Glycopeptide hormones and neoplasms

Human chorionic gonadotrophin producing epithelioid sarcoma metastatic to the placenta

Pregnancy complicated by sarcoma is a rare event, and metastasis to the placenta is exceptionally rare. Of reported malignancies involving the products of conception, only 8% are sarcomas. We report the first case of placental metastasis of an epithelioid sarcoma, an uncommon malignancy which most frequently affects young adults. In addition to the typical histological features and immunophenotypic profile expected of epithelioid sarcoma, this tumor also expressed human chorionic gonadotrophin (HCG). Although uncharacteristic, the production of HCG has been previously reported in other nontrophoblastic tumors. It may have contributed to the pathogenesis of the tumor metastatic to the placenta in this case.

Elevated serum beta-human chorionic gonadotropin in nonpregnant conditions

Positive serum beta-human chorionic gonadotropin (beta-hCG) in reproductive-age women generally indicates a pregnancy, and to a lesser extent, gestational trophoblastic disease, ovarian or peripheral germ cell tumor. Besides gynecologic conditions, nongynecologic cancers can be associated with beta-hCG positivity as well. The hormone in these tumors varies from detection by the immunohistochemistry studies of the tumor tissue only to a high serum level. This is illustrated by our case report of a 26-year-old woman who was diagnosed with a spindle cell osteosarcoma of the shoulder. The serum beta-hCG became undetectable after chemotherapy.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians Learning

OBJECTIVES

After completion of this article, the reader should be able to recall that elevated serum hCG can be related to pregnancy, gestational neoplasias, and ovarian and nongynecologic tumors and explain that it is important to appreciate that the hCG detected in these conditions may differ in type and be a marker of the success of treatment.

The use of biomarkers in the prediction of survival in patients with pulmonary carcinoma

Data on ten variables and 16 biomarkers were obtained on 119 patients with newly diagnosed pulmonary cancer. The prognostic value of 16 biomarkers (alpha-1-antitrypsin [AAT], adrenocorticotropic hormone [ACTH], alpha-fetoprotein [AFP], carcinoembryonic antigen [CEA], human chorionic gonadotropin [HCG], immune complexes, immunoglobulins, N-terminal peptide of proopiomelanocortin [NTERM], and tumor-associated antibody [TAA]) was tested by adding these to the model of age, gender, stage, morphology, Feinstein's classification of symptoms, Karnofsky scale, leukocyte count, recent weight loss, and liver enzymes. Using Cox's regression method and a forward stepwise procedure, seven biomarkers (ACTH, AAT, AFP, calcitonin, HCG, TAA, and prolactin) entered the model. Elevated levels of cortisol and TAA were associated with longer survival. The selection of biomarkers by stepwise regression needs to be interpreted with caution, especially since the Z scores were found to be dependent on the particular variables included in the model. Furthermore, when dichotomized on maximum of the normal laboratory values, HCG and AFP were infrequently (2%) elevated. The lack of correlation among the biomarkers supports the hypothesis of random derepression of the genome of cancer cells. Further studies in improved modeling and the formulation of a biomarker index could enhance our understanding of the biology of cancer.

Purification and characterization of the glycoprotein hormone alpha-subunit-like material secreted by HeLa cells

The protein secreted by HeLa cells that cross-reacts with antiserum developed against the alpha-subunit of human chorionic gonadotropin (hCG) has been purified approximately 30,000-fold from concentrated culture medium by organic solvent fractionation followed by ion exchange, gel filtration, and lectin affinity chromatography. The final preparation had a specific activity (by RIA) of 6.8 x 10(5) ng of alpha/mg of protein and appeared homogeneous by electrophoresis on reducing/denaturing polyacrylamide gels (SDS-PAGE). Amino acid analysis indicated that HeLa-alpha had a composition very similar to that of the urinary hCG alpha-subunit. Peptide fingerprints of the HeLa protein and hCG-alpha revealed that several of the Tyr-, Met-, and Cys-containing tryptic peptides were held in common, thus identifying the tumor protein as a glycoprotein hormone alpha-subunit with a primary structure similar to that of hCG-alpha. However, comparison of hCG-alpha and HeLa-alpha demonstrated that the tumor-associated subunit was not identical with its normal counterpart. Only two of the three Tyr-containing tryptic peptides present in hCG-alpha could be detected in HeLa-alpha after iodination with 125I. HeLa-alpha eluted prior to hCG-alpha during Sephadex G-75 chromatography, but the subunits coeluted when the tumor protein was first subjected to mild acid hydrolysis. The purified tumor protein had an apparent molecular weight greater than that of the urinary alpha-subunit when analyzed by SDS-PAGE (Coomassie blue staining), and this difference was even greater when a partially purified preparation was examined by an immunoblot technique (Western). Isoelectric focusing of the HeLa and hCG subunits demonstrated that the tumor protein had a lower pI (4.7-5.5 compared to 6.5-7.8), and removal of sialic acid by mild acid hydrolysis did not entirely eliminate this difference. Immunoprecipitation and electrophoresis of alpha-subunit from HeLa cultures labeled with [3H]fucose indicated that the tumor subunit was fucosylated, whereas analysis of hCG-alpha hydrolysates by HPLC confirmed previous reports that the placental subunit does not contain fucose. HeLa alpha-subunit was unable to combine with hCG beta-subunit to form holo-hCG under conditions where the hCG alpha-subunit was able to do so. The results indicate that, regardless of whether or not a single alpha-subunit gene is being expressed in both normal and neoplastic tissues, posttranslational modifications lead to a highly altered subunit in the tumor. The differences observed may be useful in diagnosing neoplastic vs hyperplastic conditions and may lend insight into the mechanism of ectopic hormone production by tumors

Cancer incidence in hypertensives

Cancer incidence was measured over a 5-year period (1978 to 1982) in 4067 hypertensive patients, and 10,366 normotensive patients from general practices in southwestern Ontario. For cancer of all sites an elevated incidence was found among hypertensive patients. The elevation was most pronounced among newly diagnosed hypertensive patients, with hypertension of moderate or greater severity, and for sites that have been described in clinical reports as being capable of producing a rise in blood pressure. It is tentatively concluded that the causal direction is from cancer to hypertension, rather than the reverse. If this conclusion is correct, the associations that have been reported between cancer mortality and hypertension may be due to an effect of blood pressure upon survival from cancer.

Ectopic production of human chorionic gonadotropin by poorly differentiated transitional cell tumors of the urinary tract

We performed a 5-year histopathological review of 41 consecutive cases of transitional cell carcinoma. Of these cases 8 were positive for human chorionic gonadotropin immunoperoxidase tissue staining. All tumors were grade III and stages ranged from A to D. Three patients presented with gynecomastia as the clinical manifestation of elevated serum levels of beta-human chorionic gonadotropin. These findings document the association of this phenomenon with lesions of an aggressive nature. As with the loss of cell surface antigens, the appearance of human chorionic gonadotropin within the tumor cells may be further evidence of dedifferentiation. Human chorionic gonadotropin production may be a potential marker to gauge tumor response to chemotherapy and, perhaps, a predictor of future aggressiveness and over-all progression.

NALL-1, an acute lymphoblastic leukemia cell line with peroxidase activity

All cells examined from the non-B, non-T acute lymphoblastic leukemia cell line, NALL-1, stained positive both for terminal deoxynucleotidyl transferase and for common ALL antigen. In addition, peroxidase activity was detected by light microscopy in 55 to 75% of cells and peroxidase-positive granules were detected ultrastructurally in greater than 80% of cells. Peroxidase activity in NALL-1 may result from derepression of peroxidase genes or clonal proliferation of a biphenotypic precursor cell.

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.

Human chorionic gonadotropin and alpha chain of glycoprotein hormones in patients with inflammatory bowel disease

In twenty patients with Crohn's disease and ten patients with ulcerative colitis serum levels of human chorionic gonadotropin and the common alpha-subunit of glycoprotein hormones were determined by radioimmunoassay. In contrast to published data, all serum samples except one revealed levels within the normal range of 148 controls (human chorionic gonadotropin levels up to 3.9 IU/l, alpha-subunit up to 3.8 micrograms/l). Neither the serum levels of human chorionic gonadotropin nor of the alpha-subunit differed significantly between patients with Crohn's disease (median/maximum: 0.9/4.4 IU/l; 0.7/3.6 micrograms/l) and ulcerative colitis (1.0/3.4 IU/l; 0.8/2.2 micrograms/l). Furthermore, the serum levels studied in patients with active (0.9/3.0 IU/l; 0.7/3.5 micrograms/l) and inactive (0.9/4.4 IU/l; 0.8/3.6 micrograms/l) Crohn's disease and in patients with active (1.1/3.4 IU/l; 0.9/2.2 micrograms/l) and inactive (0.9/2.9 IU/l; 0.8/1.3 micrograms/l) ulcerative colitis were not significantly different. There was no relationship of the duration of the disease or a bowel resection to the serum levels of human chorionic gonadotropin or the alpha-subunit. It is concluded that both parameters are not useful as markers in patients with Crohn's disease or ulcerative colitis. The normal serum levels found in patients with inflammatory bowel diseases indicate human chorionic gonadotropin as a highly specific marker for malignant diseases.

Prospective evaluation of some candidate tumor markers in the diagnosis of pancreatic cancer

As part of a prospective diagnostic protocol, patients suspected of having pancreatic cancer had systemic and portal venous blood samples assayed, in coded batches, for peptide hormones and enzymes thought to be of potential value as tumor markers. An average of 111 patients were tested for each candidate marker. Results were analyzed by dividing patients into three groups according to the definitive diagnoses. These were pancreatic cancer (32% of patients), other cancers (27%), and benign diseases (41%). Although elevated mean levels of fasting plasma glucose and serum alkaline phosphatase were found in the pancreatic cancer group, there were no significant differences in the mean levels of any of the candidate markers studied in the three groups. The diagnostic values of normal and elevated levels of each candidate marker studied have been calculated. None has proven to be as useful as the serum level of pancreatic oncofetal antigen, fasting plasma glucose, or serum alkaline phosphatase in the diagnosis or exclusion of pancreatic cancer.