Perinatalna opieka paliatywna realizowana w oddziale polozniczym i neonatologicznym we wspólpracy z hospicjum dla dzieci - doswiadczenia wlasne.

INTRODUCTION: Wady letalne prowadza do wewnatrzmacicznego zgonu plodu lub dziecka bezposrednio po urodzeniu lub we wczesnym okresie niemowlecym, bez wzgledu na zastosowane leczenie. W przypadku wad letalnych nie ma mozliwosci skutecznej pomocy dziecku, mimo postepu mi zeadsytcoysnoyw ania najnowoczesniejszej aparatury lub terapii. Rodzice, którzy decyduja sie na urodzenie dziecka z wada letalna moga byc objeci perinatalna opieka hospicyjna, która ma charakter kompleksowy. Polega ona na wsparciu ciezarnej w okresie przygotowania do porodu, w czasie porodu i po porodzie oraz na wsparciu jej rodziny oraz obejmuje udzielenie rodzicom pelnej informacji o chorobie ich dziecka. Opieka nad dzieckiem po urodzeniu jest nastawiona na ochrone przed uporczywa terapia i zapewnienie dziecku opieki paliatywnej. CEL: Wykazanie znaczenia perinatalnej opieki paliatywnej dla kobiet w ciazy, u których wyniki badan prenatalnych wskazywaly na ciezkie zaburzenie rozwojowe u plodu o potencjalnie letalnym rokowaniu oraz przedstawienie schematu postepowania wedlug modelu wewnatrzszpitalnego hospicjum perinatalnego. MATERIAL I METODY: Analiza retrospektywna objeto dokumentacje 67 pacjentek skierowanych do Programu RAZEM we Wroclawiu w latach 2014-2018 z powodu nieprawidlowych wyników badan prenatalnych (ultrasonograficznych lub/i genetycznych), które wskazywaly na ciezkie zaburzenie rozwojowe u plodu o potencjalnie letalnym rokowaniu. Dokonanoanalizy danych socjodemograficznych, danych klinicznych rozpoznania choroby u plodu, przebiegu ciazy i porodu, trybu postepowania w okresie prenatalnym, podczas porodu i po urodzeniu sie dziecka. WYNIKI: Do Programu zostalo skierowanych 67 kobiet w wieku 20-43 lat (srednio 31,2), które zglaszaly sie w okresie od 15 do 39 tygodnia ciazy (srednio w 25. tygodniu ciazy). Do opieki paliatywnej zakwalifikowano 57 kobiet, czyli 85% skierowanych do programu. Opieke paliatywna kontynuowano u 51 pacjentek, poniewaz 6 kobiet w trakcie procesu diagnostycznego zdecydowalo sie na zakonczenie ciazy (10,5%). Najczestszymi zaburzeniami u plodów byly aberracje chromosomowe, wady OUN i wady nerek. W 95% przypadków doszlo do obumarcia wewnatrzmacicznego plodu lub smierci noworodka. WNIOSKI: Perinatalna opieka paliatywna jest niezbedna forma opieki dla kobiet w ciazy, u których wyniki badan prenatalnych wskazuja na ciezkie zaburzenie rozwojowe u plodu o potencjalnie letalnym rokowaniu. Model wewnatrzszpitalny hospicjum perinatalnego jest korzystna forma opieki, zapewnia jej spójnosc i dobra komunikacje w zespole, co wplywa na dobra jakosc opieki. INTRODUCTION: Lethal defects lead to the intrauterine death of the fetus or the passing away of the child immediately after birth or in early infancy, regardless of the treatment used. In the case of lethal defects, it is not possible to effectively help the child, despite using the most modern equipment or medicines in the treatment or the progress made by medicine. Parents, who decide to continue the pregnancy, although the fetus has a lethal defect that cannot be cured, may be covered by perinatal hospice care, which is comprehensive and consists in supporting the pregnant woman during the prenatal time, during delivery and after delivery and support of her family, giving full information to the parents about their child's illness. Childcare after birth is focused on protecting the infant from persistent therapy and providing him with appropriate conditions. AIM: To demonstrate the role of perinatal palliative care for pregnant women in whom the results of prenatal tests pointed to a severe developmental disorder in the fetus with a potentially lethal prognosis, and to present a pattern of behavior for their hospitalization in the perinatal hospice. MATERIALS AND METHODS: The retrospective analysis included documentation of 67 patients referred to the RAZEM (TOGETHER) Program in Wroclaw in 2014-2018 due to abnormal results of (ultrasound and / or genetic) prenatal tests, which indicated a serious developmental disorder in the fetus with potentially lethal prognosis. Analysis was conducted of sociodemographic data, clinical data on fetal diagnosis, pregnancy and delivery, the procedure for prenatal delivery and postnatal birth. RESULTS: 67 women aged 20-43 years (mean 31.2) were referred to the RAZEM Program. Out of these, 57 women were enrolled for palliative care, which accounted for 85% of those referred to the program. Palliative care was continued in 51 patients, because 6 women decided to terminate their pregnancy during the diagnostic process (10.5%). The most common abnormalities in the fetuses were chromosomal aberrations, CNS defects and kidney defects. In 95% of the cases, intrauterine fetal death or neonatal death occurred. CONCLUSIONS: Perinatal palliative care is an indispensable form of care for pregnant women in whom the results of prenatal tests indicate a serious developmental disorder in the fetus with potentially lethal prognosis. The in-hospital model of a perinatal hospice is a beneficial form of care, as it ensures consistency and good communication in the team, which favourably affects its quality.

Interfamilial clinical variability in four Polish families with cranioectodermal dysplasia and identical compound heterozygous variants in WDR35.

Cranioectodermal dysplasia (CED) is a rare autosomal recessive disorder primarily characterized by craniofacial, skeletal, and ectodermal abnormalities. CED is a chondrodysplasia, which is part of a spectrum of clinically and genetically heterogeneous diseases that result from disruptions in cilia. Pathogenic variants in genes encoding components of the ciliary transport machinery are known to cause CED. Intra- and interfamilial clinical variability has been reported in a few CED studies and the findings of this study align with these observations. Here, we report on five CED patients from four Polish families with identical compound heterozygous variants [c.1922T>G p.(Leu641Ter) and c.2522A>T; p.(Asp841Val)] in WDR35. The frequent occurrence of both identified changes in Polish CED families suggests that these variants may be founder mutations. Clinical evaluation of the CED patients revealed interfamilial clinical variability among the patients. This includes differences in skeletal and ectodermal features as well as variability in development, progression, and severity of renal and liver insufficiency. This is the first report showing significant interfamilial clinical variability in a series of CED patients from unrelated families with identical compound heterozygous variants in WDR35. Our findings strongly indicate that other genetic and non-genetic factors may modulate the progression and expression of the patients' phenotypes.

Genetic testing in Poland and Ukraine: should comprehensive germline testing of BRCA1 and BRCA2 be recommended for women with breast and ovarian cancer?

PURPOSE: To characterize the spectrum of BRCA1 and BRCA2 pathogenic germline variants in women from south-west Poland and west Ukraine affected with breast or ovarian cancer. Testing in women at high risk of breast and ovarian cancer in these regions is currently mainly limited to founder mutations. METHODS: Unrelated women affected with breast and/or ovarian cancer from Poland (n = 337) and Ukraine (n = 123) were screened by targeted sequencing. Excluded from targeted sequencing were 34 Polish women who had previously been identified as carrying a founder mutation in BRCA1. No prior testing had been conducted among the Ukrainian women. Thus, this study screened BRCA1 and BRCA2 in the germline DNA of 426 women in total. RESULTS: We identified 31 and 18 women as carriers of pathogenic/likely pathogenic (P/LP) genetic variants in BRCA1 and BRCA2, respectively. We observed five BRCA1 and eight BRCA2 P/LP variants (13/337, 3.9%) in the Polish women. Combined with the 34/337 (10.1%) founder variants identified prior to this study, the overall P/LP variant frequency in the Polish women was thus 14% (47/337). Among the Ukrainian women, 16/123 (13%) women were identified as carrying a founder mutation and 20/123 (16.3%) were found to carry non-founder P/LP variants (10 in BRCA1 and 10 in BRCA2). CONCLUSIONS: These results indicate that genetic testing in women at high risk of breast and ovarian cancer in Poland and Ukraine should not be limited to founder mutations. Extended testing will enhance risk stratification and management for these women and their families.

DNA methylation abundantly associates with fetal alcohol spectrum disorder and its subphenotypes.

Aim: Fetal alcohol spectrum disorder (FASD) involves prenatal growth delay, impaired facial and CNS development and causes severe clinical, social-economic burdens. Here, we aim to detect DNA-methylation aberrations associated with FASD and potential FASD diagnostic and prognostic biomarkers. Patients & methods: The FASD diagnosis was established according to golden-standard protocols in a discovery and independent replication cohort. Genome-wide differential methylation association and replication analyses were performed. Results: We identified several loci that were robustly associated with FASD or one of its sub phenotypes. Our findings were evaluated using previously reported genome-wide surveys. Conclusion: We have detected robust FASD associated differentially methylated positions and differentially methylated regions for FASD in general and for FASD subphenotypes, in other words on growth delay, impaired facial and CNS development.

[Perinatal palliative care performed in obstetrics and neonatology wards and hospices for children - own experience].

OBJECTIVE: Lethal defects lead to the intrauterine death of the fetus or the passing away of the child immediately after birth or in early infancy, regardless of the treatment used. In the case of lethal defects, it is not possible to effectively help the child, despite using the most modern equipment or medicines in the treatment or the progress made by medicine. Parents, who decide to continue the pregnancy, although the fetus has a lethal defect that cannot be cured, may be covered by perinatal hospice care, which is comprehensive and consists in supporting the pregnant woman during the prenatal time, during delivery and after delivery and support of her family, giving full information to the parents about their child's illness. Childcare after birth is focused on protecting the infant from persistent therapy and providing him with appropriate conditions. Aim: To demonstrate the role of perinatal palliative care for pregnant women in whom the results of prenatal tests pointed to a severe developmental disorder in the fetus with a potentially lethal prognosis, and to present a pattern of behavior for their hospitalization in the perinatal hospice. PATIENTS AND METHODS: Materials and methods: The retrospective analysis included documentation of 67 patients referred to the RAZEM (TOGETHER) Program in Wroclaw in 2014-2018 due to abnormal results of (ultrasound and / or genetic) prenatal tests, which indicated a serious developmental disorder in the fetus with potentially lethal prognosis. Analysis was conducted of sociodemographic data, clinical data on fetal diagnosis, pregnancy and delivery, the procedure for prenatal delivery and postnatal birth. RESULTS: Results: 67 women aged 20-43 years (mean 31.2) were referred to the RAZEM Program. Out of these, 57 women were enrolled for palliative care, which accounted for 85% of those referred to the program. Palliative care was continued in 51 patients, because 6 women decided to terminate their pregnancy during the diagnostic process (10.5%). The most common abnormalities in the fetuses were chromosomal aberrations, CNS defects and kidney defects. In 95% of the cases, intrauterine fetal death or neonatal death occurred. CONCLUSION: Conclusions: Perinatal palliative care is an indispensable form of care for pregnant women in whom the results of prenatal tests indicate a serious developmental disorder in the fetus with potentially lethal prognosis. The in-hospital model of a perinatal hospice is a beneficial form of care, as it ensures consistency and good communication in the team, which favourably affects its quality.

Phenotypic consequences of gene disruption by a balanced de novo translocation involving SLC6A1 and NAA15.

Mapping of de novo balanced chromosomal translocations (BCTs) in patients with sporadic poorly characterized disease(s) is an unbiased method of finding candidate gene(s) responsible for the observed symptoms. We present a paediatric patient suffering from epilepsy, developmental delay (DD) and atrial septal defect IIº (ASD) requiring surgery. Karyotyping indicated an apparently balanced de novo reciprocal translocation 46,XX,t(3;4)(p25.3;q31.1), whereas aCGH did not reveal any copy number changes. Using shallow mate-pair whole genome sequencing and direct Sanger sequencing of breakpoint regions we found that translocation disrupted SLC6A1 and NAA15 genes. Our results confirm two previous reports indicating that loss of function of a single allele of SLC6A1 causes epilepsy. In addition, we extend existing evidence that disruption of NAA15 is associated with DD and with congenital heart defects.

Genetic variants in ATM, H2AFX and MRE11 genes and susceptibility to breast cancer in the polish population.

BACKGROUND: DNA damage repair is a complex process, which can trigger the development of cancer if disturbed. In this study, we hypothesize a role of variants in the ATM, H2AFX and MRE11 genes in determining breast cancer (BC) susceptibility. METHODS: We examined the whole sequence of the ATM kinase domain and estimated the frequency of founder mutations in the ATM gene (c.5932G > T, c.6095G > A, and c.7630-2A > C) and single nucleotide polymorphisms (SNPs) in H2AFX (rs643788, rs8551, rs7759, and rs2509049) and MRE11 (rs1061956 and rs2155209) among 315 breast cancer patients and 515 controls. The analysis was performed using high-resolution melting for new variants and the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method for recurrent ATM mutations. H2AFX and MRE11 polymorphisms were analyzed using TaqMan assays. The cumulative genetic risk scores (CGRS) were calculated using unweighted and weighted approaches. RESULTS: We identified four mutations (c.6067G > A, c.8314G > A, c.8187A > T, and c.6095G > A) in the ATM gene in three BC cases and two control subjects. We observed a statistically significant association of H2AFX variants with BC. Risk alleles (the G of rs7759 and the T of rs8551 and rs2509049) were observed more frequently in BC cases compared to the control group, with P values, odds ratios (OR) and 95% confidence intervals (CIs) of 0.0018, 1.47 (1.19 to 1.82); 0.018, 1.33 (1.09 to 1.64); and 0.024, 1.3 (1.06 to 1.59), respectively. Haplotype-based tests identified a significant association of the H2AFX CACT haplotype with BC (P <  0.0001, OR = 27.29, 95% CI 3.56 to 209.5). The risk of BC increased with the growing number of risk alleles. The OR (95% CI) for carriers of ≥ four risk alleles was 1.71 (1.11 to 2.62) for the CGRS. CONCLUSIONS: This study confirms that H2AFX variants are associated with an increased risk of BC. The above-reported sequence variants of MRE11 genes may not constitute a risk factor of breast cancer in the Polish population. The contribution of mutations detected in the ATM gene to the development of breast cancer needs further detailed study.

Personalized medicine in oncology. New perspectives in management of gliomas.

Studies on genetic and epigenetic mechanisms of carcinogenesis have led to the discovery of crucial genetic events for many of particular malignancies. This was followed by invention of new therapeutic approaches based on molecular mechanisms underlying cancer development and progression that bears the name of personalised medicine. In the case of gliomas, ascertainment of genetic/epigenetic markers was the basis for re-classification of tumours that until now depended on histopathological analysis. This article reviews recent advances in personalised medicine and the new World Health Organisation classification of gliomas.

Pan-cancer analysis reveals presence of pronounced DNA methylation drift in CpG island methylator phenotype clusters.

AIM: To provide characteristics of major genomic correlates in CpG island methylator phenotype-high (CIMP-H) subgroups in relation to corresponding non-CIMP-H subgroups by use of phenotypic, DNA methylation and RNAseq data. MATERIALS & METHODS: Twenty-three datasets generated by The Cancer Genome Atlas project encompassing over 7200 unique samples were analyzed. We identified 23 CIMP-H clusters by use of unsupervised clustering. RESULTS & CONCLUSION: More than 90% of CIMP-H clusters were significantly associated with accelerated epigenetic mitotic clock, demethylation of enhancer sites, backbone and repetitive sequences. Pronounced epigenetic drift observed in majority of CIMP-H subgroups may be related to increased cell division rate, which leads to expansion of DNA methylation errors. This may explain pan-cancer mechanism of establishing CIMP-H in majority of tissue types.

May autophagy be a novel biomarker and antitumor target in colorectal cancer?

Autophagy is a catabolic process associated with intracellular self-digestion of damaged organelles or redundant proteins enabling maintenance of cell homeostasis. It is accepted that impaired autophagy is closely linked to cancer development and has been extensively studied in a variety of malignancies including colorectal cancer (CRC) to elucidate its influence on carcinogenesis, metastasis and antitumor therapy response. CRC remains a great epidemiological problem because of poor 5-year survival and treatment resistance. Many studies concerning autophagy in CRC gave inconsistent and contradictory results, illustrating a multifaceted nature of this process. In this review, we focus on current knowledge of autophagy in CRC development to determinate its role as a potential prognostic and predictive biomarker as well as target in antitumor therapy.

Polymorphisms in nucleotide excision repair genes and basal cell carcinoma of the skin.

BACKGROUND: Mutations in nucleotide excision repair (NER) genes are the cause of xeroderma pigmentosum, a genetic syndrome with proneness to basal cell carcinoma (BCC) of the skin. Single nucleotide polymorphisms (SNPs) may affect the effectiveness of DNA repair and hence influence individual susceptibility to a variety of neoplasms. The aim of this study was to find associations between SNPs in selected NER genes and sporadic BCC development. MATERIALS AND METHODS: The study group consisted of 100 patients with histopathologically confirmed BCCs and the control group of 100 elderly individuals with no personal history of any cancer. DNA isolated from peripheral blood lymphocytes was genotyped for seven SNPs in five different NER genes. Statistical analyses for associations were performed. RESULTS: A weak association between XPD exon 6 silent C/A polymorphism and BCC development risk was found when comparing single polymorphisms between the two groups. When considering sex and SNPs, men with the A-allele in XPC intron 11 C/A have been found to have a decreased risk of BCC. CONCLUSIONS: There is no consistency in association studies between SNPs and BCC susceptibility. SNPs in NER genes seem to have an insignificant influence on the risk of developing BCC of the skin.

Indices of insulin resistance and dyslipidemia are correlated with lymphocyte proneness to apoptosis in obese or overweight low birth weight children.

AIMS: Our aim was to study the relationship between markers of cell proneness to apoptosis and indices of insulin resistance and dyslipidemia in children born with low birth weight (LBW). METHODS: The study comprised 177 prepubertal children stratified by birth weight and their nutritional status into LBW (n = 138) and normal birth weight (NBW; n = 39) groups. We analyzed DNA from peripheral blood lymphocytes, separated by pulsed-field gel electrophoresis (PFGE), as well as the serum levels of cholesterol, HDL-cholesterol, triglycerides, fasting insulin and glucose, caspase 3, and BCL2. RESULTS: LBW children with a BMI SDS >1.55 demonstrated increased content of the large fragments of the lymphocyte DNA [300-500 kb (DNA300-500 kb)] in electrophoretic slides (a marker of decreased chromatin stability and susceptibility of cells to apoptosis) compared to the NBW group. In these children the level of DNA300-500 kb exhibited a strong negative correlation with the serum level of antiapoptotic protein of BCL2 (r = -0.901). DNA300-500 kb significantly correlated with calculated indices of insulin resistance: HOMA-IR and QUICKI as well as with the indices of lipid homeostasis (Castelli and AIP). CONCLUSIONS: Increased susceptibility of lymphocytes to apoptosis correlated with a higher risk of insulin resistance and lipid disturbance in overweight or obese LBW children. A comprehensive study of the proneness of cells to apoptosis should be implemented to further investigate the pathomechanism of the metabolic syndrome in these children.

Basal cell carcinoma of the skin: whole genome screening by comparative genome hybridization revisited.

Basal cell carcinoma (BCC) of the skin is considered to be the most common malignancy in people of European ancestry. It is often not clinically aggressive and has been regarded as genetically stable. However, histopathologic subtypes of BCC differ in their ability to invade surrounding tissues and recur. The aim of this work was to present a comprehensive study of chromosomal imbalances of cutaneous BCC and to correlate the findings with their histopathologic and clinical features. In all, 101 tumor samples were classified according to the current microscopic classification of BCC and then analyzed by comparative genomic hybridization (CGH). Over 60% of BCC were found to carry chromosomal imbalances - partial or whole chromosome gains and losses. Different subtypes of BCC presented common chromosomal alterations. No single chromosomal imbalance was found to be characteristic of a particular subtype of BCC, although the frequency of some chromosomal changes differed from one group to the other. The significance of chromosome 2 gains as a phenomenon that does not coexist with the losses in 9q is discussed.

Assessment of chromosomal imbalances in CIMP-high and CIMP-low/CIMP-0 colorectal cancers.

Data presented in a number of recent studies have revealed a negative correlation between CpG island methylator phenotype (CIMP) and chromosomal instability (CIN) measured by a loss of heterozygosity (LOH) of selected loci, suggesting that CIN and CIMP represent two independent mechanisms in sporadic colorectal cancer (CRC) carcinogenesis. However, CIN is a heterogeneous phenomenon, which may be studied not only by employing LOH analysis but also by observing chromosomal imbalances (gains and deletions). The current study aimed to investigate the relationship between CIMP and chromosomal gains and deletions (assessed by comparative genomic hybridization) in a group of 20 CIMP-high and 79 CIMP-low/CIMP-0 CRCs. Our results revealed that the mean numbers of gains and of total chromosomal imbalances were significantly greater (p = 0.004 and p = 0.007, respectively) in the CIMP-low/CIMP-0 group compared to the CIMP-high group, while no significant difference was observed between the mean numbers of losses (p = 0.056). The analysis of copy number changes of 41 cancer-related genes by multiplex ligation-dependent probe amplification showed that CRK gene was exclusively deleted in CIMP-low/CIMP-0 tumors (p = 0.02). Given that chromosomal losses play an important role in tumor suppressor inactivation and chromosomal gains, in the activation of proto-oncogenes, we hypothesize that tumor suppressor inactivation plays similar roles in both CIMP-high and CIMP-low/CIMP-0 CRCs, while the predominance of chromosomal gains in CIMP-low/CIMP-0 tumors may suggest that the activation of proto-oncogenes is the underlying mechanism of CIMP-low/CIMP-0 CRC progression.

The C/A polymorphism in intron 11 of the XPC gene plays a crucial role in the modulation of an individual's susceptibility to sporadic colorectal cancer.

Epidemiological data show that colorectal cancer (CRC) is the second most frequent malignancy worldwide. The involvement of "minor impact genes" such as XME and DNA-repair genes in the etiology of sporadic cancer has been postulated by other authors. We focused on analyzing polymorphisms in DNA-repair genes in CRC. We considered the following genes involved in DNA-repair pathways: base excision repair (OGG1 Ser326Cys, XRCC1 Trp194Arg and Arg399Gln); nucleotide excision repair [XPA (-4)G/A, XPC C/A (i11) and A33512C (Lys939Gln), XPD Asp312Asn and A18911C (Lys751Gln), XPF Arg415Gln, XPG Asp1104His, ERCC1 C118T]; homologous recombination repair [NBS1 Glu185Gln, Rad51 135G/C, XRCC3 C18067 (Thr241Met)]. The study group consisted of 133 patients diagnosed with sporadic CRC, while the control group was composed of 100 age-matched non-cancer volunteers. Genotyping was performed by PCR and PCR-RFLP. Fisher's exact test with a Bonferroni correction for multiple testing was used. We found that: (i) XPC C/A (i11) heterozygous variant is associated with increased risk of CRC [OR is 2.07 (95% CI 1.1391, 3.7782) P=0.038], (ii) XPD A18911C (Lys751Gln) is associated with decreased risk of CRC [OR=0.4497, (95% CI 0.2215, 0.9131) P=0.031] for an individual with at least one A allele at this locus. (1) The XPC C/A (i11) genotype is associated with an increased risk of sporadic colorectal cancer. (2) The NER pathway has been highlighted in our study, as a most important in modulation of individual susceptibility to sCRC.

Panhypopituitary insufficiency in a patient with clinical diagnosis of Chitayat-Hall syndrome.

We report an 8-year-old proband with severe motor and intellectual disability presenting a variety of dysmorphic features such as microcephaly, prominent glabella (ridged metopic suture) and congenital distal limb contractures. As well as panhypopituitary insufficiency, brain defects, e.g. agenesis of corpus callosum, colpocephaly, and pachygyria as well as strabismus and tracheo-laryngeal hypoplasia, were diagnosed. Genetic examination revealed a normal karyotype and excluded Wolf-Hirschhorn syndrome and subtelomeric deletions. Chitayat-Hall syndrome was diagnosed based on clinical traits.

Cancer stem cells: the theory and perspectives in cancer therapy.

The cancer stem cell theory elucidates not only the issue of tumour initiation and development, tumour's ability to metastasise and reoccur, but also the ineffectiveness of conventional cancer therapy. This review examines stem cell properties, such as self-renewal, heterogeneity, and resistance to apoptosis. The 'niche' hypothesis is presented, and mechanisms of division, differentiation, self-renewal and signalling pathway regulation are explained. Epigenetic alterations and mutations of genes responsible for signal transmission may promote the formation of cancer stem cells. We also present the history of development of the cancer stem cell theory and discuss the experiments that led to the discovery and confirmation of the existence of cancer stem cells. Potential clinical applications are also considered, including therapeutic models aimed at selective elimination of cancer stem cells or induction of their proper differentiation.

Polymorphism in nucleotide excision repair gene XPC correlates with bleomycin-induced chromosomal aberrations.

Chromosomal aberrations (CAs) are important genetic alterations in the development and progression of the majority of human cancers. The frequency with which such alterations occur depends to a large extent on polymorphisms of DNA-repair genes and in genes coding for xenobiotic metabolizing enzymes, which are involved in the processes of activation and inactivation of xenobiotics. The frequency of bleomycin (BLM)-induced CAs is an indirect measure of the effectiveness of DNA repair mechanisms, and a predictor of environment-related risk of cancer. Our study was conducted on the human peripheral blood lymphocytes of 82 healthy volunteers. The aim of the study was to elucidate whether the frequency of BLM-induced CAs is correlated with polymorphisms of selected genes involved in different mechanisms of DNA repair such as: XRCC1 [base excision repair]; XPA, XPC, XPG, XPD, XPF, ERCC1 [nucleotide excision repair], NBS1, RAD51, XRCC2, XRCC3, RAD51, and BRCA1 [homologous recombination], as well as in genes encoding xenobiotic metabolizing enzymes, such as CYP1A, CYP2E1, NAT2, GSTT1, and EPHX (mEH). Our study indicated that, of the polymorphisms studied, only XPC (exon 15 and intron 11) is associated with BLM-induced CAs, suggesting a role of the NER pathway in the repair of BLM-induced chromosomal aberrations.

Influence of polymorphisms in xenobiotic-metabolizing genes and DNA-repair genes on diepoxybutane-induced SCE frequency.

Analysis of the combined effects of polymorphisms in genes encoding xenobiotic metabolizing enzymes (XMEs) and DNA repair proteins may be a key to understanding the role of these genes in the susceptibility of individuals to mutagens. In the present study, we performed an in vitro experiment on lymphocytes from 118 healthy donors that measured the frequency of diepoxybutane (DEB) induced sister chromatid exchanges (SCEs) in relation to genetic polymorphisms in genes coding for XMEs (CYP1A1, CYP2E1, GSTT1, EPHX, and NAT2), as well as DNA repair proteins (XRCC1, XRCC2, XRCC3, XPD, XPA, XPC, XPG, XPF, ERCC1, BRCA1, NBS1, and RAD51). We found that GSTT1(-) and CYP2E1 c1/c2 polymorphisms were associated with higher DEB-induced SCE frequencies, and that NAT2 G(590)A was associated with lower SCE induction by DEB. Analysis of the effect of pairs of genes showed that for a fixed GSTT1 genotype, the SCE level increased with an increasing number of Tyr alleles in EPHX codon 113. We found that among GSTT1(+) individuals the DEB-induced SCE level was significantly lower when the EPHX 139 codon was His/Arg rather than His/His. An interaction between polymorphisms in CYP2E1 and at EPHX codon 113 was also observed. The results of our study confirm observations in cancer patients and in people exposed to xenobiotics indicating that sensitivity to mutagens depends upon a combined effect of a variety of "minor impact" genes. Moreover, our results indicate that polymorphisms in genes coding for XMEs have a greater influence on the genotoxic activity of DEB, measured by DEB-induced SCE frequency, than polymorphisms in genes encoding DNA repair proteins.

Single nucleotide polymorphisms in the RET gene and their correlations with Hirschsprung disease phenotype.

Hirschsprung disease (HSCR) is a congenital, heterogeneous disorder, characterized by the absence of intestinal ganglion cells. Recent advances show that the RET gene is a major locus involved in the pathogenesis of HSCR. The aim of this study was to analyse if the HSCR phenotype in the Polish population is associated with the presence of polymorphisms in exons 2, 3, 7, 11, 13, 14 and 15 of the RET gene. Molecular results were compared with clinical and long-term follow-up data in 70 Polish patients with HSCR (84.3% with a short segment and 15.7% with a long segment of aganglionic gut). Single-nucleotide polymorphisms were analysed by using the minisequencing SNaPshot multiplex method. The 135G>A polymorphism in RET exon 2 was overrepresented in HSCR patients, compared with a healthy control group. Moreover, the 135G>A variant was shown to be associated with the severe HSCR phenotype. Two other polymorphisms, 2071G>A in exon 11 and 2712C>G in exon 15, were underrepresented in the patients. The results confirm that these RET polymorphisms play a role in the aetiology of HSCR.