This study aimed to investigate the associations of XPC c.2815A>C, XPD c.934G>A and c.2251A>C, XPF c.2505T>C and ERCC1 c.354C>T single nucleotide polymorphisms (SNPs) of nucleotide excision repair pathway in outcome of head and neck squamous cell carcinoma (HNSCC) patients treated with cisplatin (CDDP) chemoradiation. Patients with XPC c.2815AC or CC and XPD c.934GA or AA genotypes had 0.20 and 0.38 less chances of presenting moderate/severe ototoxicity and nausea, respectively. Patients with XPD c.934AA and c.2251AC or CC genotypes had 8.64, 12.29 and 3.55 more chances of achieving complete response (CR), consistent ototoxicity and nephrotoxicity, respectively. AA haplotype of XPD and ACT haplotype of XPD and ERCC1 SNPs were associated with 9.30 and 3.41 more chances of achieving CR and consistent nephrotoxicity, respectively. At 24 months of follow-up, patients with XPD c.934AA genotype presented lower progression-free survival and overall survival in Kaplan-Meier estimates, and differences between groups remained the same in univariate Cox analysis. Patients with XPD c.934AA genotype had 2.13 and 2.04 more risks of presenting tumor progression and death than others in multivariate Cox analysis. Our data present preliminary evidence that XPC c.2815A>C, XPD c.934G>A and c.2251A>C, and ERCC1 c.354C>T SNPs alter outcome of HNSCC patients treated with CDDP chemoradiation.

Head and neck squamous cell carcinoma (HNSCC) is treated with cisplatin (CDDP) and radiotherapy (RT), and distinct results are observed among patients with similar clinicopathological aspects. This prospective study aimed to investigate whether MLH1 c.-93G>A (rs1800734), MSH2 c.211+9C>G (rs2303426), MSH3 c.3133G>A (rs26279), EXO1 c.1765G>A (rs1047840), and EXO1 c.2270C>T (rs9350) single nucleotide polymorphisms (SNPs) of the mismatch repair (MMR) pathway change side effects and response rate of 90 HNSCC patients treated with CDDP and RT. DNA from peripheral blood was analyzed by PCR-based methods to obtain genotypes. It was observed 4.27-fold and 4.69-fold increased risks of presenting pronounced nephrotoxicity with treatment in patients with MSH3 GG and EXO1 rs9350 CC genotypes compared with patients with GA or AA and CT or TT genotypes, respectively. MSH3 GG or GA and GT haplotype of EXO1 rs1047840 and rs9350 SNPs conferred to patients 10.29 and 4.00 more chances of presenting pronounced ototoxicity after treatment than MSH3 AA genotype and other EXO1 haplotypes, respectively. Patients with EXO1 rs1047840 GA or AA genotype and AC haplotype of EXO1 rs1047840 and rs9350 SNPs had both 9.55-fold increased risks of achieving partial response or stable disease instead of complete remission after treatment than patients with EXO1 GG genotype and other EXO1 haplotypes, respectively. For the first time, our data show preliminary indication that inherited alterations of DNA MMR pathway, related to MSH3 rs26279, EXO1 rs1047840 and EXO1 rs9350 SNPs, modify toxicity and response to chemoradiation in HNSCC, and may contribute to future personalized treatment of patients.

We examined the influence of MLH1 c.293G>A, MSH2 c.211 1 9C>G, MSH3 c.3133G>A and EXO1 c.1765G>A polymorphisms, involved in DNA mismatch repair (MMR), on head and neck (HN) squamous cell carcinoma (SCC) risk and prognosis. Aiming to identify genotypes, DNA from 450 HNSCC patients and 450 controls was analyzed by PCR-RFLP or real time PCR. MSH2 GG plus MSH3 GG (31.7% vs. 18.7%, p 5 0.003) genotypes were higher in laryngeal SCC (LSCC) patients than in controls. Carriers of the respective combined genotype were under a 3.69 (95% CI: 1.54-8.81)-fold increased risk of LSCC. Interactions of tobacco and tobacco plus all the above-mentioned polymorphisms on HNSCC and LSCC risk were also evident in study (p 5 0.001). At 60 months of follow-up, relapse-free survival (RFS) was shorter in patients with EXO1 GG genotype (54.8% vs. 61.1%, p 5 0.03) and overall survival (OS) was shorter in patients with MSH3 GG genotype (42.8% vs. 52.5%, p 5 0.02) compared to those with other genotypes, respectively. After multivariate Cox analysis, patients with EXO1 GG and MSH3 GG genotypes had worst RFS (HR: 1.50, 95% CI: 1.03-2.20, p 5 0.03) and OS (HR: 1.59, 95% CI: 1.19-2.13, P 5 0.002) than those with the remaining genotypes, respectively. Our data present, for the first time, evidence that inherited MLH1 c.-93G>A, MSH2 c.211 1 9C>G, MSH3 c.3133G>A, and EXO1 c.1765G>A abnormalities of DNA MMR pathway are important determinants of HNSCC, particularly among smokers, and predictors of patient outcomes.Exposure to tobacco smoke is considered the most important etiological factor in the development of head and neck (HN) squamous cell carcinoma (SCC). 1 Carcinogens present in tobacco, such as benzo(a)pyrene, could bind to DNA from epithelial cells of the upper aerodigestive tract, forming covalent DNA adducts and inducing replication errors, which can be associated with HNSCC origin. 2,3 However, not all smokers develop HNSCC suggesting that individual genetic background may also participate in the tumor etiology. 4 DNA mismatch repair (MMR) pathway contributes to maintain genetic stability. 5 MutL homolog 1 (MLH1), MutS homolog 2 (MSH2), MutS homolog 3 (MSH3) and exonuclease 1 (EXO1) proteins play important roles in this process, recognizing DNA damage induced by carcinogens from tobacco, and enabling its excision. 6,7 The ability to promote DNA repair of damaged cells is variable in humans, since several DNA repair proteins, such as MLH1, MSH2, MSH3 and EXO1, are encoded by polymorphic genes. 8,9 Variant alleles of MLH1 c.293G>A, 10 MSH2 c.211 1 9C>G 11 and EXO1 c.1765G>A 12 single nucleotide polymorphisms (SNPs) reduce the expression of encoded proteins when compared with the respective wild-type alleles, and have decrease in DNA repair as consequence. The role of MSH3 c.3133G>A in protein activity is not totally clarified. 13-15 GG genotype of MLH1 c.293G>A and variant allele A of EXO1 c.1765G>A SNP were associated with increased risk of oral SCC only in India 16 and Taiwan, 17 respectively. To the best of our knowledge, the roles of the ...

Cisplatin (CDDP) combined with radiotherapy (RT) is employed in head and neck squamous cell carcinoma (HNSCC) with variable toxicities and clinical response. Glutathione S-transferases (GSTs) participate in CDDP excretion from cells, and genes encoding GSTs, GSTM1 , GSTT1 and GSTP1 , are polymorphic in humans. This prospective study aimed to evaluate the roles of GSTM1 , GSTT1 , and GSTP1 Ile105Val polymorphisms in outcomes of HNSCC patients treated with CDDP chemoradiation. Ninety patients were genotyped by multiplex PCR. Urinary CDDP measurements were performed by HPLC. Treatment side effects and response were analysed by conventional criteria. Patients with GSTT1 genes showed 7.23- and 5.37-fold higher likelihood of presenting vomiting and ototoxicity, lower glomerular filtration rate (GFR), and lower elimination of CDDP in urine relative to patients with deleted genes. Patients harbouring the GSTP1 IleVal or ValVal genotypes showed 4.28-fold higher likelihood of presenting grade 2 or 3 vomiting and lower GFR with treatment than those harbouring the IleIle genotype. In multivariate Cox analysis, patients with the GSTP1 105ValVal genotype had 3.87 more chance of presenting disease progression than those with the IleIle or IleVal genotype ( p < 0.01). Our findings provide preliminary evidence that inherited abnormalities in CDDP metabolism, related to GSTT1 and GSTP1 Ile105Val polymorphisms, alter outcomes of HNSCC patients treated with CDDP and RT.

Cisplatin (CDDP) chemotherapy associated with radiation (RT) has been used in advanced head and neck squamous cell carcinoma (HNSCC) patients, and vomiting is a common side effect during treatment. This prospective study aimed to identify the roles of GSTM1 and GSTT1 (presents or nulls), GSTP1 c.313A>G, XPC c.2815A>C, XPD c.934G>A and c.2251A>C, XPF c.2505T>C, ERCC1 c.354C>T, MLH1 c.-93G>A, MSH2 c.211 + 9C>G, MSH3 c.3133G>A, EXO1 c.1765G>A, TP53 c.215G>C, CASP3 c.-1191A>G and c.-1168G>T, CASP9 c.-1339A>G, CASP8 c.-937_-932delAGTAAG, FAS c.-1378G>A and c.-671A>G, and FASL c.-157-687C>T single nucleotide polymorphisms, involved in CDDP metabolism, in vomiting severity in 88 HNSCC patients treated with CDDP and RT. Ondansetron and dexamethasone were administered as anti-emetic therapy. Patients with GSTP1 c.313AG or GG genotype alone and combined with XPD c.934GA or AA, XPF c.2505TC or CC, and CASP9 c.-1339AG or GG genotypes had 4.28, 5.00, 5.45 and 5.38 more chances of presenting moderate/severe vomiting than patients with others genotypes. Our data suggest, for the first time, that inherited abnormality in apoptosis pathway alone or combined with inherited abnormalities in DNA repair pathway, is capable of modulating emesis in HNSCC patients under CDDP chemoradiation and may be used for selecting patients who should receive pre-emptive anti-emetic therapy.