Biomedical subjects

L N Liubchenko

Publications and source records attributed to L N Liubchenko.

At least 19 recordsLinked to original sources

PubMed2003

[Analysis of mutations in the RET proto-oncogene in patients with medullary thyroid tumor].

The spectrum of mutations of the RET protooncogene was analyzed in Russian patients with inherited or sporadic medullary thyroid carcinoma (MTC). Four RET exons (11, 13, 15, and 16) were subjected to molecular analysis, and mutations were revealed and identified in 47.4% (9/19) patients with sporadic MTC. In total, six mutations (including three new ones) were observed. The most common mutation affected codon 918 to cause substitution of methionine with threonine and accounted for 31.6% alleles. Analysis of exons 11 and 16 revealed four mutations in patients with inherited multiple endocrine neoplasia type 2 (MEN 2). Mutations were found in each patient. Thyroidectomy was performed in four asymptomatic carriers of RET mutations from three MET 2A families (in two families, affected relatives had bilateral pheochromocytoma). In two patients, analysis of the surgery material revealed MTC microfoci in both lobes of the thyroid gland. The results provide the ground for constructing a bank of genetic information on Russian MTC patients with the clinically verified diagnosis.

Adolescent↗

PubMed2001

[Molecular diagnosis of multiple type 2 endocrine neoplasia].

The paper reviews the data on the molecular structure of the protooncogene RET encoding for receptor-type protein kinase, on the mechanism of transformation of the normal protooncogene RET to a dominant transforming oncogene, and on RET mutations detected in patients with the MEN-2 syndrome. Moreover, it presents the authors' own findings. The familial medullary thyroid carcinoma burdened genealogy shows a new point mutation TCG(Ser)-->GCG(Ala) in codon 891, in the exon 15 of the protooncogene RET. This mutation was not detected in the chromosomes of healthy individuals. Analyzing the linkage with two known and two new polymorphic markers showed that there was a cisaggregation of informative polymorphic markers, phenotypic manifestation of the disease, and mutations in the genealogy in question. In the protooncogene RET, there were two new polymorphisms: G/A at position 24 in intron 14 and C/T in codon 836 (exon 14). The rate of the polymorphism encountered in codon 836 proved to be similar for the Russians and the Germans (0.96%), which was also seen for two earlier described polymorphisms in codon 691 (0.80 and 0.81, respectively) and in codon 904 (0.21 and 0.22). At the same time, there were statistically significant differences in the rates of intron 14 polymorphism (0.87 and 0.77, respectively). In a family having MEN 2, a proband displayed TGC-->CGC mutation in codon 634 of the gene RET in the heterozygous state. The mutation results in substitution of cysteine amino acid residue in the cysteine-rich extracellular domain of protein kinase encoded by the gene RET for arginine. The results of molecular analysis were used to confirm its clinical diagnosis and to indicate that effective care should be delivered in MEN 2a.

Alleles↗

PubMed2001

[Hereditary cancer: identification, genetic heterogeneity, medico-genetic consult].

The paper deals with a role of inherited factors responsible for the occurrence of malignant tumors. Inherited types of cancer are shown to occur virtually at its sites and averaged 5-15%. Formalized criteria for identifying inherited cancer diseases and their etiological and genetic heterogeneity are presented. A role of genes that genetically predispose to particular forms of cancer is shown, which allows for early (preclinical) diagnosis and prevention of cancer diseases.

Genetic Counseling↗

PubMed1984