Background. Recently, the authors reported that membrane‐associated phospholipase A2 (M‐PLA2) was one of the acute phase reactants and increased in serum of patients with various malignant tumors. Methods. M‐PLA2 concentrations in tissue specimens from 78 breast cancers, 16 benign breast tumors, and 10 normal breast tissues were determined by a specific radioimmunoassay recently developed. Immunohistochemical staining was performed on all specimens by the avidin‐biotin‐peroxidase method. Results. Tissue levels of M‐PLA2 concentration were significantly higher in breast cancer than in benign breast tumor or normal breast tissue (P < 0.01). Correlation analyses between the tissue concentration of M‐PLA2 and clinicopathologic factors showed that tissue M‐PLA2 levels were significantly higher in patients with skin or muscle invasion, vessel involvement, and distant metastasis than in those without. In addition, this enzyme concentration was significantly greater in scirrhous carcinoma than in papillotubular or solid‐tubular carcinoma. No association was found between M‐PLA2 concentration and steroid hormone receptor status. Immunohistochemically, M‐PLA2 was preferentially stained in the invading zone of breast cancer tissues, especially in scirrhous carcinoma. Patients with breast cancer with low levels of M‐PLA2 showed significantly longer overall survival and disease‐free survival compared with those with high levels of this enzyme at the cutoff point of 50 ng/100 mg protein. The combination of estrogen receptor status with M‐PLA2 concentration could be a powerful prognostic factor in predicting such survival rates. Conclusions. M‐PLA2 is closely related to the malignant potential of breast cancers, and the M‐PLA2 contents in breast cancer tissues could be a new valuable prognostic factor, other than the hormone receptor, in delineating the status of human breast cancer.

Summary Plasminogen activator (PA) is a serine protease which exists in two forms: tissue-type (t-PA) and urokinase-type (u-PA). The activity (<60 unitmg-' vs >,60 unitmg-' protein) was found to be a significant prognostic factor for disease-free and overall survival of about the same import as lymph node involvement. Furthermore, the combination of total PA activity and nodal status could be even more precise in predicting survival times and probabilities in individual patients. This retrospective study demonstrates the total PA activity is a valuable prognostic factor in determining prognosis in human breast cancer.

Summary Plasminogen activator (PA) is a serine protease existing in two forms known as tissue-type (t-PA) and urokinase-type (u-PA). To examine whether PA is related to the postoperative clinical course of human breast cancer, total PA activity, t-PA activity, u-PA activity, and immunoreactive t-PA were determined in tissue extracts from 144 breast cancer specimens. The patients were initially divided into four groups according to the postoperative clinical course: Group I (83 patients who are disease-free), Group II (20 patients whose first metastases were found only in bone), Group III (19 patients whose first metastases were found in both bone and lung), and Group IV (22 patients whose first metastases were found only in lung). Total PA activity was significantly lower in Groups, II, III and IV than in Group I. Both t-PA activity and t-PA antigen levels were also significantly lower in Groups II, III and IV than in Group I, while no significant difference was found in u-PA activity among these groups, indicating that low activity of total PA in Groups II, III and IV was due to a decrease in t-PA but not in u-PA. In the multivariate analyses, t-PA activity was found to be an independent prognostic factor for relapse-free survival. When four groups of patients were further analysed in terms of nodal status, both t-PA activity and antigen levels were markedly decreased in the node-negative Group II compared with the node-negative Groups III and IV or with the node-positive Groups II, III and IV. Of additional interest, u-PA activity was significantly higher in node-positive patients than in nodenegative patients with any group. The clinico-pathologic analyses of the patients in this series showed that node involvement and lymphatic invasion were more frequently positive in Groups III and IV than in Groups I and II. When 144 breast cancers were categorised in terms of combinations of oestrogen receptor (ER) and progesterone receptor (PgR) status, breast cancers which were positive for both receptors were found to contain the highest t-PA activity and antigen. This study provides provocative evidence suggesting a possible differential significance of t-PA and u-PA expression in human breast cancer.Many transformed or malignant tumour cells are known to produce plasminogen activator (PA), a serine-type protease converting plasminogen to plasmin (Unkeless et al., 1975;Howett et al., 1978;Orenstein et al., 1983). It is widely accepted that PA is intimately involved in the metastatic spread of tumour cells (Dano et al., 1985;Colombi et al., 1986;Mignatti et al., 1986;Reich et al., 1988;Ossowski et al., 1988;Markus et al., 1988;Yu et al., 1990;Testa et al., 1990;Hollas et al., 1991). There are two main forms of PA: urokinase type (u-PA) and tissue-type (t-PA). While both catalyse cleavage of the peptide bond between Arg-Val in plasminogen, thus converting the proenzyme to plasmin, they differ in many aspects such as their molecular weight, immunological reactivity and amino acid sequence (Ny et al., 1984;Riccio et al.,...

We examined the production of interleukin-8 and interleukin-6 by 30 human carcinoma cell lines. Serum levels of interleukin-8 were measured in 14 patients with hepatocellular carcinoma by enzyme-linked immunosorbent assay and Northern blotting. Furthermore, serum interleukin-8 was also investigated in a nude mouse bearing a tumor of the HuH7 hepatoma cell line producing interleukin-8. Of the 30 cell lines, 29 (96.7%) constitutively produced interleukin-8, and 19 of the 29 (65.5%) were high producers (> 1 ng/ml culture supernatant). Among the high producers, 4 cell lines released both interleukin-8 and interleukin-6. Interleukin-6 was constitutively produced by 17 of the 30 (56.7%) cell lines, 4 of which (23.5%) were high producers (> 1 ng/ml). By Northern blot analysis, mRNAs of interleukin-8 and interleukin-6 were detected in producing cell lines. Of 14 patients with hepatocellular carcinoma 4 (28.5%) showed increased levels of serum interleukin-8. Furthermore, inoculation of the HuH7 hepatoma cell line which produced the highest amount of interleukin-8 into a nude mouse resulted in tumor production accompanied by an elevated level of human interleukin-8 (646 pg/ml) in the peripheral blood. Thus, interleukin-8 is constitutively and commonly produced by various carcinoma cell lines. The production of interleukin-8 by carcinoma cells may be related to the elevation of serum interleukin-8 in patients with hepatocellular carcinoma. Finally, these cell lines may be valuable for studying the relationship between interleukin-8 and cancer.

Oophorectomy was found to decrease the plasminogen activator activity of rat mammary tumors induced by 7,12-dimethylbenz(a)anthracene (DMBA) to less than 7 per cent, while in vivo estradiol treatment restored its activity in a dose dependent fashion. The peroxidase activity was not changed either by oophorectomy or by the administration of estrogen. In the rat uterus, plasminogen activator activity was not changed by oophorectomy or by the administration of estrogen, however, its peroxidase activity decreased to less than 2 per cent following oophorectomy, while estrogen administration restored its activity. Estrogen regulated plasminogen activator activity in the DMBA-induced rat mammary tumors but not in the uterus and thus, the specific hormonal regulation of this enzyme may be an important factor for the hormonal dependent growth of such tumors.