Utility of assay of alpha subunit of human chorionic gonadotropin in management of gestational, trophoblastic malignancies

A CGA/EGFR/GATA2 positive feedback circuit confers chemoresistance in gastric cancer

De novo and acquired resistance are major impediments to the efficacy of conventional and targeted cancer therapy. In unselected gastric cancer (GC) patients with advanced disease, trials combining chemotherapy and an anti-EGFR monoclonal antibody have been largely unsuccessful. In an effort to identify biomarkers of resistance so as to better select patients for such trials, we screened the secretome of chemotherapy-treated human GC cell lines. We found that levels of CGA, the α-subunit of glycoprotein hormones, were markedly increased in the conditioned media of chemoresistant GC cells, and CGA immunoreactivity was enhanced in GC tissues that progressed on chemotherapy. CGA levels in plasma increased in GC patients who received chemotherapy, and this increase was correlated with reduced responsiveness to chemotherapy and poor survival. Mechanistically, secreted CGA was found to bind to EGFR and activate EGFR signaling, thereby conferring a survival advantage to GC cells. N-glycosylation of CGA at Asn52 and Asn78 is required for its stability, secretion, and interaction with EGFR. GATA2 was found to activate CGA transcription, whose increase, in turn, induced the expression and phosphorylation of GATA2 in an EGFR-dependent manner, forming a positive feedback circuit that was initiated by GATA2 autoregulation upon sublethal exposure to chemotherapy. Based on this circuit, combination strategies involving anti-EGFR therapies or targeting CGA with microRNAs (miR-708-3p and miR-761) restored chemotherapy sensitivity. These findings identify a clinically actionable CGA/EGFR/GATA2 circuit and highlight CGA as a predictive biomarker and therapeutic target in chemoresistant GC.

Serum cytokines in gestational trophoblastic diseases

Interleukin 1 beta (IL-1 beta), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) were assayed by 125I immunoradiometric assay in sera of 42 cases of vesicular mole (VM), 24 cases of choriocarcinoma and 23 normal pregnant women at their first trimester (controls). According to pathologic diagnosis and serial serum hCG beta assays, the cases with VM and choriocarcinoma were subdivided into remission and progressive tumor groups. The progressive tumor groups--both VM and choriocarcinoma--showed marked elevations of serum IL-1 beta, IL-6 and TNF alpha. For choriocarcinoma in remission this elevation was considerably less pronounced. The VM cases in remission had only a slight increase of the mean serum IL-6 value and none of the cases had elevated IL-1 beta or TNF values. These results may indicate that serum IL-1 beta and TNF-alpha assays are valuable biomarkers in the differential diagnosis of gestational trophoblastic disease (GTD). Moreover, normal values of these cytokines may rule out high-risk GTD, whereas markedly elevated values may indicate poor prognosis.

Gestational trophoblastic disease: what have we learned in the past decade?

Hydatidiform moles can be classified into two distinct entities: complete and partial. Complete moles are androgenetically derived, are characterized by a predominance of the 46,XX karyotype, and are associated with a significantly higher incidence of malignant sequelae than are partial moles. A subset of complete moles resulting from dispermy are heterozygous (46,XY) and appear to be associated with the greatest risk of malignancy. Free subunits of human chorionic gonadotropin, beta core fragments, and acidic variants of human chorionic gonadotropin can now be readily measured by radioimmunoassays, fluoroimmunoassays, or isoelectric focusing techniques. Determination of these markers can be of value not only in monitoring response to therapy, but also as prognostic indicators. A subgroup of patients, traditionally classified as "high risk" or poor prognosis, who show poor responses to conventional combination chemotherapy have recently been designated as "ultra-high-risk" patients. They require more complex chemotherapy and possibly surgery and radiotherapy to achieve remission. The development of chemotherapy over the past decade, including the introduction of etoposide and cisplatin into current protocols and the treatment of patients with advanced gestational trophoblastic disease, are considered in this review.

Comparison of the analytical characteristics of ten urinary hCG tests for early pregnancy diagnosis

A comparison of assay design, sensitivity and specificity is given for 10 urinary human chorionic gonadotrophin (hCG) test kits for early pregnancy diagnosis. One slide test applies a polyclonal anti-hCG serum, while nine, more recently developed, tube and slide tests use one or more monoclonal antibodies toward intact hCG or its free subunits. Colour development for five immunoenzymetric (IEMA) 'sandwich' assays, or (haem/latex) agglutination (HA, LA)-inhibition (HAI, LAI) for the other systems provide assay sensitivities from 1000-50 IU/L within 3-120 min. The 'best' slide-(i.e., LA, LAI), haem-(i.e., HA, HAI) and IEMA-tests detect respectively 500, 75 and 50 IU/L within 2.5, 120 and 3 min. Assay specificities (i.e., as false-positive and false-negative test results) are studied using intact hCG, hLH and their free alpha- and beta-subunits. The presented assays are improved, perform more sensitively at shorter reaction times with increased specificity, and may, therefore, establish pregnancy at an earlier stage with greater reliability.

Comparison of the analytical characteristics and clinical usefulness in tumour monitoring of fifteen hCG(-beta) immunoassay kits

Fifteen immunoassay kits for serum hCG(-beta) measurements have been compared for their analytical characteristics and clinical usefulness in tumour monitoring. Three out of 13 radioimmunoassays and two sandwich hCG immunoassays represent the 'one-component' techniques for intact hCG detection since they are based on antiserum raised against intact hCG. Within this group, method-comparison slopes ranged between 0 X 149 and 0 X 374. The remaining 10 radioimmunoassays all apply antiserum against hCG-beta and are designated 'two (or more)-component' assays since they detect both intact hCG and the free beta-subunit ('total hCG'). For this reason these assays are of potential value for tumour monitoring. Additional criteria for this are: (1) the expression of assay results in terms of 1st IRP-hCG instead of the unstructured use of the 2nd IS or the 1st IRP-hCG-beta; (2) documentation of cross-reactivities especially for the free beta-subunits of hCG and hLH which are almost completely lacking; (3) establishment of the minimum detectable dose in the presence of normo-to-hypergonadotrophic hLH levels in serum (the 'clinical sensitivity') to allow the follow-up of tumour regression especially in the low-dose region. Method-comparison analysis for these assays revealed regression slopes between 0 X 001 and 0 X 873.

New horizons in hCG detection

The advent of high technology in the field of hCG measurement has created a greater requirement for high expertise in the analysis and evaluation of hCG levels, particularly low-positive levels, and for the concomitant clinical management of the patient. This implies an imperative to treat trophoblastic disease patients in trophoblast disease referral centers.

Dissociation of chorioadenoma destruens from hydatidiform mole by urinary steroid analysis

Dissociation between hydatidiform mole (HM) and chorioadenoma destruens (CA) was attempted by gas chromatographic analysis of urinary steroids. In the chromatogram, fraction 2 (F2) including four pregnane steroids (17-hydroxypregnanolone, pregnanolone, pregnanediol, and pregnanetriol) reflected the biologic activity of molar human chorionic gonadotropin (hCG), and the ratio of F2 to fraction 1 (F1) (17-ketosteroids) was found useful in monitoring secondary growth of trophoblastic tumor: Urinary log F2/F1 after curettage declined quickly and unidirectionally in HM, but the same parameter exhibited a temporal rise in CA at 11 to 20 days after curettage because of the molar hCG from residual tumor tissue. The resolution between HM and CA at that stage (11 to 20 curettage days) was of the order of diagnostic use and superior to that with immunoreacive hCG. The data obtained are discussed in the light of pathophysiology of CA.