The DNA content in epitheliocytes of the mucous membrane of the oral cavity and expression of carcinoembryonic antigen and trophoblast-specific beta-1 glycoprotein on peripheral blood lymphocytes, peripheral blood T-lymphocytes subsets into three groups of patients: 1--diffusion mastopathy; 2--diffusion mastopathy with fibromyoma uteri and 3--fibroadenoma were studied. It was indicated that DNA content was higher in all groups in comparison with healthy women and it was shown that in contrast to healthy women, 45% of patients studied had abnormal rate of T-cells subsets, about 30% of them had abnormal expression of CEA and TSG on peripheral blood lymphocytes. The data obtained show the significant disbalance in the mechanisms of defence and compensation taking place in the organisms of patients with nonmalignant mammary diseases.

A new point mutation, TCG(Ser)-->GCG(Ala) in codon 891, exon 15 of the RET protooncogene was revealed in two patients from a pedigree with familial medullary thyroid carcinoma (FMTC), but not in healthy persons. A linkage analysis with two well-known and two new intragene polymorphisms showed that informative polymorphic markers, the phenotypic expression of the disease, and the mutation are cosegregated in the studied pedigree. Two new polymorphisms, G/A at position-24 of intron 14 and C/T in codon 836 of exon 14, were found in the RET protooncogene. The frequencies of allele 1 of the polymorphic site in codon 836 were the same (0.96) in the Russian and German populations. This was also characteristic of two polymorphisms revealed earlier, namely, the sites in codons 691 (0.80 and 0.81, respectively) and 904 (0.21 and 0.22). However, the frequency of allele 1 of the polymorphisms in intron 14 differed significantly (0.87 and 0.77, respectively).

Most colorectal tumors are characterized, among other genetic alterations, by allele loss of the genes located on the short arm of chromosome 17 (17p13.1), including the p53 suppressor gene. In ovarian and mammary-gland tumors, deletions of another candidate tumor-suppressor gene, located in the 17p13.3 chromosome region, were observed. We analyzed allele losses in the loci of the short arm of chromosome 17 (YNZ22, MCT35.1, and the p53 gene) in colorectal-cancer patients from the former Soviet Union. Tumors with cytogenetic alterations in 17p and/or with a detected loss of heterozygosity at the YNZ22 (D17S30) locus were examined for allele losses in the p53 gene using two polymorphic sites. Different methods revealed alterations on 17p in 24 (48%) out of 50 patients with colorectal carcinomas. In all tumors with an allele loss of the YNZ22 marker (15 out of 44 informative cases), which was detected by means of PCR, allele loss of the p53 gene was found (12 out of 15 informative cases). In 5 out of 13 tumors with cytogenetic alterations in 17p, allele loss of the p53 gene was found, with the YNZ22 marker being unaffected. In one of these tumors, the i(17q) marker was found, and in the remaining four tumors, 17p translocations were detected. In 4 out of 5 tumors with translocations affecting 17p, the t(17;20)(q21;p12) translocation was detected. The informativeness of the screening for 17p translocations, using PCR for the YNZ22 locus, and the reasons for discrepancy between the data of PCR and cytogenetic analyses are discussed.

To determine genetic factors of predisposition marked HLA with reference to serological and molecular characteristics.

To confirm clonal nature of idiopathic hypereosinophilic syndrome (IHES), its relevance to Ph'-positive chronic myeloid leukemia.

To elucidate prognostic value of MDR-1 gene expression in patients with chronic myeloid leukemia (CML).

Analysis of cytostatic therapy effects on expression of gene MDR-1 in hemopoietic cells of patients with acute leukemia (AL) in complete clinicohematological remission (CCHR).

A boy with a large intracranial glioma of the optic tract and probable neurofibromatosis of the first type was observed for 8 years since the age of 7 years. A series of MR scans was made over this period. A notable decrease of the tumor size was seen on its signals on the MR scans. This was paralleled by an improvement of the vision acuity, color field, and visual field on the involved eye. Patient's grandmother had an intracranial glioma of the optic nerve with a slight but stable decrease of the visual functions. The tumor shape in the grandmother and grandchild is remarkably similar. This finding in the grandmother and stability of her vision decreased from childhood permit us to propose that the tumor did not develop and even regressed with time.

The majority of thyroid tumors are not homogeneous histologically, this creating difficulties in interpretation of different carcinoma variants. The aim of the study was a complex comparative study of morphogenetic changes in carcinoma, adenoma and surrounding thyroid tissue. Surgical material from 48 patients operated because of nodular (multinodular) euthyroid goiter in Moscow Medical Academy in 1990-1997 was used. It was established that all the observations of early thyroid carcinoma diagnosed clinically as a nodular (multinodular) euthyroid goiter were represented by differentiated forms of thyroid carcinoma. Thyroid carcinoma was characterized by higher values of biomolecular markers as compared to adenomas and surrounding tissue. High values of c-myc expression in adenomas and surrounding tissue may indicate possible genetic rearrangements. A peculiar feature of carcinomas was the fact that deletions and replication errors in malignant tumors in this study were found simultaneously in the three genes investigated. As to different histological types of carcinoma, the most frequent deletions of the genes studied were observed in medullary and papillary-follicular carcinoma. High values of heterozygosity loss were found already in adenomas and surrounding tissues, this indicating the presence of the genetic changes already in the benign tumors and surrounding tissue.

The investigation deals with a simplified modification or molecular-genetic detection of translocation t(9;22) using a combination of reverse transcription and polymerase chain reactions (RT-PCR). Unlike the available protocols, analysis is carried out using one enzyme--TET-Z polymerase--(instead of two) which has both revertase and DNA-polymerase activities. The present modification is highly sensitive, less time-consuming and cheaper. The method has proved useful for both diagnosing t(9;22) translocation and diagnosing and monitoring minimal residual disease remaining after marrow transplantation.

The results of molecular investigations of blood mononuclears from 120 clean-up workers after 7-9 years of Chernobyl accident with the total exposure radiation doses ranging from 5 to 76 cGr are presented. Structural polymorphism of the leukemia associated bcr and ribosomal RNA (rRNA) genes were studied using Southern blot hybridization. Allelic polymorphism of bcr gene with characteristic for leukemia allele distribution was detected in 16.6%. Rearrangements of rRNA genes were observed in 13% of Chernobyl accident clean-up workers.

A model of effector and regulatory determinants of the rate and coordination of proliferation of epithelial and stromal cells in the normal prostate in benign hyperplasia and cancer of the prostate was developed. The direct effector factors-protein growth factors, the regulatory factors: activators (5-alpha-reductase, dehydrotestosterone, prostatic specific antigen) and inhibitors (tumor suppressors and metastatic suppressors, insulin-like growth factor-binding protein type 3) were analyzed and systematized. The molecular mechanisms responsible for the occurrence and progression of prostatic tumors, the role of the above factors, genetic changes in the chromosomes and genes, impaired coordination in the action of oncogenes and antioncogenes were under investigation. Directions of experimental search for the earlier unknown links in the analyzed system are outlined. The prospects for designing and using new diagnostic and prognostic omcomarkers and new means for the prevention and treatment of benign hyperplasia and cancer of the prostate are defined.

Chromosomal aberrations (CAs), sister-chromatid exchanges (SCEs), aneuploidy and proliferative potential (PP) were investigated in peripheral blood lymphocytes of healthy cows (control group-C), BLV-(bovine leucosis virus)-infected cattle without hematological abnormalities (RID--seropositive group (I) and affected with leucaemia (lymphocytosis (LC), lymphoma (L)). Nonrandom chromosomal (marker) aberrations were not found in the cow group at stage LC. The levels of aneuploidy and SCEs increased in the cow group at stage L compared to the cow group at stage I. Polyploidy: C--1.9 +/- 0.28, I--3.5 +/- 0.22, LC--6.1 +/- 0.82, L--10.5 +/- 0.51 (P < 0.01). Hypoploidy (2n = 58): C--3.0 +/- 0.17, I--54 +/- 0.71, LC--12.1 +/- 0.72, L--14.0 +/- 0.65 (P < 0.01). SCEs: C--3.8 +/- 0.26, I--5.4 +/- 0.15, LC--7.2 +/- 0.16, L--9.7 +/- 0.26 (P < 0.01). There are no differences in CAs rates and PP between groups of cows at all the observed stages of leucaemic process. The obtained results are discussed in terms of cytogenetic aspects of leucaemic process in cows.

In the present paper we have shown that JB6 and PDV murine skin carcinoma cells, as well as previously described sarcoma B6-4 cells, can revert to a nontumor phenotype. Revertant carcinoma clones could not grow in soft agar conditions and like sarcoma revertants acquired dependence on peptide growth factors, and exhibited a reduced expression of c-jun. Spontaneous revertants were shown to be instable. They could revert back to a transformed phenotype in 1-5 months of in vitro passaging. Being inoculated in syngeneic animals, these transformed cells show a recurrence in 2-5 months, similar to that of a dormant metastasis. Thus, dormant revertant cells are believed to be included in many tumors of different origin. So, spontaneous reversions of tumor cells may play an important role in the dormant metastatic process. The cause of these frequent spontaneous transient reversions and revertant instability appears to be of epigenetic nature. Causes and mechanisms of cell transformations and reversions remain to be clarified.

Due to immunophenotypic examination of bioptic samples from 30 patients with non-Hodgkin's lymphoma (NHL), malignancy of B-cell NHL was identified at an early stage of diagnosis, before histological analysis yielded the results. Negative expression of T-cell antigens, monoclonal character of light-weight chains of immunoglobulins, positive expression of B-cell antigens and marked expression of CD5+ are immunologic markers of low-malignancy B-cell NHL. A similar immunophenotypic pattern, involving negative expression of CD5- and positive one for Calla-antigen as well as one identifiable by monoclonal non-cluster antibody IPO3, is a marker of highly-malignant B-cell NHL.