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Tobacco smoke, recognized as a major etiological factor for cancers of the upper aerodigestive tract, represents an abundant source of reactive oxygen species (ROS), which are believed to play a significant role in mutagenesis and carcinogenesis. An additional source of ROS in tissues exposed to tobacco smoke may be metabolic oxidation of polycyclic aromatic hydrocarbons (PAH). To investigate the relationships between oxidative DNA lesions and aromatic DNA adducts, six modified DNA bases 5-hydroxyuracil, 5-hydroxycytosine, 7,8-dihydro-8-oxoguanine, 7,8-dihydro-8-oxoadenine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine and 4,6-diamino-5-formamidopyrimidine and the total level of PAH-related DNA adducts were measured in cancerous and the surrounding normal larynx tissues (68 subjects), using gas chromatography/isotopedilution mass spectroscopy with selected ion monitoring and the [sup32]P-postlabeling-HPLC assay, respectively. The levels of oxidative DNA lesions in cancerous and adjacent tissue were comparable; the differences between the two types of tissue were significant only for 5-hydroxypyrimidines (slightly higher levels were observed in the adjacent tissue). Comparable levels of DNA lesions in cancerous and the surrounding normal tissues observed in the larynx tumors support a field cancerization theory. The surrounding tissues may still be recognized as normal by histological criteria. However, molecular alterations resulting from the chronic tobacco smoke exposure, which equally affects larynx epithelia, may lead to multiple premalignant lesions. Thus, a demonstration of similar levels of DNA damage in cancerous and the adjacent tissue could explain a frequent formation of secondary tumors in the larynx and the frequent recurrence in this type of cancer. A weak, but distinct effect of tumor grading and metastatic status was observed in both kinds of tissue in the case of 5-hydroxyuracil, 5-hydroxycytosine, 7,8-dihydro-8-oxoguanine, 7,8-dihydro-8-oxoadenine... [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAH) are a well-characterized group of mutagens and carcinogens. Benzo(a)pyrene [B(a)P], the best knowncompound in the group, exerts its genotoxic activity following metabolic activation, when it acquires the properties of an electrophilic reagent that is capable of interacting with DNA. Reactive oxygen species (ROS) can remerge during the PAH metabolic activation. Because oftheir antioxidant activity, vitamins C and E are thought to act as antimutagenic agents. We designed an in vitro protocol to study the potential protective effect of vitamins C and E toward B(a)P-induced DNA damage. In this study, we examined peripheral blood lymphocytes obtained from healthy nonsmoking female volunteers, 22 to 25 years of age. The cells were exposed in vitro to 1 muM B(a)P in the presence of 40 muM or 100 muM of vitamin C or, alternatively, to 30 muM or 100 muM of vitamin E. The B(a)P-induced DNA damage and repair were estimated as the generation and removal of single-strand DNA breaks measured by the alkaline version of the single-cell gel electrophoresis (comet) assay. The protective effect of vitamins C and E was demonstrated when the vitamins were applied simultaneously with or after the B(a)P.The background level of DNA damage in the presence of vitamins C andE was lower than in the system without the vitamins. The experimentswere conducted according to various protocol schemes of the vitamin treatment and the results offer additional evidence of the antigenotoxic activity of vitamins C and E. The vitamin activity does not appear to be connected with the steps in metabolic activation or DNA repair. It seems that both vitamins act as competitors of DNA molecule in reaction with the reactive oxygen species. [ABSTRACT FROM AUTHOR]

We have turned our attention to CEACAM6 gene, already described as deregulated in various types of cancer. By using the expression microarrays performed on the set of 16 laryngeal squamous cell carcinoma (LSCC) samples: 11 cell lines and 5 primary tumors we have shown downregulation of CEACAM6 gene as compared to non cancer controls from head and neck region. CEACAM6 gene downregulation, further confirmed by quantitative PCR on 25 LSCC cell lines, was observed in cell lines derived from recurrent tumors in comparison to controls. A significant gene downregulation was observed in cell lines derived from advanced, high grade tumors in comparison to controls. Intrigued by the recurrent transcriptional loss of CEACAM6 we searched for the mechanism potentially responsible for its downregulation and hence we analyzed DNA copy number changes (a-CGH), promoter DNA methylation status and occurrence of gene mutations ( in silico ). Neither the analysis of gene copy number, nor the mutation screen has shown recurrent deletions or mutations, that could contribute to the observed downregulation of the gene. However, by using bisulfite pyrosequencing, we have shown DNA hypermethylation (mean DNA methylation > 78%) of CEACAM6 promoter region in 9/25 (36%) LSCC cell lines. Importantly, the 5-aza-2-deoxycytidine-induced inhibition of DNA methylation resulted in restoration of CEACAM6 expression in the two LSCC cell lines on mRNA level. In summary, we have shown that recurrent downregulation of CEACAM6 in LSCC is dependent on the gene's promoter DNA methylation and is observed predominantly in large, poorly differentiated tumors and recurrences., Competing Interests: None.

Patient: Female, 6 FINAL DIAGNOSIS: Phenotype-genotype discordance in congenital malformations with communication disorders resembling trisomy 18 (Edwards syndrome) Symptoms: -, Medication: - Clinical Procedure: - Specialty: Otolaryngology., Objective: Congenital defects., Background: Communication process disorders are very frequent in rare cases of chromosomal aberrations (deletions, insertions, and trisomies) such as Down syndrome (trisomy 21), Turner syndrome, Edwards syndrome (trisomy 18), or Patau syndrome (trisomy 13). Sometimes phenotype may delusively correspond to the characteristic features of a given syndrome, but genotype tests do not confirm its presence., Case Report: We present the case of a 6-year-old girl admitted to the Clinic of Phoniatrics and Audiology for the assessment of communication in the course of congenital malformations with phenotype characteristic for trisomy 18 (Edwards syndrome). Immediately upon birth, dysmorphic changes suggesting trisomy 18 (Edwards syndrome) were observed, but trisomy 18 was excluded after karyotype test results were normal (46, XX)., Conclusions: DISTURBED ARTICULATION WAS DIAGNOSED: deformed linguo-dental and palatal sounds, interdental realization with flat tongue of the /s/, /z/, /c/, /dz/, /ś/, /ź/, /ć/, /dz/ sounds (sigmatismus interdentalis). Hearing loss was confirmed.

According to epidemiological data head and neck cancers constitute for 12% of all malignancies in the world. It is estimated that a total of 400 000 cases of the mouth and throat and of 160 000 cases of laryngeal cancer, 300 000 people die each year. History of head and neck cancers developed and underwent many changes at the turn of the century. Treatment, pathogenesis and possessed state of knowledge on the subject has changed. Starting from the ancient times there were texts on how to treat and examine patients. The Edwin Smith and Ebers Papyrus are two of the oldest medical documents describing the treatment of cancer patients. Hippocrates was the first person who used the word "cancer" and probably he was the first who divided the tumors into benign and malignant. In a document known as the Doctrine of Hippocrates he described skin cancer and cancer treatments. Over the next centuries, medical science did not develop because of religious concerns about autopsy and surgical procedures. The 17th century is a period in which there were a lot of new information about how to treat such oral cancer. Cancer of the tongue was removed by cauterization, which in the 18th century was replaced by the use of surgical instruments. In the same age glossectomy has been accepted as the treatment of choice performed in the treatment of cancer. The 19th century brought a major breakthrough in the treatment of surgical, diagnostic, anesthetic techniques and understanding of the pathological mechanisms. Histological evaluation of tumors has become mandatory and standard practice in the assessment of cancer. Laryngectomy and neck lymph nodes removal has become commonplace. Modified Radical Neck Dissection (MRND), became popularized as another cancer treatment technique. Describing ways to treat cancer, radiotherapy can not be ignored - there are several new techniques such as Intensity Modulated Radiotherapy (IMRT) and hypofractionation currently used. Chemotherapy and the introduction of many new drugs have changed the outlook for patients suffering from cancer. Recently there are expectations about the targeted therapy, especially in medicaments blocking epidermal growth factor receptor (EGFR).

It was established, that HPV virus (Human Papilloma Virus) is responsible for tumor induction in some anatomical regions of head and neck, mainly in palatine tonsils. The characteristics of HPV-related tumors as well as the course of the disease are definitely different compared to tobacco-smoking related tumors; patients HPV-positve have better prognosis - less patients develops recurrences and dies from the disease. There is no full compliance about patients' characteristics, although most indications concern "young adults" with their intensive sexual life. Because the course of HPV-related tumors is milder, there is a need to distinguish the cause of disease to carry on the therapy adjusted to the causative factor. This approach might help to select HPV-negative patients with severe course of disease to apply more aggressive chemotherapy.

Cigarette smoking and excessive alcohol drinking result in the rise of numbers of patients suffering from the head and neck cancer. Addiction to any of these stimulants carry a risk of developing a cancerogenesis process. Using them simultaniously lead not to a summary of each of those risks but multiplies them. Scientific research also indicates the important difference in the incidence of cancer in people who have never smoked cigarettes or drunk alcohol in comparison to those, whose exposure to these stimulatns was longterm - in such case, the former group had a lower percentage of developing the disease. Human body burdened with the ongoing cancer shows disturbances on various levels of the system. One of such disturbances is change of the concetration levels of physiological metals, such as calcium, magnesium, iron, copper, zinc or mangenese. They play key roles in maintaing the hormonal and ionic stability, they act as cofactors in many enzymes in metabolic processes. Diagnostic research of any deviations in levels of those essential elements enables a full estimation of a patient condition. The aim of this study was physiological metal levels evaluation in different kinds of biological material in patients with tumors of larynx, salivary glands and oral cavity and tongue. Hair and nail samples were used as examples of alternative material, beside the serum samples, which is a standard material and often used. Subjects were patients of Otolaryngology and Laryngological Oncology Clinic of Poznan University of Medical Sciences (Samodzielny Publiczny Szpital Kliniczny nr 2 im. Heliodora Swiecickiego Uniwersytetu Medycznego im. Karola Marcinkowskiego w Poznaniu) and The Head and Neck Surgery Ward of The Greater Poland Cancer Centre in Poznan. Subjects were 41 men and 18 women with tumors of larynx, salivary glands and oral cavity and tongue. The control group consisted of patients from the Otolaryngology and Laryngological Oncology Clinic of Poznan University of Medical Sciences (Samodzielny Publiczny Szpital Kliniczny nr 2 im. Heliodora Swiecickiego Uniwersytetu Medycznego im. Karola Marcinkowskiego w Poznaniu), The Head and Neck Surgery Ward of The Greater Poland Cancer Centre in Poznan and patients of Department of Endocrinology, Metabolism and Internal Medicine of Poznan University of Medical Sciences (Samodzielny Publiczny Szpital Kliniczny nr 2 im. Heliodora Swiecickiego Uniwersytetu Medycznego im. Karola Marcinkowskiego w Poznaniu) and Department of Conservative Dentistry and Periodontology Poznań University of Medical Sciences. They gave answers to the questionnaire concerning smoking habits, alcohol consumption and dietary habits, Then the samples of their serum, hair and nails were collected. After careful preparations the biological material has underwent the process of digestion, and then calcium, magnesium, iron, copper, zinc, mangenese were determined quantitatively using the method of ICP-MS. Profile of the patients who took part in the research displayed a strong correlation between tobacco smoking with alcohol drinking and appearance of larynx, salivary gland and oral cavity and tongue cancer as well as between exclusively tobacco smoking and appearance of these types of cancer. There is a higher incidence of larynx, salivary gland and oral cavity and tongue cancer when there is a deficiency of grain products or fibre in everyday diet. A higher level of calcium, magnesium, iron and manganese was found in patients' hair and nails who suffered from salivary gland cancer. According to applied Chemometric Analysis of Principal Component 1 - concentrations of iron, copper and manganese with magnesium and zinc in patients' nail samples showed strong correlation between measured variables. In patiens' hair samples measured correlation between variables was decreased - concentrations of calcium and magnesium as well as of iron and manganese were highlighted as two groups of variables which showed some correlation in this type of biological material. Further research is required to indicate which of alternative biological materials - hair or nail samples - in relation to serum, would provide a better evaluation of physiological metal levels.

Fanconi anemia (FA) associated genes [FANCA, -B, -C, FANCD1(BRCA2), -D2, -E, -F, -G, -I, -L, -M, FANCN (PALB2), FANCJ(BRIP1) and FA-linked BRCA1] encode proteins of DNA damage response pathways mutated in FA patients. FA is characterized by congenital malformations, chromosomal instability and high cancer susceptibility. FA patients have a 500-700 times higher risk of head and neck squamous cell carcinoma (HNSCC) compared to the non-FA population. As DNA methylation comprises one of the known gene inactivation mechanisms in cancer we have investigated the methylation status of 13 FA and one FA-linked gene in order to assess the role of FA in sporadic laryngeal squamous cell carcinoma (LSCC) tumor samples. Thirteen laryngeal squamous carcinoma cell lines (UT-SCC) and 64 primary laryngeal carcinoma cases were analyzed by bisulfite pyrosequencing. DNA from buccal swabs of 10 healthy volunteers was used as a control group. Promoter regions of FANCA, BRCA1 and BRCA2 displayed recurrent alterations in the methylation levels in cancer samples as compared to buccal swabs controls. For FANCA, hypomethylation was observed in 11/13 cell lines (p<0.0003) and all 64 primary larynx samples (p<0.001) compared to buccal swabs. For BRCA1, 4/13 cell lines (p=0.04) and 3/58 primary laryngeal cases (p=0.22) showed hypomethylation. In BRCA2, all 13 cell lines (p<0.0001) 4/63 primary LSCC (p<0.01) showed hypermethylation as compared to controls. In conclusion, we show recurrent alterations of DNA methylation levels in three Fanconi anemia genes which might contribute to the pathogenesis of LSCC.

Statistics concerning tobacco smoking confronted with cancer epidemiology indicates that only a minority of smokers develops terminal cancer. To much extent it could be explained by genetic polymorphism responsible for a variable risk to develop cancer and its further progression. Then, a comparative analysis of the data concerning cancer deaths regarding a decline of smoking in developed countries unravels other factors previously not considered to represent carcinogenic agents. Human papilloma virus (HPV) could serve as an example of such agent exerting adverse health effects once attributed only to tobacco.

Mutations in mitochondrial DNA are associated potentially with nonsyndromic and aminoglycoside-induced hearing loss. Several nucleotide changes associated with hearing impairment were described; however, a variable frequency of deafness-associated mutations in different populations has been observed. The aim of the present study was to determine the frequency of pathological mutations in mitochondrial 12S rRNA and tRNA(Ser(UCN)) genes in a group of 500 individuals representative of the general population of Poland. Mutational screening of 12S rRNA revealed the presence of three deafness-associated mutations, A827G, T961C, and A1555G, and one potentially pathogenic substitution, T669C. The carrier frequency of pathological mutations was estimated to be 1.2% (6/500) in the general Polish population. A deafness-associated G7444A mutation in the precursor of tRNA(Ser(UCN)) gene was identified in 8/500 (1.6%) unrelated blood donors. Seven nucleotide changes identified in 12S rRNA (G709A, G750A, G930A, T1243C, T1420C, and G1438A) and tRNA(Ser(UCN)) (C7476T), based on a frequency exceeding 1.0%, were considered as polymorphisms of 12S rRNA and tRNA(Ser(UCN)) in the studied population. Mitochondrial 12S rRNA gene seems to be the hot spot for deafness-associated mutations in the Polish population. The relatively high carrier frequency of tRNA(Ser(UCN)) G7444A (1/62) suggests that this substitution might be a nonpathogenic polymorphism in the Polish population.

Initiation and progression of laryngeal cancer is associated with tobacco smoking and abusing of strong alcoholic beverages. A significance of genetic factor, although not defined sufficiently yet has been raised as well. The studies were focused on an influence of AHR gene polymorphism on survival of squamous cell carcinoma laryngeal subjects. The study material was 65 archival DNA samples analyzed by RLP-PCR. The samples varying with electrophoretic mobility were DNA sequenced. In the study group 9 heterozygotic variants Arg554Lys (codon 554) were detected. One case was a carrier of two other mutations in codon: 490 (1468 A > G) and 570 (1708 G > A). Survival time, metastasis and occurrence of second primary tumors were compared in carriers of wild type and Arg554Lys variant AHR. Preliminary results indicate for a necessity of further studies as until now the study group is too small to find a conclusive association.

Tumour suppressor gene TP53 is a subject of frequent lesions and mutations in a majority of cancer types that is followed by its dysfunction in regulation of cell proliferation, apoptosin and DNA repair. Mutation profile reflects the presence of mutagen-vulnerable sites (including tobacco smoke carcinogens) in its structure. A number of mutations in tobacco smoke-associated cancers are higher than in other types. Particularly, G > T mutation is recognized a signature to benzo(a)pyrene exposure. Further, a mutation profile is dependent on cancer anatomic localization and histological type. There were put forward suggestions concerning estimation of cancer risk and disease prognosis basing of TP53 gene status and expression. The protocols of gene therapy involving TP53 gene are still not satisfactory.

The article presents the current techniques used for the identification of genes involved in tobacco smoke-associated cancers. The focus is set on the techniques derived from the conventional cytogenetics and includes fluorescence in situ hybridization (FISH), comparative genomes hybridization (CGH) and its further improvement that is array-CGH, and other aspects of microarray DNA technology. The second part deals with the main findings concerning participation of oncogenes and tumor suppressor genes in development and progression of tobacco smoke-associated head and neck cancers.

Laryngeal cancer in Poland is characterized by high levels of morbidity and mortality. The main risk factors for the larynx cancer are alcohol drinking and tobacco smoking. In contrary to well established tobacco-related evidence for an increased risk of larynx cancer, alcohol-related mechanisms of carcinogenesis remain unknown. Nevertheless the effect of alcohol is modulated by polymorphisms in genes encoding enzymes for ethanol metabolism. Hence we investigated the ADH1C *1 genotype and allele frequency in a group of 102 larynx cancer patients with heavy alcohol consumption recruited from the Department of Otolaryngology and Laryngological Oncology of the University of Medical Sciences in Poznan. The data were compared with 112 non-cancer age-matched individuals consuming similar amounts of ethanol. Blood samples were used for analysis of restriction fragment length polymorphism. DNA was isolated from the whole blood leucocytes and PCR with specific primers was used to amplify polymorphic region of rs698 in the ADH1C gene. The method was based on allele detection by Sspl restriction enzyme digestion and after the incubation with enzyme, samples run on an electrophoresis. The statistic analysis was performed to calculate Odds Ratio (ORs), 95% confidence intervals (CIs) and significance. Results suggest a slightly increased risk of larynx cancer for individuals who have inherited the ADH1C *1 allele (rs 698), however they did not reach the level of statistic significance.

The woody Amazonian vine Uncaria tomentosa (cat's claw) has been recently more and more popular all over the world as an immunomodulatory, antiinflammatory and anti-cancer remedy. This study investigates anti-proliferative potency of several cat's claw preparations with different quantitative and qualitative alkaloid contents on HL-60 acute promyelocytic human cells by applying trypan blue exclusion and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction assay (MTT). By standardization and statistical comparison of the obtained results pteropodine and isomitraphylline are indicated to be most suitable for standardization of medical cat's claw preparations.

A role of tobacco products in cancer incidence is commonly known and accepted. It is estimated that roughly 1/3 of all the cancers is resulted from previous exposure to tobacco. An impact of tobacco smoke carcinogens in formation of DNA lesions and mutations is well established. Contrary to that, less is known about rearrangements of chromosomes. Nevertheless, there are many indications associating rearrangements of chromosome arms 3p, 3q, 8q, 9p, 17p i 18q with a clastogenic activity of tobacco smoke. An evolution of cytogenetics from conventional techniques to molecular cytogenetics provides an opportunity to find some links between chromosome aberrations and activation of oncogenes as well as deactivation of tumor suppressor genes.

The impact of genetic factors on laryngeal cancer risk was studied in relation to DNA repair capacity on the phenotypic and genotypic level. DNA lesions induced by bleomycin or S9-activated benzo[a]pyrene were determined in blood lymphocytes using the alkaline comet assay. Laryngeal cancer subjects (n = 52) were shown to have higher levels of spontaneous and mutagen-induced DNA damage as compared to healthy controls (n = 56). A level of spontaneous DNA damage tended to increase with tumour grading. A percentage of individuals with an efficient DNA repair was higher in controls than in cancer subjects for both used mutagens. The distribution of polymorphic variants of XPD, XRCC1 and XRCC3 DNA repair genes in the group of laryngeal cancer subjects (n = 293), subjects with second primary tumours (n = 84) and in the matched controls (n = 322) was estimated by PCR-based genotyping. Five polymorphisms were studied in 3 DNA repair genes. There were found only 2 XPD alleles significantly overrepresented in laryngeal cancer that could be interpreted as an increase in genetic risk. There were no significant differences in distribution of 'risk' and 'protective' genotypes between single primary and second primary tumours. Altogether, the established phenotypic deficit of DNA repair in laryngeal cancer subjects was only partly confirmed by overrepresentation of 'risk' genotypes of the studied DNA repair genes.

A review presents an incidence of multiple (second) primary tumors of head and neck region resulted from an exposure to tobacco smoke and ethanol. Further, epidemiology, clinical implications, molecular alterations and an impact of genetic factor are described. Finally, alternative theories of origin of multiple primary tumors are discussed.

The aim of the present study was to estimate the genotoxicity of desflurane, applied as a volatile anaesthetic. The potential genotoxicity was determined by the comet assay as the extent of DNA fragmentation in human peripheral blood lymphocytes in vitro. The comet assay detects DNA strand breaks induced directly by genotoxic agents as well as DNA fragmentation due to cell death. Another anaesthetic, halothane, already proved to be a genotoxic agent, was used as a positive control. Both analysed drugs were capable of increasing DNA migration in a dose-dependent manner under experimental conditions applied. The results of the study demonstrated that the genotoxicity of desflurane was comparable with that of halothane. However, considering the pharmacodynamics of both drugs, the genotoxic activity of desflurane may be connected with a less harmful effect on the exposed patients or medical staff.

Background: Loss of heterozygosity, frequently observed during the development of many tumor types, also occurs in larynx cancer. This disease has a very complex genetic background, with numerous alterations involving oncogenes and tumor suppressor genes. The upper parts of the respiratory-digestive tract are exposed to many carcinogens, which can result in the appearance of multiple tumors or primary tumor relapses. The examination of normal-appearing tissues makes it possible to recognize genetic events occurring at early stages., Material/methods: 65 larynx cancer patients were examined for loss of heterozygosity (LOH) on the 13q chromosomal arm, with the application of three microsatellite markers. The material from each patient consisted of blood, tumor, safe margin, and 1-2 clinically unchanged mucosal samples., Results: High frequencies of LOH in tumor tissues (49-64%) were observed in both studied chromosomal regions (13q14 and 13q34). The frequency of LOH in safe margin ranged from 12 to 31%. In normal-appearing mucosa, LOH was observed less frequently: 6-26% of informative cases., Conclusions: The data obtained from this investigation suggest that losses in the region of the 13q arm occur frequently during larynx cancer development. Moreover, they were observed not only in tumor tissues, but also in clinically unchanged mucosa. This could be a highly reliable predictor of the occurrence of relapse or second primary tumor in this anatomical site.

The incidence of laryngeal cancer is strongly connected with exposure to tobacco smoke containing at least 40 genotoxic carcinogens. DNA lesions induced by tobacco smoke carcinogens can be turned into stable mutations. Oncogenes and tumor suppressor genes are first of all responsible for initiation of carcinogenesis. The same time cells provide such self-protection processes as: carcinogen detoxication, DNA repair and apoptosis. The initiation of carcinogenesis followed by oncogenesis results from the competition between DNA lesions/mutations formation and the protection processes; the latter are genetically controlled.

A moderate genotoxic activity of halothane and isoflurane applied as volatile anaesthetics has already been shown. The aim of this work was to estimate a potential genotoxicity of sevoflurane, introduced to clinical practice later than halothane and isoflurane. A genotoxic activity of all three compounds was estimated by using the comet assay in human peripheral blood lymphocytes (PBL) proliferating in vitro. We demonstrated that in contrast to the previously studied anaesthetics, sevoflurane did not induce any increase in DNA migration in the studied conditions. To estimate a genotoxic effect of a prolonged exposure to halogenated anaesthetics in vivo, PBL taken from operating room personnel (n = 29) were tested for DNA degradation and compared with those from a control non-exposed group (n = 20). No significant differences were detected between the groups. We conclude that sevoflurane does not have genotoxic properties, both in vitro and in vivo.

In terms of growing interest in molecular analysis of genetically determined hearing impairment, it is of clinical importance to know problems and obstacles that arise on the way to molecular diagnosis. Although for clinicians a genetic factor as a reason for hearing problem is easier accepted, still an understanding the limits of such identification remains unclear. Technical issues, as well as social and legal aspects of genetic analysis are described. Authors try to explain why such impressive progress in understanding of hearing loss physiology, especially from the genetic point of view, does not have its transfer into clinical practice.

The occurrence of second primary tumors after curative treatment or simultaneous multiple malignancies are current problem in head and neck cancer. The mutagen sensitivity is well known marker to predict patient proneness to develop the second tumor. The frequency and localization of spontaneous and mutagen induced chromatid breaks in peripheral blood lymphocytes (PBLs) in patients with multiple primary tumors (MPT) may help in defining regions involved in cancerogenesis process. The case control study using the bleomycin sensitivity assay (number of chromatid breaks per cell (b/c) was performed in 36 patients with MPT and two control groups: 52 patients with one malignancy and 47 healthy individuals. The differences between examined patients and control groups were estimated using U Mann-Whitney test. The b/c level in PBLs of patients with MPT ranged from 0.26 to 4.12 (mean 1.53) and was significantly higher (p<0.000006) both compared with patients with one malignancy (b/c ranged from 0.02 to 3.08; mean 0.74) and healthy controls (b/c ranged from 0.04 to 1.14; mean 0.41). An increase of b/c index was observed in almost all chromosomal arms. The majority of chromosomal locations with the increased proportion of breaks in the group of patients with multiple tumors were identified as regions where loci involved in DNA repair, cell cycle regulation suppressor genes and oncogenes were found. Statistically higher induced individual susceptibility in MPT patients compared with single tumor and healthy controls was confirmed. Comparable induced mean b/c was found in patients with two smoking-related cancers as well as with not smoking related tumors.

Ionizing radiation is a known "universal carcinogen" for a wide variety of tumors in man. Human populations are exposed to radiation coming from natural and industrial environment, and from medical sources. However, these are radiotherapy patients who receive the highest doses. Radiation both mutates and sterilizes cells (lethal effect). The risk of cancer induction from cells that have received very high doses of radiation (therapeutic dose about 2 Gy) is lower then from the cells with low doses, since the majority of them will have been sterilized. The epidemiological studies based on the population of atomic bomb survivors have indicated that the most acceptable model of carcinogenesis is the linear non-threshold model. The evaluation of clinical risk related to a wide range of radiation doses, which range from 0.01 Gy to 2 Gy, is connected with many methodological problems such as: differences in treatment factors (dose range, irradiated volume, anatomical site), unknown epidemiological data (smoking abuse, comorbidity), shortening of the follow-up (short lifespan, migration), evaluation of small groups of patients. The most important difficulty is lack of the sufficient knowledge of genetic background which is probably most significant in carcinogenesis process. The introduction into clinical practice of a new sophisticated method of irradiation such as the three-dimensional conformal radiotherapy (3D CRT) or intensity modulated radiotherapy (IMRT) leads to the increase of low irradiation dose for very large volume of normal tissue. Thus, the evaluation of these new methods in the context of carcinogenesis is a very important objective in the future. Today, we can only introduce the most important questions concerned with the risk of carcinogenesis induction which await answers: what is the risk of induction of cancer due to the implementation of these new methods of treatment, and how important is this risk for clinical practice, especially in the case of combined radiochemotherapy? Despite a large body of experimental and clinical studies, radiation carcinogenesis is not fully understood yet. Additional problems related to the impact of irradiation of low dose on carcinogenesis are not resolved. For example, the bystander effect, the low dose hypersensitivity and the adaptive response could modulate the total response after irradiation, but the impact on the carciongenesis is unknown.

Background: The mechanism of multistage carcinogenesis initiated by environmental carcinogens produces clonal evolution of initiated cells to the stage of metastasis. However, the simultaneous co-existence of various cell clones is not excluded. The analysis of chromosome alterations appears to be the best method to assess the clonal composition of a tumor., Material/methods: Laryngeal tumor specimens and their corresponding metastases to the adjacent lymph nodes (20 pairs) were analysed by comparative genome hybridization (CGH)., Results: The profile of gains and losses of DNA copy number was found to be fairly similar in the primary tumor location and in its metastasis. In this study the most frequent losses were found on 3p, 5q, 9p, 13p, and 13q, while gains occurred in 1q, 3q, 5p and 11q. The gains and losses were found more frequently in metastasis than in primary tumor, except for the loss of 3p and the gain of 5p. The biological function of the latter chromosome alterations seems to be limited to tumor growth, rather than metastasis formation., Conclusions: A comparison of the profiles of chromosome alterations in primary tumor locations and metastases indicate that the progression of laryngeal cancer is connected with the clonal evolution of tumor cells.

Sprague-Dawley rats and several inbred strains of mice were compared with respect to the induction of 4S BNF-binding protein expression by treatment with beta-naphthoflavone (BNF), an aryl hydrocarbon receptor (AhR) ligand. Inbred strains of mice chosen for the study encompassed 3 allelic forms of AhR found in Mus musculus so far. As it was reported by us earlier, treating rats with BNF caused a significant induction of BNF-binding protein expression. By contrast, no BNF-binding protein was detected in mice treated with BNF in corn oil as a vehicle or with corn oil itself.