Capecitabine‐based treatment of a patient with a novel DPYD genotype and complete dihydropyrimidine dehydrogenase deficiency

Fluoropyrimidines are frequently used anti‐cancer drugs. It is known that patients with reduced activity of dihydropyrimidine dehydrogenase (DPD), the key metabolic enzyme in fluoropyrimidine inactivation, are at increased risk of developing severe fluoropyrimidine‐related toxicity. Upfront screening for DPD deficiency and dose reduction in patients with partial DPD deficiency is recommended and improves patient safety. For patients with complete DPD deficiency, fluoropyrimidine‐treatment has generally been discouraged. During routine pretreatment screening, we identified a 59‐year‐old patient with a sigmoid adenocarcinoma who proved to have a complete DPD deficiency. Genetic analyses showed that this complete absence of DPD activity was likely to be caused by a novel DPYD genotype, consisting of a combination of amplification of exons 17 and 18 of DPYD and heterozygosity for DPYD*2A. Despite absence of DPD activity, the patient was treated with capecitabine‐based chemotherapy, but capecitabine dose was drastically reduced to 150 mg once every 5 days (0.8% of original dose). Pharmacokinetic analyses showed that the area under the concentration‐time curve (AUC) and half‐life of 5‐fluorouracil were respectively tenfold and fourfold higher than control values of patients receiving capecitabine 850 mg/m². When extrapolating from the dosing schedule of once every 5 days to twice daily, the AUC of 5‐fluorouracil was comparable to controls. Treatment was tolerated well for eight cycles by the patient without occurrence of capecitabine‐related toxicity. This case report demonstrates that a more comprehensive genotyping and phenotyping approach, combined with pharmacokinetically‐guided dose administration, enables save fluoropyrimidine‐treatment with adequate drug exposure in completely DPD deficient patients.     

Increased risk of grade IV neutropenia after administration of 5-fluorouracil due to a dihydropyrimidine dehydrogenase deficiency: high prevalence of the IVS14+1g>a mutation

Dihydropyrimidine dehydrogenase (DPD) is the initial and rate-limiting enzyme in the catabolism of 5-fluorouracil (5-FU), and it is suggested that patients with a partial deficiency of this enzyme are at risk of developing severe 5-FU-associated toxicity. We evaluated the importance of DPD deficiency, gender and the presence of the IVS14+1G>A mutation in the etiology of 5-FU toxicity. In 61% of cases, decreased DPD activity could be detected in peripheral blood mononuclear cells. Furthermore, the number of females (65%) in the total group of patients appeared to be higher than the number of males (35%) (p = 0.03). Patients with partial DPD deficiency appeared to have a 3.4-fold higher risk of developing grade IV neutropenia than patients with normal DPD activity. Analysis of the DPYD gene of patients suffering from grade IV neutropenia for the presence of the IVS14+1G>A mutation showed that 50% of the patients investigated were heterozygous or homozygous for the IVS14+1G>A mutation. Adopting a threshold level for DPD activity of 70% of that observed in the normal population, 14% of the population is prone to the development of severe 5-FU-associated toxicity. Below this threshold level, 90% of individuals heterozygous for a mutation in the DPYD gene can be identified. Considering the common use of 5-FU in the treatment of cancer, the severe 5-FU-related toxicities in patients with low DPD activity and the apparently high prevalence of the IVS14+1G>A mutation, screening of patients at risk before administration of 5-FU is warranted.     

Rs895819 in MIR27A improves the predictive value of DPYD variants to identify patients at risk of severe fluoropyrimidine‐associated toxicity

The objective of this study was to determine whether genotyping of MIR27A polymorphisms rs895819A>G and rs11671784C>T can be used to improve the predictive value of DPYD variants to identify patients at risk of severe fluoropyrimidine‐associated toxicity (FP‐toxicity). Patients treated previously in a prospective study with fluoropyrimidine‐based chemotherapy were genotyped for rs895819 and rs11671784, and DPYD c.2846A>T, c.1679T>G, c.1129‐5923C>G and c.1601G>A. The predictive value of MIR27A variants for early‐onset grade ≥3 FP‐toxicity, alone or in combination with DPYD variants, was tested in multivariable logistic regression models. Random‐effects meta‐analysis was performed, including previously published data. A total of 1,592 patients were included. Allele frequencies of rs895819 and rs11671784 were 0.331 and 0.020, respectively. In DPYD wild‐type patients, MIR27A variants did not affect risk of FP‐toxicity (OR 1.3 for ≥1 variant MIR27A allele vs. none, 95% CI: 0.87–1.82, p = 0.228). In contrast, in patients carrying DPYD variants, the presence of ≥1 rs895819 variant allele was associated with increased risk of FP‐toxicity (OR 4.9, 95% CI: 1.24–19.7, p = 0.023). Rs11671784 was not associated with FP‐toxicity (OR 2.9, 95% CI: 0.47?18.0, p = 0.253). Patients carrying a DPYD variant and rs895819 were at increased risk of FP‐toxicity compared to patients wild type for rs895819 and DPYD (OR 2.4, 95% CI: 1.27–4.37, p = 0.007), while patients with a DPYD variant but without a MIR27A variant were not (OR 0.3 95% CI: 0.06?1.17, p = 0.081). In meta‐analysis, rs895819 remained significantly associated with FP‐toxicity in DPYD variant allele carriers, OR 5.4 (95% CI: 1.83–15.7, p = 0.002). This study demonstrates the clinical validity of combined MIR27A/DPYD screening to identify patients at risk of severe FP‐toxicity.     

Effectiveness and safety of reduced-dose fluoropyrimidine therapy in patients carrying the DPYD*2A variant: A matched pair analysis

Carriers of the genetic DPYD*2A variant, resulting in dihydropyrimidine dehydrogenase deficiency, are at significantly increased risk of developing severe fluoropyrimidine-associated toxicity. Upfront DPYD*2A genotype-based dose reductions improve patient safety, but uncertainty exists whether this has a negative impact on treatment effectiveness. Therefore, our study investigated effectiveness and safety of DPYD*2A genotype-guided dosing. A cohort of 40 prospectively identified heterozygous DPYD*2A carriers, treated with a ~50% reduced fluoropyrimidine dose, was identified. For effectiveness analysis, a matched pair-analysis was performed in which for each DPYD*2A carrier a matched DPYD*2A wild-type patient was identified. Overall survival and progression-free survival were compared between the matched groups. The frequency of severe (grade ≥ 3) treatment-related toxicity was compared to 1] a cohort of 1606 wild-type patients treated with full dose and 2] a cohort of historical controls derived from literature, i.e. 86 DPYD*2A variant carriers who received a full fluoropyrimidine dose. For 37 out of 40 DPYD*2A carriers, a matched control could be identified. Compared to matched controls, reduced doses did not negatively affect overall survival (median 27 months versus 24 months, p = 0.47) nor progression-free survival (median 14 months versus 10 months, p = 0.54). Risk of severe fluoropyrimidine-related toxicity in DPYD*2A carriers treated with reduced dose was 18%, comparable to wild-type patients (23%, p = 0.57) and significantly lower than the risk of 77% in DPYD*2A carriers treated with full dose (p < 0.001). Our study is the first to show that DPYD*2A genotype-guided dosing appears to have no negative effect on effectiveness of fluoropyrimidine-based chemotherapy, while resulting in significantly improved patient safety.     

Augmentation of the antitumor activity of capecitabine by a tumor selective dihydropyrimidine dehydrogenase inhibitor,RO0094889

Capecitabine is an orally available fluoropyrimidine and is finally converted to 5-FU selectively in tumor tissues. In our study, we examined whether the antitumor activity of capecitabine is directly affected by a modulation of dihydropyrimidine dehydrogenase (DPD). The modulations were carried out by the overexpression of DPD in tumor cells and by tumor selective DPD inhibition. The DPD-overexpressing cells were obtained by transfection of human DPD cDNA into HCT116 human colorectal cancer cells. The HCT116 cells bearing DPD cDNA expressed about 13 times higher DPD activities than the parental HCT116 cells, and they became significantly less susceptible to capecitabine than the parental cells when transplanted into nude mice. Administration of RO0094889 that is converted to a DPD inhibitor 5-vinyluracil selectively in tumor tissues restored the antitumor activity of capecitabine against the tumor of the HCT116 cells carrying DPD cDNA and various tumors expressing DPD. As compared to 5-ethynyluracil or 5-vinyluracil, which inhibited DPD not only in tumor tissues but also in other non-cancerous tissues, the effective dose range of RO0094889 in augmenting the efficacy of capecitabine was much broader. These results indicate that the antitumor activity of capecitabine is directly affected by DPD activities in tumor tissues and therefore, the combination of capecitabine and a tumor selective DPD inhibitor, RO0094889, will be beneficial to patients who have tumors with high levels of DPD.     

Thymidylate synthase and dihydropyrimidine dehydrogenase mRNA expression after administration of 5-fluorouracil to patients with colorectal cancer

This study explores the effect of 5-fluorouracil (5FU) exposure on mRNA levels of its target enzyme thymidylate synthase (TS) and the rate-limiting catabolic enzyme dihydropyrimidine dehydrogenase (DPD) in tumors of colorectal cancer patients. TS and DPD mRNA levels were determined in primary tumor and liver metastasis samples from patients who were either not pretreated (n = 29) or given one presurgery bolus of 5FU (n = 67). In both groups a wide variation in TS mRNA levels was observed. Median TS mRNA expression in 17 primary tumors of exposed patients was 3.0-fold higher than in 19 primary tumors of unexposed patients (p = 0.015). TS mRNA expression in liver metastasis samples of exposed patients (n = 16) was also higher (5.2-fold) than that of unexposed patients (n = 48; p < 0.001). Also DPD mRNA expression displayed a large degree of interpatient variation. No difference in DPD expression in liver metastasis samples was observed between exposed and unexposed patients. However, median DPD mRNA expression in 15 primary tumors of exposed patients was 3.2-fold lower than in 18 primary tumors of unexposed patients (p = 0.027). In conclusion, administration of 5FU in vivo influences the gene expression of TS and DPD.     

Lack of large intragenic rearrangements in dihydropyrimidine dehydrogenase (DPYD) gene in fluoropyrimidine-treated patients with high-grade toxicity

Purpose  Deficiency of dihydropyrimidine dehydrogenase (DPD) has been associated with severe fluoropyrimidines (FP) toxicity. Mutations in DPD-coding gene (DPYD) were shown to increase the risk of severe toxicity in FP-treated cancer patients. However, the majority of DPYD alterations characterized in these patients has been considered as polymorphisms and known deleterious mutations are rare and present in only limited subgroup of patients with high toxicity. Recently, the common fragile site FRA1E was mapped within DPYD locus but intragenic rearrangements in DPYD gene were not studied so far. Methods  We performed the analysis of intragenic rearrangements of DPYD using multiplex ligation-dependent probe amplification in 68 patients with high-grade gastrointestinal and/or hematological toxicity developed at the beginning of FP treatment. Results  We did not detect any deletion/duplication of one or more DPYD exons in analyzed patients. Conclusions  We assume that rearrangements in DPYD gene play insignificant role in the development of serious FP-related toxicity. I. Ticha, P. Kleiblova contributed equally to this work.     

Increased risk of severe fluoropyrimidine‐associated toxicity in patients carrying a G to C substitution in the first 28‐bp tandem repeat of the thymidylate synthase 2R allele

The fluoropyrimidines act by inhibiting thymidylate synthase (TS). Recent studies have shown that patients' risk of severe fluoropyrimidine‐associated toxicity is affected by polymorphisms in the 5′‐untranslated region of TYMS, the gene encoding TS. A G>C substitution in the promoter enhancer region of TYMS, rs183205964 (known as the 2RC allele), markedly reduces TS activity in vitro, but its clinical relevance is unknown. We determined rs183205964 in 1605 patients previously enrolled in a prospective multicenter study. Associations between putative low TS expression genotypes (3RC/2RC, 2RG/2RC, and 2RC/2RC) and severe toxicity were investigated using univariable and multivariable logistic regression. Activity of TS and TYMS gene expression were determined in peripheral blood mononuclear cells (PBMCs) of a patient carrying genotype 2RC/2RC and of a control group of healthy individuals. Among 1,605 patients, 28 patients (1.7%) carried the 2RC allele. Twenty patients (1.2%) carried a risk‐associated genotype (2RG/2RC, n=13; 3RC/2RC, n=6; and 2RC/2RC, n=1), the eight remaining patients had genotype 3RG/2RC. Early severe toxicity and toxicity‐related hospitalization were significantly more frequent in risk‐associated genotype carriers (OR 3.0, 95%CI 1.04–8.93, p=0.043 and OR 3.8, 95%CI 1.19–11.9, p=0.024, respectively, in multivariable analysis). The patient with genotype 2RC/2RC was hospitalized twice and had severe febrile neutropenia, diarrhea, and hand‐foot syndrome. Baseline TS activity and gene expression in PBMCs of this patient, and a healthy individual with the 2RC allele, were found to be within the normal range. Our study suggests that patients carrying rs183205964 are at strongly increased risk of severe, potentially life‐threatening, toxicity when treated with fluoropyrimidines.     

Clinical validity of a DPYD‐based pharmacogenetic test to predict severe toxicity to fluoropyrimidines

Pre‐therapeutic DPYD pharmacogenetic test to prevent fluoropyrimidines (FL)‐related toxicities is not yet common practice in medical oncology. We aimed at investigating the clinical validity of DPYD genetic analysis in a large series of oncological patients. Six hundred three cancer patients, treated with FL, have been retrospectively tested for eight DPYD polymorphisms (DPYD‐rs3918290, DPYD‐rs55886062, DPYD‐rs67376798, DPYD‐rs2297595, DPYD‐rs1801160, DPYD‐rs1801158, DPYD‐rs1801159, DPYD‐rs17376848) for association with Grade ≥3 toxicity, developed within the first three cycles of therapy. DPYD‐rs3918290 and DPYD‐rs67376798 were associated to Grade ≥3 toxicity after bootstrap validation and Bonferroni correction (p = 0.003, p = 0.048). DPYD‐rs55886062 was not significant likely due to its low allelic frequency, nonetheless one out of two heterozygous patients (compound heterozygous with DPYD‐rs3918290) died from toxicity after one cycle. Test specificity for the analysis of DPYD‐rs3918290, DPYD‐rs55886062 and DPYD‐rs67376798 was assessed to 99%. Among the seven patients carrying one variant DPYD‐rs3918290, DPYD‐rs55886062 or DPYD‐rs67376798 allele, not developing Grade ≥3 toxicity, 57% needed a FL dose or schedule modification for moderate chronic toxicity. No other DPYD polymorphism was associated with Grade ≥3 toxicity. Our data demonstrate the clinical validity and specificity of the DPYD‐rs3918290, DPYD‐rs55886062, DPYD‐rs67376798 genotyping test to prevent FL‐related Grade ≥3 toxicity and to preserve treatment compliance, and support its introduction in the clinical practice.     

Reduced 5-FU clearance in a patient with low DPD activity due to heterozygosity for a mutant allele of the DPYD gene

5-fluorouracil pharmacokinetics, dihydropyrimidine dehydrogenase-activity and DNA sequence analysis were compared between a patient with extreme 5-fluorouracil induced toxicity and six control patients with normal 5-fluorouracil related symptoms. Patients were treated for colorectal cancer and received chemotherapy consisting of leucovorin 20 mg m(-2) plus 5-fluorouracil 425 mg m(-2). Blood sampling was carried out on day 1 of the first cycle. The 5-fluorouracil area under the curve(0-->3h) in the index patient was 24.1 mg h l(-1) compared to 9.8+/-3.6 (range 5.4-15.3) mg h l(-1) in control patients. The 5-fluorouracil clearance was 520 ml min(-1) vs 1293+/-302 (range 980-1780) ml min(-1) in controls. The activity of dihydropyrimidine dehydrogenase in mononuclear cells was lower in the index patient (5.5 nmol mg h(-1)) compared to the six controls (10.3+/-1.6, range 8.0-11.7 nmol mg h(-1)). Sequence analysis of the dihydropyrimidine dehydrogenase gene revealed that the index patient was heterozygous for a IVS14+1G>A point mutation. Our results indicate that the inactivation of one dihydropyrimidine dehydrogenase allele can result in a strong reduction in 5-fluorouracil clearance, causing severe 5-fluorouracil induced toxicity.     

Pharmacogenetic variants in the DPYD,TYMS, CDA and MTHFR genes are clinically significant predictors of fluoropyrimidine toxicity

Background:

Fluoropyrimidine drugs are extensively used for the treatment of solid cancers. However, adverse drug reactions are a major clinical problem, often necessitating treatment discontinuation. The aim of this study was to identify pharmacogenetic markers predicting fluoropyrimidine toxicity.

Methods:

Toxicity in the first four cycles of 5-fluorouracil or capecitabine-based chemotherapy were recorded for a series of 430 patients. The association between demographic variables, DPYD, DPYS, TYMS, MTHFR, CDA genotypes, and toxicity were analysed using logistic regression models.

Results:

Four DPYD sequence variants (c.1905+1G>A, c.2846A>T, c.1601G>A and c.1679T>G) were found in 6% of the cohort and were significantly associated with grade 3–4 toxicity (P<0.0001). The TYMS 3′-untranslated region del/del genotype substantially increased the risk of severe toxicity (P=0.0123, odds ratio (OR)=3.08, 95% confidence interval (CI): 1.38–6.87). For patients treated with capecitabine, a MTHFR c.1298CC homozygous variant genotype predicted hand–foot syndrome (P=4.1 × 10⁻⁶, OR=9.99, 95% CI: 3.84–27.8). The linked CDA c.−92A>G and CDA c.−451C>T variants predicted grade 2–4 diarrhoea (P=0.0055, OR=2.3, 95% CI: 1.3–4.2 and P=0.0082, OR=2.3, 95% CI: 1.3–4.2, respectively).

Conclusion:

We have identified a panel of clinically useful pharmacogenetic markers predicting toxicity to fluoropyrimidine therapy. Dose reduction should be considered in patients carrying these sequence variants.     

Predictive value of dihydropyrimidine dehydrogenase expression in tumor tissue,regarding the efficacy of postoperatively administered UFT (Tegafur + Uracil) in patients with p-stage I nonsmall-cell lung cancer

BACKGROUND AND OBJECTIVES: Dihydropyrimidine dehydrogenase (DPD) activity in tumor cells has been suggested to be one of the factors determining the effectiveness of 5-fluorouracil (5-FU). In the present study, we analyzed DPD expression in tumors and investigated retrospectively the relationship between the efficacy of UFT (Tegafur + Uracil) as adjuvant chemotherapy and DPD expression in nonsmall-cell lung cancer (NSCLC). METHODS: DPD expression of 166 resected p-stage I NSCLC was examined immunohistochemically. Patients who were administered UFT alone as adjuvant therapy comprised the UFT group (n = 54), and those who underwent only surgery comprised the control group (n = 112). DPD expression was categorized as either high or low, according to intensity of staining. RESULTS: DPD expression was high in 98 patients (59.0%) and low in 68 patients (41.0%). Patients with low-DPD tumors who were administered UFT had a significantly better prognosis than those who did not receive adjuvant treatment (P = 0.021). No significant difference was found between the two groups of patients with high-DPD tumors (P = 0.598). CONCLUSIONS: DPD expression may predict the efficacy of UFT after surgery for p-stage I NSCLC. A prospective study is needed to confirm the role of DPD expression as a predictor of UFT efficacy.     

Impacts of excision repair cross-complementing gene 1 (ERCC1), dihydropyrimidine dehydrogenase, and epidermal growth factor receptor on the outcomes of patients with advanced gastric cancer

Using laser-captured microdissection and a real-time RT-PCR assay, we quantitatively evaluated mRNA levels of the following biomarkers in paraffin-embedded gastric cancer (GC) specimens obtained by surgical resection or biopsy: excision repair cross-complementing gene 1 (ERCC1), dihydropyrimidine dehydrogenase (DPD), methylenetetrahydrofolate reductase (MTHFR), epidermal growth factor receptor (EGFR), and five other biomarkers related to anticancer drug sensitivity. The study group comprised 140 patients who received first-line chemotherapy for advanced GC. All cancer specimens were obtained before chemotherapy. In patients who received first-line S-1 monotherapy (69 patients), low MTHFR expression correlated with a higher response rate (low: 44.9% vs high: 6.3%; P=0.006). In patients given first-line cisplatin-based regimens (combined with S-1 or irinotecan) (43 patients), low ERCC1 correlated with a higher response rate (low: 55.6% vs high: 18.8%; P=0.008). Multivariate survival analysis of all patients demonstrated that high ERCC1 (hazard ratio (HR): 2.38 (95% CI: 1.55-3.67)), high DPD (HR: 2.04 (1.37-3.02)), low EGFR (HR: 0.34 (0.20-0.56)), and an elevated serum alkaline phosphatase level (HR: 1.00 (1.001-1.002)) were significant predictors of poor survival. Our results suggest that these biomarkers are useful predictors of clinical outcomes in patients with advanced GC.     

Impact of DPYD,DPYS, and UPB1 gene variations on severe drug‐related toxicity in patients with cancer

Cancer treatment with a fluoropyrimidine (FP) is often accompanied by severe toxicity that may be dependent on the activity of catalytic enzymes encoded by the DPYD, DPYS, and UPB1 genes. Genotype‐guided dose individualization of FP therapy has been proposed in western countries, but our knowledge of the relevant genetic variants in East Asian populations is presently limited. To investigate the association between these genetic variations and FP‐related high toxicity in a Japanese population, we obtained blood samples from 301 patients who received this chemotherapy and sequenced the coding exons and flanking intron regions of their DPYD, DPYS, and UPB1 genes. In total, 24 single nucleotide variants (15 in DPYD, 7 in DPYS and 2 in UPB1) were identified including 3 novel variants in DPYD and 1 novel variant in DPYS. We did not find a significant association between FP‐related high toxicity and each of these individual variants, although a certain trend toward significance was observed for p.Arg181Trp and p.Gln334Arg in DPYS (P = .0813 and .087). When we focused on 7 DPYD rare variants (p.Ser199Asn, p.IIe245Phe, p.Thr305Lys, p.Glu386Ter, p.Ser556Arg, p.Ala571Asp, p.Trp621Cys) which have an allele frequency of less than 0.01% in the Japanese population and are predicted to be loss‐of‐function mutations by in silico analysis, the group of patients who were heterozygous carriers of at least one these rare variants showed a strong association with FP‐related high toxicity (P = .003). Although the availability of screening of these rare loss‐of‐function variants is still unknown, our data provide useful information that may help to alleviate FP‐related toxicity in Japanese patients with cancer.     

Induced miR‐31 by 5‐fluorouracil exposure contributes to the resistance in colorectal tumors

Drug resistance makes treatment difficult in cancers. The present study identifies and analyzes drug resistance‐related miRNA in colorectal cancer. We established 4 types of 5‐fluorouracil (5‐FU)‐resistant colon cancer cell lines in vitro and in vivo. We then analyzed the miRNA expression profile by miRNA array in these 4 cell lines, and identified the drug resistance‐related miRNAs. We examined the expression levels of the identified miRNA in 112 colorectal tumor samples from the patients. We identified 12 possible miRNAs involved in 5‐FU resistance by miRNA arrays. We then examined the relationship between miR‐31, which was the most promising among them, and drug resistance. The ectopic expression of mimic miR‐31 showed significant 5‐FU resistance in the parental DLD‐1 cells, while anti–miR‐31 caused significant growth inhibition in DLD/F cells; that is, 5‐FU‐resistant colon cancer cell line DLD‐1 under exposure to 5‐FU. When we exposed high doses of 5‐FU to parent or 5‐FU‐resistant cells, the expression levels of miR‐31 were raised higher than those of controls. Notably, the expression levels of miR‐31 were positively correlated with the grade of clinical stages of colorectal tumors. The protein expression levels of factors inhibiting hypoxia‐inducible factor 1 were downregulated by transfection of mimic miR‐31 into DLD‐1 cells. This study provides evidence supporting the association of miR‐31 with 5‐FU drug resistance and clinical stages of colorectal tumors.     

Increased risk of cancer in patients with early‐onset cataracts: A nationwide population‐based study

Early‐onset cataracts are associated with insufficient antioxidative activity, and, therefore, a potential risk of cancer. This study investigated the risk of cancer after being diagnosed with early‐onset cataracts. Retrospective claims data from the Taiwan National Health Insurance Research Database were analyzed. Study subjects were comprised of patients with early‐onset cataracts, aged 20–55 years (International Classification of Diseases, 9th Revision, Clinical Modification [ICD‐9‐CM] code 366.00, 366.01, 366.02, 366.03, 366.04, 366.09, 366.17 and 366.18) and newly diagnosed between 1997 and 2010 (n = 1281), and a comparison cohort without the disease (n = 5124). Both cohorts were followed up until 2010 to estimate the incidences of cancer. We used the Poisson regression model to compare incidence rate ratios and the 95% confidence interval (CI). Cox proportional hazards regression was used to assess the hazard ratio (HR) of cancer associated with early‐onset cataracts. The overall incidence rate of all cancers was 2.19‐fold higher in the early‐onset cataract cohort than in the comparison cohort (8.06 vs 3.68 per 1000 person‐years) with an adjusted HR of 2.13 (95% CI = 1.48, 3.07). The site‐specific analysis also showed a strong relationship, with adjusted HR of 3.24 ((95% CI = 1.30, 8.10) for head and neck cancer, 3.29 (95% CI 1.16, 9.31) for hepatoma and 3.19 (95% CI 1.34, 7.58) for breast cancer. The present study suggests that patients with early‐onset cataracts are at an increased risk of being diagnosed with cancer in subsequent years.     

Association of variants in the interleukin‐27 and interleukin‐12 gene with nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is multifactorial, and the genetic background may be a crucial etiologic factor. Interleukin‐12 (IL‐12) is a multifunctional cytokine that induces interferon (IFN)‐gamma secretion and plays an important role in antitumor immunity. Interleukin‐27 (IL‐27) is a novel IL‐12 family member, the present studies demonstrate that IL‐27 mediates potent antitumor activity. Variations in the DNA sequence in the IL‐12 and IL‐27 gene may lead to altered cytokines production and/or activity, and so this can modulate an individual's susceptibility to NPC. To test this hypothesis, we investigated the relationship of IL‐12 and IL‐27 gene polymorphisms and NPC in a Chinese population. We analyzed single nucleotide polymorphisms (SNPs) of IL‐12 gene 16974 A/C and IL‐27 gene ?964 A/G, 2905 T/G, 4730 T/C in 302 patients with NPC and 310 age‐ and sex‐matched controls, using polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) and DNA sequencing methods. There were significant differences in the genotype and allele distribution of 16974 A/C polymorphism of the IL‐12 gene among cases and controls. The 16974 CC and AC genotypes were associated with a significantly increased risk of NPC as compared with the 16974 AA genotypes (OR = 2.225, 95% CI 1.395–3.549, P = 0.001 and OR = 1.834, 95% CI 1.239–2.716, P = 0.002, respectively). The 16974 C allele was associated with a significantly increased risk of NPC as compared with the 16974 A allele (OR = 1.334, 95% CI 1.065–1.670, P = 0.012). However, genotype and allele frequencies of the IL‐27 gene ?964 A/G, 2905 T/G, 4730 T/C polymorphisms in NPC patients were not significantly different than that in healthy controls (P > 0.05). Our data suggest that IL‐12 gene may play a role in the development of NPC. © 2009 Wiley‐Liss, Inc.     

Single nucleotide polymorphism in the 5' tandem repeat sequences of thymidylate synthase gene predicts for response to fluorouracil-based chemotherapy in advanced colorectal cancer patients

Thymidylate synthase (TS) is the primary target of 5-fluorouracil (5-FU). A VNTR polymorphism in the TS promoter region is associated with the efficacy of 5-FU-based chemotherapy in colorectal cancer. A common G>C SNP at the 12th nucleotide of the second repeat in the TS*3 alleles has been recently described. The combination of SNP and VNTR allows the definition of 3 TS alleles: *2, *3G and *3C. The aim of our study was to evaluate the predictive value of clinical response and survival of these new defined TS alleles. TS genotypes of 89 patients diagnosed with metastatic colorectal cancer and undergoing 5-FU-based chemotherapy were carried out. The clinical outcome was evaluated according to the genotype (high expression genotype: *2R/*3G; *3C/*3G; *3G/*3G; and low expression genotype: *2R/*2R; *2R/*3C; *3C/*3C. A higher overall response was observed in the group of patients with a low expression genotype (p = 0.035). The probability of achieving a clinical response of patients with a low expression-related genotype was 2.9 higher than that of the other group (95% CI = 1.03-5.6, p = 0.04). The median time to progression was 12 months and 9 months in the low and high expression groups, respectively (p = 0.07, log rank test). Overall survival was significantly longer in the low expression group. In this group the median OS was not achieved at 50 months of follow-up in contrast to the 20 months observed in the high expression group (p = 0.03). TS genotype was an independent predictor of progression-free and overall survival in the Cox regression models after adjustment to the other clinical variables. The selection of patients who are likely to respond to 5-FU therapy may be considerably improved if the TS genotype were to include both the VNTR and the SNP located within the promoter region of the gene.