Serum levels of the tumour-associated trypsin inhibitor in patients with endometriosis.

OBJECTIVE: To show that in patients with endometriosis a 6 kD polypeptide, the tumour-associated trypsin inhibitor (TATI), can occur at elevated concentrations in serum. DESIGN: In a prospective study TATI serum levels were assessed prior to surgery in 368 consecutive patients suffering from benign gynaecological diseases (e.g. pelvic pain, infertility, elective sterilisation, uterine fibroids and pelvic masses) with (n = 71) and without (n = 297) endometriosis, who underwent laparoscopy or laparotomy for diagnosis and/or treatment. RESULTS: The TATI serum levels of patients suffering from endometriosis were significantly different from those in the control group and showed a positive correlation with the stage of endometriosis. The sensitivity of TATI was 0.34 with a specificity of 0.85 for all cases of endometriosis, with an increase of sensitivity (0.67) and slight decrease of specificity (0.82), considering only a group of Stage III/IV patients. Excluding patients with benign ovarian cysts, the specificity of TATI was 0.91 and 0.85, respectively. The combination of TATI and CA125 showed an increase of sensitivity to 0.59 for all cases of endometriosis and 0.89 for patients with Stage III/IV endometriosis. CONCLUSIONS: The sensitivity of TATI as a screening method for endometriosis is too low, but considering its high specificity, TATI in combination with CA125 could provide an additional diagnostic tool in diagnosis and follow up of patients with endometriosis.