This blog post covers important points about CA125 which are taken from a recently published TOG article in January 2021. CA125 has been used as a tumor marker for ovarian cancer but with some limitations.
I hope this quick post is helpful.
Feel free to leave your feedback in comments and suggestions to improve future posts are welcome.
Thanks
Introduction
- Leading cause of death from any gynae malignancy → Ovarian Cancer
- Over 70% present with late stage disease (Stage III or IV)
- Normal Level CA 125→ <35 IU/ml
- Level can increase in both physiological or pathological conditions
- CA125 expressed in tissues derived from embryonic coelomic epithelia which includes endometrium, mullerian epithelium, peritoneum, pleura & pericardium
- CA125 has role in cell-mediated immunity
- Antigen is not produced directly by tumour & not a tumour marker per se
CA125 & mechanical stress
- Highest levels of CA125 seen in ascites associated with ovarian cancer
- CA125 correlates positively with ascites volume
- Levels are much higher in ascitic fluid than blood levels which shows that antigen originates in ascitic fluid rather than tumour itself
Ovarian Cancer & CA125
Use in Diagnosis
- CA125 increased in epithelial ovarian cancers & less commonly in non-epithelial
- Used with TVS to calculate RMI which guides further management
- If RMI >250 iu/ml → Refer to Cancer Centre
- 50% with stage I & occult cancers have normal levels
Use in follow-up
- After surgical resection→ serum levels fall by half within 10 days