Thymidylate Synthase Gene Polymorphisms Research Articles

Association of Thymidylate Synthase (TS) Gene Polymorphisms with Incidence and Prognosis of Coronary Artery Disease.

Coronary artery disease (CAD) is a prevalent cardiovascular condition characterized by the accumulation of plaque within coronary arteries. While distinct features of CAD have been reported, the association between genetic factors and CAD in terms of biomarkers was insufficient. This study aimed to investigate the connection between genetic factors and CAD, focusing on the thymidylate synthase (TS) gene, a gene involved in DNA synthesis and one-carbon metabolism. TS plays a critical role in maintaining the deoxythymidine monophosphate (dTMP) pool, which is essential for DNA replication and repair. Therefore, our research targeted single nucleotide polymorphisms that could potentially impact TS gene expression and lead to dysfunction. Our findings strongly associate the TS 1100T>C and 1170A>G genotypes with CAD susceptibility. We observed that TS 1100T>C polymorphisms increased disease susceptibility in several groups, while the TS 1170A>G polymorphism displayed a decreasing trend for disease risk when interacting with clinical factors. Furthermore, our results demonstrate the potential contribution of the TS 1100/1170 haplotypes to disease susceptibility, indicating a synergistic interaction with clinical factors in disease occurrence. Based on these findings, we propose that polymorphisms in the TS gene had the possibility of clinically useful biomarkers for the prevention, prognosis, and management of CAD in the Korean population.

The Association Between Thymidylate Synthase Gene Polymorphisms and the Risk of Ischemic Stroke in Chinese Han Population

Family history of hypertension, smoking, diabetes and alcohol consumption and atherosclerotic plaque were identified as common risk factors in IS. We aimed at investigating the relationship between Thymidylate Synthase (TS) gene polymorphisms and ischemic stroke (IS).This case–control research selected and genotyped three single nucleotide polymorphisms (SNPs)of TS( rs699517, rs2790, and rs151264360) with Sanger sequencing in Chinese Han population. We also adopted logistic regression analysis in genetic models for calculating odds ratios and 95% confidence intervals. Genotype-Tissue Expression(GTEx) database analyzed the tissue-specific expression and TS polymorphisms. The ischemic stroke patients showed higher low-density lipoprotein cholesterol and total homocysteine (tHcy). It was found that patients with the TT genotype of rs699517 and GG genotype of rs2790 had larger degrees of tHcy than those with CC + CT genotypes and AA + AG genotypes, respectively. The genotype distribution of the three SNPs did not deviate from Hardy–Weinberg equilibrium (HWE). Haplotype analysis showed that T-G-del was the major haplotype in IS, and C-A-ins was the major haplotype in controls. GTEx database indicated that the rs699517 and rs2790 increased the expression of TS in healthy human and associated with TS expression level in a single tissue. In conclusion: This study has shown that TS rs699517 and rs2790 were significantly related to ischemic stroke patients.

The 3'-UTR Polymorphisms in the Thymidylate Synthase (TS) Gene Associated with the Risk of Ischemic Stroke and Silent Brain Infarction.

Thymidylate synthase (TS) is a key gene involved in the repair of DNA damage and DNA synthesis that plays an important role in vascular development and recovery. In particular, TS gene polymorphisms play a major role in the progression of vascular disease and cancer metastasis. Therefore, the aim of this study was to investigate the association of three TS polymorphisms (1100T>C [rs699517], 1170A>G [rs2790], and 1494ins/del [rs151264360]) with ischemic stroke and silent brain infarction (SBI) in Koreans. A total of 1299 participants (507 stroke patients, 383 SBI patients, and 409 controls) were enrolled in the study. Genotyping of the three TS polymorphisms was performed by polymerase chain reaction-restriction fragment length polymorphism analysis. To examine the association between TS gene polymorphisms and the diseases, we performed statistical analyses, including multivariable logistic regression and Fisher’s exact tests. We found that TS 1100T>C and 1170A>G genotypes were strongly associated with ischemic stroke and SBI susceptibility. More specifically, the TS 1100T>C polymorphism was associated with the likelihood of ischemic stroke (TT vs. CC: AOR = 2.151, 95% CI = 1.275–3.628, P = 0.004) and SBI (TT vs. TC+CC: AOR = 1.443, 95 % CI = 1.009–2.063, P = 0.045). In contrast, the TS 1170A > G polymorphism exhibited lower correlation with the risk of stroke (AA vs. GG: AOR = 0.284, 95% CI = 0.151–0.537, P < 0.0001) and SBI (AA vs. GG: AOR = 0.070, 95% CI = 0.016–0.298, P = 0.0002). Furthermore, we confirmed that the TS 1100T>C polymorphism was synergistic with low folic acid levels (AOR = 6.749, P < 0.0001). Altogether, these results suggest that TS 1100T>C and 1170A > G polymorphisms are associated with the risk of ischemic stroke and SBI, and our study provides the first evidence that 3′-UTR variants in TS are potential biomarkers in ischemic stroke and SBI.

Polymorphisms in TYMS for Prediction of Capecitabine-Induced Hand-Foot Syndrome in Chinese Patients with Colorectal Cancer.

PurposeCapecitabine is an extensively used oral prodrug of 5-fluorouracil in treatment of colon cancer and is known to cause hand-foot syndrome (HFS). As the target enzyme for capecitabine, thymidylate synthase (TYMS) plays a key role for 5-fluorouracil metabolism and has been associated with some side effects caused by capecitabine. The aim of our study is to identify the possible genetic predictors of capecitabine-induced HFS (CAP-HFS) in Chinese colorectal cancer patients.Materials and MethodsWhole exons of TYMS were sequenced for 288 extreme phenotype HFS patients, including 144 severe or early-onset (first 2 cycles) moderate HFS extreme cases and 144 extreme controls with no reported HFS. The associations between polymorphisms and CAP-HFS were analyzed using logistic regression under an additive model.ResultsWe identified a novel risk mutation (c.1A>G, chr18:657743), was associated with severe HFS in an extreme case who was affected during the first cycle of treatment. Moreover, we identified three new variants, rs3786362, rs699517, rs2790, and two previously reported variants, 5’VNTR 2R/3R and 3′-untranslated region 6-bp ins-del, which were significantly associated with CAP-HFS (p < 0.05). In silico analysis revealed that the effect of these polymorphisms in the TYMS region on the development of HFS might not be restricted solely to the regulation of TYMS expression, but also the TYMS catalytic activity through the indirect effect on ENOSF1 expression.ConclusionThis study identified new polymorphisms in TYMS gene significantly associated with CAP-HFS, which may serve as useful genetic predictors for CAP-HFS and help to elucidate the underlying mechanism of HFS.

A Case-Control Study on the Correlation Between Thymidylate Synthase Gene Polymorphisms and Raltitrexed Treatment Combined with Transcatheter Arterial Chemoembolization in Hepatocellular Carcinoma Treatment.

Background: To study the effect of single nucleotide polymorphisms (SNPs) in the thymidylate synthase (TYMS) gene for their value in predicting the efficacy of raltitrexed treatment combined with transcatheter arterial chemoembolization (TACE) for the treatment of primary hepatocellular carcinoma (HCC). Methods: We conducted a genotypic analysis of the TYMS SNPs rs2790, rs8423, rs502396, rs699517, and rs1004474 in150 HCC patients who were subjected to raltitrexed treatment combined with TACE (study group) and another 150 HCC patients who were treated with doxorubicin combined with TACE (control group). After 1 year of follow-up and interventional therapy, the relationship between the TYMS SNPs and survival rate, and the prognosis for survival were analyzed. Results: After interventional therapy, the response rate (RR) and disease control rate (DCR) of the study group were 52.67% and 87.33%, respectively; whereas the RR and DCR of the control group were 54.67% and 84.67%, respectively. No significant differences were detected by comparison of the RRs (p = 0.728) and DCRs (p = 0.506) between the two groups. The HCC patients' TYMS SNPs rs2790, rs8423, rs502396, rs699517, and rs1004474 were associated with the efficacy and prognosis of the raltitrexed-combined TACE intervention (p < 0.05) yet showed no correlation to the efficacy and prognosis of doxorubicin-combined TACE interventional therapy (p > 0.05). Conclusions: The SNPs of the TYMS genes (rs2790, rs8423, rs502396, rs699517, and rs1004474) are associated with the efficacy and prognosis of raltitrexed treatment in HCC patients.

TYMS/KRAS/BRAF molecular profiling predicts survival following adjuvant chemotherapy in colorectal cancer.

BACKGROUNDPatients with stage II-III colorectal cancer (CRC) treated with adjuvant chemotherapy, gain a 25% survival benefit. In the context of personalized medicine, there is a need to identify patients with CRC who may benefit from adjuvant chemotherapy. Molecular profiling could guide treatment decisions in these patients. Thymidylate synthase (TYMS) gene polymorphisms, KRAS and BRAF could be included in the molecular profile under consideration.AIMTo investigate the association of TYMS gene polymorphisms, KRAS and BRAF mutations with survival of CRC patients treated with chemotherapy.METHODSA retrospective study studied formalin-fixed paraffin-embedded tissues (FFPEs) of consecutive patients treated with adjuvant chemotherapy during January/2005-January/2007. FFPEs were analysed with PCR for the detection of TYMS polymorphisms, mutated KRAS (mKRAS) and BRAF (mBRAF). Patients were classified into three groups (high, medium and low risk) according to 5’UTR TYMS polymorphisms Similarly, based on 3’UTR polymorphism ins/loss of heterozygosity (LOH) patients were allocated into two groups (high and low risk of relapse, respectively). Cox regression models examined the associated 5-year survival outcomes.RESULTSOne hundred and thirty patients with early stage CRC (stage I-II: 55 patients; stage III 75 patients; colon: 70 patients; rectal: 60 patients) were treated with surgery and chemotherapy. The 5-year disease free survival and overall survival rate was 61.6% and 73.9% respectively. 5’UTR polymorphisms of intermediate TYMS polymorphisms (2RG/3RG, 2RG/LOH, 3RC/LOH) were associated with lower risk for relapse [hazard ratio (HR) 0.320, P = 0.02 and HR 0.343, P = 0.013 respectively] and death (HR 0.368, P = 0.031 and HR 0.394, P = 0.029 respectively). The 3’UTR polymorphism ins/LOH was independently associated with increased risk for disease recurrence (P = 0.001) and death (P = 0.005). mBRAF (3.8% of patients) was associated with increased risk of death (HR 4.500, P = 0.022) whereas mKRAS (39% of patients) not.CONCLUSIONProspective validating studies are required to confirm whether 2RG/3RG, 2RG/LOH, 3RC/LOH, absence of ins/LOH and wild type BRAF may indicate patients at lower risk of relapse following adjuvant chemotherapy.

High thymidylate synthase gene expression predicts poor outcome after resection of hepatocellular carcinoma.

IntroductionPrognosis after resection of hepatocellular carcinoma (HCC) is highly variable. Compared to clinicopathologic factors, the use of molecular markers to predict outcome has not been well studied. We investigated the prognostic importance of thymidylate synthase (TS) gene expression and polymorphisms in patients after resection of HCC.MethodsPatients who underwent complete resection of HCC for whom tissue was available were identified. TS gene expression level and polymorphisms were determined in HCC specimens. Prognostic factors were evaluated using Kaplan-Meier curves and Cox proportional hazard models.ResultsThe study included 67 patients. In univariate analysis, variables that negatively influenced survival included TNM stage, microvascular invasion, and high TS expression. For the high TS expression group, median survival was 54 months and 5-year actuarial survival was 47%. For the low TS expression group, median survival was not reached and the 5-year actuarial survival was 91%. In multivariate analysis, only high TS expression remained an independent predictor of poor survival (HR = 10.77, 95% CI 1.36–84.91; P = 0.02). TS gene polymorphisms were not associated with TS expression or overall survival.ConclusionsHigh TS expression predicts poor outcome after resection of HCC. Molecular markers might be robust predictors of patient outcome after resection of HCC.

Thymidylate synthase gene polymorphism predicts disease free survival in stage II-III rectal adenocarcinoma patients receiving adjuvant 5-FU-based chemotherapy.

The objective is to investigate whether thymidylate synthase gene TS 5'-UTR polymorphism of peripheral blood mononuclear cells are associated with clinical outcomes of patients with stage II-III rectal adenocarcinoma treated with adjuvant 5-fluorouracil (5-FU) chemotherapy in Chinese population. One hundred and seventeen pathologically diagnosed colorectal adenocarcinoma patients with stage II-III, who underwent curative resection and received 5-fluoropyrimidine-based adjuvant chemotherapy were enrolled to this study. The 5'-TSER polymorphisms determined from the peripheral blood mononuclear cells were measured by Direct Sequencing. Kaplan-Meier curves and log-rank tests were used for survival analysis. The independent prognostic factors influencing DFS and OS were estimated by Cox proportional hazards model. The distribution of TS 5'-UTR polymorphisms ware 2.6% 2R/2R, 31.6% 2R/3R and 65.8% 3R/3R respectively, which was fitted with Hard-Weinberg equilibrium (χ2=0.345, P=0.558). Stage, N stage, number of mesenteric lymph node metastasis, KPS, and 5'-UTR polymorphisms (2R/2R/2R/3R vs. 3R/3R, P<0.001) were significantly associated with DFS. Meanwhile, gender (female vs. male, P=0.025) and adjuvant radiotherapy (yes vs. no, P=0.025) were significantly associated with OS. Multivariate Cox regression showed that KPS score (HR =0.947, P=0.007), TS 5'-UTR polymorphism (HR =0.455, P=0.004) were independent prognostic factors for DFS. Whereas, KPS score was the only independent prognostic factors for OS (HR =0.910, P=0.005). TS 5'-UTR tandem repeat polymorphisms had potential utilization for personalized therapy in Chinese population.

Allelic polymorphisms of thymidylate synthase gene and their haplotypes as predictors of the therapeutic response to methotrexate in patients with rheumatoid arthritis

Methotrexate (MT) is recognized as the main component of the treat to target strategy in patients with rheumatoid arthritis (RA). Unfortunately, MT therapy is not equally effective in all patients with RA, some of them are resistant to such treatment, and have steady progression of destructive changes of the joints, reducing quality of life and leading to disability.Objective: examination of genetic predictors of therapeutic efficacy and resistance to MT among single-nucleotide polymorphisms (SNP) of folate cycle genes, in particular polymorphisms of the thymidylate synthase gene TSER 2R/3R and TS 6bp del/ins and their haplotypes.Subjects and methods. The study included 85 patients with RA, who were prescribed MT at a dose of 10 to 17.5 mg/week as a the «first line» disease-modifying antirheumatic drug. The therapeutic response was evaluated with DAS28 after 6 months of continuous treatment. According to the results of this assessment groups of «respondents» and «non-respondents» to MT were identified. Genetic typing of SNP TSER 2R/3R and TS 6bp del/ins was performed by real-time polymerase chain reaction.Results and discussion. In RA patients with different efficacy of MT, statistically significant differences in the frequency of alleles and genotypes of polymorphic variants of the gene thymidylate synthase were revealed. Thus, in patients resistant to MT homozygous genotype TS 6bp ins/ins frequency was significantly increased (OR 4,3; 95% CI of 1.58 to 11.7; p=0.003), whereas response to the treatment was associated with occurrence of TS 6bp allele del (HR OF 0.48; 95% CI of 0.23 to 1.0; p=0.049), of TSER 2R/3R (OR 0,32; 95% CI 0,12–0,88; p=0.042) and TS 6bp del/ins (OR 0.23; 95% CI 0.08–0.65; p=0.008) genotypes. We have not established statistically significant differences in the frequency of occurrence of haplotypes of the thymidylate synthase gene in RA patients with different therapeutic efficacy of MT, but we found a tendency to increase of the haplotype TS 3R-6bp del (OR 0.39; 95% CI 0.24–1.09; p=0.081) frequency in the «respondents» to the treatment.Conclusion. Our results may indicate the relationship of the thymidylate synthase gene single nucleotide polymorphisms with therapeutic response to MT in patients with RA.

A Pharmacogenetic Study of VDR fok1 and TYMS Polymorphisms and Their Association With Glucocorticoid-Induced Osteonecrosis in Egyptian Children With Acute Lymphoblastic Leukemia.

Purpose: Osteonecrosis is a significant toxicity resulting from the treatment of pediatric Acute Lymphoblastic Leukemia (ALL). This study aimed to investigate the relationship between vitamin D receptor fok1 (VDR fok1) and thymidylate synthase (TYMS) gene polymorphisms with the glucocorticoid (GC) induced osteonecrosis (ON) in Egyptian pediatric ALL patients. In addition, to identify the possible association of genetic polymorphisms with other factors such as gender and ALL subtypes.Patients and Methods: A retrospective case-control study was conducted on 102 pediatric ALL patients under the age of 18 who were treated at Children Cancer Hospital Egypt according to St Jude SR/HR total XV protocol. The recruited patients were composed of 51 cases who developed GC-induced osteonecrosis and 51 age- and gender-matched patients who received glucocorticoids but remained osteonecrosis-free (controls). Genotyping of the VDR fok1 and TYMS genes was performed using restriction fragment length polymorphism (RFLP) and conventional PCR, respectively.Results: For the total 102 studied patients, the VDR fok1 single nucleotide polymorphisms (SNPs) frequency distribution were TT (8.8%), CT (34.3%), and CC (56.9%), while the TYMS tandem repeat gene variations were reported as 2R2R (20.6%), 2R3R (45.1%), and 3R3R (34.3%). VDR fok1 and TYMS polymorphic variants showed no association neither with gender; P-values 0.3808 and 0.1503, respectively, nor with ALL subtypes; P-values 0.9396 and 0.6596, respectively. The VDR fok1 polymorphisms showed a significant association with the development of ON; P-value = 0.003, on the other hand, TYMS tandem repeats did not show significant impact on osteonecrosis development; P-value = 0.411.Conclusion: This study showed a significant association between the VDR fok1 polymorphism and osteonecrosis. Such clinical pharmacogenetics results would be promising to discuss the possibility of dose adjustments aiming a regimen with the highest efficacy and least toxicity.

524P - Implications of thymidylate synthase gene polymorphisms, KRAS and BRAF mutations in the survival of patients with colorectal cancer treated with adjuvant chemotherapy

524P - Implications of thymidylate synthase gene polymorphisms, KRAS and BRAF mutations in the survival of patients with colorectal cancer treated with adjuvant chemotherapy

Influence of TS (rs34743033) and RUNX1 (rs2014300) gene polymorphisms on survival outcomes of fluorouracil-based chemotherapy in Chinese advanced gastric cancer patients

BackgroundThis study aimed to explore the clinical correlation of single-nucleotide polymorphisms of thymidylate synthase (TS) and runt-related transcription factor 1 (RUNX1) in patients with postoperative stage II and III gastric cancer (GC).Patients and methodsSamples were obtained from 661 patients with postoperative stage II and III GC. TS (rs34743033) and RUNX1 (rs2014300) were genotyped in 261 patients who received postoperative basic platinum and fluorouracil chemotherapy regimens and 400 patients who did not accept chemotherapy.ResultsTS (rs34743033) variant genotypes significantly prolonged the median overall survival (OS) time compared to the patients who only received adjuvant chemotherapy (HR 1.604, 95% CI 1.068–2.410, p=0.021). Moreover, 3R/3R variant genotypes were demonstrated to have a positive effect on the OS of patients who received chemotherapy based on cisplatin (HR 1.754, 95% CI 1.041–2.954, p=0.031) compared to oxaliplatin. A stratification analysis indicated that 2R/3R and 2R/2R variant genotypes were associated with inferior survival in GC patients with intestinal-type tumors, tumor less than 5 cm in size, and poorly differentiated tumors (p<0.05). However, RUNX1 (rs2014300) AA genotypes markedly increased the risk of death in GC patients compared with the GG/GA genotypes (p=0.007), but no significant difference was observed between chemotherapy based on platinum. The stratification analysis showed that the GA/AA genotype was significantly associated with inferior survival in well to moderately differentiated tumors (HR 2.001, 95% CI 1.082–3.703, p=0.023).ConclusionThese preliminary results indicated that the two polymorphisms had a significant effect on postoperative adjuvant chemotherapy. TS (rs34743033) and RUNX1 (rs2014300) may be used as biomarkers to predict prognosis and select chemotherapy regimens in GC patients.

3'-UTR Polymorphisms of MTHFR and TS Associated with Osteoporotic Vertebral Compression Fracture Susceptibility in Postmenopausal Women.

Postmenopausal osteoporosis is one of the most prominent diseases in postmenopausal women and it is increasing in prevalence with the aging population. Furthermore, osteoporosis and osteoporotic vertebral compression fractures (OVCFs) are related to mortality and decreased quality of life. Therefore, searching for biomarkers that are able to identify postmenopausal women who are at high risk of developing OVCFs is an effective strategy for improving the quality of life of patients and alleviating social and economic burdens. In this study, we investigated methylenetetrahydrofolate reductase (MTHFR) and thymidylate synthase (TS) gene polymorphisms in postmenopausal women with OVCF. We recruited 301 postmenopausal women and performed genotyping for the presence of MTHFR 2572C>A, 4869C>G and TS 1100C>T, 1170A>G. Genotyping was analyzed using the polymerization chain reaction restriction fragment length polymorphism assay. MTHFR 2572C>A and TS 1100C>T were associated with the prevalence of osteoporosis (MTHFR 2572CC versus CA+AA: odd ratio [OR] adjusted age, hypertention [HTN], and diabetes mellitus [DM] = 0.49, p = 0.012) and the occurrence of OVCFs (MTHFR 2572CC versus CA+AA: OR adjusted age, HTN, and DM = 0.38, p = 0.013; TS 1100CC versus CT+TT: OR adjusted age, HTN, and DM = 0.46, p = 0.02). Our novel finding is the identification of MTHFR and TS genetic variants that decrease susceptibility to OVCFs. Our findings suggest that polymorphisms in the MTHFR and TS genes are associated with susceptibility to osteoporosis and OVCFs in postmenopausal women.

Polymorphisms in folate metabolism genes are associated with susceptibility to presbycusis

AimPresbycusis or age related hearing loss is caused by several extrinsic and intrinsic factors that damage the auditory system. Gene polymorphisms in folate metabolism were found to play an important role in the etiology of presbycusis. The present study aimed to investigate the role of 5,10-methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTR) and thymidylate synthase (TYMS) gene polymorphisms in the onset of presbycusis in a South Indian population. Main methodsA total of 220 subjects confirmed with presbycusis along with 270 age and sex matched healthy controls visiting MAA ENT Hospitals, Hyderabad, India were enrolled for the study. Genotyping of MTHFR C677T (rs180133) and A1298C (rs1801131), MTR A2756G (rs1805087), TSER (rs1801136) and TS1494indel6 bp (rs16430) was carried out using PCR & PCR-RFLP methods. Key findingsThe ‘TT’ genotype of MTHFR C677T and ′152 bp/152 bp′ genotype of TS1494indel6 bp showed statistically significant risk for presbycusis while CC genotype of MTHFR A1298C, ‘2R/2R’ genotype of TSER at 3′UTR and 6 bp ins/6 bp ins of TYMS at 5′UTR were found to be protective. The T-A-A haplotype combination of MTHFR C677T, MTHFR A1298C and MTR A2756G as well as 3R- 152 bp of TYMS at 5′UTR and 3′UTR were also found to contribute significant risk for the onset of presbycusis. Further, the combination of SNP loci TSER: TS1494indel6 bp exhibited moderate linkage in presbycusis. SignificanceThe present pilot study identified the significant association of gene variants of MTHFR and TYMS with presbycusis. These findings aid in early diagnosis of hearing loss in the elderly population.

Abstract LB-254: Thymidylate synthase gene polymorphisms is negatively associated with gastric cancer survival

Abstract Background: Gastric cancer (GC) is a major public health problem in China and its carcinogenesis has not been fully understood. It was found that genetic variation played an important role in the etiology. Thymidylate synthase (TYMS) is a critical target for cancer chemo-therapy, which functions in DNA replication, synthesis and repair. However, the results of the relationship between TYMS and cancer is unclear. To find the genomic susceptibility in TYMS, bio-markers are necessary for preventing and understanding the etiology of gastric cancer. Objectives: The research explores the relationship between TYMS and survival time of 876 Chinese gastric cancer patients. Methods: A retrospective cohort of 876 surgically resected gastric cancer patients with clinicopathologic and follow up information were collected. The genotypes of SNPs were examined by SNaPshot method. The median survival time (MST) for each categorical variable and survival curve were estimated by Kaplan-Meier method. The overall survival was analyzed by univariate and multivariate Cox proportional hazard model. Results: TYMS was significantly associated with survival time. The study found eight samples (1.0%) with the novel allele (4R). In univariate analysis, the group of including 4R allele had lowest survival condition (P value = 0.006). The hazard ratio of individual with 4R allele was 2.48 (95% CI: 1.10-5.58) after controlling age, gender, smoking, drinking and TNM stage. Conclusion: Our study found a novel allele (4R) in TYMS in gastric cancer patients. Key words: Gastric cancer; TYMS; overall survival Citation Format: Jinfei Chen, Maggie Haitian Wang, Benny Chung-Ying Zee. Thymidylate synthase gene polymorphisms is negatively associated with gastric cancer survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-254. doi:10.1158/1538-7445.AM2017-LB-254

Effect of thymidylate synthase (TYMS) gene polymorphisms with methotrexate treatment outcome in south Indian Tamil patients with rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease causing joint damage and significant functional impairment. Methotrexate (MTX) remains the mainstay for the treatment of RA. MTX inhibits several enzymes of the folate and nucleotide pathways. Thymidylate synthase (TYMS) is an important enzyme in the de novo pyrimidine pathway responsible for DNA replication. The two common gene polymorphisms analyzed in TYMS are 28-bp tandem repeat polymorphism and a 6-bp insertion/deletion polymorphism. The present study was carried out to find the role of these TYMS gene polymorphisms with clinical phenotype, treatment response, and MTX adverse events in 254 patients with RA of south Indian Tamil ethnicity. TYMS gene polymorphisms were analyzed by PCR. The allele frequencies of TYMS gene polymorphisms did not differ between good and non-responders. However, the TYMS 28-bp tandem repeat 3R allele was higher in non-responders than in patients undergoing remission [64 vs 51.11%, p=0.06, OR 0.58, 95% CI (0.34-1.00)]. The TYMS 6-bp deletion allele was higher in non-responders than good responders [78.20 vs 64.92%, p=0.06, OR 0.51 95% CI (0.27-0.98)]. TYMS 3R allele and TYMS 6-bp deletion allele may favor non-response to MTX in south Indian Tamils. TYMS gene polymorphisms did not influence MTX adverse events.

The role of pharmacogenetics in the new ESMO colorectal cancer guidelines.

The role of pharmacogenetics in the new ESMO colorectal cancer guidelines.

Thymidylate synthase gene polymorphisms as important contributors affecting hepatocellular carcinoma prognosis

Thymidylate synthase (TYMS), a key rate-limiting enzyme in the folate metabolism, plays essential roles in the development of several malignancies including hepatocellular carcinoma (HCC). Nonetheless, the association of the single nucleotide polymorphisms (SNPs) in TYMS gene with the prognosis of Chinese HCC patients remains unknown. A total of 492 HCC patients who underwent surgery treatment were included in this study. Five functional SNPs (rs2847153, rs2853533, rs502396, rs523230, and rs9967368) in TYMS gene were genotyped using the iPLEX genotyping system. Multivariate Cox proportional hazards regression model and Kaplan-Meier curve were used to analyze the association of SNPs with survival and recurrence of HCC patients. Two SNPs (rs523230 and rs9967368) in TYMS gene were significantly associated with the overall survival of HCC patients. Patients carrying homozygous variant genotype (VV) of rs523230 had significantly decreased risk of death (hazard ratio [HR], 0.68; 95% confidence interval [CI], 0.46-1.00; P=0.048) when compared with those carrying homozygous wild-type (WW) or heterozygous (WV) genotypes, while patients carrying WV+VV genotype of rs9967368 had significantly increased risk of death (HR, 1.46; 95% CI, 1.05-2.04; P=0.026) when compared with those carrying WW genotypes. Cumulative effect analysis showed a significant dose-dependent effect of unfavorable SNPs on OS. Our study for the first time demonstrates the association of SNPs in TYMS gene and clinical outcome of HCC, suggesting that rs523230 and rs9967368 in TYMS gene might be used to predict clinical outcome of Chinese HCC patients.

Association between polymorphisms of thymidylate synthase gene 5'- and 3'-UTR and gastric cancer risk: meta-analysis.

Gastric cancer is the most common cancer and the most frequent cause of cancer death worldwide. Several studies have identified the role of thymidylate synthase (TS) 5′- and 3′-UTR and gastric cancer susceptibility; however, the results still remain inconclusive. The purpose of this meta-analysis was to reinvestigate this correlation. In the present study, online databases were searched to retrieve relevant articles published between January 2000 and 2016. The odds ratio (OR) and 95% confidence interval (CI) were employed to calculate the strength of association. Overall, a total of 13 articles were screened out, including 2382 gastric cancer patients and 3171 healthy controls. We found that polymorphisms of TS 5′-UTR 2R (double repeats)/3R (triple repeats) of a 28-bp sequence (11 articles) and 3′-UTR del6/ins6 (seven articles) were not significantly associated with increased risk of gastric cancer. Subgroup analysis by ethnicity showed that 2R allele and 2R/2R genotype in TS 5′-UTR were associated with gastric cancer susceptibility in Caucasian and African populations; del6 allele, del6/del6 and del6/ins6 genotypes were correlated with gastric cancer in Caucasian population. In conclusion, our result suggested that TS polymorphisms might be the risk factors for gastric cancer risk in Caucasian population, although this association needs further study, and future large-scale researches are still required.

Prognostic implications of thymidylate synthase gene polymorphisms in patients with advanced small bowel adenocarcinoma treated with first-line fluoropyrimidine-based chemotherapy.

Thymidylate synthase (TS) gene polymorphisms such as tandem repeat (TR) polymorphisms and single-nucleotide polymorphisms (SNPs) affect transcriptional efficiency of the TS gene and may be prognostic markers for fluoropyrimidine-based therapy in various gastrointestinal cancers. However, data for TS polymorphisms on clinical outcomes in advanced small bowel adenocarcinoma (SBA) are limited. We retrospectively enrolled 58 locally advanced/metastatic SBA patients treated with first-line fluoropyrimidine-based chemotherapy and analyzed the relationship between TS genotypes and clinical outcomes in 30 patients who were available for tumor tissue. Based on TR polymorphisms and a G>C SNP in the promoter region of the TS gene, 74% of patients had high TS expression genotypes (2R/3RG, 3RG/3RC, 3RG/3RG); the remainder had low TS expression genotypes (2R/2R, 2R/3RC, 3RC/3RC). After a median follow-up of 48.8 months, median progression-free survival (PFS) and overall survival (OS) in all patients were 6.0 and 11.3 months, respectively. However, patients with low TS expression genotypes had better median PFS (12.8 vs. 4.3 months, P=0.027) and OS (28.8 vs. 8.9 months, P=0.025) than those with high TS expression genotypes. In multivariate analysis, poor Eastern Cooperative Oncology Group performance status [hazard ratio (HR), 2.85; 95% CI, 1.02-7.93] and high TS expression genotypes (HR, 3.49; 95% CI, 1.13-10.78) were independent prognostic factors for worse OS. Therefore, TS genotypes, based on a G>C SNP in the TR sequence of the TS gene, may be a useful biomarker for predicting outcomes for fluoropyrimidine-based chemotherapy in patients with locally advanced/metastatic SBA.