Preparing Triple-Compound Heterozygous Control Material for Molecular Diagnostics of TPMT Allelic Variants.

The aim of the study is to present a novel approach for preparing triple-compound heterozygous reference material (TCH-RM) for thiopurine S-methyltransferase (TPMT) genotyping by using the gene synthesis technology. The polynucleotide chain we prepared consisted of three wild-type and three mutant segments corresponding to the TPMT 238G>C, 460G>A, and 719A>G polymorphic sites. TCH-RM characteristics were assessed via four methods: reverse hybridization, real-time PCR with hydrolysis probes, real-time PCR followed by subsequent melting temperature analysis, and DNA sequencing. Consequently, we investigated the TPMT genotype of 371 patients suffering from autoimmune diseases requiring immunosuppressive therapy with thiopurine drugs, mostly inflammatory bowel disease. All methods confirmed the triple heterozygous character and commutability of TCH-RM. In evaluating its stability we obtained very comparable data before and after six months of storage at -80 °C. The determined genotypes were as follows: 352 wild-type subjects (94.8%), 17 TPMT*3A heterozygotes (460G>A and 719A>G, 4.6%), one patient heterozygous for the TPMT*2 allele (238G>C, 0.3%), and one TPMT*3C heterozygote (719A>G, 0.3%). The frequencies of TPMT*1, *3A, *3C, and *2 in the patients were 97.5%, 2.3%, 0.1%, and 0.1 %, respectively. Assembling segments of synthetic DNA into long polynucleotide chains is a universal way of obtaining compound heterozygous material for performing any simultaneous analysis of polymorphic sites in the human genome. The batches are manufactured with a perfect concentration match of wildtype and mutant fragments, and can be made in large quantities for most diagnostic techniques.

Dopamine 2 and somatostatin 1-5 receptors coexpression in clinically non-functioning pituitary adenomas.

This study investigated quantitated expression of dopamine 2 receptor (D2R) and somatostatin receptors of the five types (SSTR1-SSTR5) in a large series of clinically non-functioning pituitary adenomas (CNFAs). Co-expression of these receptors in individual adenomas was studied as well as correlation between receptor types. Adenoma tissue from 198 patients who underwent surgery for CNFAs was analyzed by immunohistochemistry and quantitative real-time PCR. D2R and SSTR1-3 mRNA was expressed in all 198 adenomas. SSTR4 and SSTR5 were detectable in 85 % and 61 % of adenomas, respectively. Expression of D2R was significantly higher than that of the somatostatin receptors. The median relative expressions were as follows from highest D2R >> SSTR3 > SSTR2 > SSTR1 > SSTR5 > SSTR4. High relative expression (ratio to beta-glucuronidase mRNA > 1) of D2R was found in 60 % of tumors, high expression of SSTR1 in 7.5 %, SSTR2 in 7 %, SSTR3 in 4 % and SSTR5 in 0.5 %. The quantity of D2R correlated positively with expression of SSTR2 and SSTR3, and negatively with SSTR1 and SSTR5. Among histological adenoma types, SSTR1 was significantly higher in null-cell adenomas and SSTR3 was lower in silent corticotroph adenomas. In conclusions, in CNFAs, high expression of somatostatin receptors is much less common than that of D2R, and co-expression of both these receptors is exceptional. D2R and SSTR3 seem to be the most promising targets for pharmacological treatment.

ATM and TGFB1 genes polymorphisms in prediction of late complications of chemoradiotherapy in patients with locally advanced cervical cancer.

The purpose of our study was to evaluate a possible correlation between genetic polymorphisms in ATM and TGFB1 genes and late toxicity of chemoradiotherapy for locally advanced cervical cancer. Fifty five patients with FIGO stage IIB and higher without a disease recurrence with a mean follow up of 6 years were included. Late toxicity was assessed by EORTC/RTOG late toxicity criteria. Univariate and multivariate logistic regression model was used for statistical analysis. Degree of association between polymorphisms and late toxicity of chemotherapy was assessed on the basis of phi-coefficient (φ) as well. We did not find any association between 5557G>A polymorphism in the ATM gene or single TGFB1 polymorphisms and late toxicity. TGFB1 compound homozygosity (-1552delAGG, -509C>T, L10P) was a significant predictive factor of grade III-IV and any grade of complications in both univariate and multivariate logistic regression analyses and statistical significance of association between polymorphisms and late toxicity of chemoradiotherapy was confirmed also by the evaluation of phi-coefficient (φ). We conclude that haplotypes instead of single nucleotide polymorphic sites in the genes may better characterize the individual radiosensitivity.

Molecular predictive factors of outcome of radiotherapy in cervical cancer.

Radical radiotherapy with concurrent cisplatin-based chemotherapy is an established treatment for cervical cancer patients with stage FIGO IIB and higher. The tumor control can be achieved in 40-80% of patients, the treatment is associated with the risk of late postiradiation complications in 10 - 15% of cases. Detection of the factors predictive for tumor control and late morbidity is a possible direction how to individualize radiotherapy dose and technique. The aim of our review is to summarize results of studies inquiring various molecular markers predicting tumor response to radiotherapy and a risk of late complications. A lot of candidate molecules were evaluated in histochemical studies: membrane receptors (EGFR, HER-2), cell cycle regulators (p53, p21), proliferative markers (Ki-67), hypoxia and angiogenetic factors (HIF, VEGF), HPV status, and others (COX-2), with promising results in some of them (HPV, HIF-1α, Ku80, ATM polymorphism). Microarray studies identified decades of genes with different expression in radiosensitive/radioresistant cervical tumors and sets of genes are able to comletely separate responding and nonresponding tumors, but these sets differ across studies. Further well designed studies will be necessary to achieve results matured for use in clinical practice.