Forum für Wissenschaft, Industrie und Wirtschaft

Hauptsponsoren:     3M 
Datenbankrecherche:

 

Cervical Tissue Changes May Explain False Negative Pap Smears

25.06.2002


Study findings suggest the routine tests for cervical cancer sometimes cannot pick up abnormal cells because cells are tightly adhered to cervix

... mehr zu:
»PapSure

­Some women may be getting false negative results on their routine Pap tests early picked up during the exam, according to a study released today.

Writing in the June issue of the American Journal of Obstetrics & Gynecology, physicians at the Keck School of Medicine of USC and colleagues in California and Taiwan are the first to suggest this explanation for the frequent occurrence of false negative Pap smears.


Nationwide, physicians perform about 55 million Pap tests every year to look for cervical cells that are becoming abnormal, a precursor to cancer. To perform such a smear, a physician inserts a swab through a patient¹s vagina and scrapes the cervix to collect a sample of cells shed from its surface. Pathologists analyze the cells under a microscope to see if they are healthy.

Unfortunately, as many as four in 10 test results come back negative even when a biopsy shows abnormal lesions, and researchers have not been able to conclusively explain the inconsistencies.

A substance called E-cadherin may lie at the heart of the problem, says the study¹s lead author, Juan C. Felix, M.D., professor of clinical pathology and obstetrics and gynecology at the Keck School of Medicine of USC.

E-cadherin is a molecule that helps cells in the cervical tissue stick together, Felix explains. Normally, E-cadherin can be found in cervical tissue, except on the cervix¹s surface (the superficial epithelial layers). With no E-cadherin there, older cells can detach and slough away from the surface of the cervix, much like dead cells are regularly exfoliated from the surface of the skin.

However, the researchers found that in some cervical lesions, E-cadherin also was abnormally present in cells on the cervix¹s surface, keeping the abnormal epithelial cells anchored to the cells beneath them. Researchers theorize that this bond keeps these telltale aberrant cells from being collected during testing.

"I am convinced that the findings of this study are extremely important in understanding the biology of the false negative Pap smear," Felix says. "Never before have we seen such clear evidence that barriers to exfoliation are linked to false negative Pap smears."

The team conducted the study with tissue samples from 25 women known to have cervical dysplasia (aberrant cells preceding cancer). Researchers analyzed whether the tissue samples showed normal distribution of E-cadherin, and then compared each tissue sample to its corresponding Pap smear result.

Of the 25 women, 12 had had a normal Pap smear. All 12 of these women, however, had a positive result through speculoscopy with PapSure. PapSure is a testing system that includes a special light used during the pelvic examination, allowing physicians to actually see suspicious lesions on the cervix.

The remaining 13 women had abnormal Pap smears. Researchers were able to analyze E-cadherin distribution in 10 of these samples. Eight of 10 of these samples showed normal distribution of E-cadherin.

In contrast, of the 12 women with false negative Pap smears, 10 of 11 samples that could be examined showed the abnormal presence of E-cadherin in the superficial layers of the cervix.

"Of the patients with known cervical abnormalities who had normal Pap smears, 91 percent had an abnormal distribution of the E-cadherin adhesion molecule," Felix says. Felix cautions, however, that larger studies with randomly selected patients are needed to verify the findings. Other adhesion molecules also may be involved in the process.

Possible alternative reasons for false-negative Pap smears include poor cell sample collection, mistakes in transferring cells to slides and human error in evaluating the collected cells.

The American Cancer Society estimates that 13,000 women in the United States will be diagnosed with cervical cancer this year and 4,100 women will die of the disease.

The study was supported in part by Torrance-based Trylon Corp., which developed the PapSure system. Watson Pharmaceuticals Inc., of Corona, Calif., now owns rights to PapSure.


Juan C. Felix, Neal M. Lonky, Kimi Tamura, Ken-Jen Yu, Yathi Naidu, Chung-Rui Lai and Stewart A. Lonky. "Aberrant expression of E-cadherin in cervical intraepithelial neoplasia correlates with a false negative Papanicolaou smear." American Journal of Obstetrics & Gynecology, Vol. 186, No. 6, June 2002.

Jon Weiner | USC Health Sciences
Weitere Informationen:
http://uscnews3.usc.edu/experts/index.html

Weitere Berichte zu: PapSure

Weitere Nachrichten aus der Kategorie Medizin Gesundheit:

nachricht Dimethylfumarat – eine neue Behandlungsoption für Lymphome
28.03.2017 | Wilhelm Sander-Stiftung

nachricht Die bestmögliche Behandlung bei Hirntumor-Erkrankungen
28.03.2017 | Ernst-Moritz-Arndt-Universität Greifswald

Alle Nachrichten aus der Kategorie: Medizin Gesundheit >>>

Die aktuellsten Pressemeldungen zum Suchbegriff Innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Entwicklung miniaturisierter Lichtmikroskope - „ChipScope“ will ins Innere lebender Zellen blicken

Das Institut für Halbleitertechnik und das Institut für Physikalische und Theoretische Chemie, beide Mitglieder des Laboratory for Emerging Nanometrology (LENA), der Technischen Universität Braunschweig, sind Partner des kürzlich gestarteten EU-Forschungsprojektes ChipScope. Ziel ist es, ein neues, extrem kleines Lichtmikroskop zu entwickeln. Damit soll das Innere lebender Zellen in Echtzeit beobachtet werden können. Sieben Institute in fünf europäischen Ländern beteiligen sich über die nächsten vier Jahre an diesem technologisch anspruchsvollen Projekt.

Die zukünftigen Einsatzmöglichkeiten des neu zu entwickelnden und nur wenige Millimeter großen Mikroskops sind äußerst vielfältig. Die Projektpartner haben...

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Das anwachsende Ende der Ordnung

Physiker aus Konstanz weisen sogenannte Mermin-Wagner-Fluktuationen experimentell nach

Ein Kristall besteht aus perfekt angeordneten Teilchen, aus einer lückenlos symmetrischen Atomstruktur – dies besagt die klassische Definition aus der Physik....

Im Focus: Wegweisende Erkenntnisse für die Biomedizin: NAD⁺ hilft bei Reparatur geschädigter Erbinformationen

Eine internationale Forschergruppe mit dem Bayreuther Biochemiker Prof. Dr. Clemens Steegborn präsentiert in 'Science' neue, für die Biomedizin wegweisende Forschungsergebnisse zur Rolle des Moleküls NAD⁺ bei der Korrektur von Schäden am Erbgut.

Die Zellen von Menschen und Tieren können Schäden an der DNA, dem Träger der Erbinformation, bis zu einem gewissen Umfang selbst reparieren. Diese Fähigkeit...

Im Focus: Designer-Proteine falten DNA

Florian Praetorius und Prof. Hendrik Dietz von der Technischen Universität München (TUM) haben eine neue Methode entwickelt, mit deren Hilfe sie definierte Hybrid-Strukturen aus DNA und Proteinen aufbauen können. Die Methode eröffnet Möglichkeiten für die zellbiologische Grundlagenforschung und für die Anwendung in Medizin und Biotechnologie.

Desoxyribonukleinsäure – besser bekannt unter der englischen Abkürzung DNA – ist die Trägerin unserer Erbinformation. Für Prof. Hendrik Dietz und Florian...

Alle Focus-News des Innovations-reports >>>

Anzeige

Anzeige

IHR
JOB & KARRIERE
SERVICE
im innovations-report
in Kooperation mit academics
Veranstaltungen

Industriearbeitskreis »Prozesskontrolle in der Lasermaterialbearbeitung ICPC« lädt nach Aachen ein

28.03.2017 | Veranstaltungen

Neue Methoden für zuverlässige Mikroelektronik: Internationale Experten treffen sich in Halle

28.03.2017 | Veranstaltungen

Wie Menschen wachsen

27.03.2017 | Veranstaltungen

 
VideoLinks
B2B-VideoLinks
Weitere VideoLinks >>>
Aktuelle Beiträge

Von Agenten, Algorithmen und unbeliebten Wochentagen

28.03.2017 | Unternehmensmeldung

Hannover Messe: Elektrische Maschinen in neuen Dimensionen

28.03.2017 | HANNOVER MESSE

Dimethylfumarat – eine neue Behandlungsoption für Lymphome

28.03.2017 | Medizin Gesundheit