[Carcinofetal antigens. I. alpha-fetoprotein (author's transl)]

Alpha fetoprotein (AFP) participates in the build up of hematopoietic cells in the early embryonic stage: an abortion case observation

Background

At the 3rd week of human embryo, some cell clumps are formed by the hyperplasia of mesenchymal cells at the germ layer of the yolk sac wall. These cell clumps are known as blood islands. The cells in the center of the blood islands further develop into primitive blood cells, such as hematopoietic stem cells. The blood island in the yolk sac further develops into the extramedullary hematopoietic tissue in 1 week at the 3rd to 4th week.

Case presentation

A 32-year-old pregnant woman who missed menstruation for 42 days discovered that her pregnancy required an abortion. The tissue collected after the abortion was a piece of gray-yellow and villus-like intrauterine tissue of a size of approximately 4 cm × 3 cm × 1.3 cm. The paraffin section stained with hematoxylin and eosin and observed under the light microscope showed a visible small embryo tissue in the early placental tissue. In the embryonic tissue, a large amount of extramedullary hematopoietic tissue was present, including myeloid, erythroid and megakaryocytic cells. The extramedullary hematopoietic cells were located in the blood vessels or naive liver sinus, were positive for alpha fetoprotein (AFP) and were without lymphocytes. The erythrocytes consisted of a large number of nucleated red blood cells. In addition, a neural tube and cystic structure were found. The final pathological diagnosis was as follows: Early embryonic tissue with a cystic structure formation in the embryo. After medical abortion the pregnant woman recovered well, without complications.

Conclusions

Our case illustrates that AFP is an important structural protein of nucleated erythrocytes and myeloid hematopoietic cells, suggesting that it may participate in the build up of nucleated erythrocytes and myeloid hematopoietic cells. Furthermore, our case suggests that nucleated red blood cells can be detected from the 42nd day of pregnancy by a peripheral blood sample from the mother.

High Alpha-Fetoprotein Persistence after Orchiectomy. On a Case of Uncommon Etiology

Background

The following report describes a case of inherited elevation of alpha-fetoprotein (AFP) in a young male suspected for testicular cancer. AFP shows very high values during fetal life. After birth the synthesis of AFP decreases dramatically, and only trace amounts are detected in the adult. From this age on, serum AFP can rise above normal in some diseases, e.g. liver disorders, and in some kind of tumors. A condition in which persistent high levels of AFP are found, named Hereditary Persistence of AFP [HPAFP), was first reported in 1983 by Ferguson-Smith, and then recorded in the literature only on eleven occasions till 2004. The occurrence of HPAFP may be underestimated. HPAFP can be easily confirmed by testing AFP levels in blood-related family members.

Methods

An elevated serum AFP (about 20 μg/mL) was found in a 27–year-old white man with an unremarkable medical history, who was concerned to have left testicular cancer. By our examination, his left testis was markedly reduced in size. β-HCG, LDH, and liver function were normal. Surgical inguinal exploration with testis and spermatic cord excision was carried out. Postoperative repeated AFP levels remained persistently elevated, in the range from 20 to 30 μg/mL. Careful evaluation for occult cancer showed no abnormality. Histology showed necrotic tissue and could not make a reliable diagnosis. A literature search was done using PubMed by key word “alpha-fetoprotein” and “elevation”. Thinking of a hereditary trait, we decided to screen patient's blood-related family members.

Results

AFP was found to be elevated in another four out of six relatives within three generations, unrelated to any disease. This pedigree was consistent with an autosomal dominant inheritance pattern.

Conclusions

HPAFP could mislead the physician. Failure to recognize HPAFP can lead to unsuitable treatments. The existence of this clinically benign condition needs to be considered in both children and adults with unexplained and persistent elevation of AFP, e.g. those diagnosed or suspected for germ cell tumor.

Occupational hazards to male fecundity

Research methods and knowledge in the field of male reproductive toxicology have gradually improved since reports in the late 1970s on severe impairment of spermatogenesis in workers with occupational exposure to certain chlorinated hydrocarbon pesticides (the nematocide 1,2-dibromochloropropan and the insecticide and fungicide chlordecone, but still we have only vague answers to basic questions about the overall significance of the environmental and occupational impact of these compounds on male reproductive capability.

Diagnostic value of alpha 1-fetoprotein and beta-human chorionic gonadotropin in infancy and childhood

This article provides a comprehensive review of the current literature and summarizes the experience of the German cooperative protocols for nontesticular germ cell tumors (MAKEI) on the use of alpha 1-fetoprotein (AFP) and beta-human chorionic gonadotropin (beta-hCG) for diagnostic evaluation in pediatric oncology. Based on this evaluation, this review proposes guidelines for the initial diagnostic work-up for children with clinically suspected secreting tumors. AFP and beta-hCG represent the characteristic tumor markers of malignant epithelial liver tumors and malignant germ cell tumors (GCT). They play an important role in the initial diagnostic evaluation as well as in the follow-up examination during therapy. Current therapeutic strategies for both tumor types include preoperative chemotherapy followed by delayed tumor resection. Therefore, it is essential for the pediatrician in charge to be aware of the broad differential diagnosis of elevated AFP and beta-hCG. In a well-defined clinical setting, these tumor markers allow clinical diagnosis without histological confirmation, but the physiologically elevated AFP serum levels in infancy or unrecognized benign conditions, such as hepatic diseases or hereditary disorders, must also be considered as differential diagnoses. Therefore, the laboratory investigations should include liver parameters in all patients to exclude hepatic disease. In addition, pregnancy must be excluded in adolescents. Careful history taking and clinical examination will further help to rule out metabolic disorders or ataxia teleangiectasia that are associated with elevated AFP levels. Having excluded these conditions, elevated AFP levels above the age-related normal range (with or without high beta-hCG), indicate malignant epithelial liver tumors in primary liver lesions. At virtually all other sites, the diagnosis of a malignant GCT with a substantial yolk sac tumor and/or choriocarcinoma component can be established. Pancreaticoblastoma should be considered in the differential diagnosis of tumors of the upper abdomen, and biopsy must be performed. Other childhood tumors are rarely associated with AFP or beta-hCG production, usually at only moderately elevated serum levels, and in most patients these tumors can be excluded by clinical and radiological examination.

[Experiments on the induction of embryopathies and changes in alpha-foetoprotein and serum albumin concentrations in the chick embryo]

Administration of 3 microg dexamethasone at day 8 of incubation into the allantoic cavity resulted in various embryopathies in embryos by the 15th day of incubation. Chicken alpha-foetoprotein (chAFP) and serum albumin concentrations, when examined at the 12th day of incubation, were below the corresponding controls (P<0.01), whereas total serum protein was only slightly lower, On day 15 chAFP concentrations were similar to those of the controls, serum albumin values were markedly reduced and total serum protein was significantly decreased. The results suggested a selective reduction of serum albumin synthesis in the 15-day-old chick embryo. Following administration of 2 IU insulin on the first day of incubation, into the yolk sac, one third of the embryos developed embryopathies. ChAFP, serum albumin and whole serum protein values were unchanged on either the 12th day or 15th day of incubation. Inoculation of 100 microg adrenaline into the allantoic cavity on the sixth day of incubation resulted in embryopathies in only a few instances. ChAFP total serum protein values were not affected. However, serum albumin concentrations were significantly lower on the 12th day, but not on the 15th. The responses to L-thyroxine were both time- and dose-dependent. Inoculation of 2 microg thyroxine on the second day of incubation resulted in few embryopathies. ChAFP levels were significantly lower on the 12th and 15th day of incubation. In contrast, serum albumin and total serum protein concentrations were normal at both times. Similar results were obtained when 2 microg of thyroxine were administered at the third day of incubation. Thus in order to inhibit selectively chAFP synthesis, administration of 2 microg thyroxine on day 2 or 3 of incubation is suggested. When 10 microg thyroxine were injected on day 8 of incubation, 80% of the embryos showed embryopathies on day 12 of incubation. ChAFP and serum albumin levels were markedly depressed. The concentration of total serum protein was significantly decreased on day 12 but less so, though still significantly, on day 15. These results demonstrate the possibility to influence selectively chAFP and serum albumin synthesis, thereby facilitating studies on chemically induced teratological, including pathophysiological, processes in the avian embryo.

Studies on lectin affinities of chicken alpha-fetoprotein during ontogeny

Alpha-fetoprotein in the sera of chicken embryos (ch-AFP) of the 7th, 10th, 13th, 16th, and 19th day of incubation and of one-day-old chickens were examined in crossed-immunoaffino-electrophoresis (CIAE) using different lectins [concanavalin A (Con A), lentil, wheat germ lectin, and soybean lectin] as ligands. Differences in lectin affinities, suggesting different degrees or forms of glycosylation of ch-AFP during ontogeny, were demonstrated by this method. Sera of chicken embryos of the same stages were also subjected to Con A affinity chromatography and the elution patterns were evaluated qualitatively in CIAE and quantitatively in rocket immunoelectrophoresis. These experiments revealed a major Con A-nonreactive and a minor Con A-reactive fraction at the 7th day of incubation. In contrast, a minor Con A nonreactive fraction and a major Con A-reactive fraction were observed at later stages of embryonic life. Extracts from embryos of the 8th and 15th day of incubation did not exhibit heterogeneity when subjected to CIAE. The biological significance of these observations, as well as the biological role of AFP in general, remains to be elucidated. Examination of ch-AFP glycosylation patterns might be included into the spectrum of analyses when certain early teratological processes in the chicken embryo are to be monitored. In addition, these molecular changes have to be considered when in vitro or in vivo experiments on the biological, especially immunological, role of ch-AFP are envisaged.

The possible role of the carcinoembryonic antigen (CEA) and other carcinofetal antigens in maligant and benign diseases of the gastrointestinal tract

In the present review we have discussed antigens, principally the CEA, which have their well defined place in the clinical management of the (malignant) diseases of the gastrointestinal tract. Though the immunological diagnosis of neoplasia is one of the research areas where the most effort and hopes are invested, it is also there, that the carcinofoetal antigens have the least usefullness at the moment. However, studies like those undertaken by Edgington and Plow are probably pointing out if not proving, that even relatively simple procedures like further purification of the antigen can improve its tumor specificity and consequently its diagnostical value (1975). Following their results the final verdict is not spoken yet as to whether CEA (or any other CFA) will even be more than an adjunctive tool in the diagnosis of malignant tumors specially those of the G.I. tract. The 0.6% of "false" positives these authors have obtained in their series with their highly purified CEA-S (against the 30% usually seen with classical CEA preparations) are provocative: one will have to discuss the question, on which grounds the decision "false positive" has been reached and whether these cases are not simply "clinically silent", hence true positive observations. The problem then would be shifted away from the CEA test (or any other CFA test) toward the improvement of all the other conventionally employed diagnostical measurements, which should allow the early confirmation--and localization--of a beginning neoplasia, which has been screened out by an immunological test. Until this is not warranted, the CEA test has its definite place and vocation at the present time in the follow-up of the treated cancer patient, whatever therapy he has received.

Cord serum levels of IgM, IgA, and alpha-fetoprotein and their interrelationships

IgM, IgA, and AFP concentrations were determined in a group of 30 umbilical cord sera chosen at random from the cord sera sampled over a period of one year. Because low levels were expected, use was made of sensitive techniques, which were standardized on the basis of international reference preparations. Geometric mean levels were 5.58 mg/l for IgA, 142 mg/l for IgM and 53.6 mg/l for AFP. Statistical analysis of the distinct IgM, IgA, and AFP levels showed no significant correlation with either birth weight or birth length. The difference between the sexes in the levels of these proteins was not significant either. The difference between the IgA concentration in sera from children of primipara and those of multipara mothers was significant. Moreover, a statistically significant negative correlation was found between the IgA and AFP levels. The results are discussed in relation to current knowledge about the ontogeny of humoral immunity in man and a possible biological function of AFP in ontogeny.

[Immunohistochemical and radioimmunological demonstration of alpha1-fetoprotein in nonmalignant changes of human gastric mucosa (author's transl)]

The occurrence of alpha1-fetoprotein in nonmalignant changes of the gastric mucosa was investigated by means of immunohistochemistry and radioimmunoassay. The investigations were performed in tissue sections, cytological imprint preparations as well as in homogenized tissue samples (obtained by gastroscopy). alpha1-fetoprotein could be demonstrated by immunohistochemistry in about 90% of the samples originating from the surroundings of gastric ulcer and the region of gastrojejunostomy after B II-resection. The RIA was positive in about 75% of the tissue samples, whereas from gastric juice only 40% of positive results could be obtained. No alpha1-fetoprotein-activity could be demonstrated in serum samples. These investigations indicate that alpha1-fetoprotein is not exclusively synthesized by embryonic or neoplastic tissues and also can be synthesized also by regenerating cell-systems. It may be supposed that this synthesis represents an unspecific answer to growth-stimulation.

Human chorionic gonadotropin (HCG) in monitoring the course of testicular tumours

In 29 patients with metastasising testicular tumours serial determination of HCG was performed for monitoring cytostatic chemotherapy. Clinical remissions and stable disease were accompanied by normalisation of elevated HCG values in 85% and 80% of all cases, respectively. Despite the normalisation of HCG levels, no complete disappearance of clinically detectable tumour lesions could be seen in the herein presented cases. Seventeen percent of the patients showed normal HCG levels, although they had progressive disease. Recurrent disease was associated with preceeding increase of HCG in only 33% of the cases. Because of the frequency of mixed tumour tissues in teratomas, additional methods for monitoring therapy should be used.

Serum-alpha1-fetoprotein in patients with testicular tumours

Serum-alpha1-fetoprotein (A.F.P.) was assayed in 88 men with testicular teratomas and 34 with seminomas. 61% of teratoma patients with clinically evident disease had serum-A.F.P. greater than 25 ng/ml, whilst it is highly unlikely that any patient with a pure seminoma had a titre above this level. A.F.P. concentrations correlated with response to radiotherapy and chemotherapy and predicted relapse in some patients. Serum-A.F.P. should be measured in all patients with testicular tumours.