Cancer Antigen 125
TumormarkerZuletzt geprüft: 7. April 2026. Quellenansatz: Standardkontext zur Laborinterpretation, allgemeine medizinische Referenzmaterialien sowie öffentliche Gesundheits- oder klinische Leitlinien, sofern relevant.
Was ist Cancer Antigen 125?
Cancer Antigen 125 (CA-125) is a glycoprotein encoded by the MUC16 gene that is expressed on the surface of cells derived from coelomic epithelium, including the mesothelial lining of the peritoneum, pleura, and pericardium, as well as the epithelium of the fallopian tubes, endometrium, and endocervix. CA-125 is shed from cell surfaces into the bloodstream and can be measured via immunoassay. It was first identified in 1981 using monoclonal antibody OC125, which recognized an antigen consistently elevated in the serum of patients with epithelial ovarian cancer.
CA-125 is most widely used as a serum biomarker for monitoring treatment response and detecting recurrence in patients with epithelial ovarian cancer, particularly serous carcinomas. It is not recommended as a standalone screening tool for ovarian cancer in the general population because of its limited sensitivity in early-stage disease and its poor specificity—many benign conditions also elevate CA-125. However, in combination with transvaginal ultrasound, it may have a role in screening high-risk populations. Serial measurements are generally more informative than single values.
Warum der Wert wichtig ist
CA-125 is the most established serum biomarker for epithelial ovarian cancer, used primarily to monitor treatment response and detect disease recurrence. A rising CA-125 after treatment can signal relapse months before imaging findings appear. However, CA-125 has important limitations: it is elevated in only about 80% of advanced ovarian cancers and fewer than 50% of early-stage cases. Many benign gynecological and non-gynecological conditions can raise CA-125, so results must always be interpreted in clinical context. In premenopausal women, benign elevations are particularly common.
Normale Referenzbereiche
| Gruppe | Bereich | Einheit |
|---|---|---|
| Adults (general) | 0–35 | U/mL |
| Premenopausal women | 0–35 | U/mL |
| Postmenopausal women | 0–20 | U/mL |
Referenzbereiche können je nach Labor variieren. Vergleichen Sie Ihre Ergebnisse immer mit den Bereichen Ihres Testlabors.
Was hohe CA-125-Werte bedeuten
Häufige Ursachen
- Epithelial ovarian cancer (especially serous carcinoma)
- Endometriosis
- Uterine fibroids
- Pelvic inflammatory disease
- Menstruation and first trimester pregnancy
- Liver cirrhosis and ascites
- Peritoneal, pleural, or pericardial inflammation
- Endometrial, fallopian tube, and primary peritoneal cancers
- Pancreatitis and pancreatic cancer
- Congestive heart failure
Mögliche Symptome
- Abdominal bloating or swelling
- Pelvic or abdominal pain
- Feeling full quickly when eating
- Urinary urgency or frequency
- Unexplained weight loss or gain
- Fatigue
- Back pain
Was zu tun ist: Elevated CA-125 requires clinical correlation. In postmenopausal women with an adnexal mass, elevated CA-125 strongly suggests malignancy and warrants surgical evaluation. In premenopausal women, benign causes should be excluded first. For patients with known ovarian cancer, serial CA-125 measurements are used to assess treatment response—a 50% decline correlates with response, while a doubling from nadir suggests progression. Additional imaging (transvaginal ultrasound, CT) and possibly further biomarkers (HE4, ROMA score) may be ordered.
Was niedrige CA-125-Werte bedeuten
Häufige Ursachen
- Normal physiological state (no clinical concern)
- Successful treatment of ovarian cancer
- Non-mucinous ovarian cancers may not produce CA-125
Mögliche Symptome
- No symptoms are associated with low CA-125
Was zu tun ist: Low or undetectable CA-125 is normal and generally reassuring. In ovarian cancer patients, declining CA-125 toward normal during chemotherapy indicates treatment response. However, a normal CA-125 does not exclude ovarian cancer—some histological subtypes (mucinous, clear cell) may not elevate CA-125 even in advanced disease.
Wann wird ein CA-125-Test empfohlen?
- Monitoring treatment response in epithelial ovarian cancer
- Surveillance for ovarian cancer recurrence after treatment
- Evaluating an adnexal mass in postmenopausal women
- Screening high-risk women (BRCA1/2 mutation carriers) in combination with ultrasound
- Assessing response to neoadjuvant chemotherapy in ovarian cancer
Häufig gestellte Fragen
Verwandte Biomarker
Quellen- und Prüfungsansatz
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