Skin cancer risk factors among primary school children: investigations in Western Hungary.

OBJECTIVE: To evaluate the factors associated with sunburns and with sun protection practice in Hungarian primary school children. METHOD: We investigated children's (the median age: 8, range 5 to 12 years) and parents' assessment of sun sensitivity and sun protection characteristics in cities Gyor and Zalaegerszeg (Hungary) in 2004. This cross-sectional study was part of a programme intended to increase children's and parents' awareness of harmful effects of excessive sunbathing. Analyses were based on 1804 multiple choice questionnaires. RESULTS: At multivariate analysis a significant association between sunburns and fairness of complexion, freckles, use of sunscreens and T-shirts, and higher school-class level was observed. Sunburn was inversely associated with hat-wearing. Parents were more likely to apply sunscreen to children with light eyes and to the younger ones, to protect fair skinned children with T-shirts; to protect males and children with fair skin and light eyes with hats. CONCLUSION: Since environmental factors play an important role in the development of skin cancer, morbidity could be reduced by primary prevention. Sun protection habits should therefore be taught early in life, and parents' behaviour adapted. Phenotype is not only related to sunburns but it also appears to influence parents' sun safety behaviour.

Epigenetic modifiers exacerbate oxidative stress in renal proximal tubule cells.

BACKGROUND: Increased production of reactive oxygen species (ROS) by anticancer drugs has been described in patients with various malignancies, which might attribute to their nephrotoxicity. MATERIALS AND METHODS: The effects of two epigenetic modifiers - trichostatin A (TSA) and 5-aza-deoxycytidine (5AZA) - on ROS production and cell injury alone or in combination with mild oxidative stress were studied in mouse renal proximal tubule cells. RESULTS: Both agents increased mitochondrial ROS production and consequent lactate dehydrogenase (LDH) release either alone or in combination with a low dose of H(2)O(2). The antioxidant N-acetyl-cysteine (NAC) abolished LDH release. It was also found that CREB-mediated transcription, vital for survival of proximal tubule cells, is attenuated by these anticancer agents. CONCLUSION: The ROS-inducing activity of TSAI and 5AZA might explain the in vivo nephrotoxicity of epigenetic modifiers. The mechanisms that are responsible for this injury could involve attenuation of pro-survival signaling and/or activation of death signaling pathway(s) associated with mitochondrial ROS release.

Oncogene and tumor suppressor gene expression changes in the peripheral blood leukocytes of patients with colorectal cancer.

AIMS AND BACKGROUND: The mortality of colorectal cancer continues to stagnate despite the development of new therapeutic approaches. Therefore, identifying high-risk population groups could contribute to the prevention of a considerable part of deaths caused by colorectal tumors. METHODS: Fifty patients with colon cancer and 50 patients with other, nonmalignant diseases were selected for the study. Expression of the c-myc, Ha-ras and p53 genes was determined in the peripheral leukocytes of the participants. RESULTS: Marked elevations of the expression of all three investigated genes were seen in the colon cancer patients when compared to the controls. CONCLUSIONS: Our investigations showed that increases in the expression of c-myc, Ha-ras and p53 genes can be demonstrated in the peripheral leukocytes of colon cancer patients. By applying our method to clinical investigations, individuals with a high risk of having developed colon cancer may be identified and early diagnosis may be established.

Effect of a plant-derived natural compound, Flavin7, on the ERK signaling pathway in immortalized mouse proximal tubule cells.

BACKGROUND: Since MAP kinases represent an important pathway of transducing external stimuli to internal signals in cells, determining their possible role in cancer cells may offer a promising way for the treatment and prognosis of malignant diseases. Our previous experiments have shown that a flavonoid-rich solution, Flavin7, was able to diminish kidney tumor growth in vivo. MATERIALS AND METHODS: Effects of Flavin 7 on the MAPK signaling pathway were determined in immortalized mouse proximal tubule cells by determining cell viability, flow cytometric analysis, luciferase assays and Western blots. RESULTS: At a nontoxic dose, Flavin7 markedly reduced phosphorylation of ERK and inhibited activity of its downstream targets such as Elk1 and CREB via inhibition of the ERK-kinase MEK1. CONCLUSION: Because of its ability to temporarily inhibit kidney tumor growth and activation of the MEK1/ERK pathway in vitro, further in vivo investigations may determine the potential role of Flavin7 in the treatment of malignancies.

Comparison of mtDNA haplogroups in Hungarians with four other European populations: a small incidence of descents with Asian origin.

Hungarians are unique among the other European populations because according to history, the ancient Magyars had come from the eastern side of the Ural Mountains and settled down in the Carpathian basin in the 9th century AD. Since variations in the human mitochondrial genome (mtDNA) are routinely used to infer the histories of different populations, we examined the distribution of restriction fragment length polymorphism (RFLP) sites of the mtDNA in apparently healthy, unrelated Hungarian subjects in order to collect data on the genetic origin of the Hungarian population. Among the 55 samples analyzed, the large majority belonged to haplogroups common in other European populations, however, three samples fulfilled the requirements of haplogroup M. Since haplogroup M is classified as a haplogroup characteristic mainly for Asian populations, the presence of haplogroup M found in approximately 5% of the total suggests that an Asian matrilineal ancestry, even if in a small incidence, can be detected among modern Hungarians.

Prognostic factors in Hungarian breast cancer patients.

BACKGROUND: Breast cancer is the most common cancer among women, with variable outcomes, justifying a continuous search for new parameters to predict accurate prognosis and indicate suitable adjuvant therapy for patients. MATERIALS AND METHODS: Fourty-four stage I-III breast cancer specimens were investigated immunohistochemically for the expression of cyclooxygenase-2 enzyme (COX-2), hormone receptors, tumor suppressor gene p53, oncogene HER2 and proliferation marker Ki-67. Additionally, twelve specimens were also investigated for the presence of the phosphorylated extracellular signal-regulated kinase (pERK). RESULTS: It was demonstrated that expressions of biological markers were related to each other (ER to p53 and Ki-67, COX-2 to ER, PgR, Ki-67 and p53, Ki-67 to p53 and PgR, p53 to PgR). CONCLUSION: Our data indicate that concomitant immunohistochemical evaluation of cyclooxygenase-2, hormone receptors, p53 and Ki-67 may be of clinical value in determining an accurate prognosis.

Effect of the chalcone analog E,E-bis(2-hydroxybenzylidene) acetone on the 7,12-dimethylbenz[a]anthracene-induced Ha-ras gene activity in vivo.

The chalcone analog E,E-bis(2-hydroxybenzylidene)acetone (HBA) was found to display strong NAD(P)H:quinone reductase (NQO1) inducer potency in Hepa 1c1c7 cells. In order to determine whether this promising chemopreventive activity would extend to anticarcinogenic properties, the effect of HBA on the 7,12-dimethylbenz[a]anthracene (DMBA)-induced expression of the Ha-ras gene in isolated RNA from liver, lung, kidney, spleen, thymus, lymph nodes and bone marrow of CBA/Ca inbred mice was investigated. DMBA is a well-known chemical carcinogen, which can act as initiator by causing point mutations in certain oncogenes and tumor suppressor genes. According to the previous results, elevated Ha-ras expression has been noted even 24 h after DMBA treatment. Administration of HBA simultaneously with DMBA resulted in a decrease of the DMBA-induced Ha-ras gene expression in all the investigated tissues. This observation suggests metabolic interaction of HBA and DMBA. Administration of HBA 24 h prior to the DMBA treatment reduced the Ha-ras gene expression in all the tissues but the liver, where a slight elevation could be detected. This latter effect could be the result of a possible CYPIA inducer and pro-oxidant effects of HBA. The pro-oxidant effect of HBA can be taken into consideration based on its previously demonstrated GSH-reactivity and the present results obtained by investigation of the time-course of Fenton reaction-initiated degradation of 2-deoxyribose in the presence of HBA.

Carcinogenic potential of trans-2-hexenal is based on epigenetic effect.

BACKGROUND: Trans-2-hexenal (2-hexenal) is an alpha,beta-unsaturated carbonyl compound protecting plants against harmful substances. Since humans have a permanent intake of 2-hexenal via vegetable products, this genotoxic and mutagenic compound is considered to play a role in human carcinogenicity. MATERIALS AND METHODS: Ha-ras and p53 gene expression changes and tumor development were investigated in mice and rats after 2-hexenal administration. RESULTS: 2-Hexenal exposure did not result in gene expression alterations 24, 48 or 72 hours after administration while 10 out of the 72 mice and rats included in the long-term study developed a malignancy by the end of the 18-month follow-up. CONCLUSION: Our results suggest that, although 2-hexenal showed no effect on the expression of the investigated onco- and suppressor genes, it has a marked carcinogenic potential, which may be explained only by an epigenetic effect of the compound.

Phenotypic changes of p53, HER2, and FAS system in multiple normal tissues surrounding breast cancer.

To determine whether phenotypic field changes occur in tissues adjacent to carcinoma, we assayed, by immunohistochemistry, the expression of HER-2, p53, Fas, and FasL in 72 breast cancers (BC) and multiple autologous peritumoral tissues (PTTs) sampled up to 5 cm distance and in 44 benign breast tumors (BBTs). About 5% and 3% of the PTTs and 4.5% and 6.8% of BBTs showed alterations in HER2 and p53 expression, respectively. Of interest, gene amplification was observed in 50% of HER2 positive PTTs, but not in any HER2 positive BBTs. Fas, highly expressed in BBTs and downregulated in BC, maintained its expression in PTTs, whereas FasL, usually negative in BBTs, was upregulated in BC as well as in the PTTs closest (1 cm) to the invasive lesion. Our data suggest that FasL could be a potential novel biomarker of transformation, which may identify, along with HER2 and p53, precursor lesions in a genetically altered breast tissue.

[Mitochondrial DNA deletions in newborn brain samples]. / Mitokondriális DNS-deletio vizsgálata újszülöttek agymintáiban.

INTRODUCTION: Mitochondrial DNA deletion affecting 4977 base pairs (mtDNA4977) thought to be the most common somatic mutation in man was analysed in samples taken from various parts of the brains at autopsy in order to analyse the supposition whether this mitochondrial damage may play a role in the causation of neurological dysfunction in childhood. METHODS: DNA was isolated from the samples of 15 newborns and 8 adults taken during autopsy. mtDNA4977 deletion was determined by polymerase chain reaction. RESULTS: mtDNA4977 could be demonstrated not only in adults but also in every newborn sample. Estimation of the amount of mtDNA4977 indicated that the level of mtDNA4977 was smaller in the newborn samples than in the elderly's. CONCLUSION: Results suggest that mtDNA4977, contrary to the generally accepted opinion stating that it is acquired during life span, may already be present in the beginning of life. However, the possibility can not be excluded that mutations in the extreme sensitive mtDNA against oxidative damage might be generated by perinatal hypoxia and intensive care. Such a causative role of mtDNA mutations may be an important additional factor in explaining the pathomechanism of cerebral palsy and mental retardation frequently observed in surviving children.

Congenital cataract as the first symptom of a neuromuscular disease caused by a novel single large-scale mitochondrial DNA deletion.

The male proband reported here was born with appropriate anthropometric parameters at term as the second child of healthy nonconsanguineous parents. His only clinical symptom was bilateral congenital cataracts with strabismus at birth, and both lenses were removed surgically at the age of 8 months. The perinatal and infantile period thereafter was clinically uneventful and his psychomotor development appeared almost normal. At the age of 6 years he was hospitalized for slight muscle weakness, minor ptosis, nystagmus and decreased physical activity. Soon after, his general condition worsened, gait ataxia presented, dysphagia and difficulty of speech followed by rapidly progressive generalized ataxia, and myopathy developed. Typical progressive gray matter degeneration with focal necrosis in the basal ganglia characteristic of the Leigh type of neuropathology could be detected by cranial MRI, the muscle histology showed ragged-red fibers. At the age of 7.5 years, unexpected left side hemiparesis with speech disability resembling that seen in MELAS syndrome developed, from which he recovered within 1.5 days. The mtDNA of the patient showed single 6.7 kb large-scale deletion harboring between 7817 and 14 536 bp. This case represents the first report of a verified mtDNA mutation associated with congenital cataracts as the first clinical sign of a later developing progressive neuromuscular disease presented with a combination of Leigh neuropathology, ragged-red fiber histopathology and stroke-like attack.

Mitochondrial DNA4977 deletion in brain of newborns died after intensive care.

Mitochondrial DNA (mtDNA) deletion affecting 4977 base pairs (mtDNA4977), the most common mtDNA mutation in humans, was analysed in brain specimens (frontal, temporal, and cerebellar cortices, caudate nucleus, thalamus, and hippocampus) and in other tissues (blood clot, liver, kidney, heart, and muscle) taken at autopsy of deceased neonates. mtDNA4977 deletion determined by polymerase chain reaction (PCR) could be demonstrated in each neonatal sample, however, quantity of mtDNA4977 deletion was less in the newborn samples than in those of the elderlies. Results obtained suggest that contrary to certain data mtDNA4977 deletion can be present in neonates. The mtDNA4977 deletion could be generated by perinatal hypoxia or temporary oxygen oversaturations during the intensive care of the neonates, as the mtDNA is sensitive to oxidative damage. In combination with other factors an additional causative role of mtDNA4977 deletion reported here cannot be ruled out in development of cerebral palsy or mental retardation of unknown origin often seen in neonates underwent neonatal intensive care procedures.

Effect of cisplatin treatment on early activation of oncogenes in vivo.

The aim of the study was to monitor the early effect of cytostatics containing platinum on oncogenes in inbred CBA/Ca mice. In human head-neck tumors after treatment with the Cisplatin supplemented BVM (Bleomycin, Vincristine, Methotrexate) protocol, further surgeries are often necessary due to regional recurrence. Body weight equivalent amounts of human dose of Cisplatin were administered intraperitoneally to 6-8-week-old, inbred, female CBA/Ca mice. Twenty four 48 and 72 hours after the treatment RNA was isolated from the target organs and the quantitative expression of c-myc, Ha-ras and p53 genes was examined by dot-blotting in potential target tissues. Significant overexpression of Ha-ras and p53 genes was measured in the bone marrow. Regarding the expression of Ha-ras gene, a significant increase was also found in the lymph nodes after 48 hours. The p53 expression in the lungs was down-regulated compared to the control group. In the "short-term" in vivo test, 24-hour examination of gene expression and amplification is suitable for detecting the early effects of carcinogenetic exposure. Cisplatin-induced gene expression alterations call attention to its possible role in the development of regional recurrence in patients treated with cisplatin-containing regimens.

Flow cytometric analysis of DMBA-induced early in vivo ras expression.

According to recent publications 7,12-dimethylbenz[a]anthracene (DMBA) induces not only mammary cancer but also leukemia in Long-Evans (LE) rats. After treatment with DMBA, trisomy of the chromosome bearing N-ras and mutations in the codon 61 of different ras family genes are frequent. These alterations are already visible within 48 hours. Since there are very few data on ras genes' expression in the early stages of leukemogenesis, in our investigations LE rats were treated with DMBA and the expression of ras genes was measured within two days. DMBA was administered to outbred Long-Evans rats and the fluorescence intensity of the antibody recognizing the ras gene family was measured in femoral bone marrow cells 24 and 48 hours after the treatment. One of the bone marrow cell populations, separated by FSC and SSC, showed elevated ras gene expression at both 24 and 48 hours after the administration of the carcinogen. These results suggest that, besides the specific chromosomal aberrations and gene mutations, elevated ras gene expression could also be the marker of DMBA exposure.