Cytokeratin fragment 21-1 in gynecologic malignancy: comparison with cancer antigen 125 and squamous cell carcinoma-related antigen.

We measured serum cytokeratin fragment 21-1 (CYFRA 21-1) levels by a solid-phase immunoradiometric assay in 102 healthy Japanese women, and set the reference value at 1.9 ng/ml (mean +2 SD of the serum levels based on a linear distribution). Pretreatment serum CYFRA 21-1 levels were also analyzed in 235 women with benign (n = 94) or malignant (n = 141) gynecologic disease, and were compared with the serum levels of CA 125 and SCC. The respective positivity rates for CYFRA 21-1 and CA 125 were 64.0 and 77.2% in ovarian malignancy, while they were 4.2 and 30.8% in benign ovarian masses. CYFRA 21-1 had an accuracy of 61.3% in diagnosing ovarian malignancy, which was higher than that of CA 125 (53.4%). The positive predictive value of CYFRA 21-1 for ovarian malignancy reached 94.1%, which was significantly (p < 0.005) higher than that of CA 125 (68.8%). These findings indicate the potential usefulness of CYFRA 21-1 as a tumor marker for ovarian malignancy. In addition, the positivity rates fo CYFRA 21-1 in cervical cancer (51.2%) and endometrial cancer (52.2%) were also similar to the respective rates for SCC and CA 125, which suggests that CYFRA 21-1 seems to be a general tumor marker for gynecologic malignancy.