Associations between UGT1A1*6/*28 polymorphisms and irinotecan-induced severe toxicity in Chinese gastric or esophageal cancer patients

Incidence and non-genetic risk factors of irinotecan-induced severe neutropenia in Chinese adult inpatients

To analyze the incidence and nongenetic risk factors of irinotecan-induced severe neutropenia in the hospital, and provide additional reference and help for clinical treatment. A retrospective analysis of patients who received irinotecan based chemotherapy from May 2014 to May 2019 in Renmin Hospital of Wuhan University was conducted. Univariate analysis and binary logistic regression analysis with the forward stepwise method were used to assess the risk factors associated with severe neutropenia induced by irinotecan. Of the 1312 patients treated with irinotecan-based regmines, only 612 patients met the inclusion criteria, and 32 patients developed irinotecan-induced severe neutropenia. In the univariate analysis, variables associated with severe neutropenia were tumor type, tumor stage, and therapeutic regimen. In the multivariate analysis, irinotecan plus lobaplatin, lung cancer or ovarian cancer, tumor stage T2, T3, and T4, were identified as risk factors that contributed independently to irinotecan-induced severe neutropenia (P < .05), respectively. The results showed that the incidence of irinotecan-induced severe neutropenia was 5.23% in the hospital. The risk factors included tumor type (lung cancer or ovarian cancer), tumor stage (T2, T3, and T4) and therapeutic regimen (irinotecan plus lobaplatin). Therefore, for patients with these risk factors, it might be advisable to actively consider optimum management to reduce the occurrence of irinotecan-induced severe neutropenia.

The UGT1A9*22 genotype identifies a high-risk group for irinotecan toxicity among gastric cancer patients

Several studies have shown associations between irinotecan toxicity and UGT1A genetic variations in colorectal and lung cancer, but only limited data are available for gastric cancer patients. We evaluated the frequencies of UGT1A polymorphisms and their relationship with clinicopathologic parameters in 382 Korean gastric cancer patients. Polymorphisms of UGT1A1*6, UGT1A1*27, UGT1A1*28, UGT1A1*60, UGT1A7*2, UGT1A7*3, and UGT1A9*22 were genotyped by direct sequencing. In 98 patients treated with irinotecan-containing regimens, toxicity and response were compared according to the genotype. The UGT1A1*6 and UGT1A9*22 genotypes showed a higher prevalence in Korean gastric cancer patients, while the prevalence of the UG1A1*28 polymorphism was lower than in normal Koreans, as has been found in other studies of Asian populations. The incidence of severe diarrhea after irinotecan-containing treatment was more common in patients with the UGT1A1*6, UGT1A7*3 and UGT1A9*22 polymorphisms than in controls. The presence of the UGT1A1*6 allele also showed a significant association with grade III–IV neutropenia. Upon haplotype and diplotype analyses, almost every patient bearing the UGT1A1*6 or UGT1A7*3 variant also had the UGT1A9*22 polymorphism, and all severe manifestations of UGT1A polymorphism-associated toxicity were related to the UGT1A9*22 polymorphism. By genotyping UGT1A9*22 polymorphisms, we could identify high-risk gastric cancer patients receiving irinotecan-containing chemotherapy, who would experience severe toxicity. When treating high-risk patients with the UGT1A9*22 polymorphism, clinicians should closely monitor them for signs of toxicity such as severe diarrhea or neutropenia.

Association of UGT1A1*6, UGT1A1*28, or ABCC2 c.3972C>T genetic polymorphisms with irinotecan-induced toxicity in Asian cancer patients: Meta-analysis

Effects of UGT1A1*6 and UGT1A1*28 genetic polymorphisms on irinotecan-induced severe toxicities in Asian cancer patients are inconclusive. Also, ABCC2 c.3972C>T may affect toxicity of irinotecan. The aim was to assess the aggregated risk of neutropenia or diarrhea in Asian cancer patients taking irinotecan and inherited UGT1A1*6, UGT1A1*28, or ABCC2 c.3972C>T genetic variants. A PubMed literature search for eligible studies was conducted. Odds ratios (ORs) were measured using RevMan software where p values <0.05 were statistically significant. Patients that inherited both UGT1A1*6 and UGT1A1*28 genetic variants (heterozygous: UGT1A1*1/*6 + *1/*28 and homozygous: UGT1A1*6/*6 + *28/*28) were significantly associated with increased risk of neutropenia and diarrhea compared to patients with UGT1A1*1/*1 (neutropenia: OR 2.89; 95% CI 1.97-4.23; p < 0.00001; diarrhea: OR 2.26; 95% CI 1.71-2.99; p < 0.00001). Patients carrying homozygous variants had much stronger effects in developing toxicities (neutropenia: OR 6.23; 95% CI 3.11-12.47; p < 0.00001; diarrhea: OR 3.21; 95% CI 2.13-4.85; p < 0.00001) than those with heterozygous variants. However, patients carrying the ABCC2 c.3972C>T genetic variant were not significantly associated with neutropenia (OR 1.67; 95% CI 0.98-2.84; p = 0.06) and were significantly associated with a reduction in irinotecan-induced diarrhea (OR 0.31; 95% CI 0.11-0.81; p = 0.02). Asian cancer patients should undergo screening for both UGT1A1*6 and UGT1A1*28 genetic variants to reduce substantially irinotecan-induced severe toxicities.

WGCNA reveals key gene modules regulated by the combined treatment of colon cancer with PHY906 and CPT11

Irinotecan (CPT11) is one of the most effective drugs for treating colon cancer, but its severe side effects limit its application. Recently, a traditional Chinese herbal preparation, named PHY906, has been proved to be effective for improving therapeutic effect and reducing side effects of CPT11. The aim of the present study was to provide novel insight to understand the molecular mechanism underlying PHY906-CPT11 intervention of colon cancer. Based on the GSE25192 dataset, for different three treatments (PHY906, CPT11, and PHY906-CPT11), we screened out differentially expressed genes (DEGs) and constructed a co-expression network by weighted gene co-expression network analysis (WGCNA) to identify hub genes. The key genes of the three treatments were obtained by merging the DEGs and hub genes. For the PHY906-CPT11 treatment, a total of 18 key genes including Eif4e, Prr15, Anxa2, Ddx5, Tardbp, Skint5, Prss12 and Hnrnpa3, were identified. The results of functional enrichment analysis indicated that the key genes associated with PHY906-CPT11 treatment were mainly enriched in ‘superoxide anion generation’ and ‘complement and coagulation cascades’. Finally, we validated the key genes by Gene Expression Profiling Interactive Analysis (GEPIA) and RT-PCR analysis, the results indicated that EIF4E, PRR15, ANXA2, HNRNPA3, NCF1, C3AR1, PFDN2, RGS10, GNG11, and TMSB4X might play an important role in the treatment of colon cancer with PHY906-CPT11. In conclusion, a total of 18 key genes were identified in the present study. These genes showed strong correlation with PHY906-CPT11 treatment in colon cancer, which may help elucidate the underlying molecular mechanism of PHY906-CPT11 treatment in colon cancer.

Impact of UGT1A1 genetic polymorphism on toxicity in unresectable pancreatic cancer patients undergoing FOLFIRINOX

Studies have indicated an association between UDP‐glucuronosyltransferase‐1A1 (UGT1A1) genetic polymorphisms and irinotecan‐induced toxicity. We undertook this study to investigate the association between UGT1A1 genetic polymorphisms and toxicity in patients treated with the FOLFIRINOX (comprising oxaliplatin, irinotecan, fluorouracil, and leucovorin) chemotherapy regimen in the JASPAC 06 study. Patients screened for UGT1A1*6 and UGT1A1*28, and treated with either the original FOLFIRINOX (oxaliplatin 85 mg/m², irinotecan 180 mg/m², leucovorin 200 mg/m², bolus 5‐fluorouracil [5‐FU] 400 mg/m², and continuous 5‐FU 2400 mg/m²) or a modified FOLFIRINOX (oxaliplatin 85 mg/m², irinotecan 150 mg/m², leucovorin 200 mg/m², and continuous 5‐FU 2400 mg/m²) as first‐line chemotherapy were included. Of 199 patients eligible for this analysis, 79 patients were treated with the original FOLFIRINOX regimen and 120 patients were treated with the modified FOLFIRINOX regimen. In the original FOLFIRINOX group, 54 were UGT1A1 WT, and 25 were UGT1A1 heterozygous type (−/*6, 12 patients; −/*28, 13 patients). In the modified FOLFIRINOX group, 64 were UGT1A1 WT and 56 were UGT1A1 heterozygous type (−/*6, 33 patients; −/*28, 23 patients).

In the original FOLFIRINOX group, the incidence of diarrhea was significantly higher among patients with UGT1A1 heterozygous type than among those with UGT1A1 WT and the incidence of leukopenia and diarrhea was significantly higher among patients with UGT1A1 −/*6 than among those with UGT1A1 −/*28. Patients with UGT1A1 heterozygous type, especially those with UGT1A1 −/*6, tended to show a higher incidence rate of severe adverse events, but this was not statistically significant. However, for patients who received the modified FOLFIRINOX, there was no difference in the frequency of adverse events due to UGT1A1 status. In conclusion, patients with heterozygous UGT1A1 polymorphisms treated with the original FOLFIRINOX regimen experienced severe toxicity more frequently than patients with WT UGT1A1.

Effects of Shengjiangxiexin decoction on irinotecan-induced toxicity in patients with UGT1A1*28 and UGT1A1*6 polymorphisms

OBJECTIVE

To evaluate the efficacy of Shengjiangxiexin decoction (SXD), prepared with a formula from Traditional Chinese Medicine (TCM), in reducing irinotecan-induced hematological and gastrointestinal toxicities in patients with UDP-glucuronosyltransferase (UGT)1A1*28 and UGT1A1*6 polymorphisms.

METHODS

This clinical trial included 115 patients receiving irinotecan combined with 5-fluorouracil plus l-leucovorin (FOLFIRI) treatment. All patients consented to UGT1A1*28 and *6 gene polymorphism detection prior to chemotherapy. SXD were administered from 1 day prior to chemotherapy to 6 day post chemotherapy. Chemotherapy induced adverse reactions (neutropenia, diarrhea, nausea, vomiting, anorexia and infection) were recorded, and short-term effect of chemotherapy was evaluated regularly.

RESULTS

A total of 50 patients had *1/*1 wild genotype, 58 patients had single allele variants with genotype *1/*6 or *1/*28 , and 7 patients had two alleles variants with genotype *6/*6, *28/*28 or *6/* 28. In *1/*6 or *1/*28 patients (high risk group), 9 patients (15.5% ) developed Ⅰ-Ⅱ grade diarrhea and no patient developed severe diarrhea; neutropenia occurred in 19 patients (32.8%) and only 3 patients (8.6% ) developed sever neutropenia. There were no significant differences in any toxic effects (neutropenia, diarrhea, nausea, vomiting, anorexia or infection) between *6 or *28 variant patients (high risk group) and wild type patients. No sever toxicity was found in high risk two alleles variants patients (*6/*6, *6/*28 or *28/*28). No significant differences were observed between UGT1A1*6/*28 polymorphisms and clinical response of chemotherapy.

CONCLUSION

SXD could significantly reduce irinotecan-induced hematological and gastrointestinal toxicities in UGT1A1*28 or *6 variant patients (high risk group), while this treatment didn't affect clinical response of chemotherapy.

A systematic review of molecular responses to cancer therapy in normal human mucosa

OBJECTIVE

Cancer therapy-induced inflammation of oral and gastrointestinal mucosae affects patients nonuniformly. Preventive strategies are limited; no biomarker exists for pretreatment identification of patients likely to be severely affected. Animal models are preferred for studying molecular responses in mucosae during chemotherapy, but translation into clinical practice is difficult. We performed a systematic review to retrieve articles that described molecular changes in human mucosae during cancer therapy.

STUDY DESIGN

We searched MEDLINE and Ovid Embase searches for studies reported in the English language literature from January 1990 to November 2016 and studies referenced in selected articles, which analyzed mucosae from patients at risk of developing mucositis during cancer therapy. Two authors extracted data according to predefined data fields, including study quality indicators.

RESULTS

We identified 17 human studies on chemotherapy (n = 9) and radiotherapy (n = 8), but no studies on targeted therapy. Studies were heterogeneous with regard to patient cohorts, analysis methods, cancer treatments, biopsy timings, and correlations to clinical mucositis. Consequently, a meta-analysis was not feasible.

CONCLUSIONS

Few human studies described the molecular responses of the normal mucosa to cancer therapy. Studies were heterogeneous and had sparse correlations to clinical mucositis. We proposed a model for acquiring data on treatment- and disease-specific phenotypes and transcriptomes for predictive or preventive initiatives.

UGT1A1*6 polymorphisms are correlated with irinotecan-induced neutropenia: a systematic review and meta-analysis

Irinotecan (IRI) chemotherapy toxicities can be severe, and may result in treatment delay, morbidity and in some rare cases death. Neutropenia is a life-threatening side effect of irinotecan, and UDP glucuronosyltransferases (UGTs) gene polymorphisms could predict the side effects in cancer patients and then reduce IRI-induced toxicity by preventative treatment or a decrease in dose. Both UGT1A1*6 and *28 were reliably demonstrated to be risk factors for IRI-induced neutropenia, with tests for both polymorphisms potentially being particularly useful in Asian cancer patients. However, some researchers reported that UGT1A1*6 could predict IRI-induced toxicities in Asian populations, controversial conclusions still remained. Thus, the association between UGT1A1*6 polymorphisms and IRI-induced severe toxicity in cancer patients is still needed to be explored. Therefore, this study aims to investigate the association between UGT1A1*6 polymorphisms and IRI-related severe neutropenia in cancer patients on a large scale. A total of 12 studies that included 746 wild genotype (G/G) cases and 394 variant genotype (G/A and A/A) cases were included on the basis of inclusion criteria. Then we assessed the methodologies quality; odds ratio (OR), risk difference (RD) and 95% confidence intervals (95% CI) were used to assess the strength of association. Overall, an increased risk of severe neutropenia in cancer patients with UGT1A1*6 polymorphisms was found. Patients with recessive models (GA + AA vs. GG) of UGT1A1*6 showed an increased risk (OR 2.03, 95% CI 1.54-2.68; RD = 0.11, P < 0.001). Specifically, the heterozygous variant of UGT1A1*6 showed an increased risk (OR 1.83, 95% CI 1.36-2.46; RD = 0.09, P < 0.001), and homozygous mutation showed also high risk (OR 2.95, 95% CI 1.83-4.75; RD = 0.18, P < 0.001) for severe neutropenia. Subgroup meta-analysis revealed that for patients harboring both heterozygous and homozygous variants, cancer types, low dose of IRI and the duration of treatment also presented comparably increased risk in suffering severe neutropenia. As for country, in China and Japan, there was a statistically increased severe neutropenia with variant genotype of UGT1A1*6 (China: GA + AA vs. GG, OR 1.83, 95% CI 1.28-2.59; RD = 0.08, P = 0.001; Japan: GA + AA vs. GG, OR 2.39, 95% CI 1.45-3.92; RD = 0.15, P = 0.001). In conclusion, in this meta-analysis, the UGT1A1*6 polymorphisms were associated with an increased risk of IRI-induced neutropenia in cancer patients, and increased incidences of severe neutropenia could be correlated with diverse regions, cancer type, low dose of IRI and the duration of treatment.

UGT1A1 polymorphisms in cancer: impact on irinotecan treatment

Mutations in the UGT1A1 gene have been implicated in Gilbert syndrome, which shows mild hyperbilirubinemia, and a more aggressive childhood subtype, Crigler–Najjar syndrome. To date, more than 100 variants have been found in the UGT1A1 gene. Among them, UGT1A1*28 and UGT1A1*6 have been reported to be associated with severe toxicities in patients treated with irinotecan-based chemotherapy by increasing the dose of SN-38 (7-ethyl-10-hydroxycamptothecin), an active form of irinotecan. Many association studies and meta-analyses have demonstrated the contribution of UGT1A1*28 and UGT1A1*6 polymorphisms to the toxicities caused by irinotecan-based therapy. The aim of this review was to evaluate the impact of these variants upon the toxicities and the efficacy of irinotecan-based chemotherapy.

Predictive Value of UGT1A1*28 Polymorphism In Irinotecan-based Chemotherapy

The UGT1A1*28 polymorphism was suggested to be significantly connected with irinotecan-induced toxicity and response to chemotherapy. However, the results of previous studies are controversial. Hence we carried out a meta-analysis to investigate the effect of UGT1A1*28 polymorphism on severe diarrhea, neutropenia, and response of patients who had undergone irinotecan-based chemotherapy. The PubMed, Web of Science, Wanfang, and CNKI databases were searched for clinical trials assessing the association of UGT1A1*28 polymorphism with severe diarrhea, neutropenia, and response to irinotecan-based chemotherapy. The combined odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate the relationship under a fixed- or random-effects model. Fifty-eight studies including 6087 patients with cancer were included. Our results showed that patients carrying the TA6/7 and TA7/7 genotypes had a greater prevalence of diarrhea and neutropenia than those with the TA6/6 genotype (TA6/7+TA7/7 vs. TA6/6: diarrhea, OR = 2.18, 95%CI = 1.68-2.83; neutropenia, OR = 2.15, 95%CI = 1.71-2.70), particularly patients with metastatic colorectal cancer. Stratified analysis showed that Asians with the TA6/7 and TA7/7 genotypes were more likely to have diarrhea and neutropenia, and Caucasians with the TA6/7 and TA7/7 genotypes were more likely to have neutropenia than other groups. However, patients with the TA6/7+TA7/7 genotypes showed a higher response than patients with TA6/6 genotype (OR = 1.20, 95%CI = 1.07-1.34), particularly Caucasians (OR = 1.23, 95%CI = 1.06-1.42) and patients with metastatic colorectal cancer (OR = 1.24, 95%CI = 1.05-1.48). Our data showed that the UGT1A1*28 polymorphism had a significant relationship with toxicity and response to irinotecan-based chemotherapy. This polymorphism may be useful as a monitoring index for cancer patients receiving irinotecan-based chemotherapy.

Clinical significance of UGT1A1 polymorphism and expression of ERCC1, BRCA1, TYMS, RRM1, TUBB3, STMN1 and TOP2A in gastric cancer

BACKGROUND

Individualized therapeutic regimen is a recently intensively pursued approach for targeting diseases, in which the search for biomarkers was considered the first and most important. Thus, the goal of this study was to investigate whether the UGT1A1, ERCC1, BRCA1, TYMS, RRM1, TUBB3, STMN1 and TOP2A genes are underlying biomarkers for gastric cancer, which, to our knowledge, has not been performed.

METHODS

Ninety-eight tissue specimens were collected from gastric cancer patients between May 2012 and March 2015. A multiplex branched DNA liquidchip technology was used for measuring the mRNA expressions of ERCC1, BRCA1, TYMS, RRM1, TUBB3, STMN1 and TOP2A. Direct sequencing was performed for determination of UGT1A1 polymorphisms. Furthermore, correlations between gene expressions, polymorphisms and clinicopathological characteristics were investigated.

RESULTS

The expressions of TYMS, TUBB3 and STMN1 were significantly associated with the clinicopathological characteristics of age, gender and family history of gastric cancer, but not with differentiation, growth patterns, metastasis and TNM staging in patients with gastric cancer. No clinical characteristics were correlated with the expressions of ERCC1, BRCA1, RRM1 and TOP2A. Additionally, patients carrying G allele at -211 of UGT1A1 were predisposed to developing tubular adenocarcinoma, while individuals carrying 6TAA or G allele respectively at *28 or -3156 of UGT1A1 tended to have a local invasion.

CONCLUSIONS

The UGT1A1 polymorphism may be useful to screen the risk population of gastric cancer, while TYMS, TUBB3 and STMN1 may be potential biomarkers for prognosis and chemotherapy guidance.

Phenotyping of UGT1A1 Activity Using Raltegravir Predicts Pharmacokinetics and Toxicity of Irinotecan in FOLFIRI

Background

Irinotecan toxicity correlates with UGT1A1 activity. We explored whether phenotyping UGT1A1 using a probe approach works better than current genotyping methods.

Methods

Twenty-four Asian cancer patients received irinotecan as part of the FOLFIRI regimen. Subjects took raltegravir 400 mg orally and intravenous midazolam 1 mg. Pharmacokinetic analyses were performed using WinNonLin and NONMEM. Genomic DNA was isolated and screened for the known genetic variants in UGT1A1 and CYP3A4/5.

Results

SN-38G/SN-38 AUC ratio correlated well with Raltegravir glucuronide/ Raltegravir AUC ratio (r = 0.784 p<0.01). Midazolam clearance correlated well with irinotecan clearance (r = 0.563 p<0.01). SN-38 AUC correlated well with Log10Nadir Absolute Neutrophil Count (ANC) (r = -0.397 p<0.05). Significant correlation was found between nadir ANC and formation rate constant of raltegravir glucuronide (r = 0.598, P<0.005), but not UGT1A1 genotype.

Conclusion

Raltegravir glucuronide formation is a good predictor of nadir ANC, and can predict neutropenia in East Asian patients. Prospective studies with dose adjustments should be done to develop raltegravir as a probe to optimize irinotecan therapy.

Trial Registration

Clinicaltrials.gov NCT00808184

Relationship between UGT1A1*6/*28 polymorphisms and severe toxicities in Chinese patients with pancreatic or biliary tract cancer treated with irinotecan-containing regimens

PURPOSE

The aim of this retrospective study was to investigate the relationship between UGT1A1 polymorphisms and toxicities in Chinese patients with pancreatic or biliary tract cancer receiving irinotecan-containing regimens as the second- or third-line chemotherapy.

PATIENTS AND METHODS

A total of 36 patients with unresectable pancreatic cancer and 12 patients with unresectable biliary tract cancer were included. Approximately 33 patients were treated with FOLFIRI regimen, a chemotherapy regimen, where FOL stands for folinic acid, F for fluorouracil, and IRI for irinotecan (irinotecan 180 mg/m(2) at day 1, CF 200 mg/m(2) at day 1-2, 5-FU 400 mg/m(2) at day 1-2, followed by continuous infusion of 5-FU 600 mg/m(2) for 22 hours at day 1-2, every 2 weeks). The other 15 patients were treated with irinotecan monotherapy (180 mg/m(2), every 2 weeks). UGT1A1*6/*28 polymorphisms were detected by direct sequencing.

RESULTS

The frequencies of GG, GA, AA genotypes for UGT1A1*6 were 70.8% (n=34), 25.0% (n=12), and 4.2% (n=2), respectively. And those of TA6/TA6, TA6/TA7, TA7/TA7 for UGT1A1*28 were 79.2% (n=38), 18.8% (n=9), and 2.0% (n=1), respectively. A total of 22 patients (45.8%) had grade III-IV neutropenia, and six patients (12.5%) experienced grade III-IV diarrhea. The incidence of grade III-IV neutropenia in patients with UGT1A1*6 GA or AA genotype was 71.4%, which was significantly higher than that with GG genotype (35.3%, P=0.022). No relationship was found between grade III-IV neutropenia and UGT1A1*28 polymorphism. The statistical analysis between grade III-IV diarrhea and UGT1A1*6/*28 polymorphisms was not conducted in view of the limited number of patients.

CONCLUSION

In Chinese patients with pancreatic or biliary tract cancer administered irinotecan-containing regimens, those with UGT1A1*6 variant may have a high risk of severe neutropenia.

Associations between UGT1A1*6 or UGT1A1*6/*28 polymorphisms and irinotecan-induced neutropenia in Asian cancer patients

PURPOSE

Neutropenia is a life-threatening side effect of irinotecan, and uridine diphosphate glucuronosyltransferases (UGTs) gene polymorphisms are considered to be one of the predictive markers of irinotecan-related toxicities. Many studies have demonstrated that patients bearing UGT1A1*28 have a higher risk of severe neutropenia on toxicity of irinotecan. However, UGT1A1 (TA7/TA7) was very rare in Asian populations. Some researches reported that UGT1A1*28 and/or UGT1A1*6 could predict irinotecan-induced toxicities in Asian populations, but controversial conclusions still remained. This study aims to investigate the association between UGT1A1 gene polymorphisms *6, *6/*28 and irinotecan-related neutropenia in Asian cancer patients receiving irinotecan regimen chemotherapy.

EXPERIMENTAL DESIGN

Meta-analyses were done to assess the relationship between UGT1A1*6 or UGT1A1*6/*28 and irinotecan-induced neutropenia.

RESULTS

The risk of neutropenia was significantly higher among patients with a UGT1A1*6 genotype than among those carrying the UGT1A1*1 allele(s) [odds ratio (OR) 3.276; 95 % confidence interval (CI) 1.887-5.688; P = 0.000 (*6/*6 vs. *1/*6 or *1/*1)], [OR 1.542; 95 % CI 1.180-2.041; P = 0.001 (*6/*6 or *1/*6 vs. *1/*1)]. Also, the risk was significantly higher among patients with a UGT1A1*6/*28 than among those carrying the UGT1A1*1 allele(s) [OR 3.275; 95 % CI 2.152-4.983; P = 0.000 (*6/*6 or *28/*28 or *6/*28 vs. *1/*6 or *1/*28 or *1/*1)].

CONCLUSIONS

In conclusion, the UGT1A1*6 and UGT1A1*6/*28 genotypes were associated with an increased risk of irinotecan-induced neutropenia in Asian cancer patients.

UGT1A1*6 polymorphisms are correlated with irinotecan-induced toxicity: a system review and meta-analysis in Asians

PURPOSE

Previous studies confirmed that genotyping uridine diphosphate glucuronosyltransferase (UGT) 1A1*28 polymorphisms could predict the side effects in cancer patients using irinotecan (IRI) and then reduce IRI-induced toxicity by preventative treatment or decrease in dose. However, the association between UGT1A1*6 polymorphisms and IRI-induced severe toxicity in Asian patients is still unclear. The aim of this study was to evaluate the association between UGT1A1*6 polymorphisms and IRI-induced severe neutropenia as well as diarrhea in Asian patients.

METHODS

We searched all papers on PubMed and Embase from February 1998 to August 2013. Then we assessed the methodologies quality, extracted data and made statistics analysis using STATA software. To uncover the sources of heterogeneity, subgroup meta-analysis was conducted according to the dosage of IRI.

RESULTS

Eleven papers were included according to the inclusion and exclusion criteria after searching Pubmed and Embase. Overall, an increased risk of severe toxicity in Asian patients with UGT1A1*6 polymorphisms was found. Patients with heterozygous variant of UGT1A1*6 showed an increased risk [odds ratio (OR) = 1.98, 95 % confidence intervals (CI) 1.45-2.71, P < 0.001], and homozygous mutation showed an even higher risk (OR = 4.44, 95 % CI 2.42-8.14, P < 0.001) for severe neutropenia. For severe diarrhea, heterozygous variant of UGT1A1*6 showed no significant risk, while the homozygous variant performed a notable risk (OR = 3.51, 95 % CI 1.41-8.73, P = 0.007). Subgroup meta-analysis indicated that for patients harboring either heterozygous or homozygous variant, low dose of IRI also presented comparably increased risk in suffering severe neutropenia.

CONCLUSION

In this meta-analysis, UGT1A1*6 polymorphisms were revealed as potential biomarkers, predicting IRI-induced severe toxicity in patients from Asia, and increased incidences of severe neutropenia could occur in both high/medium and low doses of IRI.