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Head and neck cancer (HNC) is a multistep process proceeding from single gene mutations generated by carcinogens to the substantial dysregulation of metabolic processes [...].

MAF is a transcription factor that may act either as a tumor suppressor or as an oncogene, depending on cell type. We have shown previously that the overexpressed miR-1290 influences MAF protein levels in LSCC (laryngeal squamous cell carcinoma) cell lines. In this study, we shed further light on the interaction between miR-1290 and MAF , as well as on cellular MAF protein localization in LSCC. We confirmed the direct interaction between miR-1290 and MAF 3'UTR by a dual-luciferase reporter assay. In addition, we used immunohistochemistry staining to analyze MAF protein distribution and observed loss of MAF nuclear expression in 58% LSCC samples, of which 10% showed complete absence of MAF, compared to nuclear and cytoplasmatic expression in 100% normal mucosa. Using TCGA data, bisulfite pyrosequencing and CNV analysis, we excluded the possibility that loss-of-function mutations, promoter region DNA methylation or CNV are responsible for MAF loss in LSCC. Finally, we identified genes involved in the regulation of apoptosis harboring the MAF binding motif in their promoter region by applied FIMO and DAVID GO analysis. Our results highlight the role of miR-1290 in suppressing MAF expression in LSCC. Furthermore, MAF loss or mislocalization in FFPE LSCC tumor samples might suggest that MAF acts as a LSCC tumor suppressor by regulating apoptosis.

Purpose of Review: Observational studies have shown that serum 25-OH vitamin D [25(OH)D] is inversely associated with overall cancer risk in many malignancies. We performed a systematic literature review to determine whether vitamin D deficiency is related to head and neck cancer (HNC) etiology and outcome., Recent Findings: The search yielded five prospective studies reporting 25(OH)D levels prior to cancer diagnosis and their effect on the risk of HNC. Eight studies were cross-sectional or case-control studies, in which 25(OH)D levels were only measured after cancer diagnosis. Two studies found an inverse association between 25(OH)D level and HNC risk, while two other prospective cohort studies demonstrated no connection between 25(OH)D and HNC risk. Several studies reported cancer patients to have significantly lower 25(OH)D levels than controls. Associations between 25(OH)D and prognosis and mortality were variable. The link between vitamin D and HNC has so far only been investigated in a few observational, prospective, and case-control studies. Vitamin D deficiency may be more common in HNC patients than in the healthy population. There is no evidence for a causal relationship. Further studies are needed to evaluate whether low 25(OH)D concentrations play a role in the development or outcome of HNCs.

The objective of the review was to compare molecular and health effects of tobacco smoking using cigars, cigarillos, pipe and water pipe in relation to the effects of cigarette smoking. In this review we will focus on the upper respiratory tract. Mechanisms of interaction of tobacco smoke constituents after products other than cigarettes are similar to these associated with cigarette smoking. Carcinogenic activity was demonstrated for any type of tobacco smoking, although the risk of developing head and neck squamous cell carcinoma (HNSCC) remains lower in users of cigars, traditional pipe and water pipe as compared to cigarette smoking. Nevertheless, there is no way of safe tobacco smoking., (© 2018 UICC.)

Purpose of Review: To focus on two novel aspects of head and neck squamous cell carcinoma (HNSCC) genetics of special interest: the epithelial-mesenchymal transition (EMT) process, an initial step in tumor progression that finally leads to metastasis formation, by explaining how genes as well as epigenetic factors control this process, and the new diagnostic options based on the analysis of circulating tumor cells (CTCs) and cell-free DNA (cfDNA) that could revolutionize diagnosis in the coming years., Recent Findings: We present an intriguing recently described group of factors, namely miRNAs, deregulated during EMT. MiRNAs could serve as novel markers of EMT and metastasis formation and are also a potential therapeutic target. Second, we show recent findings on CTC and cfDNA analysis in HNSCC that demonstrate the usefulness of this new diagnostic approach., Summary: We stress the importance of EMT in the context of metastasis formation and the potential of liquid biopsies in clinical practice.

Cellular processes like differentiation, mitotic cycle, and cell growth are regulated by tyrosine kinases with known oncogenic potential and tyrosine phosphatases that downmodulate the first. Therefore, tyrosine phosphatases are recurrent targets of gene alterations in human carcinomas. We and others suggested recently a tumor suppressor function of the PTPRD tyrosine phosphatase and reported homozygous deletions of the PTPRD locus in laryngeal squamous cell carcinoma. In this study, we investigated other gene-inactivating mechanisms potentially targeting PTPRD, including loss-of-function mutations and also epigenetic alterations like promoter DNA hypermethylation. We sequenced the PTPRD gene in eight laryngeal squamous cell carcinoma cell lines but did not identify any inactivating mutations. In contrast, by bisulfite pyrosequencing of the gene promoter region, we identified significantly higher levels of methylation (p = 0.001 and p = 0.0002, respectively) in 9/14 (64%) laryngeal squamous cell carcinoma cell lines and 37/79 (47%) of primary laryngeal squamous cell carcinoma tumors as compared to normal epithelium of the upper aerodigestive tract. There was also a strong correlation (p = 0.0001) between methylation and transcriptional silencing for the PTPRD gene observed in a cohort of 497 head and neck tumors from The Cancer Genome Atlas dataset suggesting that DNA methylation is the main mechanism of PTPRD silencing in these tumors. In summary, our data provide further evidence of the high incidence of PTPRD inactivation in laryngeal squamous cell carcinoma. We suggest that deletions and loss-of-function mutations are responsible for PTPRD loss only in a fraction of cases, whereas DNA methylation is the dominating mechanism of PTPRD inactivation.

The knowledge of the biology of head and neck squamous cell carcinoma (HNSCC) has had relatively little impact on the improvement in oncologic outcome up to date. However, the identification of oncogenes and tumor suppressor genes (TSGs) involved in cancer progression contributes to the understanding of the molecular pathways involved in oncogenesis and could contribute to individual risk assessment and provide tools for improvement of treatment and targets for therapy based on the alterations in these pathways. The aim of this article is to review the chromosomal aberrations commonly found in HNSCC, to identify the genes in these chromosomal regions suggested to act as (candidate) oncogenes or TSGs, and to discuss the molecular mechanisms modulating their expression.

Head and neck cancers are one of the most frequent cancers worldwide. This paper attempts to evaluate disturbances of homeostasis of the necessary elements (calcium, magnesium, zinc, copper, iron, manganese) and changes in the levels of toxic metals (lead, cadmium, cobalt, chromium VI) in hair of patients with head and neck cancers, as well as people without a diagnosed neoplastic disease. In order to quantify the necessary elements and toxic metals, a method using ICP-MS and ICP-OES techniques had been developed and validated. The studies have shown that patients with head and neck cancer used to drink alcohol and smoked much more frequently than healthy individuals, both in the past and presently. Statistically significant differences in concentrations of average metal content in the group of patients with head and neck cancers compared to the control group were confirmed. Significant differences in metal content between the group of patients with head and neck cancers and healthy individuals were found which enabled distinguishing between the study groups. To this end, a more advanced statistical tool, i.e. chemometrics, was used. The conducted research analyses and the use of advanced statistical techniques confirm the benefits of using alternative material to distinguish the patients with head and neck cancers from the healthy individuals.

The results of treatment of head and neck tumors remain poor for decades. It means that after surgery, chemotherapy is not a proper choice, as tumors of this region are relatively resistant to cytotoxic drugs. A little progress was noted only for radiotherapy outcome. Consequently, clinicians and researchers' expectations are focused on targeted therapy, where microRNAs (miRNAs, miRs) seem to be the most promising target. After the year 2000, miRNAs became new players on the scene of cancer science. Since then, extensive investigations have been performed with a hope of finding a new prognostic and diagnostic tool and bridging them with a bright new way of understanding the basis of molecular carcinogenesis. miRNAs display astonishing specificity and thus are associated with pathoclinical parameters of the disease. After more than a decade of ongoing studies, in this review we attempt to summarize the current knowledge of miRNAs in malignancies arising in head and neck sites and with a majority of squamous cells of the epithelium., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Although down-regulation of GNG7 in cancer was reported before, its role in carcinogenesis is poorly understood. It belongs to a family of large G-proteins that may be involved in cell-contact-induced growth arrest and function in tumor suppression. In the present study, we stained immunohistochemically 188 tumors derived from larynx or floor of the mouth for GNG7 protein and confronted it with clinicopathologic data. Moreover, we performed bisulfite pyrosequencing to analyze GNG7 promoter methylation. We identified recurrent loss of GNG7 protein expression in 68/188 (36%) cases and promoter hypermethylation in (42/98; 43%) primary tumors, predominantly in young patients (p < 0.001). Loss of GNG7 expression correlated with hypermethylation of GNG7 promoter region (p < 0.001). Moreover, loss of GNG7 protein expression correlated with tumor size (p = 0.012) and lack of cervical metastasis (p = 0.02) whereas sustained expression correlated with keratinization (p = 0.008). Taken together, loss of GNG7 protein expression is a frequent event in head and neck cancer. Moreover, our data suggest that hypermethylation of the promoter region of GNG7 is probably the mechanism of the observed inactivation.

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.

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.

Patients with squamous cell carcinoma of the head and neck (HNSCC) aged less than 45 years are categorized as young adults (YA) and in opinion of many authors in comparison to older (typical) patients (OP) are characterized with more serious form of the disease and often lack the classical risk factors associated with the illness. Hence, there is a need of an exact clinical analysis and a search for additional causative factors. The purpose of this study was to estimate the role of genetic factors in the etiology of HNSCC in YA. Studies carried out on 60 patients of the study group (YA) and 72 older control patients were directed to: (1) a degree of spontaneous and induced chromosome breaks estimated by bleomycin test, (2) a degree of spontaneous and induced DNA damage and a potential of DNA repair determined by comet assay and (3) polymorphism of genes of glutathione transferases M1 and T1, responsible for detoxification of metabolites of carcinogens of tobacco smoke, studied by PCR-based genotyping. The level of chromosome breaks (spontaneous and induced), the level of DNA damage (spontaneous and induced), DNA repair potential and the distribution of polymorphic variants of GSTT1 gene are not significantly different in YA and in OP, which suggests that these factors do not appear the causative factors for HNSCC in young age. The significant risk factor of HNSCC in YA may be GSTM1 null genotype, which may cause the defective detoxification of metabolites of polycyclic aromatic hydrocarbons of tobacco smoke.

Unlabelled: Squamous cell carcinoma of the head and neck (HNSCC) is the malignant tumor arising most frequently in non-keratinized epithelial tissue of the upper part of the respiratory or gastrointestinal tracts. These tumors develop most commonly in the sixth or seventh decade of life and significantly less frequently in patients younger than 45 years defined as young adults. In literature, there are still many controversies concerning the origin of these tumors in this group of patients., Aim: To estimate the role of exogenous and epidemiological factors in etiology of HNSCC in young adults., Material and Methods: The study group consisted of 95 young adults (< or =< 45 years) with HNSCC and the control group of 95 older patients (> 45 years) with HNSCC, who were treated in the Department of Otolaryngology and Laryngological Oncology of Karol Marcinkowski University of Medical Sciences in Poznan during the period 2000-2004. The analysis was based on etiological questionnaires and the medical records of patients., Results and Conclusions: 1. A significant role of typical exogenous factors (active and passive exposure to tobacco smoke and alcohol abuse) was established in the etiology of HNSCC in young adults. 2. Daily active exposure to tobacco smoke in young adults is nearly the same as in older patients, but daily passive exposure is higher than in older patients. 3. Significantly higher alcohol consumption in young adults than in older patients, found in this study, may be one of the reasons of HNSCC onset in young age. 4. Occupational exposure to the HNSCC causative factors in young adults is not higher than in older patients. 5. A frequency of familial cancer in young adults with HNSCC seems to be higher than in older patients, but further observations are needed.

Unlabelled: Squamous cell carcinoma of the head and neck (HNSCC) is the malignant tumor arising most frequently in non-keratinized epithelial tissue of the upper part of the respiratory or gastrointestinal tracts. These tumors develop most commonly in the sixth or seventh decade of life and significantly less frequently in patients younger than 45 years defined as young adults. In literature, there are still many controversies concerning the clinical course of these tumors in this group of patients., Aim: Clinical and histopathological analysis of HNSCC in young adults., Material and Methods: The study group consisted of 95 young adults (< or = 45 years) with HNSCC and the control group of 95 older patients (> 45 years) with HNSCC, who were treated in the Department of Otolaryngology and Laryngological Oncology of Karol Marcinkowski University of Medical Sciences in Poznań during the period 2000-2004. The analysis was based on medical records of patients., Results and Conclusions: 1. In the young adults group and particularly in patients younger than 40 years there is a higher percentage of patients with oral cancer and lower percentage of patients with larynx cancer in comparison to older patients group, but in all analysed groups larynx cancer is the most frequent localization. 2. The tumors in young adults are clinically more advanced than in older patients, because young adults tend to delay the visit to physician, in spite of evident clinical symptoms. 3. HNSCC in young adults are histological more mature and less malignant.

One of the most troublesome failures in head and neck tumors treatment is the incidence of multiple primary tumors (MPT). The aim of the study was to identity the genetic factors associated with the predisposition of second cancer occurrence. The polymorphisms of genes involved in carcinogen metabolic activation (CYP1A1, CYP2E1), detoxication (GSTM1, GSTT1, GSTM3, NAT2,) and DNA repair (XPD /A35931C-exon 23 and C22541A-exon 6/, XRCC1 /G28152A-exon 10 and C26304T-exon 6/, XRCC3/C18067T/) were studied by PCR-based techniques to analyze genotypes and allele distribution in 84 patients with MPT correlated with 182 subjects with a single tumor of head and neck and 143 cancer-free male volunteers recruited from healthy smokers. Out of 11 polymorphisms examined significant differences between studied groups in CYP1A1, GSTM1, NAT2 genes, but not at the CYP2E1, GSTT1, GSTM3, XPD (exon 23 and 6), XRCC1 (exon 10 and 6) and XRCC3 were established. Further, the coexistence of some genotypes/alleles associated with a higher cancer risk, so called 'risk genotypes' was established as an added genetic factor to MPT development. The interpretation of our data indicates that the same group of low-penetration genes is involved in the development of single and multiple primary head and neck cancer but their association with MPT is significantly stronger.

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 loss of chromosome Y has often been observed in human solid tumors. This chromosome aberration has been proposed as one of genetic changes predisposing men to squamous cell carcinoma of the head and neck (SCCHN). In this study, using cytogenetic analysis and fluorescence in situ hybridization we analyzed: 16 cell lines derived from primary and recurrent SCCHN, a group of 22 samples derived from of previously analyzed primary larynx tumors and their corresponding metastases and a group of eight multiple primary tumors received from two different locations within the head and neck region of the same patients. In the majority of analyzed cell lines we found both loss of chromosome Y and SRY-probe signals (68.7% of samples) and these were nearly always found in the analyzed metaphases. The whole chromosome Y was usually lost, but in two cases we observed translocation of this chromosome to chromosomes 1, 3 and 17. Among all primary tumors, 14 (63.6%) and 15 of their metastases (68.2%) showed a loss of chromosome Y in a prevailing number of analyzed nuclei. Also, in the group of primary tumors and second primary tumors, all samples had a loss of the chromosome Y in the majority of analyzed nuclei.

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.

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.