# CA-125

Source: https://onco.cc/terms/ca-125/  
OnCo record `ca-125` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

A blood protein that rises in most ovarian cancers; useful for tracking treatment, useless for screening on its own.

## Summary

MUC16 glycoprotein elevated in ~80% of advanced high-grade serous ovarian cancers but also in endometriosis, pregnancy, and other cancers. Used to monitor response (GCIG criteria) and relapse; UKCTOCS showed a CA-125 algorithm plus ultrasound detects cancer earlier without reducing deaths. HE4 and the ROMA index refine triage of pelvic masses.

## Fields

- Kind: Term
- Last checked: 2026-09-07

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/CA-125
- Wikipedia: https://en.wikipedia.org/wiki/CA-125

## Connected records

- cancers: [Ovarian cancer](https://onco.cc/cancers/ovarian/)
- trials: [UKCTOCS](https://onco.cc/trials/ukctocs/)
- targets: [MUC16 (CA-125)](https://onco.cc/targets/muc16/)
- collections: [Ovarian Cancer Research Alliance (OCRA)](https://onco.cc/collections/ovarian-cancer-research-alliance/)
- technologies: [Serum tumour markers: proper use and misuse](https://onco.cc/technologies/serum-tumour-markers/)

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