Ectopic synthesis of pregnancy specific ?1-glycoprotein (SP1) and placental specific tissue proteins (PP5, PP10, PP11, PP12) in nontrophoblastic malignant tumours possible markers in oncology

Abstract

By using an enzyme-bridge immunoperoxidase (PAP) technique, localization of so-called pregnancy-specific beta 1-glycoprotein (SP1) and placental-specific tissue proteins (PP5, PP10, PP11, PP12) was investigated in 19 cases of breast cancer, 24 cases of testicular malignant tumours, 12 cases of gastric cancer and some cases of other malignant tumours. These five glycoproteins isolated from human term placentae and characterized by Bohn are localised mainly in the cytoplasm, or nucleus of syncytiotrophoblast and appear to be specific for the trophoblast. But to a certain percentage these proteins could also be detected in the cytoplasma of malignant cells: In breast cancer, SP1 was present in 52.6% of cases, PP5 in 63.2%, PP10 in 68.4%, PP11 in 55.6% and PP12 in 31.6%. In testicular malignant tumours the detection rates of these proteins varied from 20.8 to 75.0% and in gastric cancer from 41.7 to 66.7%. In total 50% of the tumours tested were SP1-positive, 58.3% PP5-positive, 55.6% PP10-positive, 38.0% PP11-positive and 31.9% PP12-positive. In addition, it was found that mononuclear histiocytes showed a strong cytoplasmic staining for PP10 and PP12 and that a few other non-cancerous cells (i.e. striated cells in gastric metaplasia, gastric polyps etc.) stained for PP5, PP10, PP11 and/or PP12. All control sections were negative in malignant cells as well as in other tissue cells. This study confirms the reports that some kinds of malignant tumours produce SP1 and indicates that the ectopic production of proteins normally produced by the trophoblast is a common finding in malignant tumours. It furthermore suggests that such proteins may be useful as markers in monitoring patients with malignant diseases. The possible mechanisms of ectopic production of these inappropriate proteins in malignant tumours are discussed.

Expression of Human Skin-Specific Genes Defined by Transcriptomics and Antibody-Based Profiling

“…A subset of the group enriched genes are less-well characterized, such as the ENDOU gene, which encodes for the poly (U)-specific endoribonuclease protein (placenta protein 11), which has not been previously reported to be expressed in squamous epithelium. This protein has been described as a placentaspecific protein and also shown to be expressed in certain tumors (Inaba et al 1980). As expected, the protein showed a distinct expression pattern in the placenta (3 FPKM) but was also expressed in differentiated layers of squamous epithelium in both skin (21 FPKM) and esophagus (66 FPKM) (Fig.…”

Serum levels of human placental lactogen and pregnancy-specific β1-glycoprotein in breast cancer

“…; Engvall et al, Unpub.). Nevertheless the study of localization of SP1 by immunocytochemistry by Inaba et al (1980) compares favourably with that by [lorne et al (1976): 526°/ and 600%, respectively.…”

“…Their "ectopic" secretion by breast tumours has been claimed. hPL has been found in the sera of breast-cancer patients (Gaspard et al, 1973;Sheth et al, 1977) and in breast-carcinoma tissue (Horne et al, 1976) while SP1 has been detected in sera (Searle et al, 1978;Wiirz, 1979;Grudzinskas et al, 1980;Bremner et al, 1981), breast-tumour tissue (Horne et al, 1976;Wurz, 1979;Inaba et al, 1980;Bremner et al, 1981) and in the culture medium in which a breast-cancer cell line has been grown (Horne et al, 1979). Perhaps the most potentially important study has been that of Horne et al (1976) 24 h, after which the anti-rabbit-yglobulin was added and the tubes were incubated for a fuirther 24 h. The sensitivity limit of the assay was 0-2 pug/l.…”

Pregnancy-specific β 1-glycoprotein (SP1) in serum and tissue from patients with benign and malignant breast tumours

“…In another study no benign tumours out of 12 were found to be SP1 positive (Home et al, 1976). In malignant breast tumours SP1 was present in only 17% of the patients compared with 76, 53 and 37% in other studies (Horne et al, 1976;Inaba et al, 1980;Walker, 1981). The explanation may be differences in the methods, the antisera, or the representativeness of the histological sections since SP1 positive cells are irregularly distributed in the tumour, or in the composition of the tumours.…”

“…However, SP1 does not seem to be specific to pregnancy since it has been detected by radioimmunoassay in sera from 3 to 54% of healthy persons (Searle et al, 1978;Wurz, 1979;Tatarinov, 1980) and in sera from patients with a variety of malignant diseases, for instance 8-55% of breast cancer patients (Searle et al, 1978;Wiirz, 1979;Tatarinov, 1980), depending on the detection limit of the assay. By means of a histological immunoperoxidase technique SP1 has been demonstrated in 37-76% of malignant tumours of the breast (Horne et al, 1976;Inaba et al, 1980;Walker, 1981). Furthermore, the survival time was significantly longer for women with SP1 negative tumours than those with SP1 positive tumours (Horne et al, 1976).…”