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The purpose of the study was to evaluate the prognostic significance of carcinoerembryonic antigen in patients with rectal cancer and correlate its baseline with the degree of therapeutic pathomorphosis after neoadjuvant chemoradiotherapy.Materials and methods. An estimate of the informative value of carcinoerembryonic antigen (CEA) indices in 179 patients with colorectal cancer determined before and after preoperative chemoradiotherapy (CRT) in SOD 50 Gy.Results. Analysis of the results presented in the study showed that in all patients, CRT caused a significant decrease in the level of CEA (–71%) 10 weeks after its end (p < 0.001). In the course of the pathomorphological study, after the neoadjuvant treatment, the first degree of tumor pathomorphism was recorded in 4.5% of patients, II – 38.5%, III – 45%, IV – 12% (the degree of pathomorphosis is not related to the clinical stage and the degree of differentiation of colorectal cancer). It was revealed that patients with III and IV degrees of therapeutic pathomorphosis initially had a CEA level lower, in comparison with patients with grade I-II. Clinical progression of the disease is diagnosed in 24% of cases (43/179). It was noted that in patients with the IV degree of therapeutic pathomorphism of the tumor, no recurrence of the rectal cancer was detected in either case.Conclusion. The results of the study showed that the problem of individual prediction of the effectiveness of combined treatment of the rectal cancer remains very relevant, rather complicated and yet not completely solved. However, it can be assumed that the use of such an indicator as CEA in monitoring patients after the treatment, can serve as a criterion for the sensitivity of colorectal cancer to CRT. Initially low antigen level can be considered as a positive factor of tumor response to ongoing treatment and disease-free survival of patients with locally advanced rectal cancer.

Introduction. The results of the calcitonin (Ctn) study in patients with thyroid nodules are included in the clinical guidelines for the treatment of differentiated thyroid cancer. However, the management of patients with moderately elevated Ctn up to 100 pg/mL is not clearly defined.Materials and methods. The study included 103 patients with thyroid nodules and a Ctn level above the reference, but not more than 100 pg/ml. The Ctn concentration was determined using the Cobas e platform (Roche, Germany) or by the immunoradiometric method (Izotop, Hungary). 45 patients were operated on. The analysis of the incidence of medullary thyroid carcinoma (MTC), other thyroid and nonthyroid pathology in patients with elevated Ctn scan was carried out. The results of additional examination are presented: the serum cancer embryonic antigen, Ctn in wash-out, stimulated Ctn, gene RET mutation testing.The study objective is to evaluate the probability MTC with Ctn level 2000 pg/mL in mTC and up to 938 pg/mL in patients with histologically confirmed absence of MTC.Conclusion. If the Ctn level is

Objective: in paper direct results of investigation the products of tumor makers – CEA (carcino-embryonic antigen), CYFRA 21-1 and SCC and heat shock proteins hsp27, hsp70, hsp90. reflacting the possibility of malignization epithelial cells in chronic hyperpiastic laryngitis.Materials and methods. There were investigated 36 patients with chronic hyperplastic laryngitis. It was investigated the production of CEA (carcino-embryonic antigen), CYFRA 21-1, SCC and heat shock proteins hsp27, hsp70 in immune-enzyme method. The variation of serum concentration oncomarkers was investigated in dependent on the maximum production of heat shock proteins reflactihg the value of cell stress in chronic hyperplastic laryngitis. Statistics analysis was convey in programs Statistica (version 6,0) and “Biostat 4.03”.Results. It was shown more prognostic informative in chronic hyperplastic laryngitis the level of CEA, CYFRA 21-1 and SCC on the background of maximum production of heat shock proteins hsp27, hsp70, hsp90. The serum level of CEA was higher in comparison with control. On the maximum of production hsp27, hsp70, hsp90 the concentration of CEA was 2–3 ng/ml, Cyfra 21-1 – 0–1,2 ng/ml and SCC 1–2 ng/ml. Conclusions. Variation of serum oncomarkers level of CEA – 2–3 ng/ml, CYFRA 21-1 – 0–1,2 ng/ml and SCC – 1–2 ng/ml are the prognostic value in the possibility of malignization epithelial cells in chronic hyperpiastic laryngitis. This results is important in clinical practice.

The study was concerned with a comparison of immune response to antigen obtained from human embryonic intestine in patients with malignant and benign tumors of the breast and ovaries, cancer of the urinary bladder, cases of various inflammatory diseases and healthy controls. Application of this marker in the skin test of time-delayed hypersensitivity reaction provided a means of evaluation of tumor-associated immunological vigor. The results point to the similarity of skin reactions of time-delayed hypersensitivity in cases of mastopathy and early stages of breast cancer. Therefore, human embryonic antigen may be used as an additional criterion of assessment of immunocompetence of patients with precancerous lesions and malignant neoplasms.

The indirect method of immunofluorescent analysis was applied to the study of the localization of the carcinoembryonic antigen (CEA) in pseudomucinous cystoma of the ovary and adenocarcinoma of the large intestine. CEA proved to be concentrated in the membranes and the basal part of the epithelial cells both in the pseudomucinous cystoma of the ovary and in the carcinoma of the large intestine.

The occurrence of a tumour-specific antigen in the intestinal tumours (induced in 51 albino rats by subcutaneous injection of 1,2-dimethylhydrazine), as well as in the blood serum was studied by double immunodiffusion in agar gel. Intestinal tumours proved to contain a water-soluble antigen absent in other tissues, including the colonic mucosa of control animals. This antigen was found in 70 per cent of the tumour-bearing rats. The antigen is perchloric acid-solubilized and is also present in the embryonic tissues in toto on the 7th and the 9th days of rat gestation. The features of this antigen were analogous with those of the carcino-embryonic antigen in human digestive tract tumours.

The spatial structure features of intact and deglycosylated carcino-embryonic antigen (CEA) have been studied by circular dichroism. Raman and UV-spectroscopy methods in order to elucidate a pattern and localization of CEA immunodominants. The temperature-induced changes in the spatial structure of the protein moiety were compared with data on the CEA immunochemical activity estimated by EIA procedure. A conformational transition was found within the 55-75 degrees range that produced irreversible alterations in the tertiary structure, while the secondary structure could be restored after lowering the temperature to 20 degrees C. Spectral studies of intact and deglycosylated CEA demonstrated that immunochemical activity, at least partly, was associated with the tertiary structure of the CEA protein portion.

Temperature-, ionic strength-, calcium ion- and pH-dependence of spatial structure of crustacin have been studied using CD and fluorescent spectroscopy. Secondary structure of crustacin was estimated by CD spectra. An irreversible conformational transition of crustacin's protein moiety connected with the loss of CEA-binding activity has been found at ca. 50 degrees C. Crustacin is shown to be calcium-binding protein, stability of the native crustacin conformation being markedly enhanced by calcium ions (1 mM Ca2+ shifted up the transition temperature by approximately 10 degrees C). Calcium binding and ionic strength increase led to alteration of both secondary and tertiary structures of crustacin. The highest CEA-binding activity was observed for the calcium-bond form of crustacin. A lack of specific interaction of crustacin with some saccharides was shown. Interrelation between conformation and immunochemical activity of crustacin is discussed.

To obtain highly efficient immunosorbents for solid-phase immunoassay and affinity chromatography, methods for immobilization of antibodies against the carcino-embryonic antigen (CEA) on insoluble matrices were optimized. The immunosorbents obtained were characterized by equilibrium parameters of the reaction between immobilized anti-CEA and CEA calculated from rather a simple kinetic model. This model describes the interaction of the monovalent antigen with two independent types of binding sites. The role of some amino acid residues of anti-CEA in the interaction with CEA was investigated. The effects of immobilization density and the spacer arm length on the functional properties of the immobilized antibodies were studied. The optimal immunosorbent was used to purify 125I-CEA by immunoaffinity chromatography.

The purpose of this review was to analyze the most perspective methods for risk stratification of malignant transformation of pancreatic intraductal papillary mucinous neoplasms (IPMN). Advisability of humoral predictors (tumor markers, inflammatory markers, circulating leptin and branched-chain amino acids, etc.) is in identifying prognostic signs suitable for risk stratification of IPMN malignant transformation and, therefore, determining treatment strategy for a particular patient. According to data screening, the most advisable predictors of malignant transformation of neoplasms are carbohydrate antigen 19-9, carcinoembryonic antigen, neutrophil-to-lymphocyte ratio and high-grade dysplasia. At the same time, DNA sequencing, analysis of miRNA and telomere expression, as well as liquid biopsy have a high potential and require further research for routine clinical practice.

The purpose of this work is to determine the optimal markers for clarifying the degree of proliferative activity in benign breast lesions, which can be used in surgical treatment planning. Materials and methods. The immunocytochemical results of tumor proliferation marker (Ki-67), cancer-embryonic antigen (CEA), matrix metalloproteinase-9 (MMP-9) and vascular endothelial growth factor (VEGF) expression were studied in biopsy samples collected from 108 patients with benign breast lesions and 49 patients with breast cancer. Results. It was found that the proliferative processes rising was accompanied by an increase in the number of patients with expression of Ki-67 to 28.0 %, CEA to 44.0 %, VEGF to 80.0 %, and a decrease in the number of patients with MMP-9 expression from 75.0 % to 36.4 %. Among patients with breast cancer, cells expressing Ki-67 were observed in 36.8 %, MMP-9 in 20.7 %, CEA in 36.4 %, VEGF in 48.3 %. The results indicate the presence of a neoplastic potential in benign lesions and its enhancement with an increase in proliferative properties. Conclusions. This diagnostic method can be used to determine the malignant potential in benign breast lesions and for therapeutic decision making.

This review reveals the anatomical, physiological and embryogenetic features of the proximal colon to explain the reasons for such frequent localization of mucinous phenotype of adenocarcinoma (MAC) here. It was shown that later differentiation in embryogenesis causes relative insufficiency of the proximal part as a structure of the digestive and immune systems. Physiologically lower lymphoid tissue (GALT) density here leads to the formation of a certain composition of the intestinal microbiota, which is different from that in the distal part, which is a significant link in the etiopathogenesis of proximal colon cancer. It is confirmed also by different composition of biofilms on the surface of epithelial tumors in the right and left halves of the colon, as well as differences in the molecular mechanisms of carcinogenesis, depending on the location of the cancer. Common for proximal part genetic changes, called as CIMP-phenotype, microsatellite instability and BRAF proto-oncogene mutation lead to excessive secretion of specific mucin fractions (mainly MUC2 and MUC5AC), the imbalance of its composition and the formation of MAC. An earlier age of onset, frequent association with hereditary non-polypous colorectal carcinoma, the predominance of MUC2 and MUC5AC fractions, similar to the embryonic period, as well as a higher level of cancer-embryonic antigen in patients with MAC indicate the influence of anatomical, physiological and embryogenetic features of the proximal colon on carcinogenesis long before its formation. Thus, a detailed understanding of MAC carcinogenesis is necessary for an adequate assessment of its effective prevention in time, as well as dealing with it as with specific nosological unit requiring specific treatment principles.

Aim of the case presentation. To demonstrate the rare case of extranodal lymphoma with primary extensive liver involvement which caused difficulties at diagnosis verification. Despite of rapid disease progression with development of severe liver failure, that resulted in poor prognosis, patient demonstrated significant response to high-dose chemotherapy and achieved long-term remission. Summary. Male 38-year-old patient developed acute symptoms: sweating, general weakness, febrile fever, weight loss (50 kg for 4 months), abdominal pain combined to hepatomegaly and multiple focal lesions in the liver according to abdominal US, with 5 unsuccessful attempts for 6 months to receive informative tissue sample. Laboratory tests revealed progressive signs of liver failure at normal level of alpha-fetoprotein and carcino-embryonic antigen; clinical signs included progressive manifestations of liver encephalopathy, skin hemorrhages, severe edema, ascites, pruritis and excoriations. Empirical therapy by prednisolon resulted in no responce and was complicated by development of steroid diabetes. The diagnosis of diffuse B-macrocellular lymphoma was established only via open liver biopsy. Four sessions of high-dose polychemotherapy according to mNHL-BFM-90 program resulted in rapid reduction of liver size, recovery of consciousness, resolution of encephalopathy signs, however the liver and the spleen remained enlarged with focal parenchimatous lesions that required laparoscopy with biopsy of the pathological foci, the latter revealed no remaining neoplastic cells. During 10 years of patient follow-up liver function remains compensated, focal lesions in the liver and the spleen are undetectable, that indicates achievement of 113-months complete tumor remission. Conclusion. Presence of multiple focal lesions in the liver and signs of progressive liver failure at normal level of tumor markers requires taking into account primary liver lymphoma in the spectrum of possible etiologies. Potentially poor life prognosis in similar clinical situations at detection of primary liver lymphoma can flip to favorable due to high efficacy of modern chemotherapeutic agents.

Introduction. Now the uterine leiomyoma (LM) remains the most common benign tumor of the female genitalia. Data on the histological composition, structure and properties of expression of hormones receptors of LM tissue are important for understanding the mechanisms of development of various clinical and pathogenetic variants of the tumor. Aim is to study the relationship between morphological and immunohistochemical features of LM with a pathogenetic variant of the disease development aimed at developing differentiated methods of tumor treatment. Materials and methods. The research included 188 women of reproductive age (30 to 49 years old) who underwent hysterectomy for symptomatic LM. Depending on the presence of concomitant pathology of mammary gland (MG) and thyroid gland (TG), patients were divided into groups: the first group were 67 (35.64 %) women with isolated LM (ILM), the second – 32 (17.02 %) patients with a combination of LM and dyshormonal diseases of the MG (DSMG), the third – 48 (25,53 %) women with LM associated with thyroid pathology, and the fourth – 41 (21.81 %) patients with a combination of LM, DSMG and thyroid pathology – combined leiomyoma of the uterus (CLU). The morphofunctional condition of the removed tissue and the proliferative potential of LM were determined by the results of histological, ultrastructural, immunohistochemical studies (antigen of receptors for estradiol, progesterone, prolactin, type IV collagen, nuclei of proliferating cells and chancer-embryonic antigen) by indirect streptavidin-peroxidase method using Kit-monoclonal antibodies. Results. Single tumors occurred in 28.13 % of cases in patients of II, in 39.58 % – III and in 17.07 % – IV groups, which was significantly less than in women of group I (74.63 %; p < 0.05). In the morphological structure of uterine fibroids, removed from women of the I group, fibrous tissue prevailed in 80.6 % of cases, whereas in 73 % of the combined tumors smooth muscle components were found. According to the results of immunohistochemical studies, the highest positive expression rate of type IV collagen antigen (60.0 %) was observed in patients of group I against the background of low sensitivity to estrogens (H-score 25.83 ± 7.12), high – to progesterone (H-score 108.54 ± 12.66) and medium to prolactin. In combined leiomyoma, the highest level of receptor antigens expression to sex steroid hormones (estradiol and progesterone), prolactin (78.57 %) and markers of true proliferation and malignancy: PCNA (64.29 %) and CEA (42.86 %) was noted. For example, 84.0 % of patients in Group IV have an average expression of estrogen receptors, 76.0 % have a high level of progesterone expression in the nuclei and cytoplasm of myocytes with a high average expression in the H-score of the progesterone receptor antigen (209.94 ± 16.34), which is significantly higher than in women in group I (108.54 ± 12.66, p < 0.05). The findings indicate large hormone dependence, proliferative potential and the likelihood of malignancy of the combined uterine leyomyoma. Conclusions. Isolated uterine leiomyoma is mostly represented by large single, nodular formations that have a low sensitivity to sex steroid hormones with a superiority of progesterone, and a negligible risk of malignancy. The uterine leiomyoma, in combination with the thyroid and mammary pathology, is characterized by multiple diffuse, small nodular tumor formation with pronounced expression to sex steroid hormones, including estradiol, accompanied by high growth potentials and a significant probability of malignancy.

The searching of laboratory predictors of pneumonia in patients with ischemic stroke is an actual issue. The fetal proteins can be such biomarkers. The study was carried out to determine significance of such fetal proteins as alpha-fetoprotein, cancerous embryonic antigen, CA 19-9, CA 125, CA 15-3, CA 72-4, CYFRA 21-1 for prognosis of development of pneumonia in patients with ischemic stroke. The study included sampling of 216 patients in acute period of ischemic stroke. All patients were measured level of fetal proteins in first day from onset of disease using electrochemiluminescence immunoassay. It is demonstrated that CA 72-4 has the most significance for prognosis of development of pneumonia from all analyzed proteins and complications of ischemic stroke. The probability ratio relatively to other fetal proteins added up to 0.460 (CL 95% 0.267-0.791, p=0.011), to other complications--0.629 (CL 95% 0.433-0.913, p=0.015). The threshold value of CA 72-4 for development of pneumonia added up to 0.82 (CL 95% 0.68-0.96, p=0.011) U/ml. Under lower level of CA 72-4 the risk of development of pneumonia increases. Under higher level of CA 72-4 there is statistical probability of absence of developmnent of pneumonia. The threshold value was lower than reference interval which in the study added up to 0.85-1.42 U/ml. The detection of level of CA 72-4 on first day after onset of stroke in patients can be recommended for establishing of group of high risk of development of pneumonia and implementation of therapeutic activities.

In this article review diagnostic value of protein group-lectins for practical oncology are presented. It is indicated, that with some carbohydrate structures lectins revealed the possibility of reversible and selective action and with earlier elaborated methods, which are based on identification of antigen determinants with antibodies, they can significantly increase of tumour diagnostic sensitivity and specificity. It is consider the mechanisms of relationship between so-called mannan-binding lectins and mannans or carbohydrate structures, which are formed from the mannose residue. The presense of such mannose-enrich structures is connecting with the process of blastomic transformation. It was shown experimentally, that mannan-bindig lectins are interacting with the carbohydrate chains of the markers of blastomic transformation, particularly with the cancer-embryonic antigen. It was established the markedly increase of lectins gene expression in transformated cells. The gene therapy, which comprises the deliver of therapeutic genes to cells and tissues by virus vectors and nonvirus systems is also analysed. The last of them are the most widely using ligands containing oligosaccharides, because on the surface of many animal origin cells were identified lectins-protein receptors. It is suggested the perspectives of using oligosaccharide probes, which are the ligands for endogenous receptors-lectins in tumour diagnostic and guiding transport of medicinal products.

Preoperative indices of cancer embryonic antigen (CEA), carbohydrate antigens 19-9(CA)19-9, 72-4(CA)72-4, and alfa-fetaprotein (AFP) in 60 patients with gastric cancer were compared with the results of postoperative staging of the malignant process. It was found that increased concentration of one of the tumor markers were not a significant diagnostic sign of the metastases of gastric cancer. CEA is considered as an exception since its more than one and a half elevation (more than 3.75 ng/ml) suggests the presence of metastases with 80% probability. An increased concentration of any two oncomarkers (CEA, CA19-9, CA 72-4) points to the metastases of gastric cancer with 83.3% probability and usually coincides with the presence of distant metastases. A simultaneous elevation of indices of three tumor markers does not occur in gastric cancer. AFP is not informative in cases of gastric cancer and its dissemination.

A comprehensive examination, including clinical X-ray tomography, thermography, bronchological, cytological, immunological, and radioimmune studies, was made in 105 patients with lung pathology (tuberculosis and cancer of the lung in 56 and 49 patients, respectively) who had been detected during screenings. Among the routine methods, X-ray tomography is of the most informative value (81.9%). The informative value of telethermography for the verification of specific and malignant processes is 73.5%. A complex immunological study assisted to differentially diagnosis tuberculosis and cancer of the lung in 72% of cases. The informative value of measurements of cancer embryonic antigen in lung cancer is 89.6%, that of calcitonin and parathyroid hormone is 69.4 and 73.5%, respectively.

A comprehensive survey, including clinical, X-ray, thermographic, immunological, and radioimmunological studies, was made in 56 patients with lung cancer detected on prophylactic fluorographic surveys and erroneously referred to the Lvov Regional Clinical and Diagnostic Phthisiopulmonological Center for suspected active pulmonary tuberculosis. Routine clinical and laboratory studies provided preliminary information in only 26.8% of cases and 73.2% needed additional examination by using currently available laboratory and instrumental studies. Of the most informative value for diagnosing malignancy is radioimmunocompetitive assay of serum levels of cancer embryonic antigen.

The levels of embryonic antigens (cancer embryonic antigen, alpha-fetoprotein, beta-chorionic gonadotropin were measured in the serum, spinal fluid, the cystic fluid of tumor 83 of neuro-oncological patients. It was found that the blood concentrations of cancer embryonic antigen and alpha-fetoprotein were not generally related to the degree of malignancy and the blood level of beta-chorionic gonadotropin decreased with the higher degree of tumor anaplasia. The high content of beta-chorionic gonadotropin in the spinal fluid suggests its origin from a brain tumor. The fatal postoperative outcome was noted in patients having high preoperative serum levels of alpha-fetoprotein and cancer embryonic antigen with simultaneous much higher concentrations of alpha-fetoprotein in the serum than those in the spinal fluid.

The ability of exogenous p53 tumor-suppressor and activated N-PAS oncogene to influence differentiation state of human colon carcinoma LIM 1215 cells and their derivatives with acquired resistance to actinomycin D or methotrexate was analysed Introduction of retroviral construct expressing human wild-type (wt) p53 into LIM 1215 cells induced electron microscopic manifestations of enterocytic differentiation, i.e. caused an increase in the numbers of cells with microvilli, desmosomes and glandular-like lumens. Mutations at codons 248 or 273, the most frequent p53 changes in primary colorectal cancer, partially abrogated the ability of p53 to stimulate differentiation of LIM 1215 cells. Human M-PASasp12 showed stronger stimulation of cell differentiation as compared to p53wt. Especially high proportion (> 80%) of cells possessing pronounced manifestations of columnar enterocytic differentiation was observed after introduction of PAS-expressing construct into methotrexate-resistant LIM 1215 cell subline that originally demonstrated higher maturation than parental cell line. In cell subline with two introduced genes, activated PAS and mutant p53His273, the number of differentiated cells was similar to that observed in cell culture containing only PAS-construct. However, these two sublines differed in the quantity of desmosomes as well as in carcino-embryonic antigen (CEA) expression. Comparison of expression of different electron microscopic features of cell differentiation and CEA expression in cell sublines selected for methotrexate-resistance and/or expressing exogenous constructs allows to suppose that p53 tumor-suppressor, PAS oncogene and dhfr gene amplification may lead to somewhat distinct differentiation states.

New criteria of prognosis are established on the basis of study of 265 surgically removed stomach carcinomas. The factors of an unfavourable prognosis are as follows: young age, dysproteinemia, low blood coagulability, high leucocytosis and reaction of erythrocyte sedimentation, endocrine diseases, eosinophilic infiltration of stroma with high content of collagen type V and fibronectin, high expression of pepsinogen C, gastrin and carcino-embryonic antigen in the tumour parenchyma.

Combined versus separate exposure of male organism to cesium-137 and chemical agents results in a more pronounced hyperferritinemia in the former case. In female chemists the ferritin level is dependent to a considerable extent on the menstrual cycle showing a tendency for the iron-containing protein level to decrease because of the action of a number of chemical agents. The rise of the level of cancer embryonic antigen is more readily seen in persons with high levels of cesium-137. Concentrations of carbohydrate antigen (CA-125) and mucin-like antigen are appreciably higher in female chemists incorporating cesium-137, and in those within the 30-km radius of the ChNPP. The level of thyroglobulin was raised in the chemists having a background incorporation of cesium, the liquidators of the aftermaths, and particularly in those happened to be in the 30-km zone. Each of the unfavourable factors taken separately (chemical agent or cesium-137) had lesser effect on the degree of elevation of TG content and hormone-forming function of the thyroid gland. An additional information has been obtained concerning the risk groups, which, however, serves as an indirect measure of carcinogenic effect various environmental factors exert on the organism.

Antisera were obtained by rabbits immunization with pooled extract from ovarian carcinoma and its metastases into the ome tum. Using standard test-system antigen, precipitating in agar, was identified in the tissue of 12 out of 24 primary ovarian carcinomas and in 8 out of 20 metastases. It was not revealed in adult healthy internal organs tissues and in fetal tissues, except embryonal large intestine, where it was determined in trace amounts in isolated samples. Using immunodiffusion method it wasn't determined in blood serum of healthy people and patients, pregnant women and neonates. Immunochemical identification using standard test-systems showed that this antigen is not identical with already known carcino-embryonic antigen, placental, reactive and onco-ovarian proteins. It presents acid-soluble alpha-2-globulin (ASAG-2) with MW 55 kD determined by gel-filtration and 55 kD determined by electrophoresis in 10% polyacrylamide gel with dodecylsulfate under reducing conditions. Physico-chemical and antigenic properties of ASAG-2, as we think, give the opportunity to present it as a new onco-ovarian antigen, which differs from the known proteins.

Radioimmunoassay of carcino-embryonic antigen was conducted in lung cancer patients before and after surgery. Elevated concentrations of the antigen before operation was registered in 84.8% of cases. Antigen levels returned to normal after radical removal of tumor and rose sharply as a result of chemotherapy toxicity. A similar pattern of changes in carcino-embryonic antigen level was observed in cases of disseminated and recurrent cancer.

Chemical modification of different amino acid residues and the carbohydrate moiety of antibodies to carcino-embryonic antigen (CEA) was used to elucidate their role in the interaction with CEA and to evaluate the effect of antibody modification and steric factor in immunosorbent synthesis. The distribution of the modified groups among the structural fragments of IgG and the levels of changes in the antigen-binding properties of modified antibodies were investigated. The Fc-fragment of IgG was shown to contain carboxylic groups, tyrosine and histidine residues, whose modification influences the antigen-binding properties as a result of generalized conformational changes in the IgG molecule. A comparison of these results with earlier obtained data on the functional properties, of immobilized antibodies revealed that the decrease of antigen-binding characteristics of anti-CEA after IgG immobilization via NH2- and COOH-groups, carbohydrate moiety, tyrosine and histidine residues is due to the direct effect of antibody modification, whereas the changes in parameters of antibody interaction with antigen after IgG immobilization via SH-groups, methionine and histidine residues is due to steric hindrances.

A new embryonic antigen was found in the ovarian tumour tissues by immunodiffusion methods. This antigen consists of two components with a different electrophoretic mobility: a low peak migrates in the alha0-globulin zone, and a rapid one - in the prealbumin zone; it differs immunologically from alpha-fetoprot ein and cancer embrynoic antigen of the large intestine. This antigen was found in the fetus and newborn blood serum and also in the tissue extracts of ovarian tumours. No such antigen was revealed in the normal tissues of adults, or in the blood serum of donors and oncological patients.

Antigenic determinants of carcino-embryonic antigen (CEA) were spatially located using N-bromosuccinimide modification of tryptophan residues both in native (acetate buffer solution) and unfolded (guanidinium chloride solution) molecule of the antigen. Modification of exposed tryptophan residues failed to alter CEA antigenic activity and conformation of its protein portion as shown by CD spectroscopy. On the contrary, modification of buried tryptophan residues induced conformational changes of CEA protein portion connected with a considerable loss of its antigenic activity. It was shown that CEA antigenic activity depends on spatial structure of its protein moiety.

Radioimmunologic procedures were employed in comparing the levels of carcino-embryonic antigen in the gastric juice, blood plasma and saliva in cases of stomach cancer, gastritis, polyposis and gastric ulcer. No correlation between the antigen levels in different biological fluids was established. It was found, however, that the assay of carcino-embryonic antigen level in gastric juice may be instrumental in detecting precancerous lesions of the stomach.

The reactivity of the lymphocytes from 40 carcinoma patients and 19 patients without detectable malignancies was tested by means of the macrophage-electrophoresis-mobility (MEM) test exposing lymphocytes from one individual to a large spectrum of antigenic preparations. Besides the encephalitogenic protein (EP) and the carcino-embryonic antigen (CEA) hypertonic KCl-extracts from human cancer and normal tissues were used as antigens to be tested. When performed in such a complex manner, the MEM-test resulted in characteristic reaction patterns allowing one not only to discriminate between cancer and noncancer, but also to draw a conclusion in which organ a carcinoma has arisen. The characteristic "immunological tumor profiles", thus obtained, are obviously due to the existance of common antigens in carcinomas of the same tissue origin. The CEA seems to be another antigen of high diagnostic value in that system, since the lymphocyte response to CEA was restricted to patients with tumors of the colon, rectum and stomach. The results show for the first time that lymphocytes of the tumor patients mentioned are able to react to CEA. The human lymphocyte response to CEA seems to be far more cancer- and (or embryo-specific than the reactions obtained with xenogenic hyperimmune sera) which areused for the detection of CEA in human sera or plasma samples. The "immunological tumor profile" opens a new step of quality among the attempts to develop immunological tumor tests.

Sera of rats in which an extensive injury of the caecum was inflicted were studied by precipitation in agar. The carcino-embryonic antigen appeared in the sera of 84% of the animals 24 hours after the damage, and persisted in the majority of the animals for a period of 15-20 days; this corresponded to the period of the most pronounced regeneration of the intestinal mucosa.

Blood plasma levels of carcino-embryonic antigen in 128 patients and 50 healthy subjects were measured radioimmunologically. A significant increase was not registered until stage III of the disease. Peak level of carcino-embryonic antigen level was at stage IV. The concentration dropped rapidly after a complication-free radical surgery. A dynamic follow-up established an increase in the level of the antigen in cases of recurrences and metastases. The concentration rose, on the average, 3.5 months prior to development of the first clinical symptoms.