ECOG-ACRIN EAZ171: Prospective Validation Trial of Germline Predictors of Taxane-Induced Peripheral Neuropathy in Black Women With Early-Stage Breast Cancer

PURPOSE

Black women experience higher rates of taxane-induced peripheral neuropathy (TIPN) compared with White women when receiving adjuvant once weekly paclitaxel for early-stage breast cancer, leading to more dose reductions and higher recurrence rates. EAZ171 aimed to prospectively validate germline predictors of TIPN and compare rates of TIPN and dose reductions in Black women receiving (neo)adjuvant once weekly paclitaxel and once every 3 weeks docetaxel for early-stage breast cancer.

METHODS

Women with early-stage breast cancer who self-identified as Black and had intended to receive (neo)adjuvant once weekly paclitaxel or once every 3 weeks docetaxel were eligible, with planned accrual to 120 patients in each arm. Genotyping was performed to determine germline neuropathy risk. Grade 2-4 TIPN by Common Terminology Criteria for Adverse Events (CTCAE) v5.0 was compared between high- versus low-risk genotypes and between once weekly paclitaxel versus once every 3 weeks docetaxel within 1 year. Patient-rated TIPN and patient-reported outcomes were compared using patient-reported outcome (PRO)-CTCAE and Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity.

RESULTS

Two hundred and forty of 249 enrolled patients had genotype data, and 91 of 117 (77.8%) receiving once weekly paclitaxel and 87 of 118 (73.7%) receiving once every 3 weeks docetaxel were classified as high-risk. Physician-reported grade 2-4 TIPN was not significantly different in high- versus low-risk genotype groups with once weekly paclitaxel (47% v 35%; P = .27) or with once every 3 weeks docetaxel (28% v 19%; P = .47). Grade 2-4 TIPN was significantly higher in the once weekly paclitaxel versus once every 3 weeks docetaxel arm by both physician-rated CTCAE (45% v 29%; P = .02) and PRO-CTCAE (40% v 24%; P = .03). Patients receiving once weekly paclitaxel required more dose reductions because of TIPN (28% v 9%; P < .001) or any cause (39% v 25%; P = .02).

CONCLUSION

Germline variation did not predict risk of TIPN in Black women receiving (neo)adjuvant once weekly paclitaxel or once every 3 weeks docetaxel. Once weekly paclitaxel was associated with significantly more grade 2-4 TIPN and required more dose reductions than once every 3 weeks docetaxel.

ABCG2 Gene Polymorphisms May Affect the Bleeding Risk in Patients on Apixaban and Rivaroxaban

Purpose

Direct oral anticoagulants (DOACs) are widely used for stroke prevention in atrial fibrillation. However, they have a bleeding complication. Breast cancer resistance protein, encoded by ABCG2, is known to be an efflux transporter of apixaban and rivaroxaban among DOACs. This study aimed to investigate the association between gene variants and bleeding complications during treatment with ABCG2 substrates (apixaban and rivaroxaban).

Patients and Methods

Patients treated with apixaban and rivaroxaban were enrolled from June 2018 to December 2021. Five single nucleotide polymorphisms (SNPs) of ABCG2 were selected. Previously studied genes (ABCB1, CYP3A4, and CYP3A5) were further analyzed as possible confounders. Finally, a total of 16 SNPs were examined in this case-control study. The outcome was defined as major bleeding and clinically relevant non-major bleeding. Two models were constructed using the multivariable analysis.

Results

Among 293 patients, 64 were cases. The mean age of the patients was 68.8 years, and males comprised 62.5% of the study population. Model I revealed that a history of bleeding, concurrent use of proton pump inhibitor (PPI), ABCG2 rs3114018, and ABCB1 rs1045642 were significantly associated with bleeding complications; the AORs (95% CI) were 6.209 (2.210-17.442), 2.385 (1.064-5.349), 2.188 (1.156-4.142), and 3.243 (1.371-7.671), respectively. Model II showed that modified HAS-BLED score, concurrent use of PPI, ABCG2 rs3114018, and ABCB1 rs1045642 were significantly associated with bleeding complications.

Conclusion

The modified HAS-BLED score, a history of bleeding, concurrent use of PPI, ABCG2 rs3114018, and ABCB1 rs1045642 were significantly associated with the risk of bleeding complications in patients on apixaban and rivaroxaban, after adjusting for other confounders. These findings can be used to develop individualized treatment strategies for patients taking apixaban and rivaroxaban.

Oxaliplatin-induced peripheral neurotoxicity in colorectal cancer patients: mechanisms, pharmacokinetics and strategies

Oxaliplatin-based chemotherapy is a standard treatment approach for colorectal cancer (CRC). However, oxaliplatin-induced peripheral neurotoxicity (OIPN) is a severe dose-limiting clinical problem that might lead to treatment interruption. This neuropathy may be reversible after treatment discontinuation. Its complicated mechanisms are related to DNA damage, dysfunction of voltage-gated ion channels, neuroinflammation, transporters, oxidative stress, and mitochondrial dysfunction, etc. Several strategies have been proposed to diminish OIPN without compromising the efficacy of adjuvant therapy, namely, combination with chemoprotectants (such as glutathione, Ca/Mg, ibudilast, duloxetine, etc.), chronomodulated infusion, dose reduction, reintroduction of oxaliplatin and topical administration [hepatic arterial infusion chemotherapy (HAIC), pressurized intraperitoneal aerosol chemotherapy (PIPAC), and hyperthermic intraperitoneal chemotherapy (HIPEC)]. This article provides recent updates related to the potential mechanisms, therapeutic strategies in treatment of OIPN, and pharmacokinetics of several methods of oxaliplatin administration in clinical trials.

Association between Genetic Variants and Peripheral Neuropathy in Patients with NSCLC Treated with First-Line Platinum-Based Therapy

Background: Chemotherapy-induced peripheral neuropathy (CIPN) is a common, disabling side effect in non-small cell lung cancer (NSCLC) patients treated with platinum-based therapy. There is increasing evidence for associations between genetic variants and susceptibility to CIPN. The aim of this study was to further explore genetic risk factors for CIPN by investigating previously reported genetic associations. Methods: A multicenter prospective follow-up study (PGxLUNG, NTR NL5373610015) in NSCLC patients (stage II-IV) treated with first-line platinum-based (cisplatin or carboplatin) chemotherapy was conducted. Clinical evaluation of neuropathy (CTCAE v4.03) was performed at baseline and before each cycle (four cycles, every three weeks) of chemotherapy and at three and six months after treatment initiation. The relationship between 34 single nucleotide polymorphisms (SNPs) in 26 genes and any grade (grade ≥ 1) and severe (grade ≥ 2) CIPN was assessed by using univariate and multivariate logistic regression modelling. Results: In total, 320 patients were included of which 26.3% (n = 84) and 8.1% (n = 26) experienced any grade and severe CIPN, respectively. The GG-genotype (rs879207, A > G) of TRPV1, a gene expressed in peripheral sensory neurons, was observed in 11.3% (n = 36) of the patients and associated with an increased risk of severe neuropathy (OR 5.2, 95%CI 2.1−12.8, adjusted p-value 0.012). A quarter (25%, n = 9/36) of the patients with the GG-genotype developed severe neuropathy compared to 6% (n = 17/282) of the patients with the AG- or AA-genotype. Multivariate logistic regression analysis showed statistically significant associations between the GG-genotype (ORadj 4.7, 95%CI 1.8−12.3) and between concomitant use of paclitaxel (ORadj 7.2, 95%CI 2.5−21.1) and severe CIPN. Conclusions: Patients with the GG-genotype (rs879207) of TRPV1 have an almost 5-fold higher risk of developing severe neuropathy when treated with platinum-based therapy. Future studies should aim to validate these findings in an independent cohort and to further investigated the individualization of platinum-based chemotherapy in clinical practice.

A Systematic Review of Polygenic Models for Predicting Drug Outcomes

Polygenic models have emerged as promising prediction tools for the prediction of complex traits. Currently, the majority of polygenic models are developed in the context of predicting disease risk, but polygenic models may also prove useful in predicting drug outcomes. This study sought to understand how polygenic models incorporating pharmacogenetic variants are being used in the prediction of drug outcomes. A systematic review was conducted with the aim of gaining insights into the methods used to construct polygenic models, as well as their performance in drug outcome prediction. The search uncovered 89 papers that incorporated pharmacogenetic variants in the development of polygenic models. It was found that the most common polygenic models were constructed for drug dosing predictions in anticoagulant therapies (n = 27). While nearly all studies found a significant association with their polygenic model and the investigated drug outcome (93.3%), less than half (47.2%) compared the performance of the polygenic model against clinical predictors, and even fewer (40.4%) sought to validate model predictions in an independent cohort. Additionally, the heterogeneity of reported performance measures makes the comparison of models across studies challenging. These findings highlight key considerations for future work in developing polygenic models in pharmacogenomic research.

Biomarkers of Chemotherapy-Induced Peripheral Neuropathy: Current Status and Future Directions

Chemotherapy induced peripheral neuropathy (CIPN) is an often severe and debilitating complication of multiple chemotherapeutic agents that can affect patients of all ages, across cancer diagnoses. CIPN can persist post-therapy, and significantly impact the health and quality of life of cancer survivors. Identifying patients at risk for CIPN is challenging due to the lack of standardized objective measures to assess for CIPN. Furthermore, there are no approved preventative treatments for CIPN, and therapeutic options for CIPN remain limited once it develops. Biomarkers of CIPN have been studied but are not widely used in clinical practice. They can serve as an important clinical tool to identify individuals at risk for CIPN and to better understand the pathogenesis and avenues for treatment of CIPN. Here we review promising biomarkers of CIPN in humans and their clinical implications.

Management of Side Effects in the Personalized Medicine Era: Chemotherapy-Induced Peripheral Neurotoxicity

Pharmacogenomics is a powerful tool to predict individual response to treatment, in order to personalize therapy, and it has been explored extensively in oncology practice. Not only efficacy on the malignant disease has been investigated but also the possibility to predict adverse effects due to drug administration. Chemotherapy-induced peripheral neurotoxicity (CIPN) is one of those. This potentially severe and long-lasting/permanent side effect of commonly administered anticancer drugs can severely impair quality of life (QoL) in a large cohort of long survival patients. So far, a pharmacogenomics-based approach in CIPN regard has been quite delusive, making a methodological improvement warranted in this field of interest: even the most refined genetic analysis cannot be effective if not applied correctly. Here we try to devise why it is so, suggesting how THE "bench-side" (pharmacogenomics) might benefit from and should cooperate with THE "bed-side" (clinimetrics), in order to make genetic profiling effective if applied to CIPN.

Large-Scale Prospective Genome-Wide Association Study of Oxaliplatin in Stage II/III Colon Cancer and Neuropathy

IMPORTANCE

The severity of oxaliplatin (L-OHP)-induced peripheral sensory neuropathy (PSN) exhibits substantial interpatient variability, and some patients suffer from long-term, persisting PSN.

OBJECTIVE

To identify single-nucleotide polymorphisms (SNPs) predicting L-OHP-induced PSN using a genome-wide association study (GWAS) approach.

DESIGN, SETTING, PARTICIPANTS

A large prospective GWAS including 1,379 patients with stage II/III colon cancer who received L-OHP-based adjuvant chemotherapy (mFOLFOX6/CAPOX) under the phase II (JOIN/JFMC41) or the phase III (ACHIVE/JFMC47) trial.

MAIN OUTCOMES AND MEASURES

First, GWAS comparison of worst grade PSN (grade 0/1 vs. 2/3) was performed. Next, to minimize the impact of ambiguity in PSN grading, extreme PSN phenotypes were selected and analyzed by GWAS. SNPs that could predict time to recovery from PSN were also evaluated. In addition, SNPs associated with L-OHP-induced allergic reactions (AR) and time to disease recurrence were explored.

RESULTS

No SNPs exceeded the genome-wide significance (p < 5.0 × 10^-8) in either GWAS comparison of worst grade PSN, extreme PSN phenotypes, or time to recovery from PSN. Association study focusing on AR or time to disease recurrence also failed to reveal any significant SNPs.

CONCLUSION AND RELEVANCE

Our results highlight the challenges of utilizing SNPs for predicting susceptibility to L-OHP-induced PSN in daily clinical practice.

Predictive Biomarkers of Oxaliplatin-Induced Peripheral Neurotoxicity

Oxaliplatin (OXA) is a platinum compound primarily used in the treatment of gastrointestinal cancer. OXA-induced peripheral neurotoxicity (OXAIPN) is the major non-hematological dose-limiting toxicity of OXA-based chemotherapy and includes acute transient neurotoxic effects that appear soon after OXA infusion, and chronic non-length dependent sensory neuronopathy symmetrically affecting both upper and lower limbs in a stocking-and-glove distribution. No effective strategy has been established to reverse or treat OXAIPN. Thus, it is necessary to early predict the occurrence of OXAIPN during treatment and possibly modify the OXA-based regimen in patients at high risk as an early diagnosis and intervention may slow down neuropathy progression. However, identifying which patients are more likely to develop OXAIPN is clinically challenging. Several objective and measurable early biomarkers for OXAIPN prediction have been described in recent years, becoming useful for informing clinical decisions about treatment. The purpose of this review is to critically review data on currently available or promising predictors of OXAIPN. Neurological monitoring, according to predictive factors for increased risk of OXAIPN, would allow clinicians to personalize treatment, by monitoring at-risk patients more closely and guide clinicians towards better counseling of patients about neurotoxicity effects of OXA.

Genetic Predictors of Chemotherapy-Induced Peripheral Neuropathy from Paclitaxel, Carboplatin and Oxaliplatin: NCCTG/Alliance N08C1, N08CA and N08CB Study

Chemotherapy-induced peripheral neuropathy (CIPN) is a common and potentially permanent adverse effect of chemotherapeutic agents including taxanes such as paclitaxel and platinum-based compounds such as oxaliplatin and carboplatin. Previous studies have suggested that genetics may impact the risk of CIPN. We conducted genome-wide association studies (GWASs) for CIPN in two independent populations who had completed European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ)-CIPN20 assessments (a CIPN-specific 20-item questionnaire which includes three scales that evaluate sensory, autonomic, and motor symptoms). The study population N08Cx included 692 participants from three clinical trials (North Central Cancer Treatment Group (NCCTG) N08C1, N08CA, and N08CB) who had been treated with paclitaxel, paclitaxel plus carboplatin, or oxaliplatin. The primary endpoint for the GWAS was the change from pre-chemotherapy CIPN20 sensory score to the worse score over the following 18 weeks. Study population The Mayo Clinic Breast Disease Registry (MCBDR) consisted of 381 Mayo Clinic Breast Disease Registry enrollees who had been treated with taxane or platinum-based chemotherapy. The primary endpoint for the GWAS assessed was the earliest CIPN20 sensory score available after the completion of chemotherapy. In multivariate model analyses, chemotherapy regimen (p = 3.0 × 10-8) and genetic ancestry (p = 0.007) were significantly associated with CIPN in the N08Cx population. Only age (p = 0.0004) was significantly associated with CIPN in the MCBDR population. The SNP most associated with CIPN was rs56360211 near PDE6C (p =7.92 × 10-8) in N08Cx and rs113807868 near TMEM150C in the MCBDR (p = 1.27 × 10-8). Due to a lack of replication, we cannot conclude that we identified any genetic predictors of CIPN.

The Road so Far in Colorectal Cancer Pharmacogenomics: Are We Closer to Individualised Treatment?

In recent decades, survival rates in colorectal cancer have improved greatly due to pharmacological treatment. However, many patients end up developing adverse drug reactions that can be severe or even life threatening, and that affect their quality of life. These remain a limitation, as they may force dose reduction or treatment discontinuation, diminishing treatment efficacy. From candidate gene approaches to genome-wide analysis, pharmacogenomic knowledge has advanced greatly, yet there is still huge and unexploited potential in the use of novel technologies such as next-generation sequencing strategies. This review summarises the road of colorectal cancer pharmacogenomics so far, presents considerations and directions to be taken for further works and discusses the path towards implementation into clinical practice.

Role for Drug Transporters in Chemotherapy-Induced Peripheral Neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is a common and dose-limiting toxicity to widely used chemotherapeutics. Although the exact molecular mechanism of chemotherapy-induced peripheral neuropathy remains elusive, there is consensus that it is caused by damage to the peripheral nervous system leading to sensory symptoms. Recently developed methodologies have provided evidence of expression of drug transporters in the peripheral nervous system. In this literature review, we explore the role for drug transporters in CIPN. First, we assessed the transport of chemotherapeutics that cause CIPN (taxanes, platins, vincristine, bortezomib, epothilones, and thalidomide). Second, we cross-referenced the transporters implicated in genetic or functional studies with CIPN with their expression in the peripheral nervous system. Several drug transporters are involved in the transport of chemotherapeutics that cause peripheral neuropathy and particularly efflux transporters, such as ABCB1 and ABCC1, are expressed in the peripheral nervous system. Previous literature has linked genetic variants in efflux transporters to higher risk of peripheral neuropathy with the taxanes paclitaxel and docetaxel and the vinca alkaloid vincristine. We propose that this might be due to accumulation of the chemotherapeutics in the peripheral nervous system due to reduced neuronal efflux capacity. Thus, concomitant administration of efflux transporter inhibitors may lead to higher risk of adverse events of drugs that cause CIPN. This might prove valuable in drug development where screening new drugs for neurotoxicity might also require drug transporter consideration. There are ongoing efforts targeting drug transporters in the peripheral nervous system to reduce intraneuronal concentrations of chemotherapeutics that cause CIPN, which might ultimately protect against this dose-limiting adverse event.

Neurological safety of oxaliplatin in patients with uncommon variants in Charcot-Marie-tooth disease genes

Oxaliplatin therapy can be complicated by chemotherapy-induced peripheral neuropathy (CIPN). Other neurotoxic chemotherapies have been linked to single nucleotide variants (SNV) in Charcot-Marie-Tooth disease (CMT) genes. Whether oxaliplatin carries increased risks of CIPN due to SNV in CMT-associated genes is unknown. 353 patients receiving oxaliplatin in NCCTG N08CB were serially evaluated for CIPN using a validated patient-reported outcome (PRO) instrument, the CIPN20 questionnaire (sensory scale). 49 canonical CMT-associated genes were analyzed for rare and common SNV by nextgen sequencing. The 157 patients with the highest and lowest susceptibility to CIPN (cases and controls) harbored 270 non-synonymous SNV in CMT-associated genes (coding regions). 143 of these were rare, occurring only once ("singletons"). CIPN cases had 0.84 singletons per patient compared with 0.98 in controls. An imbalance in favor of cases was noted only in few genes including PRX, which was previously highlighted as a candidate CIPN gene in patients receiving paclitaxel. However, the imbalance was only modest (5 singleton SNV in cases and 2 in controls). Therefore, while singleton SNV were common, they did overall not portend an increased risk of CIPN. Furthermore, testing CMT-associated genes using recurrent non-synonymous SNV did not reveal any significant association with CIPN. Genetic analysis of patients from N08CB provides clinical guidance that oxaliplatin chemotherapy decisions should not be altered by the majority of SNV that may be encountered in CMT-associated genes when common genetic tests are performed, such as exome or genome sequencing. Oxaliplatin's CIPN risk appears unrelated to CMT-associated genes.

Chemotherapy-induced peripheral neurotoxicity: A multifaceted, still unsolved issue

Chemotherapy-induced peripheral neurotoxicity (CIPN) is a potentially dose-limiting side effect of several commonly used cytotoxic chemotherapy agents. The main pharmacological classes that may cause CIPN include classical anticancer drugs, as well as the recently introduced immune checkpoint inhibitors and antibody drug conjugates. The absence of a complete knowledge of CIPN pathophysiology is only one of the several unsolved issues related to CIPN. Among some of the most relevant aspects of CIPN deserving further attention include the real number of patients exposed to the risk of CIPN, the long-term impact on cancer survivors' quality of life due to incomplete recovery from CIPN, the economic burden related to acute and chronic CIPN, and the different perspective and education of the healthcare specialists in charge of managing patients with CIPN. Overall, CIPN remains a very challenging area of research as there are still several unresolved issues to be addressed in the future. In this special issue, the multifaceted profile of CIPN will be presented, with particular emphasis on bolstering the need to develop more optimized outcome measures than the existing ones to accurately evaluate the extent of CIPN, but also to ascertain the differences in the incidence, risk factors, clinical phenotype, and management of CIPN, according to the most commonly used neurotoxic chemotherapy classes. Perspectives for future research to pursue in order to cover the gaps in knowledge in the CIPN field will also be discussed.

Thyroid Cancer: The Quest for Genetic Susceptibility Involving DNA Repair Genes

The incidence of thyroid cancer (TC), particularly well-differentiated forms (DTC), has been rising and remains the highest among endocrine malignancies. Although ionizing radiation (IR) is well established on DTC aetiology, other environmental and genetic factors may also be involved. DNA repair single nucleotide polymorphisms (SNPs) could be among the former, helping in explaining the high incidence. To further clarify the role of DNA repair SNPs in DTC susceptibility, we analyzed 36 SNPs in 27 DNA repair genes in a population of 106 DTCs and corresponding controls with the aim of interpreting joint data from previously studied isolated SNPs in DNA repair genes. Significant associations with DTC susceptibility were observed for XRCC3 rs861539, XPC rs2228001, CCNH rs2230641, MSH6 rs1042821 and ERCC5 rs2227869 and for a haplotype block on chromosome 5q. From 595 SNP-SNP combinations tested and 114 showing relevance, 15 significant SNP combinations (p < 0.01) were detected on paired SNP analysis, most of which involving CCNH rs2230641 and mismatch repair variants. Overall, a gene-dosage effect between the number of risk genotypes and DTC predisposition was observed. In spite of the volume of data presented, new studies are sought to provide an interpretability of the role of SNPs in DNA repair genes and their combinations in DTC susceptibility.

Biological predictors of chemotherapy-induced peripheral neuropathy (CIPN): MASCC neurological complications working group overview

Chemotherapy-induced peripheral neuropathy (CIPN) is a common and debilitating condition associated with a number of chemotherapeutic agents. Drugs commonly implicated in the development of CIPN include platinum agents, taxanes, vinca alkaloids, bortezomib, and thalidomide analogues. As a drug response can vary between individuals, it is hypothesized that an individual's specific genetic variants could impact the regulation of genes involved in drug pharmacokinetics, ion channel functioning, neurotoxicity, and DNA repair, which in turn affect CIPN development and severity. Variations of other molecular markers may also affect the incidence and severity of CIPN. Hence, the objective of this review was to summarize the known biological (molecular and genomic) predictors of CIPN and discuss the means to facilitate progress in this field.

Electrophysiologic evaluation of facial nerve functions after oxaliplatin treatment

PURPOSE

This study analyzes the effect of oxaliplatin treatment on the facial nerve. The facial nerve is the most commonly paralyzed cranial motor nerve because it advances through a long, curved bone canal. Electroneurography and blink reflex are the electrophysiological measurements used for evaluating facial nerve function. Oxaliplatin is a cytotoxic agent used in adjuvant or palliative systemic therapy for colorectal cancer treatment.

METHODS

This study was performed on 20 individuals who were at least 18 years old at Hacettepe University Ear Nose Throat Department, Audiology and Speech Disorders Unit, and Neurology Division EMG Laboratory as they received oxaliplatin treatment from Hacettepe University Oncology Hospital. Electroneurography and blink-reflex values were recorded and examined. The parameters taken during the second and fourth months were compared for this purpose.

RESULTS

This study shows that the prolongation of distal latencies of compound muscle action potential is statistically significant, the amplitudes showed no difference. The ENoG results were analyzed, the prolongation of latency measurements between pre-treatment and the fourth month after treatment were statistically significant. The blink-reflex results showed that comparison with the baseline values, the prolongation of latencies in R1 measurements between pre-treatment, the second month, and the fourth month were significant.

CONCLUSIONS

The facial nerve is affected asymptomatically by oxaliplatin treatment. During oxaliplatin treatment, the evaluation of facial nerve function could be beneficial for patients by improving their quality of life. Electroneurography and blink-reflex tests can be used in the early evaluations of different medicines to determine their neurotoxicity.

Early colorectal cancer: diagnosis, treatment and survivorship care

CRC is the third most commonly diagnosed malignancy and the fourth leading cause of cancer-related death in the world. With advances in treatment, colorectal cancer is being transformed from a deadly disease to an illness that is increasingly curable. With this transformation has come increased interest in the unique problems, risks, needs, and concerns of survivors who have completed treatment and are cancer-free. They often suffer late/long-term side effects of therapies that may compromise their QoL such as fatigue, sleep difficulty, fear of recurrence, anxiety, depression, negative body image, sensory neuropathy, gastrointestinal problems, urinary incontinence, and sexual dysfunction. In this review, we discuss what is known about early colorectal diagnosis, staging, treatments and their long-term effects on quality of life and survivorship care.

Is a pharmacogenomic panel useful to estimate the risk of oxaliplatin-related neurotoxicity in colorectal cancer patients?

Oxaliplatin-induced peripheral neurotoxicity (OXPN) is a dose-limiting toxicity in colorectal cancer (CRC) patients. Single nucleotide polymorphisms (SNPs) in genes involved in drug transport may lead to higher intracellular oxaliplatin accumulation in the dorsal root ganglia and thus increased risk of OXPN. In this study, a panel of 5 SNPs, namely ABCC2 (-24C > T/rs717620 and c.4544 G > A/rs8187710), ABCG2 (c.421 C > A/rs2231142), ABCB1 (c.3435 C > T/rs1045642) and SLC31A1 (c.-36 + 2451 T > G/rs10981694), was evaluated to assess their association with grade 2-3 OXPN in metastatic CRC patients. SNPs were considered according to a dominant model (heterozygous + homozygous). Germline DNA was available from 120 patients who received oxaliplatin between 2010 and 2016. An external cohort of 80 patients was used to validate our results. At the univariable logistic analyses, there were no significant associations between SNPs and incidence of OXPN. Taking into account the strength of observed association between OXPN and the SNPs, a clinical risk score was developed as linear predictor from a multivariable logistic model including all the SNPs together. This score was significantly associated with grade 2-3 OXPN (p = 0.036), but the external calibration was not satisfactory due to relevant discrepancies between the two series. Our data suggest that the concomitant evaluation of multiple SNPs in oxaliplatin transporters is an exploratory strategy that may deserve further investigation for treatment customization in CRC patients.

Predictive biomarkers of chemotherapy-induced peripheral neuropathy: a review

Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of taxane treatment during chemotherapy. Identifying predictive biomarkers of CIPN would allow physicians to alter treatment given to patients according to a personal risk of developing this condition. The current literature on CIPN biomarkers is reviewed, identifying biomarkers which have been found to be significantly related to CIPN. Three genetic biomarkers are identified (ARHGEF10 rs9657362, CYP2C8 rs11572080/rs10509681 and FGD4 rs10771973) which have been found to act as predictive CIPN biomarkers in multiple studies. Possible mechanisms underlying the relationship between these single nucleotide polymorphisms and CIPN development are explored. The biomarkers identified in this study should be investigated further to generate predictive biomarkers that may be used in a clinical setting.

Influence of SLCO1B1 in gastric cancer patients treated with EOF chemotherapy

Cytochrome-P450 enzymes, ATP-binding cassette transporters, and solute carriers mediate drug metabolism as metabolic enzymes and membrane transporters, respectively. The present study investigated whether single nucleotide polymorphisms (SNPs) in genes encoding these proteins were predictive or prognostic factors in patients with metastatic gastric cancer (MGC) undergoing chemotherapy. A retrospective study of 108 MGC patients who received epirubicin, oxaliplatin, and 5-fluorouracil (EOF) as first-line treatment was performed. A total of 13 SNPs were genotyped, including SLCO1B1 (rs4149056), SLC2A9 (rs16890979, rs6449213, rs734553), ABCG2 (rs2231142), CYP2C9 (rs1057910, rs1799853), CYP2C19 (rs72552267, rs28399504, rs56337013, rs41291556) and CYP1A2 (rs12720461, rs56107638). The associations between these genotypes and disease-control rate (DCR), progression-free survival (PFS) and overall survival (OS) were analyzed. Patients with SLCO1B1 rs4149056 TT genotype had a significantly shorter OS compared with those with a C allele (CC + CT; 312 vs. 565 days, P=0.039). Multivariate analysis revealed that the rs4149056 TT homozygous genotype was an independent prognostic factor for shorter OS (hazard ratio: 2.565, 95% confidence interval: 1.215–5.415, P=0.014). However, no significant associations between SLCO1B1 rs4149056 and PFS were observed, between the other 12 SNPs and PFS or OS, or between any of the 13 SNPs and DCR. In conclusion, SLCO1B1 rs4149056 TT may be an independent predictor of survival in patients with MCG treated with EOF chemotherapy.

Genetic polymorphisms in cyclin H gene are associated with oxaliplatin-induced acute peripheral neuropathy in South Indian digestive tract cancer patients

PURPOSE

Digestive tract cancer patients treated with oxaliplatin are often associated with the development of peripheral neuropathy. The aim of the present study is to identify the influence of single-nucleotide polymorphisms (SNPs) in genes involved in oxaliplatin metabolism, cell cycle control, detoxification or excretion pathways with the development of oxaliplatin-induced acute peripheral neuropathy (acute OXAIPN) and its severity among digestive tract cancer patients treated with oxaliplatin-based chemotherapy.

PATIENTS AND METHODS

A total of 228 digestive tract cancer patients undergoing with the oxaliplatin-based chemotherapy between November 2014 and December 2016 were included in the current study. Genomic DNA was extracted from peripheral blood by standard phenol-chloroform method. Genotyping of five SNPs in four genes [GSTP₁ (rs1965), ABCG2 (rs3114018), CCNH (rs2230641, rs3093816), AGXT (rs4426527)] was carried out by Real-Time TaqMan SNP genotyping assay.

RESULTS

We found that the two genetic variants rs2230641 and rs3093816 in cyclin H (CCNH) gene were significantly associated with both the incidence and severity of acute OXAIPN. For CCNH-rs2230641 (AA vs AG+GG; dominant model) Incidence: OR 2.62, 95% CI 1.44-4.75, p = 0.001, severity; OR 4.64, 95% CI 1.58-13.62, p = 0.002. For CCNH-rs3093816 (AA vs AG+GG; dominant model); incidence: OR 3.43, 95% CI 1.57-7.50, p = 0.001; severity: OR 2.36, 95% CI 1.05-5.30, p = 0.033.

CONCLUSIONS

The results of the present study found significant association between CCNH polymorphisms and acute OXAIPN development. However, further studies are warranted from independent groups to validate our study results.

Three Versus 6 Months of Oxaliplatin-Based Adjuvant Chemotherapy for Patients With Stage III Colon Cancer: Disease-Free Survival Results From a Randomized, Open-Label, International Duration Evaluation of Adjuvant (IDEA) France, Phase III Trial

Purpose

Reduction of adjuvant treatment duration may decrease toxicities without loss of efficacy in stage III colon cancer. This could offer clear advantages to patients and health care providers.

Methods

In International Duration Evaluation of Adjuvant Chemotherapy (IDEA) France, as part of the IDEA international collaboration, patient with colon cancer patients were randomly assigned to 3 and 6 months of modified FOLFOX6 (mFOLFOX6: infusional fluorouracil, leucovorin, and oxaliplatin) or capecitabine plus oxaliplatin (CAPOX) by physician choice. The primary end point was disease-free survival (DFS), and analyses were descriptive.

Results

A total of 2,010 eligible patients received either 3 or 6 months of chemotherapy (modified intention-to-treat population); 2,000 (99%) had stage III colon cancer (N1: 75%, N2: 25%); 1,809 (90%) received mFOLFOX6, and 201 (10%) received CAPOX. The median age was 64 years, and the median follow-up time was 4.3 years. Overall, 94% (3 months) and 78% (6 months) of patients completed treatment (fluoropyrimidines ± oxaliplatin). Maximal grade 2 and 3 neuropathy rates were 28% and 8% in the 3-month arm and 41% and 25% in the 6-month arm ( P < .001). Final rates of residual neuropathy greater than grade 1 were 3% in the 3-month arm and 7% in the 6-month arm ( P < .001). There were 578 DFS events: 314 and 264 in the 3- and 6-month arms, respectively. The 3-year DFS rates were 72% and 76% in the 3- and 6-month arms, respectively (hazard ratio [HR], 1.24; 95% CI, 1.05 to 1.46; P = .0112). In the 3 and 6-month arms, respectively, for patients who received mFOLFOX6, the 3-year DFS rates were 72% and 76% (HR, 1.27; 95% CI, 1.07 to 1.51); for the T4 and/or N2 population, they were 58% and 66% (HR, 1.44; 95% CI, 1.14 to 1.82); and for the T1-3N1 population, they were 81% and 83% (HR, 1.15; 95% CI, 0.89 to 1.49).

Conclusion

IDEA France, in which 90% of patients received mFOLFOX6, shows superiority of 6 months of adjuvant chemotherapy compared with 3 months, especially in the T4 and/or N2 subgroups. These results should be considered alongside the international IDEA collaboration data.

A Prospective Study of Chronic Oxaliplatin-Induced Neuropathy in Patients with Colon Cancer: Long-Term Outcomes and Predictors of Severe Oxaliplatin-Induced Neuropathy

Background and Purpose

The objective of this study was to determine the incidence and long-term outcomes of oxaliplatin-induced peripheral neuropathy (OIPN), as well as predictors of its severe form.

Methods

Sixty-nine patients who were taking oxaliplatin for colon cancer were prospectively followed prior to starting chemotherapy and after 4, 8, and 12 cycles of chemotherapy. Thirty-six patients completed the follow-up at 1 year after the end of chemotherapy. The patients were assessed using clinical assessment scales and nerve conduction studies (NCS) at each follow-up visit.

Results

By applying the National Cancer Institute Common Toxicity criteria, OIPN was classified as grade 1 in 30 (44%) patients, grade 2 in 25 (36%), and grade 3 in 10 (14%) at the completion of therapy. At 1 year after the treatment, OIPN of grades 1, 2, and 3 was found in 50, 3, and 11% of the patients, respectively. Multivariate analysis showed that reductions of the amplitude of the sensory action potential of >11.5% in the median nerve between baseline and four cycles of chemotherapy (odds ratio=5.603, p=0.031) and of >22.5% in the sural nerve between four and eight cycles of chemotherapy (odds ratio=5.603, p=0.031) were independently associated with the risk of developing grade-3 OIPN.

Conclusions

While the severity of OIPN can improve after oxaliplatin discontinuation, more than half of the patients in this study still had OIPN at 1 year after discontinuation. Early changes in the NCS results for sensory nerves can predict the development of severe OIPN during treatment.

Association of Voltage-Gated Sodium Channel Genetic Polymorphisms with Oxaliplatin-Induced Chronic Peripheral Neuropathy in South Indian Cancer Patients

Oxaliplatin is a platinum drug active against digestive tract cancers. Among its side effects, peripheral neuropathy is one of the dose-limiting toxicities. This affects around 50 to 70% of patients but the pathophysiology of development of oxaliplatin-induced peripheral neuropathy (OXAIPN) remains unclear. Sodium channels (SCNAs) play major role in neuronal electrical signaling processes and mutations in SCNAs lead to various neuronal diseases involving the central and peripheral nervous systems. In this study, we evaluated whether SCNA genetic variants might be associated with risk of chronic OXAIPN in patients with digestive tract cancers treated with oxaliplatin. Methodology: Blood samples from 228 digestive tract cancer patients who had received oxaliplatin in adjuvant and neoadjuvant or metastatic settings were obtained and genomic DNA was extracted by phenol-chloroform extraction. Genotyping was performed with the real-time polymerase chain reaction (RT-PCR) using validated real-time TaqMan single nucleotide polymorphism (SNP) genotyping assays. Neuropathy was evaluated and graded according to National Cancer Institute Common Toxicity Criteria (NCI-CTC) version 4.03. Results: We found that the rs6746030 polymorphic variant of SCN9A was significantly associated with a higher incidence of chronic OXAIPN (GA+AA vs GG: OR=1.8, 95% CI=1.04-3.4, P=0.04; dominant model) while the rs6754031 variant was linked with a lower incidence (OR=0.45, 95% CI=0.22-0.77, P=0.005; dominant model). The SCN 10A polymorphic variant was associated with severity of chronic OXAIPN (P=0.006, OR=2.0, 95% CI=1.2 - 3.3). Conclusion: The results of the present prospective study provide evidence in support of a causal relationship between chronic OXAIPN and voltage gated sodium channel polymorphisms. However, further studies from independent groups are required to validate these results.

Susceptibility of different mouse strains to oxaliplatin peripheral neurotoxicity: Phenotypic and genotypic insights

Peripheral neurotoxicity is one of the most distressing side effects of oxaliplatin therapy for cancer. Indeed, most patients that received oxaliplatin experience acute and/or chronic severe sensory peripheral neuropathy. However, despite similar co-morbidities, cancer stage, demographics and treatment schedule, patients develop oxaliplatin-induced peripheral neurotoxicity with remarkably different severity. This suggests individual genetic variability, which might be used to glean the mechanistic insights into oxaliplatin neurotoxicity. We characterized the susceptibility of different mice strains to oxaliplatin neurotoxicity investigating the phenotypic features of neuropathy and gene expression profiles in dorsal root ganglia of six genetically different mice strains (Balb-c, C57BL6, DBA/2J, AJ, FVB and CD1) exposed to the same oxaliplatin schedule. Differential gene expression in dorsal root ganglia from each mice strain were assayed using a genome-wide expression analysis and selected genes were validated by RT-PCR analysis. The demonstration of consistent differences in the phenotypic response to oxaliplatin across different strains is interesting to allow the selection of the appropriate strain based on the pre-defined read-out parameters. Further investigation of the correlation between gene expression changes and oxaliplatin-induced neurotoxicity phenotype in each strain will be useful to deeper investigate the molecular mechanisms of oxaliplatin neurotoxicity.

The molecular genetics of chemotherapy-induced peripheral neuropathy: A systematic review and meta-analysis

Chemotherapy-induced peripheral neuropathy (CIPN) can adversely affect completion of systemic anti-cancer treatment and cause long-term morbidity. Increasingly pharmacogenetic studies have been performed to explore susceptibility to this important adverse effect. A systematic review was conducted to identify pharmacogenetic studies, assess their quality and findings and undertake meta-analysis where possible. 93 studies were included. Notable methodological issues included lack of standardisation and detail in phenotype definition and acknowledgement of potential confounding factors. Insufficient data was presented in many studies meaning only a minority could be included in meta-analysis showing mainly non-significant effects. Nonetheless, SNPs in CYP2C8, CYP3A4, ARHGEF10, EPHA and TUBB2A genes (taxanes), FARS2, ACYP2 and TAC1 (oxaliplatin), and CEP75 and CYP3A5 (vincristine) are of potential interest. These require exploration in large cohort studies with robust methodology and well-defined phenotypes. Seeking standardisation of phenotype, collaboration and subsequently, individual-patient-data meta-analysis may facilitate identifying contributory SNPs which could be combined in a polygenic risk score to predict those most at risk of CIPN.

Chemotherapy-induced peripheral neurotoxicity: management informed by pharmacogenetics

The increasing availability of sophisticated methods to characterize human genetic variation has enabled pharmacogenetic data to be used not only to predict responses to treatment (in the context of so-called personalized medicine), but also to identify patients at high or low risk of specific treatment-related adverse effects. Over the past two decades, extensive attempts have been made to understand the genetic basis of chemotherapy-induced peripheral neurotoxicity (CIPN), one of the most severe non-haematological adverse effects of cancer treatment. Despite substantial efforts, however, the identification of a genetic profile that can detect patients at high risk of CIPN still represents an unmet need, as the information obtained from pharmacogenetic studies published so far is inconsistent at best. Among the reasons for these inconsistencies, methodological flaws and the poor reliability of existing tools for assessing CIPN features and severity are particularly relevant. This Review provides a critical update of the pharmacogenetics of CIPN, focusing on the studies published since 2011. Strategies for improving the reliability of future pharmacogenetic studies of CIPN are also discussed.

Chemotherapy-induced peripheral neuropathy: A current review

Chemotherapy-induced peripheral neuropathy (CIPN) is a common dose-limiting side effect experienced by patients receiving treatment for cancer. Approximately 30 to 40% of patients treated with neurotoxic chemotherapy will develop CIPN, and there is considerable variability in its severity between patients. It is often sensory-predominant with pain and can lead to long-term morbidity in survivors. The prevalence and burden of CIPN late effects will likely increase as cancer survival rates continue to improve. In this review, we discuss the approach to peripheral neuropathy in patients with cancer and address the clinical phenotypes and pathomechanisms of specific neurotoxic chemotherapeutic agents. Ann Neurol 2017;81:772-781.

Long-Term Effects, Pathophysiological Mechanisms, and Risk Factors of Chemotherapy-Induced Peripheral Neuropathies: A Comprehensive Literature Review

Neurotoxic anticancer drugs, such as platinum-based anticancer drugs, taxanes, vinca alkaloids, and proteasome/angiogenesis inhibitors are responsible for chemotherapy-induced peripheral neuropathy (CIPN). The health consequences of CIPN remain worrying as it is associated with several comorbidities and affects a specific population of patients already impacted by cancer, a strong driver for declines in older adults. The purpose of this review is to present a comprehensive overview of the long-term effects of CIPN in cancer patients and survivors. Pathophysiological mechanisms and risk factors are also presented. Neurotoxic mechanisms leading to CIPNs are not yet fully understood but involve neuronopathy and/or axonopathy, mainly associated with DNA damage, oxidative stress, mitochondria toxicity, and ion channel remodeling in the neurons of the peripheral nervous system. Classical symptoms of CIPNs are peripheral neuropathy with a “stocking and glove” distribution characterized by sensory loss, paresthesia, dysesthesia and numbness, sometimes associated with neuropathic pain in the most serious cases. Several risk factors can promote CIPN as a function of the anticancer drug considered, such as cumulative dose, treatment duration, history of neuropathy, combination of therapies and genetic polymorphisms. CIPNs are frequent in cancer patients with an overall incidence of approximately 38% (possibly up to 90% of patients treated with oxaliplatin). Finally, the long-term reversibility of these CIPNs remain questionable, notably in the case of platinum-based anticancer drugs and taxanes, for which CIPN may last several years after the end of anticancer chemotherapies. These long-term effects are associated with comorbidities such as depression, insomnia, falls and decreases of health-related quality of life in cancer patients and survivors. However, it is noteworthy that these long-term effects remain poorly studied, and only limited data are available such as in the case of bortezomib and thalidomide-induced peripheral neuropathy.

Nucleotide excision repair and response and survival to chemotherapy in colorectal cancer patients

Several new chemotherapeutic agents have become available for the treatment of colorectal cancer, which has led to increased complexity in treatment planning. Treatment decision making for individual patients could be facilitated if guided by predictive and prognostic markers. As most cytotoxic drugs induce DNA damage, the DNA damage repair pathways hold potential for yielding such biomarkers. Here, we review the current evidence of a possible involvement of the nucleotide excision repair pathway in the efficacy of chemotherapeutic agents used in the treatment of colorectal cancer. Although a large number of studies have been conducted, they are generally of moderate size and heterogeneous in design. Up to date no firm conclusions can be drawn to translate these results into the clinic. We recommend further comprehensive investigations of the nucleotide excision repair pathway in large patient studies that include both discovery and validation cohorts.

Large-scale prospective pharmacogenomics study of oxaliplatin-induced neuropathy in colon cancer patients enrolled in the JFMC41-1001-C2 (JOIN Trial)

BACKGROUND

Peripheral sensory neuropathy (PSN) is a dose-limiting toxicity of oxaliplatin-based chemotherapy. Several genetic markers have been shown to predict oxaliplatin-induced PSN; however, results remain to be validated in a large-scale and prospective pharmacogenomics study.

PATIENTS AND METHODS

Among 882 patients enrolled in the JFMC41-1001-C2 (JOIN trial), which was designed to investigate the tolerability of adjuvant-modified FOLFOX6 (mFOLFOX6) in Japanese Patients with stage II or III colon cancers undergoing curative resection, 465 patients were eligible for this pharmacogenomics analysis. Twelve single-nucleotide polymorphisms (SNPs) were selected based on published data. The effect of each genotype on time to PSN onset was evaluated in all patients (n = 465) using the Cox proportional hazard model. For the association analysis between severity of PSN and 12 SNP markers, 84 patients who failed to complete 12 cycles of mFOLFOX6 from grade 0/1 PSN group were excluded because the termination of the protocol treatment had been caused by reasons other than PSN.

RESULTS

Comparison of grade 0/1 PSN with grade 2/3 PSN or grade 3 PSN showed no significant associations with any of the 12 SNP markers after adjustment for total dose of oxaliplatin. Time-to-onset analysis also failed to reveal any significant differences.

CONCLUSIONS

Our large-scale and prospective pharmacogenomics study of Japanese patients receiving protocol treatment of adjuvant mFOLFOX6 could not verify a role for any of the 12 SNP markers reported as being significantly associated with PSN. Considering the OR observed in this study (range: 0.76-1.89), further evaluation of these 12 SNP markers in the context of L-OHP-induced PSN is unlikely to be clinically informative.

Single Nucleotide Polymorphisms as Prognostic and Predictive Factors of Adjuvant Chemotherapy in Colorectal Cancer of Stages I and II

Colorectal cancer (CRC) is a highly heterogeneous disease regarding the stage at time of diagnosis and there is special attention regarding adjuvant chemotherapy in unselected patients with stage I and stage II. The clinicohistologically based TNM staging system with emphasis on histological evaluation of primary tumor and resected regional lymph nodes remains the standard of staging, but it has restricted sensitivity resulting in false downward stage migration. Molecular characteristics might predispose tumors to a worse prognosis and identification of those enables identifying patients with high risk of disease recurrence. Suitable predictive markers also enable choosing the most appropriate therapy. The current challenge facing adjuvant chemotherapy in stages I and II CRC is choosing patients with the highest risk of disease recurrence who are going to derive most benefit without facing unnecessary adverse effects. Single nucleotide polymorphisms (SNPs) are one of the potential molecular markers that might help us identify patients with unfavorable prognostic factors regarding disease initiation and recurrence and could determine selection of an appropriate chemotherapy regimen in the adjuvant and metastatic setting. In this paper, we discuss SNPs of genes involved in the multistep processes of cancerogenesis, metastasis, and the metabolism of chemotherapy that might prove clinically significant.

Informative gene network for chemotherapy-induced peripheral neuropathy

BACKGROUND

Host genetic variability has been implicated in chemotherapy-induced peripheral neuropathy (CIPN). A dose-limiting toxicity for chemotherapy agents, CIPN is also a debilitating condition that may progress to chronic neuropathic pain. We utilized a bioinformatics approach, which captures the complexity of intracellular and intercellular interactions, to identify genes for CIPN.

METHODS

Using genes pooled from the literature as a starting point, we used Ingenuity Pathway Analysis (IPA) to generate gene networks for CIPN.

RESULTS

We performed IPA core analysis for genes associated with platinum-, taxane- and platinum-taxane-induced neuropathy. We found that IL6, TNF, CXCL8, IL1B and ERK1/2 were the top genes in terms of the number of connections in platinum-induced neuropathy and TP53, MYC, PARP1, P38 MAPK and TNF for combined taxane-platinum-induced neuropathy.

CONCLUSION

Neurotoxicity is common in cancer patients treated with platinum compounds and anti-microtubule agents and CIPN is one of the debilitating sequela. The bioinformatic approach helped identify genes associated with CIPN in cancer patients.

Platinum-induced neurotoxicity and preventive strategies: past, present, and future

Neurotoxicity is a burdensome side effect of platinum-based chemotherapy that prevents administration of the full efficacious dosage and often leads to treatment withdrawal. Peripheral sensory neurotoxicity varies from paresthesia in fingers to ataxic gait, which might be transient or irreversible. Because the number of patients being treated with these neurotoxic agents is still increasing, the need for understanding the pathogenesis of this dramatic side effect is critical. Platinum derivatives, such as cisplatin and carboplatin, harm mainly peripheral nerves and dorsal root ganglia neurons, possibly because of progressive DNA-adduct accumulation and inhibition of DNA repair pathways (e.g., extracellular signal-regulated kinase 1/2, c-Jun N-terminal kinase/stress-activated protein kinase, and p38 mitogen-activated protein kinass), which finally mediate apoptosis. Oxaliplatin, with a completely different pharmacokinetic profile, may also alter calcium-sensitive voltage-gated sodium channel kinetics through a calcium ion immobilization by oxalate residue as a calcium chelator and cause acute neurotoxicity. Polymorphisms in several genes, such as voltage-gated sodium channel genes or genes affecting the activity of pivotal metal transporters (e.g., organic cation transporters, organic cation/carnitine transporters, and some metal transporters, such as the copper transporters, and multidrug resistance-associated proteins), can also influence drug neurotoxicity and treatment response. However, most pharmacogenetics studies need to be elucidated by robust evidence. There are supportive reports about the effectiveness of several neuroprotective agents (e.g., vitamin E, glutathione, amifostine, xaliproden, and venlafaxine), but dose adjustment and/or drug withdrawal seem to be the most frequently used methods in the management of platinum-induced peripheral neurotoxicity. To develop alternative options in the treatment of platinum-induced neuropathy, studies on in vitro models and appropriate trials planning should be integrated into the future design of neuroprotective strategies to find the best patient-oriented solution.

Genetic determinants of chronic oxaliplatin-induced peripheral neurotoxicity: a genome-wide study replication and meta-analysis

We aimed at validating the role of genetic variants identified by a recent genome-wide association study (GWAS) as determinants of chronic oxaliplatin-induced peripheral neurotoxicity (OXAIPN). Eight polymorphisms (rs10486003, rs2338, rs843748, rs797519, rs4936453, rs12023000, rs17140129, and rs6924717) were genotyped in a total of 150 colorectal cancer patients of Caucasian origin receiving oxaliplatin-based chemotherapy. The severity grade of chronic OXAIPN was assessed by NCI-CTC criteria and the clinical version of the Total Neuropathy Score(©) (TNSc(©) ). None of the polymorphisms investigated was found associated with grade ≥ 2 chronic OXAIPN (NCI-CTC criteria), while a nominal association emerged for ACYP2 rs843748 when using the TNSc(©) scale (dominant model: odds ratio [OR]: 0.27, 95% confidence interval [CI]: 0.10-0.75, P = 0.008). In the combined analysis of this results with data of the two previously published studies which assessed chronic OXAIPN by NCI-CTC criteria, evidence suggestive of association with chronic OXAIPN (NCI-CTC criteria) was found for ACYP2 rs843748 (dominant model: OR: 2.40, 95%CI: 1.40-5.24, P = 0.027), which, however, did not remain significant after correction for multiple testing (threshold P-value <0.00625). These findings suggest a minor role of the single nucleotide polymorphisms (SNPs) investigated as genetic determinants of chronic OXAIPN. These results also highlight the importance of replication studies with meta-analysis for validation of GWAS findings.

Differential transcriptome profile of peripheral white cells to identify biomarkers involved in oxaliplatin induced neuropathy

Anticancer chemotherapy (CT) produces non-desirable effects on normal healthy cells and tissues. Oxaliplatin is widely used in the treatment of colorectal cancer and responsible for the development of sensory neuropathy in varying degrees, from complete tolerance to chronic neuropathic symptoms. We studied the differential gene expression of peripheral leukocytes in patients receiving oxaliplatin-based chemotherapy to find genes and pathways involved in oxaliplatin-induced peripheral neuropathy. Circulating white cells were obtained prior and after three cycles of FOLFOX or CAPOX chemotherapy from two groups of patients: with or without neuropathy. RNA was purified, and transcriptomes were analyzed. Differential transcriptomics revealed a total of 502 genes, which were significantly up- or down-regulated as a result of chemotherapy treatment. Nine of those genes were expressed in only one of two situations: CSHL1, GH1, KCMF1, IL36G and EFCAB8 turned off after CT, and CSRP2, IQGAP1, GNRH2, SMIM1 and C5orf17 turned on after CT. These genes are likely to be associated with the onset of oxaliplatin-induced peripheral neuropathy. The quantification of their expression in peripheral white cells may help to predict non-desirable side effects and, consequently, allow a better, more personalized chemotherapy.