UGT1A1 predicts outcome in colorectal cancer treated with irinotecan and fluorouracil

Pharmacogenetics of Anticancer Drugs: Clinical Response and Toxicity

Cancer is the most challenging disease for medical professionals to treat. The factors underlying the complicated situation include anticancer drug-associated toxicity, non-specific response, low therapeutic window, variable treatment outcomes, development of drug resistance, treatment complications, and cancer recurrence. The remarkable advancement in biomedical sciences and genetics, over the past few decades, however, is changing the dire situation. The discovery of gene polymorphism, gene expression, biomarkers, particular molecular targets and pathways, and drug-metabolizing enzymes have paved the way for the development and provision of targeted and individualized anticancer treatment. Pharmacogenetics is the study of genetic factors having the potential to affect clinical responses and pharmacokinetic and pharmacodynamic behaviors of drugs. This chapter emphasizes pharmacogenetics of anticancer drugs and its applications in improving treatment outcomes, selectivity, toxicity of the drugs, and discovering and developing personalized anticancer drugs and genetic methods for prediction of drug response and toxicity.

Predicting drug response and toxicity in metastatic colorectal cancer: the role of germline markers

INTRODUCTION

Despite the introduction of targeted agents leading to therapeutic advances, clinical management of patients with metastatic colorectal cancer (mCRC) is still challenged by significant interindividual variability in treatment outcomes, both in terms of toxicity and therapy efficacy. The study of germline genetic variants could help to personalize and optimize therapeutic approaches in mCRC.

AREAS COVERED

A systematic review of pharmacogenetic studies in mCRC patients published on PubMed between 2011 and 2021, evaluating the role of germline variants as predictive markers of toxicity and efficacy of drugs currently approved for treatment of mCRC, was perfomed.

EXPERT OPINION

Despite the large amount of pharmacogenetic data published to date, only a few genetic markers (i.e., DPYD and UGT1A1 variants) reached the clinical practice, mainly to prevent the toxic effects of chemotherapy. The large heterogeneity of available studies represents the major limitation in comparing results and identifying potential markers for clinical use, the role of which remains exploratory in most cases. However, the available published findings are an important starting point for future investigations. They highlighted new promising pharmacogenetic markers within the network of inflammatory and immune response signaling. In addition, the emerging role of previously overlooked rare variants has been pointed out.

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.

Rapid detection of the irinotecan-related UGT1A1*28 polymorphism by asymmetric PCR melting curve analysis using one fluorescent probe

BACKGROUND

Determination of UGT1A1 (TA)_n polymorphism prior to irinotecan therapy is necessary to avoid severe adverse drug effects. Thus, accurate and reliable genotyping methods for (TA)_n polymorphism are highly desired. Here, we present a new method for polymerase chain reaction (PCR) melting curve analysis using one fluorescent probe to discriminate the UGT1A1*1 [(TA)₆ ] and *28 [(TA)₇ ] genotypes.

METHODS

After protocol optimization, this technique was applied for genotyping of 64 patients (including 23 with UGT1A1*1/*1, 22 with *1/*28, and 19 with *28/*28) recruited between 2016 and 2021 in China-Japan Friendship Hospital. The accuracy of the method was evaluated by comparing the results with those of direct sequencing and fragment analysis. The intra- and inter-run precision of the melting temperatures (T_m s) were calculated to assess the reliability, and the limit of detection was examined to assess the sensitivity.

RESULTS

All genotypes were correctly identified with the new method, and its accuracy was higher than that of fragment analysis. The intra- and inter-run coefficients of variation for the T_m s were both ≤0.27%, with standard deviations ≤0.14°C. The limit of detection was 0.2 ng of input genomic DNA.

CONCLUSION

The developed PCR melting curve analysis using one fluorescent probe can provide accurate, reliable, rapid, simple, and low-cost detection of UGT1A1 (TA)_n polymorphism, and its use can be easily generalized in clinical laboratories with a fluorescent PCR platform.

Drug-Drug Interactions and Disease Status Are Associated with Irinotecan-induced Hepatotoxicity: A Cross-Sectional Study in Shanghai

Irinotecan-induced hepatotoxicity can cause severe clinical complications in patients; however, the underlying mechanism and factors affecting hepatotoxicity have rarely been investigated. In this cross-sectional study, we screened all clinical, demographic, medication and genetic variables among 126 patients receiving irinotecan and explored potential associations with the incidence and time to onset of irinotecan-induced hepatotoxicity. Approximately 38.9% of the patients suffered from hepatotoxicity after irinotecan administration. The presence of cardiovascular diseases (CVDs) increases the incidence of hepatotoxicity approximately 2.9-fold and doubles the hazard of time to hepatotoxicity. Patients with liver metastasis had a more than 4-fold higher risk of hepatotoxicity and a 3.5-fold increased hazard of time to hepatotoxicity compared to those without liver metastasis. Patients who took CYP3A inducers had a 4.4-fold increased incidence of hepatotoxicity, and furthermore, concomitant use of platinum-based antineoplastics revealed 4.2 times the hazard of time to hepatotoxicity compared to those receiving antimetabolites. The cumulative dose of irinotecan (5-9 cycles) increased hepatotoxicity by 8.5 times. However, the genotypes and phenotypes of UGT1A1*28/*6 failed to be predictive factors of hepatotoxicity. The findings of this study suggest that irinotecan-induced hepatotoxicity is not directly associated with genetic variables but is mostly related to concomitant use of CYP3A inducers and platinum, as well as the presence of liver metastasis and CVD. Thus, close monitoring of liver function is recommended, especially in patients with liver impairment or using CYP3A inducers and platinum antineoplastic drugs, which may be the best way to prevent hepatotoxicity. This article is protected by copyright. All rights reserved.

Prediction of Drug-Drug Interaction Between Dabrafenib and Irinotecan via UGT1A1-Mediated Glucuronidation

BACKGROUND

Dabrafenib and irinotecan are two drugs that can be utilized to treat melanoma. A previous in vivo study has shown that dabrafenib enhances the antitumor activity of irinotecan in a xenograft model with unclear mechanism.

OBJECTIVES

This study aims to investigate the inhibition of dabrafenib on SN-38 (the active metabolite of irinotecan) glucuronidation, trying to elucidate the possible mechanism underlying the synergistic effect and to provide a basis for further development and optimization of this combination in clinical research.

METHODS

Recombinant human uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) and human liver microsomes (HLMs) were employed to catalyze the glucuronidation of SN-38 in vitro. Inhibition kinetic analysis and quantitative prediction study were combined to predict drug-drug interaction (DDI) potential in vivo.

RESULTS

Dabrafenib noncompetitively inhibited SN-38 glucuronidation in pooled HLMs and recombinant UGT1A1 with unbound inhibitor constant (K_i,u) values of 12.43 ± 0.28 and 3.89 ± 0.40 μM, respectively. Based on the in vitro K_i,u value and estimation of kinetic parameters, dabrafenib administered at 150 mg twice daily may result in about a 1-2% increase in the area under the curve (AUC) of SN-38 in vivo. However, the ratios of intra-enterocyte concentration of dabrafenib to K_i,u ([I]_gut/K_i,u) are 2.73 and 8.72 in HLMs and recombinant UGT1A1, respectively, indicating a high risk of intestinal DDI when dabrafenib was used in combination with irinotecan.

CONCLUSION

Dabrafenib is a potent noncompetitive inhibitor of UGT1A1 and may bring potential risk of DDI when combined with irinotecan.

Pharmacogenetics of Drugs Used in the Treatment of Cancers

Pharmacogenomics is based on the understanding of the individual differences in drug use, the response to drug therapy (efficacy and toxicity), and the mechanisms underlying variable drug responses. The identification of DNA variants which markedly contribute to inter-individual variations in drug responses would improve the efficacy of treatments and decrease the rate of the adverse side effects of drugs. This review focuses only on the impact of polymorphisms within drug-metabolizing enzymes on drug responses. Anticancer drugs usually have a very narrow therapeutic index; therefore, it is very important to use appropriate doses in order to achieve the maximum benefits without putting the patient at risk of life-threatening toxicities. However, the adjustment of the appropriate dose is not so easy, due to the inheritance of specific polymorphisms in the genes encoding the target proteins and drug-metabolizing enzymes. This review presents just a few examples of such polymorphisms and their impact on the response to therapy.

Impact of UGT1A1 genotype on the efficacy and safety of irinotecan-based chemotherapy in metastatic colorectal cancer

The phase III AXEPT study showed the noninferiority of modified capecitabine plus irinotecan (mXELIRI) with or without bevacizumab relative to fluorouracil, leucovorin, and irinotecan (FOLFIRI) with or without bevacizumab as a second‐line treatment for metastatic colorectal cancer. We evaluated the associations between the UGT1A1 genotype linked to adverse events—caused by irinotecan—and the efficacy and safety of mXELIRI and FOLFIRI. The UGT1A1 genotype was prospectively determined and patients were categorized into three groups according to WT (*1/*1), single heterozygous (SH; *28/*1 or *6/*1), and double heterozygous or homozygous (DHH; *28/*28, *6/*6, or *28/*6). Overall survival (OS), progression‐free survival, response rate, and safety were assessed. The UGT1A1 genotype was available in all 650 randomized patients (WT, 309 [47.5%]; SH, 291 [44.8%]; DHH, 50 [7.7%]). The median OS was 15.9, 17.7, and 10.6 months in the WT, SH, and DHH groups, respectively, with an adjusted hazard ratio (HR) of 1.53 (95% confidence interval [CI], 1.12‐2.09; P = .008) for DHH vs WT or SH. The median OS in the mXELIRI and FOLFIRI arms was 18.1 vs 14.3 months (HR 0.80; 95% CI, 0.62‐1.03) in the WT group, 16.3 vs 18.3 months (HR 1.04; 95% CI, 0.79‐1.36) in the SH group, and 13.0 vs 9.1 months (HR 0.71; 95% CI, 0.39‐1.31) in the DHH group, respectively. Modified capecitabine plus irinotecan with or without bevacizumab could be a standard second‐line chemotherapy in terms of efficacy and safety regardless of the UGT1A1 genotype.

UGT1A1 polymorphism has a prognostic effect in patients with stage IB or II uterine cervical cancer and one or no metastatic pelvic nodes receiving irinotecan chemotherapy: a retrospective study

Background

Uridine diphosphate glucuronosyltransferase 1 family polypeptide A1 (UGT1A1) is a predictive biomarker for the side-effects of irinotecan chemotherapy, which reduces the volume of tumors harboring UGT1A1 polymorphisms. We aimed to determine whether UGT1A1 polymorphisms can predict progression-free survival in patients with local cervical cancer treated with irinotecan chemotherapy.

Methods

We retrospectively analyzed the data of 51 patients with cervical cancer treated at a single institution between 2010 and 2015. All patients were diagnosed with 2009 International Federation of Gynecology and Obstetrics (FIGO) stage IB1, IB2, IIA, or IIB squamous cell carcinoma, underwent radical hysterectomy, and received irinotecan chemotherapy as neoadjuvant and/or adjuvant treatment. All patients were examined for irinotecan side effects using UGT1A1 tests. Conditional inference tree and survival analyses were performed considering the FIGO stage, age, the UGT1A1 status, and the number of metastatic lymph nodes to determine primary factors associated with progression-free survival.

Results

The tree-structured survival model determined high recurrence-risk factors related to progression-free survival. The most relevant factor was ≥2 metastatic lymph nodes (p = 0.004). The second most relevant factor was UGT1A1 genotype (p = 0.024). Among patients with ≤1 metastatic lymph node, those with UGT1A1 polymorphisms benefited from irinotecan chemotherapy and demonstrated significantly longer progression-free survival (p = 0.020) than those with wild-type UGT1A1.

Conclusions

Irinotecan chemotherapy might be beneficial in patients with cervical cancer, UGT1A1 polymorphisms, and ≤ 1 metastatic lymph nodes.

Pharmacogenetic impact of UGT1A1 polymorphisms on pulmonary neuroendocrine tumours treated with metronomic irinotecan-based chemotherapy in Chinese populations

OBJECTIVES

To evaluate the effects of UGT1A1*6 and UGT1A1*28 polymorphisms on the safety and efficacy of metronomic irinotecan-based chemotherapy (IBC) in Chinese patients with pulmonary neuroendocrine tumours (PNTs).

METHODS

Sixty-eight PNT patients who received metronomic IBC were observed. The quantitative fluorescent polymerase chain reaction was used to detect UGT1A1*6 and UGT1A1*28 polymorphisms. The follow-up data were collected to investigate the relationship between different genotypes and adverse drug reactions. The clinical outcomes of metronomic IBC were also evaluated.

KEY FINDINGS

In the genotype-toxicity association analysis, patients with homozygous UGT1A1*6 had the highest incidence of grade 3-4 diarrhoea (P = 0.010). Compared to other groups, patients with the haplotype of UGT1A1*28 showed a trend towards an increased incidence of grade 4 neutropaenia (P = 0.047). A higher incidence of grade 3-4 leucopaenia was found in groups with UGT1A1*1/*28 (P = 0.023) and UGT1A1*28/*28 (P = 0.022). Grade 1 total bilirubin elevation was associated with the homozygous UGT1A1*6 mutation (P = 0.027) or any UGT1A1*6 variants (P = 0.047). However, neither UGTA1A*28 nor UGT1A1*6 showed any significant association with tumour response or clinical outcomes.

CONCLUSIONS

The impact of UGT1A1 polymorphisms varies in different irinotecan-based chemotherapies. UGT1A1*6 and UGTA1A*28 were useful for the prediction of irinotecan-related severe toxicity in Chinese PNT patients treated with metronomic IBC.

Long non-coding RNA polymorphisms and prediction of response to chemotherapy based on irinotecan in patients with metastatic colorectal cancer

BACKGROUND

Colorectal cancer is the fourth cause of cancer related death. Drug resistance and toxicity remain major clinical issues. HOTAIR and MALAT1 are long non-coding RNAS that affect cellular proliferation, apoptosis and drug resistance; their up-regulation has been linked with a poor prognosis.

OBJECTIVE

Investigation of the association between rs4759314 HOTAIR and rs3200401 MALAT1 polymorphisms and irinotecan-based chemotherapy in terms of drug efficacy and toxicity.

METHODS

Samples from 98 patients receiving different regimens of irinotecan-based therapy were included. Efficacy and toxicity were evaluated. KRAS mutation, rs3200401 HOTAIR and rs4759314 MALAT1 polymorphisms genotyping in the tumors and peripheral blood respectively were performed with PCR.

RESULTS

Neither rs3200401 MALAT1 nor rs4759314 HOTAIR polymorphism are associated with response to treatment regimens. Rs4759314 was also not associated with increased toxicity in patients receiving irinotecan-based regimens. CT genotype of rs3200401 was associated with significantly reduced overall survival. An association between KRAS mutation and AG/GG genotypes in the rs4759314 was detected.

CONCLUSIONS

CT genotype of rs3200401 MALAT1 polymorphism could serve as a toxicity biomarker. Carriers of the G allele of the rs4759314 HOTAIR are more likely to be carriers of KRAS mutations too. However, further studies in larger patient populations are required.

Individualization of Irinotecan Treatment: A Review of Pharmacokinetics, Pharmacodynamics, and Pharmacogenetics

Since its clinical introduction in 1998, the topoisomerase I inhibitor irinotecan has been widely used in the treatment of solid tumors, including colorectal, pancreatic, and lung cancer. Irinotecan therapy is characterized by several dose-limiting toxicities and large interindividual pharmacokinetic variability. Irinotecan has a highly complex metabolism, including hydrolyzation by carboxylesterases to its active metabolite SN-38, which is 100- to 1000-fold more active compared with irinotecan itself. Several phase I and II enzymes, including cytochrome P450 (CYP) 3A4 and uridine diphosphate glucuronosyltransferase (UGT) 1A, are involved in the formation of inactive metabolites, making its metabolism prone to environmental and genetic influences. Genetic variants in the DNA of these enzymes and transporters could predict a part of the drug-related toxicity and efficacy of treatment, which has been shown in retrospective and prospective trials and meta-analyses. Patient characteristics, lifestyle and comedication also influence irinotecan pharmacokinetics. Other factors, including dietary restriction, are currently being studied. Meanwhile, a more tailored approach to prevent excessive toxicity and optimize efficacy is warranted. This review provides an updated overview on today’s literature on irinotecan pharmacokinetics, pharmacodynamics, and pharmacogenetics.

CA19-9 Concentration After First-line Chemotherapy Is Prognostic Predictor of Metastatic Colon Cancer

BACKGROUND/AIM

To evaluate whether the serum levels of CEA or CA19-9 concentration is a useful predictor of survival in patients with metastatic colon cancer (mCC).

PATIENTS AND METHODS

Between 2012 and 2015, 113 patients with mCC who underwent chemotherapy according to the Japanese Colorectal Cancer Treatment Guidelines at four Jikei University Hospitals were enrolled in this study. The two serum tumor makers, CEA and CA19-9 were measured before first-line chemotherapy and at four months thereafter.

RESULTS

Serum CA19-9 concentration at four months after first-line chemotherapy (p=0.003, HR=3.761) and first-line chemotherapy including oxaliplatin (p=0.038, HR=0.312) were independent predictors of survival in patients with mCC. By excluding the transverse colon, only serum CA19-9 concentration at four months after first-line chemotherapy (p=0.005, HR=3.660) was identified as the predictor of survival.

CONCLUSION

Serum CA19-9 concentration after first-line chemotherapy seems to be a useful predictor of survival in patients with mCC.

Pharmacokinetic and Pharmacogenetic Factors Contributing to Platelet Function Recovery After Single Dose of Ticagrelor in Healthy Subjects

Objectives: This study aimed to elucidate the contribution of candidate single nucleotide polymorphisms (SNPs) related to pharmacokinetics on the recovery of platelet function after single dose of ticagrelor was orally administered to healthy Chinese subjects.

Methods: The pharmacokinetic profiles of ticagrelor and its metabolite AR-C124910XX (M8), and the platelet aggregation (PA), were assessed after 180 mg of single-dose ticagrelor was orally administered to 51 healthy Chinese subjects. Effects of CYP2C19^*2, CYP2C19^*3, CYP3A5^*3, UGT1A1^*6, UGT1A1^*28, UGT2B7^*2, UGT2B7^*3, SLCO1B1 388A>G, and SLCO1B1 521T>C, on the pharmacokinetics of ticagrelor and M8, and platelet function recovery were investigated.

Results: The time to recover 50% of the maximum drug effect (RT₅₀) ranging from 36 to 126 h with 46.9% CV had a remarkable individual difference and was positively associated with the half-life (t_1/2) of M8 (r = 0.3901, P = 0.0067). The time of peak concentration (T_max) of ticagrelor for CYP2C19^*3 GG homozygotes was significantly higher than that of GA heterozygotes (P = 0.0027, FDR = 0.0243). Decreased peak concentration (C_max) of M8 was significantly associated with SLCO1B1 388A>G A allele (P = 0.0152, FDR = 0.1368). CYP2C19^*2 A was significantly related to decreased C_max of M8 (P = 0.0455, FDR = 0.2048). While, the influence of these nine SNPs on the recovery of platelet function was not significant.

Conclusion: Our study suggests that the elimination of M8 is an important factor in determining the recovery of platelet function. Although CYP2C19 and SLCO1B1 genetic variants were related to the pharmacokinetics of ticagrelor or M8, they did not show a significant effect on the platelet function recovery in this study.

Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT03092076, identifier: NCT03092076

Cost-effectiveness analysis of UGT1A1*6/*28 genotyping for preventing FOLFIRI-induced severe neutropenia in Chinese colorectal cancer patients

AIM

To assess the cost-effectiveness of UGT1A1*6/*28 genotyping compared with no genotyping or no dose adjustment before irinotecan administration in China.

MATERIALS & METHODS

A decision tree model was developed to evaluate costs and health outcomes represented as quality-adjusted life years gained. Model inputs for the frequency of genotypes, the probability of neutropenia under FOLFIRI chemotherapy and direct costs and utilities were obtained from published sources. One-way sensitivity analyses were performed.

RESULTS

The strategy of genotyping with dose reduction dominated all remaining strategies. Compared with the strategies of no genotyping and genotyping with unchanged dose, it resulted in only marginal quality-adjusted life year increases (0.0011 and 0.0012) but a cost reduction of $651.12 and $805.22 per patient, respectively. One-way sensitivity analyses revealed that the model was relatively robust.

CONCLUSION

UGT1A1*6/*28 genotyping was cost saving for Chinese colorectal cancer patients.

Role of Preemptive Genotyping in Preventing Serious Adverse Drug Events in South Korean Patients

INTRODUCTION

Preemptive and multi-variant genotyping is suggested to improve the safety of patient drug therapy. The number of South Koreans who would benefit from this approach is unknown.

OBJECTIVE

We aimed to quantify the number of patients who may experience serious adverse drug events (ADEs) due to high-risk pharmacogenetic variants and who may benefit from preemptive genotyping.

METHODS

The health claims dataset of the Korean Health Insurance Review and Assessment service for 3 % of the South Korean population for year 2011 was used to calculate the number of patients exposed to 84 drugs covered by National Health Insurance with pharmacogenomic biomarkers. The product of ADE risk-conferring genotype prevalence, ADE prevalence rates, and genotype effect sizes in South Koreans or East Asians derived from published literature and the 1000 Genomes Project, and the drug exposure data were solved to estimate the number of South Koreans in whom preemptive genotyping may prevent serious ADEs.

RESULTS

Among 1,341,077 patients in the dataset with prescriptions, 47.4 % were prescribed a drug whose response was affected by genetic variants and 31.9 % were prescribed at least one drug with serious ADEs modulated by these variants. Without genetic testing, the number of South Korean patients predicted to experience serious ADEs due to their higher ADE risk genotypes was estimated at 729. Extrapolating this to the total South Korean population indicated that approximately 24,300 patients in 2011 might have benefitted from preemptive genotyping.

CONCLUSIONS

This study quantified the number of South Korean patients predicted to have serious ADEs and demonstrated the need for preemptive genotyping to assist safer drug therapy in South Korea.

Distribution of uridine diphosphate glucuronosyltransferase 1A polymorphisms and their role in irinotecan-induced toxicity in patients with cancer

Uridine diphosphate glucuronosyltransferase 1A (UGT1A1), which affects irinotecan metabolism, has been associated with severe adverse reactions in patients with cancer treated with irinotecan. However, neither large-scale analysis of the distribution of UGT1A1 polymorphisms, nor standardized assessment of how UGT1A1 polymorphisms affect irinotecan treatment has been performed in China. The aim of the present study was to investigate the distribution of UGT1A1 polymorphisms (*28 and *6) in 2,093 Chinese patients with cancer who were treated with irinotecan from more than 15 hospitals in Shandong, to examine how the coexistence of UGT1A1*6 and UGT1A1*28 alleles may be able to predict toxicities induced by irinotecan in 105 of the patients, and to search for other relevant risk factors. The distribution of the genotypes was as follows: TA₆/TA₆ (1,601, 76.5%), TA₆/TA₇ (463, 22.1%) and TA₇/TA₇ (29, 1.4%) for UGT1A1*28 (n=2,093); and G/G (286, 66.4%), G/A (124, 28.8%) and A/A (21, 4.9%) for UGT1A1*6 (n=431). The most frequent severe hematological toxicity was neutropenia, and the predominant non-hematological toxicities were diarrhea and cholinergic syndrome. In toxicity comparisons, grade 3–4 leukopenia and neutropenia were significantly higher in TA₆/TA₇ compared with TA₆/TA₆ (P<0.05). The UGT1A1*6 polymorphism was associated with a higher risk of severe diarrhea and total adverse drug reactions (P<0.05). Logistic regression showed that the UGT1A1*6 genotype was an independent predictor of severe diarrhea. These findings suggested that the UGT1A1*28 and UGT1A1*6 genotypes may be associated with irinotecan-induced severe toxicity, and clarified the clinical importance of UGT1A1 polymorphisms, particularly UGT1A1*6, regarding irinotecan therapy in Chinese patients.

Integrating TYMS, KRAS and BRAF testing in patients with metastatic colorectal cancer

AIM

To investigate the impact of thymidylate synthase (TYMS), KRAS and BRAF in the survival of metastatic colorectal cancer (mCRC) patients treated with chemotherapy.

METHODS

Clinical data were collected retrospectively from records of consecutive patients with mCRC treated with fluoropyrimidine-based chemotherapy from 1/2005 to 1/2007. Formalin-fixed paraffin-embedded tissues were retrieved for analysis. TYMS genotypes were identified with restriction fragment analysis PCR, while KRAS and BRAF mutation status was evaluated using real-time PCR assays. TYMS gene polymorphisms of each of the 3’ untranslated region (UTR) and 5’UTR were classified into three groups according to the probability they have for high, medium and low TYMS expression (and similar levels of risk) based on evidence from previous studies. Univariate and multivariate survival analyses were performed.

RESULTS

The analysis recovered 89 patients with mCRC (46.1% de novo metastatic disease and 53.9% relapsed). Of these, 46 patients (51.7%) had colon cancer and 43 (48.3%) rectal cancer as primary. All patients were treated with fluoropyrimidine-based chemotherapy (5FU or capecitabine) as single-agent or in combination with irinotecan or/and oxaliplatin or/and bevacizumab. With a median follow-up time of 14.8 mo (range 0-119.8), 85 patients (95.5%) experienced disease progression, and 63 deaths (70.8%) were recorded. The 3-year and 5-year OS rate was 25.4% and 7.7% while the 3-year progression-free survival rate was 7.1%. Multivariate analysis of TYMS polymorphisms, KRAS and BRAF with clinicopathological parameters indicated that TYMS 3’UTR polymorphisms are associated with risk for disease progression and death (P < 0.05 and P < 0.03 respectively). When compared to tumors without any del allele (genotypes ins/ins and ins/loss of heterozygosity (LOH) linked with high TYMS expression) tumors with del/del genotype (low expression group) and tumors with ins/del or del/LOH (intermediate expression group) have lower risk for disease progression (HR = 0.432, 95%CI: 0.198-0.946, P < 0.04 and HR = 0.513, 95%CI: 0.287-0.919, P < 0.03 respectively) and death (HR = 0.366, 95%CI: 0.162-0.827, P < 0.02 and HR = 0.559, 95%CI: 0.309-1.113, P < 0.06 respectively). Additionally, KRAS mutation was associated independently with the risk of disease progression (HR = 1.600, 95%CI: 1.011-2.531, P < 0.05). The addition of irinotecan in 1^st line chemotherapy was associated independently with lower risk for disease progression and death (HR = 0.600, 95%CI: 0.372-0.969, P < 0.04 and HR = 0.352, 95%CI: 0.164-0.757, P < 0.01 respectively).

CONCLUSION

The TYMS genotypes ins/ins and ins/LOH associate with worst prognosis in mCRC patients under fluoropyrimidine-based chemotherapy. Large prospective studies are needed for validation of our findings.

Examination of multiple UGT1A and DPYD polymorphisms has limited ability to predict the toxicity and efficacy of metastatic colorectal cancer treated with irinotecan-based chemotherapy: a retrospective analysis

Background

To evaluate a new UGT1A and DPYD polymorphism panel to better predict irinotecan-induced toxicity and the clinical response in Chinese patients with metastatic colorectal cancer (mCRC).

Methods

The genotypes of UGT1A (UGT1A1*6, UGT1A1*27, UGT1A1*28, UGT1A7*2, UGT1A7*3, UGT1A7*4 and UGT1A9*22) and DPYD (DPYD*5, DPYD c.1896 T > C, and DPYD*2A) were examined by direct sequencing in 661 mCRC patients receiving irinotecan-based chemotherapy. The influences of UGT1A and DPYD polymorphisms on severe irinotecan-induced toxicities and clinical outcomes were assessed.

Results

In the cohort studied here, the incidence of UGT1A1*6, UGT1A1*28, UGT1A7*2, UGT1A7*3, UGT1A9*22, DPYD*5, and DPYD c.1896 T > C variants were 34.8%, 24.2%, 34.3%, 39.4%, 81.8%, 48.4% and 20.4%, respectively. UGT1A1*27 and DPYD*2A had low frequencies and UGT1A7*4 was not found. A total of 59 patients (8.9%) suffered severe diarrhea and 136 patients (20.6%) suffered severe neutropenia. UGT1A1*28 heterozygotes (OR = 2.263, 95%CI 1.395–3.670), UGT1A1*28 homozygotes (OR = 5.910, 95%CI 1.138–30.672) and UGT1A1*6 homozygotes (OR = 4.737, 95%CI 1.946–11.533) were independent risk factors for severe neutropenia. UGT1A polymorphisms were not found to relate to severe diarrhea. DPYD*5 was determined to be an independent risk factor for severe diarrhea (OR = 2.143, 95%CI 1.136–4.041). Neither DPYD*5 nor DPYD c.1896 T > C was found to relate to severe neutropenia. In the first-line irinotecan-based treatment, UGT1A1*28 and DPYD*5 contributed to higher response rates (P = 0.043 and P = 0.019, respectively), while DPYD*5 was found to associate with better progression-free survival (P = 0.015). UGT1A1*27 contributed to worse overall survival (P < 0.001).

Conclusion

Results still showed UGT1A1*6 and UGT1A1*28 to be partially associated with irinotecan-induced toxicity and clinical response. An examination of more UGT1A loci, except for UGT1A1*6 and UGT1A1*28, was not helpful to improve the predictive value of irinotecan-based toxicity and efficacy. An examination of DPYD*5 assisted in the prediction of severe diarrhea.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3406-2) contains supplementary material, which is available to authorized users.

Relationship between UGT1A1*6/*28 gene polymorphisms and the efficacy and toxicity of irinotecan-based chemotherapy

Purpose

A retrospective study was performed to analyze the relationship between uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) *6/*28 gene polymorphisms and adverse reactions associated with irinotecan (CPT-11)-based chemotherapy. The correlation between UGT1A1 polymorphisms and the clinical efficacy of CPT-11 was also analyzed, along with the influence of age and tumor type.

Patients and methods

Patients administered a CPT-11-based regimen in the Beijing Cancer Hospital from April 2015 to September 2016 were included in our study (n=81). Blood samples for detecting UGT1A1 were collected from each patient after various administration regimens.

Results

Colorectal cancer patients with the UGT1A1*6 mutant genotype had a significantly higher risk of severe delayed diarrhea than that of wild-type individuals when administered a CPT-11 dose ≥130 mg/m² (P=0.042); the same phenomenon was observed when the UGT1A1*6 and UGT1A1*28 mutant genotypes were considered together (P=0.028). However, in lung cancer patients administered a low dose of CPT-11, UGT1A1*6/*28 variants were not significantly associated with severe neutropenia or delayed diarrhea. Furthermore, adult patients with the UGT1A1*6 mutation were more likely to develop severe delayed diarrhea than did wild-type adults (P=0.013); however, the difference was not significant in elderly patients. No significant differences in tumor response were found among the different genotypes (P>0.05).

Conclusion

Thus, age and tumor type influence our ability to predict adverse reactions based on UGT1A1 gene polymorphisms in cancer patients. Further, UGT1A1 gene polymorphisms are not correlated with the efficacy of CPT-11-based regimens.

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.

Determination of irinotecan, SN-38 and SN-38 glucuronide using HPLC/MS/MS: Application in a clinical pharmacokinetic and personalized medicine in colorectal cancer patients

BACKGROUND

Irinotecan (CPT-11) is chemotherapy used mainly in the metastatic colorectal cancer. The purpose of this study was to develop and validate the LC-MS/MS for the simultaneous determination of CPT-11, SN-38, and SN-38G.

METHODS

A 100 μL of plasma was prepared after protein precipitation and analyzed on a C18 column using 0.1% acetic acid in water and 0.1% acetic acid in acetonitrile as mobile phases. The mass spectrometer worked with multiple reaction monitoring (MRM) in positive scan mode. The standard curves were linear on a concentration range of 5-10 000 ng/mL for CPT-11, 5-1000 ng/mL for SN-38, and 8-1000 ng/mL for SN-38G.

RESULTS

In this assay, the intra and interday precision consisted of ≤9.11% and ≤11.29% for CPT-11, ≤8.70% and 8.31% for SN-38, and ≤9.90 and 9.64% for SN-38G.

CONCLUSION

This method was successfully used to quantify CPT-11, SN-38, and SN-38G and applied to a pharmacokinetic study.

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.

Regorafenib Plus FOLFIRI With Irinotecan Dose Escalated According to Uridine Diphosphate Glucuronosyltransferase 1A1 Genotyping in Patients With Metastatic Colorectal Cancer

We analyzed the results of previously treated patients with metastatic colorectal cancer (mCRC) who received regorafenib plus FOLFIRI with the irinotecan dose escalation on the basis of uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) genotyping. Thirteen patients with previously treated mCRC were subjected to UGT1A1 genotyping between October 2013 and June 2015 and were administered regorafenib plus FOLFIRI with irinotecan dose escalation. Patients with UGT1A1*1/*1 and *1/*28 genotypes were administered 180 mg/m² of irinotecan, whereas those with the UGT1A1*28/*28 genotype were administered 120 mg/m² of irinotecan. For all patients, the irinotecan dose was increased by 30 mg/m² every two cycles until grade ≥3 adverse events or severe adverse events developed, following which the dose was reverted to and maintained at the previously tolerated level. The oral regorafenib dose was adjusted to 120 mg/day daily. The median follow-up period was 10.0 months (1.0–21.0 months). The disease control rate was 69.2%, whereas the median progression-free survival and overall survival were 9.5 and 13.0 months, respectively. Our findings indicate that regorafenib plus FOLFIRI with irinotecan dose escalation based on UGT1A1 genotyping in previously treated patients with mCRC and with UGT1A1*1/*1 and UGT1A1*1/*28 genotypes is clinically effective and yields improved oncological outcomes.

UGT1A1 gene polymorphism is associated with toxicity and clinical efficacy of irinotecan-based chemotherapy in patients with advanced colorectal cancer

OBJECTIVES

To investigate the relationship between uridine diphosphate glucoronosyltransferase 1A1 (UGT1A1)*28/*6 and toxicity and clinical efficacy of irinotecan-based chemotherapy in patients with advanced colorectal cancer (CRC) in Xinjiang Uygur and Han population.

METHODS

A total of 183 patients (Uygur, 114; Han, 69) with advanced CRC who received the irinotecan-based chemotherapy were enrolled in this retrospective analysis. Polymerase chain reaction amplification and direct sequencing method were used for UGT1A1*28 and UGT1A1*6 polymorphism detection. The patients were followed up to analyze the relationship between different genotypes with adverse reactions and the clinical outcome of irinotecan-based chemotherapy.

RESULTS

Significant differences were found in genotype frequencies of UGT1A1*28 and UGT1A1*28/*6 between Uygur and Han (P = 0.02 and P = 0.002). Uygur and Han patients carrying wild UGT1A1*28 and *6 genotypes appeared to have significantly lower diarrhea incidence (I/II and III/IV) than those carrying mutant genotypes (all P < 0.05). In Uygur patients, UGT1A1*28 genotypes were related with objective response rate and disease control rate (P < 0.05). Compared with *1 allele *1/*1, *1 allele *1/*28*1/*28 mutant of UGT1A1*28 was associated with shorter OS in both Uygur and Han ethnicities (all P < 0.05). Compared with double allele variants (DW), single allele variants (SV), and double allele variants (DV) of UGT1A1*28/*6 were associated with shorter overall survival (OS) in Uygur and Han (all P < 0.05). Cox regression analysis revealed factors significantly influencing OS, including UGT1A1*28, UGT1A1*6, combined genotypes and chemotherapy line in Ugyur, and only combined genotypes in Han (all P < 0.05).

CONCLUSION

UGT1A1 gene polymorphism predicts irinotecan-related adverse reactions in advanced CRC patients of Xinjiang Uygur and Han nationality; UGT1A1 gene polymorphism is correlated with efficacy and prognosis in Uygur nationality, but only related to prognosis in Han nationality in irinotecan-based chemotherapy.

Predictive effects of bilirubin on response of colorectal cancer to irinotecan-based chemotherapy

AIM: To examine the predictive effects of baseline serum bilirubin levels and UDP-glucuronosyltransferase (UGT) 1A1*28 polymorphism on response of colorectal cancer to irinotecan-based chemotherapy.

METHODS: The present study was based on a prospective multicenter longitudinal trial of Chinese metastatic colorectal cancer (mCRC) patients treated with irinotecan-based chemotherapy (NCT01282658). Baseline serum bilirubin levels, including total bilirubin (TBil) and unconjugated bilirubin (UBil), were measured, and genotyping of UGT1A1*28 polymorphism was performed. Receiver operating characteristic curve (ROC) analysis was used to determine cutoff values of TBil and UBil. The TBil values were categorized into > 13.0 or ≤ 13.0 groups; the UBil values were categorized into > 4.1 or ≤ 4.1 groups. Combining the cutoff values of TBil and UBil, which was recorded as CoBil, patients were classified into three groups. The classifier’s performance of UGT1A1*28 and CoBil for predicting treatment response was evaluated by ROC analysis. Associations between response and CoBil or UGT1A1*28 polymorphism were estimated using simple and multiple logistic regression models.

RESULTS: Among the 120 mCRC patients, the serum bilirubin level was significantly different between the UGT1A1*28 wild-type and mutant genotypes. Patients with the mutant genotype had an increased likelihood of a higher TBil (P = 0.018) and a higher UBil (P = 0.014) level compared with the wild-type genotype. Patients were stratified into three groups based on CoBil. Group 1 was patients with TBil > 13.0 and UBil > 4.1; Group 2 was patients with TBil ≤ 13.0 and UBil > 4.1; and Group 3 was patients with TBil ≤ 13.0 and UBil ≤ 4.1. Patients in Group 3 had more than a 10-fold higher likelihood of having a response in the simple (OR = 11.250; 95%CI: 2.286-55.367; P = 0.003) and multiple (OR = 16.001; 95%CI: 2.802 -91.371; P = 0.002) analyses compared with the Group 1 individuals. Patients carrying the UGT1A1*28 (TA)7 allele were 4-fold less likely to present with a response compared with the individuals harboring a homozygous (TA)6 genotype in the simple (OR = 0.267; 95%CI: 0.100-0.709; P = 0.008) and multiple (OR = 0.244; 95%CI: 0.088-0.678; P = 0.007) analyses. Classifier’s performance of CoBil and UGT1A1*28 were comparable.

CONCLUSION: CoBil and UGT1A1*28 are both independent biomarkers for predicting the treatment response of mCRC patients to irinotecan-based chemotherapy. After validation, CoBil, an easily determinable index in the clinic, might be helpful in facilitating stratification of mCRC patients for individualized treatment options.

Computational Identification of Key Regulators in Two Different Colorectal Cancer Cell Lines

Transcription factors (TFs) are gene regulatory proteins that are essential for an effective regulation of the transcriptional machinery. Today, it is known that their expression plays an important role in several types of cancer. Computational identification of key players in specific cancer cell lines is still an open challenge in cancer research. In this study, we present a systematic approach which combines colorectal cancer (CRC) cell lines, namely 1638N-T1 and CMT-93, and well-established computational methods in order to compare these cell lines on the level of transcriptional regulation as well as on a pathway level, i.e., the cancer cell-intrinsic pathway repertoire. For this purpose, we firstly applied the Trinity platform to detect signature genes, and then applied analyses of the geneXplain platform to these for detection of upstream transcriptional regulators and their regulatory networks. We created a CRC-specific position weight matrix (PWM) library based on the TRANSFAC database (release 2014.1) to minimize the rate of false predictions in the promoter analyses. Using our proposed workflow, we specifically focused on revealing the similarities and differences in transcriptional regulation between the two CRC cell lines, and report a number of well-known, cancer-associated TFs with significantly enriched binding sites in the promoter regions of the signature genes. We show that, although the signature genes of both cell lines show no overlap, they may still be regulated by common TFs in CRC. Based on our findings, we suggest that canonical Wnt signaling is activated in 1638N-T1, but inhibited in CMT-93 through cross-talks of Wnt signaling with the VDR signaling pathway and/or LXR-related pathways. Furthermore, our findings provide indication of several master regulators being present such as MLK3 and Mapk1 (ERK2) which might be important in cell proliferation, migration, and invasion of 1638N-T1 and CMT-93, respectively. Taken together, we provide new insights into the invasive potential of these cell lines, which can be used for development of effective cancer therapy.

Phase II and UGT1A1 Polymorphism Study of Two Different Irinotecan Dosages Combined with Cisplatin as First-Line Therapy for Advanced Gastric Cancer

BACKGROUND

We investigated the efficacy and safety of biweekly irinotecan and cisplatin (IP) as first-line treatment in advanced gastric cancer patients.

METHODS

Irinotecan 125 mg/m2 on day 1 and cisplatin 60 mg/m2 on day 2 were administrated every 14 days. UGT1A1*28/*6 and toxicities were analyzed.

RESULTS

Forty-one eligible patients were enrolled. Fifteen patients, who were defined as the high-dose group, received starting doses of irinotecan 125 mg/m2. Twenty-six patients, who were defined as the low-dose group, received starting doses of irinotecan 80 mg/m2 and cisplatin 50 mg/m2. The response rate was 53.3% in the irinotecan high-dose group and 53.8% in the irinotecan low-dose group. The most common grade 3/4 toxicity was neutropenia (68.3%). No significant difference in grade 3/4 neutropenia was found between patients with the wild-type genotype and those with variant genotypes for UGT1A1*28 or UGT1A1*6.

CONCLUSIONS

The combination of biweekly irinotecan 80 mg/m2 and cisplatin 50 mg/m2 was active and tolerable. The role of the UGT1A1 genotype in clinical toxicity of an IP regimen requires further investigation.

Clinical significance of UGT1A1 gene polymorphisms on irinotecan-based regimens as the treatment in metastatic colorectal cancer

Purpose

The primary aim of this research was to investigate the association between uridine diphosphate glucuronosyltransferase (UGT)1A1 gene polymorphisms and the toxicities of irinotecan-based regimens in Chinese patients with metastatic colorectal cancer.

Methods

The study analyzed the distribution of UGT1A1*28/*6 gene polymorphisms by polymerase chain reaction amplification and pyrosequencing. The adverse reactions and tumor response were evaluated according to National Cancer Institute Common Toxicity Criteria for Adverse Events, Version 3.0, and Response Evaluation Criteria In Solid Tumors, Version 1.0, criteria, respectively. The correlation between UGT1A1 gene polymorphisms and severe delayed diarrhea or neutropenia was analyzed. The influences of UGT1A1*6/*28 polymorphisms on response rate and progression-free survival were also analyzed. Survival analysis was performed by the Kaplan–Meier method, and we used the log-rank test to analyze the effect of genotypes on progression-free survival, the logistic regression model for multivariate analysis, and the Cox regression model for multivariate survival analysis.

Results

A total of 167 patients with metastatic colorectal cancer who were treated with irinotecan-based regimens and with detected UGT1A1 gene polymorphisms were enrolled in this research. The rate of UGT1A1*28 homozygous wild-type TA6/6, heterozygous mutant-type TA6/7, and homozygous mutant-type TA7/7 was 65.3% (109/167), 32.3% (54/167), and 2.4% (4/167), respectively; the incidence of UGT1A1*6 wild-type G/G was 67.1% (112/167), heterozygous mutant-type G/A accounted for 28.7% (48/167), and seven cases were homozygous mutant-type A/A (4.2%; 7/167). The incidence of grade 3 or 4 delayed diarrhea in patients carrying UGT1A1*6 (G/A and A/A) was higher than that in the wild-type (G/G) (P=0.021). The rate was significantly lower in patients with the UGT1A1*28 TA6/6 wide-type genotype than those with TA6/7 and TA7/7 mutant-type genotypes (P=0.027). However, neither UGT1A1*6 (P=0.34) nor UGT1A1*28 (P=0.232) variants were significantly associated with severe neutropenia. Our study found no significant differences of severe neutropenia in patients with different numbers of mutational alleles (P=0.354), but patients with two alleles or single allele variants had more chances to develop severe diarrhea than patients with wild-type (P=0.027). No significant differences of either response rate or progression-free survival were found among different genotypes (P>0.05).

Conclusion

For irinotecan-based regimens in metastatic colorectal cancer, the UGT1A1*28 and UGT1A1*6 locus mutations can be regarded as predictors for irinotecan-associated severe delayed diarrhea, whereas no association between UGT1A1 gene polymorphisms and severe neutropenia was observed. We also found that neither clinical response nor prognosis were significantly associated with UGT1A1 gene polymorphisms.

Gastric cancer pharmacogenetics: progress or old tripe?

Gastric cancer remains the second most frequent cause of cancer-related mortality. While surgery is traditionally the initial treatment for early-stage disease, the addition of chemotherapy has been shown to significantly increase overall survival and progression-free survival in advanced and metastatic stages of disease. However, despite the incorporation of newer chemotherapies and regimens into gastric cancer clinical trials, the response rate and median overall survival for treated patients has not significantly improved throughout the years; therefore, newer therapeutic approaches to improve upon the medication selection process are warranted. Treatment and dose selection based on patient factors, such as genetic variation, may provide a more rational and potentially more powerful means of personalizing chemotherapy. This review provides an update on the current status of pharmacogenetic studies regarding germline DNA mutations that may alter response to chemotherapeutic agents used to treat gastric cancer, including perspectives on clinical translation and future work.

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.

The association of UGT1A1*6 and UGT1A1*28 with irinotecan-induced neutropenia in Asians: a meta-analysis

BACKGROUND

The UGT1A1*28 polymorphism is known as a biomarker of irinotecan-induced neutropenia in Caucasians. However, in Asians, the UGT1A1*28 mutation is much less frequent.

METHODS

A meta-analysis was performed to assess the association of the UGT1A1*6 and UGT1A1*28 with neutropenia in Asians.

RESULTS

In a combination test of the two variations, patients with severe neutropenia displayed a 155% higher mutational load than those that were not neutropenic (ORG = 2.55; 95% CI: 1.82-3.58).

CONCLUSIONS

In Asians, a combination test of UGT1A1*6 and UGT1A1*28 might be a potential biomarker of irinotecan-induced neutropenia, an observation that will need additional trials for confirmation.

A rare case of primary choriocarcinoma in the sigmoid colon

Primary colorectal choriocarcinoma is an extremely rare neoplasm and is usually associated with a poor prognosis. Only 13 cases of colorectal choriocarcinoma have previously been reported. There is no standard chemotherapeutic regimen for this tumor type. A 68-year-old man presented with melena and was diagnosed with sigmoid colonic adenocarcinoma with multiple liver metastases. He underwent a laparoscopic sigmoidectomy. Pathology revealed choriocarcinoma with a focal component of moderately differentiated adenocarcinoma of colon origin. Based on the collagen gel droplet-embedded culture drug sensitivity test (CD-DST) results, mFOLFOX6 and bevacizumab were administered, which suppressed aggressive tumor growth for 4 mo. The patient died 9 mo after the initial diagnosis. Our study results suggest that the standard chemotherapy regimen for colorectal cancer might have suppressive effects against primary colorectal choriocarcinoma. Moreover, CD-DST may provide, at least in part, therapeutic insight for the selection of appropriate antitumor agents for such patients.

Absolute quantification of UGT1A1 in various tissues and cell lines using isotope label-free UPLC-MS/MS method determines its turnover number and correlates with its glucuronidation activities

Uridine 5'-diphosphate-glucuronosyltransferase (UGT)1A1 is a major phase II metabolism enzyme responsible for glucuronidation of drugs and endogenous compounds. The purpose of this study was to determine the expression level of UGT1A1 in human liver microsomes and human cell lines by using an isotope label-free LC-MS/MS method. A Waters Ultra performance liquid chromatography (UPLC) system coupled with an API 5500Qtrap mass spectrometer was used for the analysis. Two signature peptides (Pep-1, and Pep-2) were employed to quantify UGT1A1 by multiple reaction monitoring (MRM) approach. Standard addition method was used to validate the assay to account for the matrix effect. 17β-Estradiol was used as the marker substrate to determine UGT1A1 activities. The validated method has a linear range of 200-0.0195nM for both signature peptides. The precision, accuracy, and matrix effect were in acceptable ranges. UGT1A1 expression levels were then determined using 8 individual human liver microsomes, a pooled human liver microsomes, three UGT1A1 genotyped human liver microsomes, and four cell lines (Caco-2, MCF-7, Hela, and HepG2). The correlations study showed that the UGT1A1 protein levels were strongly correlated with its glucuronidation activities in human liver microsomes (R(2)=0.85) and in microsomes prepared from cell lines (R(2)=0.95). Isotope-labeled peptides were not necessary for LC-MS/MS quantitation of proteins. The isotope label-free absolute quantification method used here had good accuracy, sensitivity, linear range, and reproducibility, and were used successfully for the accurate determination of UGT1A1 from tissues and cell lines.

Severe irinotecan-induced toxicity in a patient with UGT1A1*28 and UGT1A1*6 polymorphisms

Many studies have demonstrated the impact of UGT1A1 on toxicity of irinotecan. In particular, patients bearing UGT1A1*28 (TA 7/7) have a higher risk of severe neutropenia and diarrhea. Based on this, prescribers of irinotecan are advised that patients with UGT1A1*28 (TA 7/7) should start with a reduced dose of irinotecan, although a particular dose is not specified. Research in Asian countries has shown a lower incidence of UGT1A1*28 (TA 7/7), while UGT1A1*6 (A/A) is more often found and is associated with severe irinotecan-related neutropenia. We report here a case of a metastatic colorectal cancer patient who is heterozygous for the UGT1A1*28 polymorphism (TA 6/7) as well as the UGT1A1*6 polymorphism (G/A). The patient was treated with FOLFIRI for 9 cycles and underwent two irinotecan dose reductions according to pharmacokinetic data regarding exposure to the active metabolite, SN-38. Simultaneous heterozygous UGT1A1*28 and UGT1A1*6 polymorphisms may produce higher exposure to SN-38 and a higher risk of adverse effects related to irinotecan. Additional studies will be necessary to determine the optimal starting dose of irinotecan for patients with both UGT1A1*28 and UGT1A1*6 polymorphisms.