Radioimmunoassay for human alpha 1 -fetoprotein

Pathfinders in oncology from the time the causal relation between tobacco use and lung cancer was established to publication of the first Cancer Staging Manual by the American Joint Committee on Cancer

During the period from 1962 to 1977, several antigens, notably carcinoembryonic antigen and prostate-specific antigen, were discovered and entered clinical use. Ultrasonography, positron emission tomography scanning, and magnetic resonance imaging were introduced, and adjuvant radiation and chemotherapy after limited surgery became routine procedures. Radioimmunoassay and immunohistochemistry techniques were standardized. The announcement in England and the United States that tobacco is a potent lung carcinogen was long delayed, important news. The US Cancer Act of 1971 made it possible to experiment with newly discovered drugs, transfer promising therapeutic agents from the laboratory to the clinic, and finance randomized clinical trials. Oncologists achieved a series of successes with combination chemotherapy in childhood cancers, adult lymphomas, and testis tumors. Clinical trials demonstrated that breast-conserving therapy is as effective as mastectomy. The discovery of retroviruses, reverse transcriptase, and vascular endothelial growth factor was coupled with learning about oncogenes. The 2-hit theory and the reciprocal translocation of chromosomes helped to solve some of the riddles of oncogenesis. The staging classification of cancers by the American Joint Committee on Cancer unified clinical and pathologic handling and prognostication of malignant tumors. The progress made in oncology between 1962 and 1977 came about through the dedicated work of many individuals. However, there were 9 pathfinders (3 medical oncologists, 2 surgeons, 1 medical nuclear physicist, 1 pediatrician geneticist, 1 hematologist geneticist, and 1 virologist) who, despite their diverse backgrounds, personalities, and interest, made extraordinary contributions to oncology.

Clinical utility of simple non-invasive liver fibrosis indices for predicting hepatocellular carcinoma (HCC) among Egyptian patients

AIM

Serological indices for liver fibrosis have been widely used to estimate liver fibrosis, but as far as we know they have not been tested to predict hepatocellular carcinoma (HCC). Our aim is to study the clinical usefulness of some simple non-invasive fibrosis indices in the prediction of HCC among Egyptian patients.

METHODS

Ninety patients with HCC who were presented to the National Cancer Institute, Cairo University, were included in this study, together with 30 patients with cirrhosis as a benign control group and 30 apparently healthy volunteers as a normal control group. FIB4 Score, Aspartate Aminotransferase (AST) to Platelet (PLT) Ratio Index (APRI) Score, AST/PLT ratio, Age/PLT Index and AST/alanine aminotransferase indices were calculated for all patients and controls and were tested for their clinical use to predict HCC.

RESULTS

Double combination between alpha-fetoprotein and FIB4 Score when either one was abnormal showed the highest diagnostic performance between the HCC group and the cirrhosis and control groups with sensitivity and specificity of (93% and 96%), respectively, whereas the APRI Score was the best to differentiate between the cirrhosis and control groups with sensitivity and specificity of 100% each.

CONCLUSIONS

Using some simple non-costly indices can accurately predict HCC and differentiate it from cirrhosis and normal control cases among Egyptian patients, it can also differentiate cirrhosis from normal controls, so can be used as diagnostic and screening tools for both HCC and liver cirrhosis among the Egyptian population.

Comparing prothrombin induced by vitamin K absence-II (PIVKA-II) with the oncofetal proteins glypican-3, Alpha feto protein and carcinoembryonic antigen in diagnosing hepatocellular carcinoma among Egyptian patients

BACKGROUND

Hepatocellular carcinoma (HCC) is usually asymptomatic in the early stage and does not show elevated alpha-feto protein (AFP). AFP shows 60-80% sensitivity in diagnosing HCC. Glypican3 (GPC-3) is an oncofetal protein that is only detected in HCC cells but not in benign liver tissues, while Carcinoembryonic antigen (CEA) is expressed in various neoplasms including HCC. Although, it is not specific for HCC. Prothrombin induced by vitamin K absence-II (PIVKA-II) is an abnormal prothrombin protein that is increased in the serum of HCC patients. It has higher sensitivity and specificity compared to AFP. The aim of this study is to compare the clinical utility of PIVKA-II with GPC-3, AFP and CEA in diagnosing HCC.

PATIENTS AND METHODS

This study included 40 patients with HCC, 10 patients with cirrhosis as a benign control group, and 10 apparently healthy volunteers as normal controls. Serum samples were subjected to routine laboratory investigations, measurement of CEA, AFP using MEIA technique (Axsym), glypican3, and PIVKA-II using ELISA technique in the sera of all patients and controls.

RESULTS

All markers showed the highest results in the HCC group. Higher concentrations of PIVKA-II were detected in patients with splenomegaly, and in tumors with size (>3cm). Combination of Glypican-3 and PIVKA-II showed the highest sensitivity, while GPC-3 alone and combination of GPC-3 and AFP showed the highest specificity to differentiate HCC from liver cirrhosis and normal controls. GPC-3, PIVKAII, and combination of both showed the highest sensitivity, while GPC-3 alone showed the highest specificity to differentiate HCC from liver cirrhosis.

CONCLUSION

Glypican-3 is the only oncofetal antigen that showed comparable high diagnostic accuracy as PIVKA-II in diagnosing HCC among Egyptian patients.

Markers of bile duct tumors

Biliary tract carcinomas are relatively rare, representing less than 1% of cancers. However, their incidence has increased in Japan and in industrialized countries like the USA. Biliary tract tumors have a poor prognosis and a high mortality rate because they are usually detected late in the course of the disease; therapeutic treatment options are often limited and of minimal utility. Recent studies have shown the importance of serum and molecular markers in the diagnosis and follow up of biliary tract tumors. This review aims to introduce the main features of the most important serum and molecular markers of biliary tree tumors. Some considerable tumor markers are cancer antigen 125, carbohydrate antigen 19-9, carcinoembryonic antigen, chromogranin A, mucin 1, mucin 5, alpha-fetoprotein, claudins and cytokeratins.

Portal vein thrombosis in Egyptian patients with liver cirrhosis: Role of methylenetetrahydrofolate reductase C677T gene mutation

AIM

The pathogenesis of non-malignant portal vein thrombosis (PVT) in cirrhotic patients is not clearly defined. This case-control study aimed to investigate the role of methylenetetrahydrofolate reductase (MTHFR) C677T gene mutation in the pathogenesis of PVT in Egyptian cirrhotic patients.

METHODS

Plasma homocysteine was measured and MTHFR C677T gene mutation was detected in 76 cirrhotic patients (21 with PVT, 55 without PVT) and 20 healthy controls.

RESULTS

The frequency of CC genotype (wide type) in cirrhotic patients with PVT was lower than controls and cirrhotics without PVT. However, the frequency of TT genotype (homozygous mutation) was elevated in cirrhotic patients with PVT as compared to controls and those without PVT. Cirrhotic patients with PVT had significantly higher homocysteine than those without PVT. Cirrhotic patients with TT genotype are at a significant risk for PVT (odds ratio = 7.7, 95% confidence interval, 1.50-42.81) when compared with CC genotype. Moreover, subjects carrying TT genotype had a higher homocysteine than those carrying CC genotype.

CONCLUSIONS

The TT genotype of MTHFR is associated with an increased risk of PVT in Egyptian cirrhotic patients. Hyperhomocysteinemia could be considered as a relatively new risk factor for PVT in cirrhotic patients and plasma homocysteine should be investigated particularly in patients with PVT of unexplained etiology. The important clinical implication is that the readily available therapy of folate, vitamin B6 and B12 supplementation may reduce homocysteine and prevent further thrombotic complications in cirrhotic patients carrying the TT genotype.

Distribution of glucose-6-phosphatase activity in normal, hyperplastic, and preneoplastic rat liver

The significance of glucose-6-phosphatase (G6P) expression by bile duct-like cells proliferating during hepatocarcinogenesis in the histogenesis of hepatocellular carcinoma is not clear. To this end, we measured the histochemical and biochemical activity of G6P in normal rat liver, and in rat livers in which bile duct-like proliferation was induced by either hyperplastic (bile duct ligation for 14 days or feeding alpha-naphthylisothiocyanate for 28 days) or neoplastic (feeding a choline-devoid diet containing 0.1% ethionine for 60 days) regimens. In normal, hyperplastic, and preneoplastic livers, G6P histochemical activity was confined to the hepatocytes; proliferated bile duct-like cells, like normal bile ducts, did not display visible G6P staining. When the enzyme activity was determined biochemically, however, hydrolysis of glucose-6-phosphate was observed in both parenchymal and nonparenchymal liver cells isolated from all experimental animals. In elutriated nonparenchymal fractions, G6P activity was directly proportional to the number of cells positive for gamma-glutamyl transpeptidase and cytokeratin no. 19 (markers of bile duct cells) and inversely proportional to the number of cells positive for vimentin (marker of mesenchymal cells). These results indicate that, while by light microscopy hepatic G6P histochemical activity is detectable only in the hepatocytes, the biochemical activity is also expressed in proliferating bile duct-like cells. However, the nonparenchymal activity is observed during both neoplastic and hyperplastic liver growth, thus indicating that the presence of this enzyme in bile duct-like cells proliferating during hepatocarcinogenesis should not necessarily be construed as supporting their stem cell nature nor their neoplastic commitment.

Biosynthesis of various types of collagen by human hepatoma cells in vitro

A cloned human hepatoma cell line (HH2-1) produced and formed collagen fibers in vitro. The relative rate of collagen synthesis by the cells was increased with an enhancement of the cell density. An analysis of the components of the collagen using sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the cells synthesized interstitial collagen, types I and III, and other collagenous proteins. Thus, human hepatoma cells may play an important role in the formation of stromal collagen in the tumor.

Analysis of maternal alpha-fetoprotein: a comparison of three radioimmunoassays

Increased levels of alpha-fetoprotein in maternal serum or amniotic fluid may be indicative of a fetal neural tube defect. The present investigation compares, prospectively and retrospectively, the analysis of serum or amniotic fluid alpha-fetoprotein from humans using three radioimmunoassays. A total of 46 sera and 137 prospective and 202 retrospective amniotic fluid samples collected at 12-26 weeks' gestation were assayed using our in-house Farr technique assay, a kit Farr technique assay, and a kit double-antibody assay. Analysis of quality control data in all three assays showed that within- and between-assay variations were less with the double-antibody technique. Additionally, the double-antibody assay offers the advantage of considerably lower nonspecific binding (1.7% vs 16-18% for the Farr technique assays). Of the 375 pregnancies sampled during this study, 340 (91%) resulted in normal singleton births, whereas three (1%) pregnancies were found to have elevated serum or amniotic fluid by all three assay methods and resulted in confirmed neural tube defects. Of the remaining, non-normal outcome without neural tube defect or elevated alpha-fetoprotein was determined in 27 (7%) pregnancies, and false-positive elevated alpha-fetoprotein levels were found for 5 (1%). Analysis of maternal alpha-fetoprotein by radioimmunoassay is a sensitive and accurate adjunct in the prenatal diagnosis of neural tube defects.

A critical evaluation of a specific radioimmunoassay for prostatic acid phosphatase

A radioimmunoassay (RIA) method for acid phosphatase detection was compared to a standard enzyme assay using sera from 210 normal volunteers and 285 patients with prostatic disease. Statistical and clinical comparisons were made between defined subgroups. All 55 normal females had RIA detectable serum acid phosphatase, implying that this assay cannot be entirely specific for enzyme of prostatic origin. Urinary catheterization did not affect acid phosphatase levels. In all stages of carcinoma there were more acid phosphatase elevations by the RIA method than enzyme method, but neither assay could differentiate intracapsular cancer from benign prostatic hyperplasia. A small number of patients with biopsy proven negative nodules had marginally elevated values, suggesting as obligation for closer follow-up. The RIA method may be superior for monitoring patients with more advanced malignancy. Additional practical advantages of the RIA include relative simplicity and elimination of the special serum handling required for the enzyme assay.

Relationship of total serum sialic acid to sialylglycoprotein acute-phase reactants in malignant melanoma

Reported elevations of total serum sialic acid may be a result of shed tumour-related membrane sialyglycoprotein and/or concurrent elevation of non-specific, acute-phase reactant sialoglycoprotein. To clarify further the specificity and sensitivity of serum sialic acid monitoring, analyses of sialic acid by the thiobarbituric acid method and acute-phase reactants by radial immunodiffusion were made using the same malignant melanoma patients' sera. Preliminary studies of IgG, IgA, IgM, ceruloplasmin and C-reactive protein suggested that these would not be valuable monitors of tumour burden. Single serum samples from 59 melanoma patients and age- and sex-matched controls were further examined for sialic acid, alpha 1-acid glycoprotein, alpha 1-antitrypsin, haptoglobin, and alpha 2-macroglobulin. Patients were grouped according to tumour burden. In pairwise statistical tests, differences between groups tended to be greater for sialic acid than for acute-phase reactants. On discriminant analysis , sialic acid was clearly the most significant single discriminator between groups, with an F statistic of P < 0.00005. Although alpha 1-acid glycoprotein was quite strongly correlated with sialic acid, it was not such a good discriminator and did not add significantly to the predictive power of sialic acid alone.

Production and characterization of xenogeneic antisera to tumor-associated antigen(s)

Tumor-associated antigen(s) from a specimen of human malignant melanoma and from spent culture medium of a melanoma cell line were extracted and purified. The incidence of antibody activity to these antigens, in sera from cancer patients with neoplasms of various histologic types, was higher (65--83%) than normal donors' (19--25%) by the complement fixation assay. These purified antigens were then used to raise antisera in rabbits and sheep. After absorption with various human normal tissues, these antisera reacted against melanoma, sarcoma, and carcinoma extracts, but not against human normal liver, skin, or muscle extracts. However, the antisera showed reactivity against a human fetal homogenate. Results indicate that the xenogeneic antisera contained antibodies to fetal antigens and to tumor-associated antigen(s). Xenogeneic antisera could be used to purify tumor-associated antigens and oncofetal antigen(s) from crude extracts by affinity chromatography.

Alpha fetoprotein in the differentiation of neonatal hepatitis and biliary atresia: current status and implications for the pathogenesis of these disorders

Neonatal hepatitis (NH) and biliary atresia (BA) are disorders of early infancy that may be difficult to differentiate. Since surgical therapy can be curative if performed early in the disease course of BA, accurate diagnosis is of great importance. Elevated levels of serum alpha fetoprotein (AFP) do occur in many cases of NH and may be helpful in differentiating this condition from BA. Evidence is presented which suggests that initially BA and NH may be the same disease. The individual host response determines the final clinical outcome and AFP could be the immunoregulatory substance which affects pathological progression from NH to BA.

Germ cell tumors of the testes

Most malignant testicular neoplasms are of germ cell origin. They are divided into five basic types: seminomas, embryonal carcinomas, teratocarcinomas, adult teratomas and choriocarcinomas. Clinically they may present as an enlarging testicular mass, or with symptoms resulting from metastases or hormonal secretions. The treatment of choice for patients with seminomas is orchiectomy, followed by radiation therapy. This combination results in an 80 to 100 percent five-year survival rate in patients with nonmetastatic or locally metastatic disease. The treatment of nonseminomatous germ cell tumors is more controversial. An aggressive approach, however, with retroperitoneal lymph node dissection and adjuvant chemotherapy has resulted in an overall 78 percent survival rate. Several placental and fetal proteins are secreted by these tumors. Two of these, human chorionic gonadotropin and alpha-fetoprotein, have been shown to be useful for the diagnosis of these neoplasms, for following the disease activity during therapy and for detection of recurrences.

Alpha-fetoprotein in fetal skin and muscle

The skin and muscles of human fetuses were used to obtain extracts of alpha-fetoprotein (AFP). Fetuses up to sixteen weeks gestation gave the highest yields. Rabbits immunized by concentrates from this source made anti-AFP of a quality suitable for use in radioimmunoassay systems.

Radioimmunoassay of serum alpha-fetoprotein in patients with different maliganant tumors

The level of serum alpha-fetoprotein (AFP) was estimated by radioimmunoassay in 153 normal healthy Malysians of different ethnic groups. The mean level was 7.5 In1/ml (SD 2.28InU/ml). Among 330 patients with malignant tumors, 11 had increased levels of AFP. The only patient who had hepatoma had a very high level of serum AFP. High levels were also found in three of four patients with dysgerminoma of the ovary, in the only two patients with carcinoma of the testis, and in one patient with secondary carcinoma of the humerus of unknown origin. Lower, but significantly increased levels were observed in one patient (of 48) with breast carcinoma, one patient (of 8) with basal cell carcinoma of the nose, one patient (0f 27) with carcinoma of the lung, and one patient (of 59) with nasopharynegeal carcinoma.

Detection of tumor-associated antigen in human melanoma cell line supernatants

Spent tissue culture medium (CDM-S) removed from a single cell line of human malignant melanoma grown in serum-free CDM, contained tumor-associated antigenic activity. Antibodies to CDM-S measured by complement fixation were detected in 44% (31/70) melanoma, 55% (15/27) sarcoma, 63% (24/38) carcinoma and 15% (11/72) normal sera. Delayed cutaneous hypersensitivity reactions (DCHR) were demonstrated in 4/5 melanoma patients at a 500 mug dose, 3/5 at a 100 mug dose and in 1/7 carcinoma patients at the 500 mug dose. One ml of CDM-S was shown to contain antigen equivalent to that obtained from the membranes of 2.9 X 10(7) tissue-cultured melanoma cells. After purification, 84% (16/19) sera from melanoma patients, 66% (12/18) from sarcoma and carcinoma patients and 8% (2/26) from normal controls were positive to the antigen by complement fixation.

Effect of surgical and chemotherapeutic treatment on alpha-fetoprotein levels in patients with hepatocellular carcinoma

Quantitative determinations of serum alpha-fetoprotein (AFP) by radioimmunoassay in 193 patients with hepatocellular carcinoma have demonstrated a wide variation in serum levels that appear to be relatively constant for each patient by the time that diagnosis is made. If there is no therapeutic intervention the serum AFP usually follows a gradual increase as the tumor progresses. A few patients have a fall in serum AFP as a preterminal event. Various forms of chemotherapy cause only minor and transient decrease in serum AFP. Surgical resection of tumor produces an immediate fall that parallels the catabolic decay rate for AFP. All AFP-positive patients treated with surgery had recurrence of their tumor with a rise in serum AFP preceeding clinical discovery. The correlation of serum AFP and effective treatment is demonstration of the usefulness of this oncofetal protein marker as an indicator of neoplastic activity for hepatocellular carcinoma and tumors with embryonal cell components and possibly for some other entodermally derived neoplasms.

Alpha-1-fetoprotein in a patient with a poorly differentiated carcinoma of the anterior mediastinum

A case of a mediastinal tumor which was associated with the production of AFP is described. The diagnostic significance of an elevated serum concentration of AFP is reviewed in both neoplastic and non-neoplastic clinical situations.

Isolation of a soluble tumor-associated antigen from human melanoma

Human melanoma-associated antigen was solubilized from fresh surgical specimens by 3 M KC1 extraction. The antigenicity of this extract was demonstrated by delayed cutaneous hypersensitivity responses and inhibition of complement fixation. Twenty-one of 33 melanoma patients had delayed cutaneous hypersensitivity responses to melanoma antigen, while only four of 28 reacted to autologous muscle. Although KC1 extracts did not fix complement directly, they reacted with antibody, thus inhibiting complement fixation by the autologous melanoma antigen extracted from tissue culture supernatants. The soluble antigenic moiety was then purified by fractionation on a G-150 Sephedex column and polyacrylamide gels, and the antigenic activity was monitored by delayed cutaneous hypersensitivity responses in melanoma patients. A 20-fold purification was achieved. Solubilization of tumor antigens with 3 M KC1 provides tumor-associated antigen of high activity which is amenable to further biochemical purification.

Foetal-associated material: its expression in long-term cultured human skin

Using immunofluorescence and electron microscopy, we have demonstrated the presence of "foetal substances" (antigens) in skin kept in tissue culture medium for periods of time ranging from 9 days-18 weeks. This is a specific reaction demonstrated with an anti-human foetal serum raised in New Zealand white rabbits. It is suggested that the expression of foetal substances by cells in the skin under these abnormal conditions might lead to the masking or modification of the normal histo-compatible antigens, enabling such skins to survive transplantation without rejection.

Carcinoembryonic antigen and alpha 1-fetoprotein in ulcerative colitis and regional enteritis

Sera were collected from 108 patients with inflammatory bowel disease and assayed for carcinoembryonic antigen (CEA) and alpha(1)-fetoprotein (AFP). Seven (14%) of 51 patients with ulcerative colitis had a positive test for CEA and one of these had associated carcinoma of the colon. Ten (19%) of 52 patients with regional enteritis were also seropositive. The sera of 4 (9%) of 47 patients with ulcerative colitis and 2 (5%) of 41 patients with regional enteritis contained small amounts of AFP. Of two unclassified patients one had a positive CEA and the other a positive AFP. No serum was positive for both CEA and AFP. In addition, multiple samples were available for sequential analysis in eight CEA-positive patients but there was no apparent relationship between seropositivity and disease activity. Continued follow-up is now in progress to determine the significance of detectable fetal antigen levels in inflammatory bowel disease.