Personalizing carbamazepine therapy

The anticonvulsant carbamazepine has a high incidence of cutaneous adverse drug reactions. A recent prospective clinical trial in Taiwan has indicated that HLA-B*1502 screening will reduce the incidence of life-threatening adverse reactions to carbamazepine, while a genome-wide association study has identified the HLA-A*3101 allele as a genetic risk factor for the full spectrum of carbamazepine-induced cutaneous adverse drug reactions in a European population. These studies should aid future decision-making for personalized use of carbamazepine treatment

Variants at HLA-A , HLA-C , and HLA-DQB1 Confer Risk of Psoriasis Vulgaris in Japanese

Psoriasis vulgaris (PsV) is an autoimmune disease of skin and joints with heterogeneity in epidemiologic and genetic landscapes of global populations. We conducted an initial genome-wide association study and a replication study of PsV in the Japanese population (606 PsV cases and 2,052 controls). We identified significant associations of the single nucleotide polymorphisms with PsV risk at TNFAIP3-interacting protein 1and the major histocompatibility complex region (P = 3.7 × 10−10 and 6.6 × 10−15, respectively). By updating the HLA imputation reference panel of Japanese (n = 908) to expand HLA gene coverage, we fine-mapped the HLA variants associated with PsV risk. Although we confirmed the PsV risk of HLA-C*06:02 (odds ratio = 6.36, P = 0.0015), its impact was relatively small compared with those in other populations due to rare allele frequency in Japanese (0.4% in controls). Alternatively, HLA-A*02:07, which corresponds to the cysteine residue at HLA-A amino acid position 99 (HLA-A Cys99), demonstrated the most significant association with PsV (odds ratio = 4.61, P = 1.2 × 10–10). In addition to HLA-A*02:07 and HLA-C*06:02, stepwise conditional analysis identified an independent PsV risk of HLA-DQβ1 Asp57 (odds ratio = 2.19, P = 1.9 × 10–6). Our PsV genome-wide association study in Japanese highlighted the genetic architecture of PsV, including the identification of HLA risk variants

Clinical Pharmacogenetics Implementation Consortium (CPIC) Guidelines for Human Leukocyte Antigen B (HLA-B) Genotype and Allopurinol Dosing: 2015 update

The Clinical Pharmacogenetics Implementation Consortium (CPIC) Guidelines for HLA-B*58:01 Genotype and Allopurinol Dosing was originally published in February 2013. We reviewed the recent literature and concluded that none of the evidence would change the therapeutic recommendations in the original guideline; therefore, the original publication remains clinically current. However, we have updated the Supplemental Material and included additional resources for applying CPIC guidelines into the electronic health record. Up-to-date information can be found at PharmGKB (http://www.pharmgkb.org)

Aromatase inhibitors, estrogens and musculoskeletal pain: estrogen-dependent T-cell leukemia 1A (TCL1A) gene-mediated regulation of cytokine expression

Introduction: Arthralgias and myalgias are major side effects associated with aromatase inhibitor (AI) therapy of breast cancer. In a recent genome-wide association study, we identified SNPs - including one that created an estrogen response element near the 3' end of the T-cell leukemia 1A (TCL1A) gene - that were associated with musculoskeletal pain in women on adjuvant AI therapy for breast cancer. We also showed estrogen-dependent, SNP-modulated variation in TCL1A expression and, in preliminary experiments, showed that TCL1A could induce IL-17RA expression. In the present study, we set out to determine whether these SNPs might influence cytokine expression and effect more widely, and, if so, to explore the mechanism of TCL1A-related AI-induced side effects. Methods: The functional genomic experiments performed included determinations of TCL1A, cytokine and cytokine receptor expression in response to estrogen treatment of U2OS cells and lymphoblastoid cell lines that had been stably transfected with estrogen receptor alpha. Changes in mRNA and protein expression after gene knockdown and overexpression were also determined, as was NF-κB transcriptional activity. Results: Estradiol (E2) increased TCL1A expression and, in a TCL1A SNP-dependent fashion, also altered the expression of IL-17, IL-17RA, IL-12, IL-12RB2 and IL-1R2. TCL1A expression was higher in E2-treated lymphoblastoid cell lines with variant SNP genotypes, and induction of the expression of cytokine and cytokine receptor genes was mediated by TCL1A. Finally, estrogen receptor alpha blockade with ICI-182,780 in the presence of E2 resulted in greatly increased NF-κB transcriptional activity, but only in cells that carried variant SNP genotypes. These results linked variant TCL1A SNP sequences that are associated with AI-dependent musculoskeletal pain with increased E2-dependent TCL1A expression and with downstream alterations in cytokine and cytokine receptor expression as well as NF-κB transcriptional activity. Conclusions: SNPs near the 3' terminus of TCL1A were associated with AI-dependent musculoskeletal pain. E2 induced SNP-dependent TCL1A expression, which in turn altered IL-17, IL-17RA, IL-12, IL-12RB2, and IL-1R2 expression as well as NF-κB transcriptional activity. These results provide a pharmacogenomic explanation for a clinically important adverse drug reaction as well as insights into a novel estrogen-dependent mechanism for the modulation of cytokine and cytokine receptor expression

Significant effect of polymorphisms in CYP2D6 and ABCC2 on clinical outcomes of adjuvant tamoxifen therapy for breast cancer patients

Purpose The clinical efficacy of tamoxifen is suspected to be influenced by the activity of drug-metabolizing enzymes and transporters involved in the formation, metabolism, and elimination of its active forms. We investigated relationships of polymorphisms in transporter genes and CYP2D6 to clinical outcome of patients receiving tamoxifen. Patients and Methods We studied 282 patients with hormone receptor–positive, invasive breast cancer receiving tamoxifen monotherapy, including 67 patients who have been previously reported. We investigated the effects of allelic variants of CYP2D6 and haplotype-tagging single nucleotide polymorphisms (tag-SNPs) of ABCB1, ABCC2, and ABCG2 on recurrence-free survival using the Kaplan-Meier method and Cox regression analysis. Plasma concentrations of tamoxifen metabolites were measured in 98 patients receiving tamoxifen 20 mg/d. Results CYP2D6 variants were significantly associated with shorter recurrence-free survival (P = .000036; hazard ratio [HR] = 9.52; 95% CI, 2.79 to 32.45 in patients with two variant alleles v patients without variant alleles). Among 51 tag-SNPs in transporter genes, a significant association was found at rs3740065 in ABCC2 (P = .00017; HR = 10.64; 95% CI, 1.44 to 78.88 in patients with AA v GG genotypes). The number of risk alleles of CYP2D6 and ABCC2 showed cumulative effects on recurrence-free survival (P = .000000055). Patients carrying four risk alleles had 45.25-fold higher risk compared with patients with ≤ one risk allele. CYP2D6 variants were associated with lower plasma levels of endoxifen and 4-hydroxytamoxifen (P = .0000043 and .00052), whereas no significant difference was found among ABCC2 genotype groups. Conclusion Our results suggest that polymorphisms in CYP2D6 and ABCC2 are important predictors for the prognosis of patients with breast cancer treated with tamoxifen

Risk of multiple myeloma is associated with polymorphisms within telomerase genes and telomere length

Compelling biological and epidemiological evidences point to a key role of genetic variants of the TERT and TERC genes in cancer development. We analyzed the genetic variability of these two gene regions using samples of 2,267 multiple myeloma (MM) cases and 2,796 healthy controls. We found that a TERT variant, rs2242652, is associated with reduced MM susceptibility (OR?=?0.81; 95% CI: 0.72-0.92; p?=?0.001). In addition we measured the leukocyte telomere length (LTL) in a subgroup of 140 cases who were chemotherapy-free at the time of blood donation and 468 controls, and found that MM patients had longer telomeres compared to controls (OR?=?1.19; 95% CI: 0.63-2.24; ptrend ?=?0.01 comparing the quartile with the longest LTL versus the shortest LTL). Our data suggest the hypothesis of decreased disease risk by genetic variants that reduce the efficiency of the telomerase complex. This reduced efficiency leads to shorter telomere ends, which in turn may also be a marker of decreased MM risk.Grant sponsor: Polish Ministry of Science and Higher Education; Grant number: NN402178334; Grant sponsors: Research Fund at Region Sjaelland, DK; Baden-Wurttemberg State Ministry of Science, Research and Arts; CRIS Foundatio

Variants in WFS1 and Other Mendelian Deafness Genes are Associated with Cisplatin-Associated Ototoxicity

Cisplatin is one of the most commonly used chemotherapy drugs worldwide and one of the most ototoxic. We sought to identify genetic variants that modulate cisplatin-associated ototoxicity (CAO). Experimental Design: We performed a genome-wide association study (GWAS) of CAO using quantitative audiometry (4-12 kHz) in 511 testicular cancer survivors of European genetic ancestry. We performed polygenic modeling and functional analyses using a variety of publicly available databases. We used an electronic health record cohort to replicate our top mechanistic finding. Results: One SNP, rs62283056, in the first intron of Mendelian deafness gene WFS1 (wolframin ER transmembrane glycoprotein) and an expression quantitative trait locus (eQTL) for WFS1 met genome-wide significance for association with CAO (P=1.4x10-8). A significant interaction between cumulative cisplatin dose and rs62283056 genotype was evident, indicating that higher cisplatin doses exacerbate hearing loss in patients with the minor allele (P=0.035). The association between decreased WFS1 expression and hearing loss was replicated in an independent BioVU cohort (n=18,620 patients, Bonferroni adjusted P\u3c0.05). Beyond this top signal, we show CAO is a polygenic trait and that SNPs in and near 84 known Mendelian deafness genes are significantly enriched for low P-values in the GWAS (P=0.048). Conclusions: We show for the first time the role of WFS1 in CAO and document a statistically significant interaction between increasing cumulative cisplatin dose and rs62283056 genotype. Our clinical translational results demonstrate that pre-therapy patient genotyping to minimize ototoxicity could be useful when deciding between cisplatin-based chemotherapy regimens of comparable efficacy with different cumulative doses

Clinical and Genome-Wide Analysis of Serum Platinum Levels after Cisplatin-Based Chemotherapy

Purpose: Serum platinum is measurable for years after completion of cisplatin-based chemotherapy (CBC). We report the largest investigation of serum platinum levels to date of 1,010 testicular cancer survivors (TCS) assessed 1-35 years after CBC and evaluate genetic contributions to these levels. Experimental Design: Eligible TCS given 300 or 400 (±15) mg/m2 cisplatin underwent extensive audiometric testing, clinical examination, completed questionnaires and had crude serum platinum levels measured. Associations between serum platinum and various risk factors and toxicities were assessed after fitting a bi-exponential model adjusted for follow-up time and cumulative cisplatin dose. A genome-wide association study (GWAS) was performed using the serum platinum residuals of the dose and time-adjusted model. Results: Serum platinum levels exceeded the reference range for approximately 31 years, with a strong inverse relationship with creatinine clearance at follow-up (age-adjusted p = 2.13×10−3). We observed a significant, positive association between residual platinum values and luteinizing hormone (age-adjusted p=6.58×10−3). Patients with high residual platinum levels experienced greater Raynaud’s phenomenon than those with medium or low levels (age-adjusted ORhigh/low = 1.46; p = 0.04), as well as a higher likelihood of developing tinnitus (age-adjusted ORhigh/low = 1.68, p = 0.07). GWAS identified one single nucleotide polymorphism (SNP) meeting genome-wide significance rs1377817 (p=4.6×10−8, a SNP intronic to MYH14). Conclusions: This study indicates that residual platinum values are correlated with several cisplatin-related toxicities. One genetic variant is associated with these levels