C. Matthias

Polymorphism in cytochrome P450 CYP2D6, CYP1A1, CYP2E1 and glutathione S-transferase, GSTM1, GSTM3, GSTT1 and susceptibility to tobacco-related cancers: studies in upper aerodigestive tract cancers.

Glutathione S-transferase GSTM1, GSTM3 and GSTT1 and cytochrome P450 CYP2D6, CYP1A1 and CYP2E1 loci are susceptibility candidates for cancers of the upper aerodigestive tract because putatively protective and risk genotypes have been identified from studies in other diseases associated with alcohol and tobacco consumption. We describe genotype frequencies in 398 oral, pharyngeal and laryngeal squamous cell carcinoma patients and 219 control individuals. Of the genotypes presumed to be protective, only GSTM1 A/B influenced susceptibility; the GSTM1 A/B frequency was lower in the patients than the control individuals both before [odds ratio = 0.3, 95% confidence interval (CI) 0.1-0.7] and after correction for imbalances in age, sex, smoking and alcohol consumption (odds ratio = 0.2, 95% CI 0.1-0.5). Of the putatively risk genotypes, GSTM3 AA, previously associated with susceptibility to skin cancer, was higher in the cases (odds ratio = 1.6, 95% CI 1.1-2.4). Dividing cases into oral/pharyngeal and laryngeal squamous cell carcinoma showed the GSTM3 AA frequency was higher in laryngeal squamous cell carcinoma than control individuals (odds ratio = 1.6, 95% CI 1.1-2.5) and the difference between control individuals and oral/pharyngeal squamous cell carcinoma approached significance (odds ratio = 1.7, 95% CI 1.0-2.8). The putatively protective GSTM3 BB genotype was lower in patients with glottic (1.0%) than supraglottic (3.0%) squamous cell carcinoma. We identified no differences between patients and control individuals in the frequencies of presumed risk genotypes (e.g. CYP2D6 EM, CYP1A1 m1/m1, CYP1A1 Ile/Ile, CYP2E1 DD, CYP2E1 c1c1, GSTT1 null) or, interactions between genotypes and smoking or alcohol consumption. We conclude, first, that mu class glutathione S-transferase influence risk of upper aerodigestive tract cancers thereby complementing studies in skin cancer patients showing GSTM1 A/B is protective, while GSTM3 AA moderately increases risk. The influence of GSTM1 A/B, but not GSTM1 A or GSTM1 B (mostly heterozygotes with GSTM1*0) suggests that two expressed alleles may attenuate risk. While we found immunohistochemical evidence of GSTM3 expression in the cilia lining the larynx, the biochemical consequences of the polymorphism are unclear. Indeed, the influence of the gene may reflect linkage disequilibrium with another gene. However, we did not find an association with GSTM1 genotypes. Second, we conclude that the CYP2D6, CYP2E1, CYP1A1 and GSTT1 alleles studied, although putatively good candidates, either do not determine the effectiveness of detoxification of tobacco-derived carcinogens in the upper aerodigestive tract or, that chronic consumption of tobacco and alcohol overwhelms enzyme defences, irrespective of genotype.

The glutathione S-transferase GSTP1 polymorphism: effects on susceptibility to oral/pharyngeal and laryngeal carcinomas.

We have examined the hypothesis that the polymorphic, glutathione S-transferase GSTP1 gene is a susceptibility candidate for squamous cell cancer of the oral/pharynx and larynx. We describe GSTP1 genotype frequencies in 380 cases and 180 controls. We found a lower frequency of GSTP1 AA in the oral/pharyngeal cases compared with controls (p = 0.003, odds ratio = 0.47) after correction for age and gender. We used an immunohistochemical approach to show widespread expression of the GSTP1 subunit throughout the pharynx and larynx. In uninfiltrated tissue, strong positivity was found throughout the squamous cell epithelium with the exception of the basal cell layer. The cilia of the respiratory epithelium of the larynx also showed positivity for GSTP1. In tumour tissue, expression of GSTP1 was similar in pharyngeal and laryngeal samples. These data are the first to show that polymorphism at GSTP1 mediates susceptibility to squamous cell cancer of the upper aerodigestive tract. No significant interactions were identified between GSTP1 and GSTM1, GSTM3, GSTT1 and the cytochrome P450 CYP1A1, CYP2D6 and CYP1A1 genotypes.

Cyclin D1 Polymorphism and Expression in Patients with Squamous Cell Carcinoma of the Head and Neck

We have previously reported that the cyclin D1 (CCND1) GG870 genotype was associated with poorly differentiated tumors and reduced disease-free interval in patients with squamous cell carcinoma of the head and neck (SCCHN). We have now examined the association of this and a second CCND1 polymorphism with gene expression and outcome in SCCHN patients. Analysis of a CCND1 G/C1722 polymorphism revealed that CCND1 CC1722 genotype was associated with poorly differentiated tumors [P = 0.005; odds ratio (OR), 5.7; 95% CI, 1.7 to 19.2), and reduced disease-free interval (P = 0.003; Hazard Ratio (HR), 7.3; 95% CI, 1.1 to 27.2.) independently from the influence of CCND1 GG870 genotype. Patients whose tumors were negative for cyclin D1 were associated with reduced disease-free interval (P = 0.028; HR, 4.1; 95% CI, 1.4 to 14.2). Although G/C1722 genotypes were not associated with expression, we found a significant trend between reduced expression of cyclin D1 in patients with the CCND1 GG870 genotype (P = 0.04). Splicing of CCND1 mRNA in head and neck tissues was modulated by CCND1 A/G870 alleles, thus CCND1 transcript a was spliced equally from CCND1 A870 and G870 alleles, whereas CCND1 transcript b was spliced mainly from the CCND1 A870 allele. Our analysis has also identified differences in cyclin D1 genotype and protein expression and the pathogenesis of SCCHN in males and females. Thus, CCND1 CC1722 genotype was more common in female patients (P = 0.019; OR, 3.3; 95% CI, 1.3 to 10) and cyclin D1 expression was more frequent (chi-square1, 3.96; P = 0.046) and at higher levels (P = 0.004) in tumors from female patients. In summary, our data show that the two CCND1 polymorphic sites are independently associated with tumor biology and clinical outcome. CCND1 A/G870 alleles affect gene expression in head and neck tissues. We also provide preliminary evidence that the molecular genetics of SCCHN development may be influenced by patient gender.

Susceptibility and outcome in oral cancer : preliminary data showing an association with polymorphism in cytochrome P450 CYP2D6

Members of the cytochrome P450 and glutathione S-transferase supergene families are candidates for susceptibility and outcome in oral squamous cell cancer. We determined GSTM1, GSTM3, GSTT1, CYP1A1 and CYP2D6 genotypes in 100 Caucasian cases and 467 control individuals. The frequency of homozygosity for mutant CYP2D6 alleles was higher in the cases (P = 0.001, OR = 3.2, 95% CI = 1.6-6.5) than control individuals. In the cases, the frequency of homozygosity for mutant alleles was greater and that of homozygosity for wild-type CYP2D6 alleles was lower in those diagnosed at > or = 65 years (P = 0.009) than in those diagnosed at < or = 64 years. The older cases included relatively more women and patients who did not consume tobacco or alcohol. The association of CYP2D6 with outcome was assessed using the Coxs proportional hazards model. The time to first cervical node metastasis was shorter in heterozygotes and homozygotes for mutant CYP2D6 alleles compared with homozygotes for wild-type alleles after correction for age at diagnosis, gender, alcohol and tobacco consumption and tumour differentiation (P = 0.04, hazard ratio 3.6, 95% CI 1.1-12.5). The mechanism for the association of CYP2D6 alleles with susceptibility and outcome is unclear though the data are compatible with the view that homozygosity for mutant alleles confers impaired detoxication of an unknown carcinogen. No associations between GSTM1, GSTM3, GSTT1 or CYP1A1 genotypes and susceptibility or, time to node metastases were identified. We previously showed that CYP2D6 genotypes were not associated with susceptibility to squamous cell cancer in the pharynx or larynx. Therefore, the data presented suggest that susceptibility to squamous cell cancer in the various parts of the upper aerodigestive tract is associated with different genes and allelic variants.

Glutathione S-transferase and cytochrome P450 genotypes as risk factors for laryngeal carcinoma.

While cigarette smoking and alcohol consumption have been linked to laryngeal squamous cell carcinoma (SCC), the role of genetic factors in determining individual susceptibility is unknown. We describe the role of allelism at the glutathione S-transferase GSTM1, GSTM3, GSTT1 and cytochrome P450 CYPIA1, CYP2E1, CYP2D6 loci in determining individual susceptibility to laryngeal SCC. Enzyme genotypes were determined using polymerase chain reaction and restriction enzyme digestion of leukocyte DNA collected from 269 patients with T1–T4 laryngeal carcinomas and 216 controls. While the frequencies of the heterozygote GSTM1 A/B genotype and the homozygote GSTM3 B/B genotype were statistically significantly lower in the patients with tumors than in controls, the frequency of the GSTT1 null genotype was higher in the patients than in controls. The data suggest that allelism at GST loci mediates susceptibility to SCC of the larynx. GSTM1 A/B and GSTM3 B/B appear to be associated with reduced risk, while GSTT1 null may confer increased risk. These findings are compatible with the view that genetic predisposition is important in determining risk for this cancer.

Influence of Tumour Necrosis Factor Microsatellite Polymorphisms on Susceptibility to Head and Neck Cancer

While cigarette smoking and alcohol consumption are recognized covariates for head and neck squamous cell carcinoma (SCC), the role of genetic factors in determining individual susceptibility is unknown. The human tumour necrosis factor (TNF) region on chromosome 6p21 within the major histocompatibility complex (MHC) includes a number of immunologically important genes. Recently, five microsatellite markers have been described in the TNF locus. TNF levels vary with different TNF microsatellite alleles, and associations of these microsatellite markers with autoimmune diseases and different types of cancer have been shown. Therefore, the TNF locus represents candidate susceptibility genes for head and neck cancer. This study describes the influence of TNF a-d microsatellite polymorphisms on susceptibility to head and neck cancer by comparing the allele frequencies of 269 patients suffering from laryngeal cancer and 123 patients suffering from oral cavity pharyngeal cancer and 113 German controls. DNA was extracted from peripheral blood samples, amplified by polymerase chain reaction with fluorescently labelled primers for TNF microsatellite (a-d) and electrophoresed on polyacrylamide gels using an automated DNA sequencer. The data showed no differences in allele frequencies between controls and pharyngeal cancer patients. By contrast, the TNF b3 allele was associated with altered risk for laryngeal cancer (p = 0.0006, odds ratio 2.2). Homozygosity for TNF b3/b3 resulted in an increased risk of developing laryngeal cancer (p = 0.004, odds ratio 5.3). Susceptibility to supraglottic SCC and multiple primary tumours was mediated by the absence of the a11 allele. The data provide the first evidence that allelism at the TNF microsatellite markers alter the risk of developing SCC of the larynx.

Genetic polymorphism and clinical outcome: identification of individuals at risk of a poor clinical outcome

Susceptibility and outcome in complex disorders such as asthma and cancer appear to be determined, at least in part, by genetic polymorphism. However, while our ability to identify new allelic variants and study them in case and control populations has greatly improved, considerable difficulties remain in elucidating how many genes determine particular clinical phenotypes. This is because most studies have concentrated on study of single genes in relatively small study groups. The important issues of gene–gene interactions (epistasis) and high‐risk subgroups have not yet been adequately addressed. We now describe a general approach, using patients with head and neck cancers as an example. Our purpose is to demonstrate candidate gene selection, statistical approaches, and identification of patient subgroups.

Electron microscopic and immunomorphological investigations on the mucosa of the human paranasal sinuses

The morphology of the mucosa from the human paranasal sinuses was investigated by electron microscopy. A total of 27 specimens was taken from 11 patients following midfacial fractures. All tissue samples were biopsied during surgery after informed consent had been given. In accordance with light microscopic investigations, the mucosa represented a highly prismatic epithelium consisting of kinocilia-carrying and mucus-producing (goblet) cells. Other cell types, such as those occurring in the respiratory epithelium of other areas, could not be demonstrated. Electron microscopic and immunomorphological investigations revealed collagen type VII beneath the lamina densa of the basal lamina. According to findings obtained to date, this collagen type accompanies only a multilayered epithelium. Another peculiarity was the small number of basophils and eosinophils. Pronounced acute reactions of the mucosa in this area cannot be expected, which is in contrast to that of the nasal mucosa.

Role of genetic polymorphisms in the development of multiple head and neck cancer

of MEK/MAPK pathways. The ELISA-based DNA-binding assays demonstrated that the binding activity of c-Jun and Egr-1 was significantly increased in UMSCC11A cells treated with HGF when compared with untreated cells. Conclusion: Multiple molecules involved in signal transduction pathways downstream of c-Met are constitutively overexpressed in HNSCC cells. Overexpression of these genes provides the molecular basis for post-translational regulation of these pathways. Activation of transcription factors c-Jun and Egr-1 was observed as a direct response to HGF/ c-Met signaling in HNSCC cells. Significance: Improved understanding of c-Met signaling in HNSCC will enable us to identify better biomarkers and develop new therapeutic agents. Support: Research supported by National Institute of Deafness and other Communication Disorders Intramural Project DC-00016. B.F.W. is supported by the Howard Hughes Medical Institute Research Scholars Program.