemosa L.) on climacteric symptoms in healthy perimenopausal women. Design:In a multicenter, randomized, placebo-controlled, double-blind study, 124 women experiencing at least five vasomotor symptoms every 24 hours were randomized to receive daily either a phytoestrogen-containing supplement (n = 60) or placebo (n = 64) for 12 weeks. The modified Kupperman Index and Greene Climacteric Scale, a visual analogue scale designed to measure quality of life and the daily number and severity of hot flushes, was used in the screening period and in weeks 6 and 12. Changes in these scores from baseline were calculated. Results:At weeks 6 and 12, all scores in both groups had improved compared with baseline, though the overall difference in scores between the groups was not statistically significant. Conclusion:The supplement containing soy isoflavones and A racemosa L. had no statistically significant effect on climacteric symptoms in perimenopausal women experiencing at least five vasomotor symptoms per day.


Laboratory Investigation | 2001

Comparative genomic hybridization of microdissected familial ovarian carcinoma: Two deleted regions on chromosome 15q not previously identified in sporadic ovarian carcinoma

Ronald P. Zweemer; Andrew M. Ryan; Antoine M. Snijders; Mario Hermsen; Gerrit A. Meijer; Uziel Beller; Fred H. Menko; Ian Jacobs; Jan P. A. Baak; René H.M. Verheijen; Peter Kenemans; Paul J. van Diest

The experience from using different hormonal trials in 33 ovarian cancer patients, who were beyond the stage of standard therapies and experimental cytotoxic therapies in a single institution, are reported. Agents used were progestins, an antiestrogen (tamoxifen), an antiandrogen (flutamide) and a GnRH-agonist (decapeptyl). Twenty-one patients completed at least 8 weeks of treatment. Two patients obtained an objective response (10%): one partial response on tamoxifen for 6 months and one complete response on decapeptyl for 38 + months. Two further patients achieved disease stabilizations on tamoxifen and flutamide for 6 and 8 months respectively. Although the objective response rate with hormonal therapies is limited in these circumstances the absence of important toxicities favor their use. It is suggested to further study this in patients who do not reach a complete response after standard induction chemotherapy, particularly in those with well-differentiated tumors.


Menopause | 2003

Oral, more than transdermal, estrogen therapy improves lipids and lipoprotein(a) in postmenopausal women: a randomized, placebo-controlled study.

Majoie Hemelaar; Marius J. van der Mooren; Velja Mijatovic; Anneke A. Bouman; Charles P. T. Schijf; Maurice V.A.M. Kroeks; Henk R. Franke; Peter Kenemans

The vast majority of familial ovarian cancers harbor a germline mutation in either the breast cancer gene BRCA1 or BRCA2 tumor suppressor genes. However, mutations of these genes in sporadic ovarian cancer are rare. This suggests that in contrast to hereditary disease, BRCA1 and BRCA2 are not commonly involved in sporadic ovarian cancer and may indicate that there are two distinct pathways for the development of ovarian cancer. To characterize further differences between hereditary and sporadic cancers, the comparative genomic hybridization technique was employed to analyze changes in copy number of genetic material in a panel of 36 microdissected hereditary ovarian cancers. Gains at 8q23-qter (18 of 36, 5 cases with high-level amplifications), 3q26.3-qter (18 of 36, 2 cases with high-level amplifications), 11q22 (11 of 36) and 2q31–32 (8 of 36) were most frequent. Losses most frequently occurred (in decreasing order of frequency) on 8p21-pter (23 of 36), 16q22-pter (19 of 36), 22q13 (19 of 36), 9q31–33 (16 of 36), 12q24 (16 of 36), 15q11–15 (16 of 36), 17p12–13 (14 of 36), Xp21–22 (14 of 36), 20q13 (13 of 36), 15q24–25 (12 of 36), and 18q21 (12 of 36). Comparison with the literature revealed that the majority of these genetic alterations are also common in sporadic ovarian cancer. Deletions of 15q11–15, 15q24–25, 8p21-ter, 22q13, 12q24 and gains at 11q22, 13q22, and 17q23–25, however, appear to be specific to hereditary ovarian cancer. Aberrations at 15q11–15 and 15q24–25 have not yet been described in familial ovarian cancer. In these regions, important tumor suppressor genes, including the hRAD51 gene, are located. These and other yet unknown suppressor genes may be involved in a specific carcinogenic pathway for familial ovarian cancer and may explain the distinct clinical presentation and behavior of familial ovarian cancer.

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Curt W. Burger

Erasmus University Rotterdam

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René H.M. Verheijen

VU University Medical Center

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Rob A. Verstraeten

Netherlands Cancer Institute

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Theo J.M. Helmerhorst

Erasmus University Medical Center

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Jan P. A. Baak

Stavanger University Hospital

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