Serum marker potential of placental alkaline phosphatase-like activity in testicular germ cell tumours evaluated by H17E2 monoclonal antibody assay

Summary Placental and placental-like alkaline phosphatase (PLAP) levels in the culture media of 87 cell lines of neoplastic and 'normal' origin were measured by a conventional immunosorbent enzymatic assay (IAEA) and by a new immunoradiometric assay (IRMA). The IRMA detected immunoreactive PLAP in 37 of 80 (46%) human epithelial and germ cell cultures, while the IAEA detected PLAP in only 25 (33%). Of the 52 non-germ cell tumour cultures, the IRMA detected expression in 24 (46%) and the IAEA in only 16 (31%). In 17 cases (21 %) the IRMA recorded levels double that of the IAEA, while in five cultures (6%) the reverse was true. The IRMA was much more robust than the IAEA and had considerably lower inter-and intra-assay coefficients of variation (3.75-8.5% vs 5.2-46%). Detection of PLAP(-like) expression by IAEA is dependent on neoplastic expression of enzymically functional molecules and quantification assumes constant enzyme kinetics. PLAP-like material has a higher catalytic rate constant than PLAP and thus will give higher values on a stoichiometric basis in an IAEA. The higher detection rate and levels of PLAP-like material in neoplastic cultures when measured by the IRMA clearly demonstrate ectopic expression of non-enzymatic PLAP and PLAP-like genes. The incidence of PLAP(-like) expression by non-germ cell and possible germ cell tumours has been underestimated and its utility as a tumour marker should be re-examined using assays which measure antigen mass rather than phosphatase activity.

Section: Discussionmentioning

confidence: 99%

Production of placental alkaline phosphatase (PLAP) and PLAP-like material by epithelial germ cell and non-germ cell tumours in vitro

Iles

Ind²,

Chard³

1994

“…Sera from 5 patients with definite evidence of disease but with negative HMFG1, HMFG2 and CA125 levels were tested in a further assay measuring serum placental alkaline phosphatase (PLAP) (Tucker et al, 1985).…”

Section: Methodsmentioning

confidence: 99%

“…Assay for CA 125 and PLAP Levels of CA125 were determined using a commercially available kit (International CIS (UK) Ltd., London) according to manufacturer's instructions, and serum PLAP was measured according to an established assay method (Tucker et al, 1985).…”

Section: Methodsmentioning

confidence: 99%

A new immunoassay using monoclonal antibodies HMFG1 and HMFG2 together with an existing marker CA125 for the serological detection and management of epithelial ovarian cancer

Dhokia¹,

Canney²,

Pectasides³

et al. 1986

Summary A new method with a low pH step to dissociate serum complexes has been developed to measure serum levels of antigens associated with ovarian cancer. The antigens are detected by monoclonal antibodies HMFG1 and HMFG2 and have been compared to an existing ovarian cancer associated antigen detected by the antibody CA125. Elevated HMFG1 was found in 56%, and elevated HMFG2 in 65% of 924 sera from 85 patients with ovarian cancer. CA125 was elevated in 85% of these sera. When the three markers were used in conjunction, 95% of sera from patients with ovarian cancer were positive -compared with 7% in sera from healthy control subjects. Therefore, the combination of HMFG1, HMFG2 and CA125 increases the diagnostic accuracy. If all three markers are normal in a patient previously treated for ovarian cancer then no further positive information regarding disease status can be obtained by ultrasound and CT scanning.

“…The development of sensitive and specific solid-phase enzyme capture immunoassays (EIA) utilising either the mAb H317 (reactive solely with PLAP) or the mAb H17-E2 (reactive with both PLAP and PLAP-like AP) has broadened investigations of this isoenzyme group in cancer 1984a, b;Epenetos et al, 1985a;Horwich et al, 1985;Tucker et al, 1985). For example, previous serological assays have been limited by detection of elevated isoenzyme levels in healthy individuals, particularly cigarette smokers (Maslow et al, 1983;Tonik et al, 1983).…”

mentioning

confidence: 99%

“…Two major forms of placental-type alkaline phosphatase have been described, the 'placental' and 'placental-like' alkaline phosphatases (PLAP and PLAP-like AP, respectively). These can be distinguished by relative sensitivity to inhibition by L-leucine (Stigbrand et al, 1982) and differential reactivity with certain monoclonal antibodies (mAbs) (McLaughlin & Johnson, 1984).The development of sensitive and specific solid-phase enzyme capture immunoassays (EIA) utilising either the mAb H317 (reactive solely with PLAP) or the mAb H17-E2 (reactive with both PLAP and PLAP-like AP) has broadened investigations of this isoenzyme group in cancer 1984a, b;Epenetos et al, 1985a;Horwich et al, 1985;Tucker et al, 1985). For example, previous serological assays have been limited by detection of elevated isoenzyme levels in healthy individuals, particularly cigarette smokers (Maslow et al, 1983;Tonik et al, 1983).…”

mentioning

confidence: 99%

Placental-type alkaline phosphatase in cervical neoplasia

Pj¹,

Warne²,

Hutchinson³

et al. 1987

Summary Monoclonal antibodies reactive with placental-type alkaline phosphatase have formed the basis of methods for detection of this oncodevelopmental antigen in patients with pre-invasive and invasive cervical neoplasia, with or without evidence of papilloma virus infection. Disease-related elevations of placental-type alkaline phosphatase were not observed in patients' sera. Solubilised cervical smears or biopsy material, and cervical mucus swabs, often contained substantial amounts of this isoenzyme; however, there was no significant difference between any of the patient and control groups. Thus, serological and smear test assays for placental-type alkaline phosphatase were not useful in differential diagnosis of cervical lesions. However, its presence in most biopsy specimens, often at high levels, indicated possible application for in vivo radioimmunoimaging studies of invasive or metastatic cervical cancer.The incidence of cervical cancer has increased markedly in younger women over the last two decades, in part due to venereal transmission of papilloma virus (HPV) infection (Crawford, 1984 (Syrjanen et al., 1985). Screening for pre-invasive cervical carcinoma involves exhaustive examination of smears, and therefore simple rapid techniques for identifying pre-invasive cervical neoplasia are attractive to seek.Potential markers for neoplastic cellular transformation are the oncodevelopmental antigens, such as placental-type alkaline phosphatase. This isoenzyme is a major glycoprotein of term placental trophoblast membranes, and is also expressed on some tumour cell lines including cervical carcinoma cells (McLaughlin et al., 1982). Two major forms of placental-type alkaline phosphatase have been described, the 'placental' and 'placental-like' alkaline phosphatases (PLAP and PLAP-like AP, respectively). These can be distinguished by relative sensitivity to inhibition by L-leucine (Stigbrand et al., 1982) and differential reactivity with certain monoclonal antibodies (mAbs) (McLaughlin & Johnson, 1984).The development of sensitive and specific solid-phase enzyme capture immunoassays (EIA) utilising either the mAb H317 (reactive solely with PLAP) or the mAb H17-E2 (reactive with both PLAP and PLAP-like AP) has broadened investigations of this isoenzyme group in cancer 1984a, b;Epenetos et al., 1985a;Horwich et al., 1985;Tucker et al., 1985). For example, previous serological assays have been limited by detection of elevated isoenzyme levels in healthy individuals, particularly cigarette smokers (Maslow et al., 1983;Tonik et al., 1983). It is now clear that this smoking-associated enzyme is PLAPlike AP, rather than PLAP, and thus ig unreactive in the H317-based assay (McLaughlin et al., 1984b Twelve patients from the Oxford region with established cancer of the cervix were also studied. These had squamous carcinoma (n = 9), adenocarcinoma (n =2) or mixed squamous and adenocarcinoma (n= 1); three of the carcinomas were Stage IA, five were Stage IB, three were IIA, and one was IIB. Monoclonal antibodies (mAbs...