Beata Smolarz

Polymorphism of the DNA repair genes RAD51 and XRCC2 in smoking- and drinking-related laryngeal cancer in a Polish population.

Introduction Cigarette smoke and alcohol can generate reactive oxygen species, which may induce DNA double-strand breaks (DSBs), the most serious DNA lesion. In humans, DSBs are repaired mainly by non-homologous end joining and homologous recombination repair (HRR). Several polymorphisms in the DNA repair gene have been extensively studied in the association with various human cancers. In the present work we investigated the association between polymorphisms of two HRR genes, XRCC2 and RAD51, and tobacco- and alcohol-related larynx cancer in a Polish population. Material and methods Two polymorphisms of the XRCC2 gene, –41657C > T (rs718282) and 31479G > A (rs3218536), as well as one polymorphism of the RAD51 gene, –135G > C (rs1801320), were investigated by PCR-RFLP in 253 patients with larynx cancer and 253 age- and sex-matched non-cancer controls. Results Analysis of the gene-smoking and -drinking interactions revealed a weak association between larynx cancer and the –41657C > T polymorphisms of the XRCC2 gene among the moderate alcohol drinkers. The C allele of the –135G > C polymorphism of RAD51 increased cancer risk in the smoker group. Increased risk was also found for heavy drinkers. Additionally, there were no significant differences between distributions of genotypes in subgroups assigned to different TNM stages and grades. Conclusions The results indicated that the –135G > C polymorphism of the RAD51 gene may be associated with smoking- and drinking-related larynx cancer in Poland.

Clinical significance of k-ras and c-erbB-2 mutations in pancreatic adenocarcinoma and chronic pancreatitis

AbstractBackground: The differentiation of chronic pancreatitis (CP) from pancreatic adenocarcinoma (PA) remains the great challenge for clinicians. The purpose of this study was to compare the prevalence of K-ras and c-erbB-2 mutations in PA and CP in order to evaluate their usefulness in differential diagnosis of those diseases. Methods: The study included 49 patients who underwent Whipple resection or distal pancreatectomy for pancreatic adenocarcinoma (26 subjects) or chronic pancreatitis (23 subjects). DNA from pancreatic tissue was analyzed for K-ras codon 12 and c-erbB-2 mutations with PCR amplifications. Results: The K-ras gene mutation has been shown in 20 (76.9%) PA cases and in 8 (34.8%) CP cases (p<0.01). Prevalence of c-erbB-2 amplification in patients with PA was 17 (65.3%), which was not different from CP, 16 (56.5%) (p=0.58). There was a significant correlation between K-ras mutation and lymph node metastases (p=0.025) as well as between K-ras mutation and G3 tumor differentiation (p=0.037). Overall median survival in patients with PA was 9.5 mo. There was no relationship between presence of K-ras (p=0.58) or c-erbB-2 (p=0.17) mutation and survival time in PA patients. Conclusion: Those results may indicate that both K-ras and c-erbB-2 play a role in pancreatic carcinogenesis, however only K-ras may provide an additional tool in differential diagnosis of CP and PC.

Single nucleotide polymorphisms of RAD51 G135C, XRCC2 Arg188His and XRCC3 Thr241Met homologous recombination repair genes and the risk of sporadic endometrial cancer in Polish women

Background:  The genes RAD51, XRCC2 and XRCC3 encode proteins that are important for the repair of double‐strand DNA breaks by homologous recombination. Therefore, genetic variability in these genes may contribute to the occurrence and progression of endometrial cancer.

p16 gene mutations in Barrett's esophagus in gastric metaplasia – intestinal metaplasia – dysplasia – adenocarcinoma sequence

PURPOSE Barretts associated esophageal adenocarcinoma (ADC) is one of the malignancies of most rapidly increasing incidence. The aim of the study was to assess p16 tumor suppressor gene alterations in the ADC premalignant conditions. MATERIAL & METHODS In the present study two p16 gene mutations (A148T and I49S) analysis with PCR- RFLP method have been performed in oesophageal biopsy specimen in 33 patients with Barretts gastric metaplasia (GM), 27 - with Barretts intestinal metaplasia (IM), 8 - with dysplasia and 11 - with ADC. RESULTS We have detected the I49S mutation in 12% (4/33) patients with GM, 18% (5/27) with IM, 50% - with dysplasia (4/8) and in 27% (3/11) - with ADC. The A148T mutation were found in 3% (1/33) patients with GM, 22% (6/27) - IM, 25% (2/8) - dysplasia and 27% patients with ADC (3/11). The frequency of the A148S mutation was rising in GM - IM - dysplasia - ADC sequence and was significantly lower in GM compared to all other grades taken together (p=0.0256). The frequency of the I49S mutation was rising in GM - IM - dysplasia sequence, to drop in ADC cases. There were no significant differences in frequency of the I49S mutation between studied groups. CONCLUSIONS These findings are consistent with the hypothesis on the role of the p16 mutations in early phase of Barretts epithelium progression to ADC. The presence of p16 mutations in esophageal metaplastic columnar epithelium without goblet cells suggest that this pathology may have malignancy potential.

Association between single nucleotide polymorphisms (SNPs) of XRCC2 and XRCC3 homologous recombination repair genes and triple-negative breast cancer in Polish women

XRCC2 and XRCC3 genes involved in homologous recombination repair (HRR) of DNA and in the maintenance of the genome integrity play a crucial role in protecting against mutations that lead to cancer. The aim of the present work was to evaluate associations between the risk of triple-negative breast cancer (TNBC) and polymorphisms in the genes, encoding for two key proteins of HRR: XRCC2 Arg188His (c. 563 G>A; rs3218536, Genbank Accession Number NT 007914) and XRCC3 Thr241Met (c. 722 C>T; rs861539, Genbank Accession Number NT 026437). The polymorphisms of the XRCC2 and XRCC3 were investigated by PCR–RFLP in 70 patients with TNBC and 70 age- and sex-matched non-cancer controls. In the present work, a relationship was identified between XRCC2 Arg188His polymorphism and the incidence of triple-negative breast cancer. The 188His allele and 188His/His homozygous variant increased cancer risk. An association was confirmed between XRCC2 Arg188His and XRCC3 Thr241Met polymorphisms and TNBC progression, assessed by the degree of lymph node metastases and histological grades. In conclusion, XRCC2 Arg188His and XRCC3 Thr241Met polymorphisms may be regarded as predictive factors of triple-negative breast cancer in female population.

DNA repair mechanisms and Toxoplasma gondii infection

Lately, we can observe significant progress in understanding mechanism of DNA repair owing to fast methods of DNA sequence analysis from different organisms the revealing of structure and function of DNA repair proteins in prokaryota and eukaryota. The protozoan parasites survival depends on DNA repair systems. Better understanding of DNA repair systems can help in new antipathogen drug development. This review is aimed at updating our current knowledge of the various repair pathways by providing an overview of DNA repair genes regarding Toxoplasma gondii infections and the corresponding proteins, participating either directly in DNA repair, or in checkpoint control and signaling of DNA damage.

An Association between Single Nucleotide Polymorphisms of Lys751Gln ERCC2 Gene and Ovarian Cancer in Polish Women

Aim. The aim of this study was to evaluate the role of the Lys751Gln (rs13181) ERCC2 gene polymorphism in clinical parameters and the risk for development of ovarian cancer. Material and Methods. The study consisted of 430 patients with ovarian cancer (mean age: 53.2 ± 10.11) and 430 healthy subjects (mean age: 50.31 ± 18.21). Analysis of the gene polymorphisms was performed using the PCR-based restriction fragment length polymorphism (PCR-RFLP). The odds ratios (ORs) and 95% confidence intervals (CIs) for each genotype and allele were calculated. Results. The results obtained indicate that the genotype Gln/Gln is associated with an increased risk of ovarian cancer (OR 5.01; 95% CI 3.37–7.43; p < 0.0001). Association of Lys751Gln polymorphism with histological grading showed increased ERCC2 Gln/Gln (OR = 6.96; 95% CI 3.41–14.21; p < 0.0001) genotype in grading 1 as well as Gln allele overrepresentation (OR = 4.98; 95% CI 3.37–7.40; p < 0.0001) in G1 ovarian patients. Finally, with clinical FIGO staging under evaluation, an increase in ERCC2 Gln/Gln homozygote frequencies in staging I and Gln allele frequencies in SI were observed. Conclusion. On the basis of these results, we conclude that ERCC2 gene polymorphism Lys751Gln may be associated with an increased risk of ovarian carcinoma.

Association of polymorphisms in the 5' untranslated region of RAD51 gene with risk of endometrial cancer in the Polish population

AbstractPurpose Many of the studies have analyzed cell repair capabilities, following cancer development. The cellular reaction to DNA damaging agents can modulate the susceptibility to various tumors. This reaction is mainly determined by DNA repair efficacy which, in turn, may be influenced by the variability of DNA repair genes, expressed by their polymorphisms.Methods This report describes studies of the distribution of genotypes and the frequency of alleles of the G135C (rs1801320) and G172T (rs1801321) RAD51 polymorphism in 630 paraffin-embedded samples of tumor tissue from patients with endometrial cancer. DNA from 630 normal endometrial tissues served as control. RAD51 polymorphisms were determined by PCR–RFLP.ResultsIn the present work, a relationship was identified between RAD51 G135C polymorphism and the incidence of endometrial cancer. Endometrial cancer patients had an overrepresentation of 135C allele. The 135C/C homozygous variant increased cancer risk. A tendency towards a decreased risk of endometrial cancer was observed with the occurrence of combined G135C–G172G genotype of RAD51 polymorphism. An association was confirmed between RAD51 G135C and G172T polymorphisms and endometrial cancer progression, assessed by the histological grades.ConclusionsThe results support the hypothesis that RAD51 G135C and G172T polymorphisms may be associated with endometrial cancer occurrence and/or progression.

Intraoperative diagnosis of sentinel lymph node metastases in breast cancer treatment with one-step nucleic acid amplification assay (OSNA)

Introduction The aim of the study was to evaluate the clinical usefulness of a one-step nucleic acid amplification assay (OSNA) for intraoperative detection of metastases to sentinel lymph nodes (SLNs) in comparison to examination of frozen sections, and to summarize the results of previous studies. Material and methods We enrolled 98 patients aged 58.13 ±10.74 years treated surgically for breast cancer, and 99 biopsies of SLNs were followed by analysis of 105 SLNs. The central 1 mm slice of SLN was used for examination of frozen sections, whereas 2 outer slices of SLNs were analyzed intraoperatively with OSNA. Detection of isolated tumor cells (ITC), micrometastases or macrometastases with OSNA extended surgery to axillary lymph node dissection. Congruency of results was assessed between OSNA and examination of frozen sections. Results One-step nucleic acid amplification assay detected metastases in 29/105 SLNs in surgery of 27/99 breasts, including ITC in 3/29 SLNs, micrometastases in 12/29 and macrometastases in 14/29. One-step nucleic acid amplification assay detected significantly more metastases to SLNs than examination of frozen sections (p < 0.0001). All 8 inconsistent results were positive in OSNA and negative in examination of frozen sections; ITC were identified in 2/8 SLNs and micrometastases in 6/8 SLNs. Sensitivity for OSNA was calculated as 100%, specificity as 90.47%, and κ was 79.16%. Conclusions One-step nucleic acid amplification assay analysis allows rapid and quantitative detection of mRNA CK19 with high specificity and a low rate of false positives. One-step nucleic acid amplification assay is a reliable tool for intraoperative diagnosis of whole SLNs during surgery of breast cancer. One-step nucleic acid amplification assay minimizes the need for secondary surgery and avoids delays in the adjuvant treatment.

DNA repair mechanisms and human cytomegalovirus (HCMV) infection

Herpesvirus infections, such as those induced by human cytomegalovirus (HCMV), induce specific DNA damages. DNA damages can lead to cell mutation, death, apoptosis and immune system activation. Various types of DNA damage are repaired through multiple repair pathways, such as base excision, nucleotide excision, homologous recombination and nonhomologous end joining. Changes in the activity of DNA repair proteins during viral infection can cause disturbances in the DNA repair system and change its mechanisms. This report reviews results from studies, assaying a DNA repair system in HCMV infection.