Pyrimidine nucleoside phosphorylase activity in normal tissues of the uterus and ovary and in benign and malignant lesions of these organs.

Abstract

Pyrimidine nucleoside phosphorylase (PyNPase) is identical to the protein, platelet-derived endothelial cell growth factor (PD-ECGF), which has angiogenic activity. The physiological roles of PyNPase activity in the uterus and ovary are not known. In this study, we measured PyNPase activity in normal tissues of the uterus, ovary, and lymph nodes, and in benign and malignant lesions of these organs, and we considered the clinical implications of PyNPase activity in the uterus and ovary. Tissue samples were obtained from 163 patients (whose diseases are listed below) during surgery. PyNPase activity was measured spectrophotometrically, by monitoring the formation of 5-fluorouridine. Mean PyNPase activity in tissues from the lesions of patients with cervical cancer (n = 20), uterine endometrial cancer (n = 26), leiomyoma (n = 23), ovarian cancer (n = 46), ovarian endometriosis (n = 21), and benign epithelial ovarian tumor (n = 27) was significantly greater than that in the corresponding normal tissues. The PyNPase activity in the normal endometrium was significantly higher in the secretory phase than in the proliferative phase. The activity in normal or metastatic lymph nodes was significantly greater than that in normal tissues of the uterus and ovary. Mean PyNPase activity in cancerous cervical tissues was significantly greater than that in cancerous endometrial tissues or cancerous ovarian tissues. There were no significant differences in PyNPase activity in cervical cancer, endometrial cancer, and ovarian cancer tissues according to tumor stage. The enzyme activity appeared to be greater in histopathological G3 grade endometrial cancer than in G1 and G2 endometrial cancer. The enzyme activity in mucinous adenocarcinoma of the ovary was significantly lower than that in serous, endometrioid, and clear cell adenocarcinomas. All patients with cervical squamous cell carcinomas with PyNPase activity greater than 500 nmol/min per mg protein exhibited lymph node metastasis. Increased PyNPase activity consistently reflected neoplastic growth, and varying levels of activity were seen in different histologic cell types. This enzyme activity may be involved in cervical squamous cell carcinomas, in normal and metastatic lymph nodes, and in the normal, secretory phase in the endometrium.