Comparison of plasma amino acid profile-based index and CA125 in the diagnosis of epithelial ovarian cancers and borderline malignant tumors.
BACKGROUND
We previously developed a new plasma amino acid profile-based index (API) to detect ovarian, cervical, and endometrial cancers. Here, we compared API to serum cancer antigen 125 (CA125) for distinguishing epithelial ovarian malignant tumors from benign growths.


METHODS
API and CA125 were measured preoperatively in patients with ovarian tumors, which were later classified into 59 epithelial ovarian cancers, 21 epithelial borderline malignant tumors, and 97 benign tumors including 40 endometriotic cysts. The diagnostic accuracy and cutoff points of API were evaluated using receiver operating characteristic (ROC) curves.


RESULTS
The area under the ROC curves showed the equivalent performance of API and CA125 to discriminate between malignant/borderline malignant and benign tumors (both 0.77), and API was superior to CA125 for discrimination between malignant/borderline malignant lesions and endometriotic cysts (API, 0.75 vs. CA125, 0.59; p < 0.05). At the API cutoff level of 6.0, API and CA125 had equal positive rates of detecting cancers and borderline malignancies (API, 0.71 vs. CA125, 0.74; p = 0.84) or cancers alone (API, 0.73 vs. CA125, 0.85; p = 0.12). However, API had a significantly lower detection rate of benign endometriotic cysts (0.35; 95 % CI, 0.21-0.52) compared with that of CA125 (0.65; 95 % CI, 0.48-0.79) (p < 0.05).


CONCLUSIONS
API is an effective new tumor marker to detect ovarian cancers and borderline malignancies with a low false-positive rate for endometriosis. A large-scale prospective clinical study using the cutoff value of API determined in this study is warranted to validate API for practical clinical use.
Department of Obstetrics and Gynecology, Yokohama City University Hospital, 3-9 Fukuura, Kanazawa-ku, Yokohama City, Kanagawa, 236-0004, Japan. emiyagi@med.yokohama-cu.ac.jp.
Etsuko
E
Miyagi
Department of Obstetrics and Gynecology, Yokohama City University Hospital, 3-9 Fukuura, Kanazawa-ku, Yokohama City, Kanagawa, 236-0004, Japan.
Yasuyo
Y
Maruyama
Department of Obstetrics and Gynecology, Yokohama City University Hospital, 3-9 Fukuura, Kanazawa-ku, Yokohama City, Kanagawa, 236-0004, Japan.
Tae
T
Mogami
Department of Obstetrics and Gynecology, Yokohama City University Hospital, 3-9 Fukuura, Kanazawa-ku, Yokohama City, Kanagawa, 236-0004, Japan.
Reiko
R
Numazaki
Institute for Innovation, Ajinomoto Co. Inc., Suzuki 1-1, Kawasaki City, Kanagawa, 210-8681, Japan.
Atsuko
A
Ikeda
Institute for Innovation, Ajinomoto Co. Inc., Suzuki 1-1, Kawasaki City, Kanagawa, 210-8681, Japan.
Hiroshi
H
Yamamoto
Department of Obstetrics and Gynecology, Yokohama City University Hospital, 3-9 Fukuura, Kanazawa-ku, Yokohama City, Kanagawa, 236-0004, Japan.
Fumiki
F
Hirahara
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000596:Amino Acids / Q000097:blood*; D019540:Area Under Curve; D018394:CA-125 Antigen / Q000097:blood*; D000077216:Carcinoma, Ovarian Epithelial; D004715:Endometriosis / Q000097:blood* / Q000175:diagnosis / Q000473:pathology; D005260:Female; D006801:Humans; D008875:Middle Aged; D009375:Neoplasms, Glandular and Epithelial / Q000097:blood* / Q000175:diagnosis / Q000473:pathology*; D010048:Ovarian Cysts / Q000097:blood* / Q000175:diagnosis / Q000473:pathology; D010051:Ovarian Neoplasms / Q000097:blood* / Q000175:diagnosis / Q000473:pathology*; D011230:Precancerous Conditions; D012372:ROC Curve; D055815:Young Adult
D000596:Amino Acids; D018394:CA-125 Antigen
Endometriotic cyst; Epithelial ovarian borderline malign tumor; Epithelial ovarian cancer; Ovarian benign tumor; Plasma amino acid profile-based index