Regulatory CDH4 Genetic Variants Associate With Risk to Develop Capecitabine-Induced Hand-Foot Syndrome.

Capecitabine-induced hand-foot syndrome (CiHFS) is a common dermatological adverse reaction affecting around 30% of patients with capecitabine-treated cancer, and the main cause of dose reductions and chemotherapy delays. To identify novel genetic factors associated with CiHFS in patients with cancer, we carried out an extreme-phenotype genomewide association study in 166 patients with breast and colorectal capecitabine-treated cancer with replication in a second cohort of 85 patients. We discovered and replicated a cluster of four highly correlated single-nucleotide polymorphisms associated with susceptibility to CiHFS at 20q13.33 locus (top hit = rs6129058, hazard ratio = 2.40, 95% confidence interval = 1.78-3.20; P = 1.2 × 10-8 ). Using circular chromosome conformation capture sequencing, we identified a chromatin contact between the locus containing the risk alleles and the promoter of CDH4, located 90 kilobases away. The risk haplotype was associated with decreased levels of CDH4 mRNA and the protein it encodes, R-cadherin (RCAD), which mainly localizes in the granular layer of the epidermis. In human keratinocytes, CDH4 downregulation resulted in reduced expression of involucrin, a protein of the cornified envelope, an essential structure for skin barrier function. Immunohistochemical analyses revealed that skin from patients with severe CiHFS exhibited low levels of RCAD and involucrin before capecitabine treatment. Our results uncover a novel mechanism underlying individual genetic susceptibility to CiHFS with implications for clinically relevant risk prediction.

Pharmacogenetic variants and response to neoadjuvant single-agent doxorubicin or docetaxel: a study in locally advanced breast cancer patients participating in the NCT00123929 phase 2 randomized trial.

OBJECTIVES: Taxanes and anthracyclines are widely used in the treatment of breast cancer, although the benefit is limited to a proportion of patients and predictive biomarkers for clinical outcome remain elusive. PATIENTS AND METHODS: We carried out a pharmacogenetic study in 181 patients with locally advanced breast cancer enrolled in a phase 2 randomized clinical trial (NCT00123929), where patients were randomly assigned to receive neoadjuvant single-agent docetaxel 100 mg/m(2) (n=84) or doxorubicin 75 mg/m(2) (n=97). We studied the association of 226 single nucleotide polymorphisms (SNPs) in 15 key drug biotransformation genes with neoadjuvant pathological tumor response residual cancer burden index to docetaxel and to doxorubicin. RESULTS: We identified a significant association for rs162561, an intronic SNP located in the cytochrome P450 family 1 subfamily B member 1 (CYP1B1) gene, with tumor response in patients treated with single-agent docetaxel (dominant model: ß=1.02, 95% confidence interval=0.49-1.55; P=1.77×10(-4)), and for rs717620, an SNP located in the promoter of the ATP-binding cassette subfamily C member 2 (ABCC2) gene, in patients treated with neoadjuvant doxorubicin (recessive model: ß=1.67; 95% confidence interval=0.26-3.11; P=0.02). CONCLUSION: We identified two polymorphisms in CYP1B1 and ABCC2 associated with tumor pathological response following docetaxel or doxorubicin neoadjuvant monotherapy, respectively. Although further validation is required, these variants could be potential predictive genetic markers for treatment outcome in breast cancer patients.

Exome sequencing of three cases of familial exceptional longevity.

Exceptional longevity (EL) is a rare phenotype that can cluster in families, and co-segregation of genetic variation in these families may point to candidate genes that could contribute to extended lifespan. In this study, for the first time, we have sequenced a total of seven exomes from exceptionally long-lived siblings (probands ≥ 103 years and at least one sibling ≥ 97 years) that come from three separate families. We have focused on rare functional variants (RFVs) which have ≤ 1% minor allele frequency according to databases and that are likely to alter gene product function. Based on this, we have identified one candidate longevity gene carrying RFVs in all three families, APOB. Interestingly, APOB is a component of lipoprotein particles together with APOE, and variants in the genes encoding these two proteins have been previously associated with human longevity. Analysis of nonfamilial EL cases showed a trend, without reaching statistical significance, toward enrichment of APOB RFVs. We have also identified candidate longevity genes shared between two families (5-13) or within individual families (66-156 genes). Some of these genes have been previously linked to longevity in model organisms, such as PPARGC1A, NRG1, RAD52, RAD51, NCOR1, and ADCY5 genes. This work provides an initial catalog of genes that could contribute to exceptional familial longevity.

A polymorphism in the cytidine deaminase promoter predicts severe capecitabine-induced hand-foot syndrome.

PURPOSE: Hand-foot syndrome (HFS) is one of the most relevant dose-limiting adverse effects of capecitabine, an oral prodrug of 5-fluorouracil used in the standard treatment of breast and colorectal cancer. We investigated the association between grade 3 HFS and genetic variations in genes involved in capecitabine metabolism. EXPERIMENTAL DESIGN: We genotyped a total of 13 polymorphisms in the carboxylesterase 2 (CES2) gene, the cytidine deaminase (CDD) gene, the thymidine phosphorylase (TP) gene, the thymidylate synthase (TS) gene, and the dihydropyrimidine dehydrogenase (DPD) gene in 130 patients treated with capecitabine. We correlated these polymorphisms with susceptibility to HFS. RESULTS: We found an association of HFS appearance with rs532545 located in the promoter region of CDD (OR = 2.02, 95% CI = 1.02-3.99, P = 0.039). Because we found no association between the rs532545 genotype and CDD mRNA expression in Epstein-Barr virus lymphoblastoid cells, we explored additional genetic variations across the CDD promoter. We found an insertion, rs3215400, in linkage disequilibrium with rs532545 (D' = 0.92), which was more clearly associated with HFS (OR = 0.51, 95% CI = 0.27-0.95, P = 0.028) in patients and with total CDD gene expression (P = 0.004) in lymphoblastoid cells. In silico analysis suggested that this insertion might create a binding site for the transcriptional regulator E2F. Using a SNaPshot assay in lymphoblastoid cells, we observed a 5.7-fold increased allele-specific mRNA expression from the deleted allele. CONCLUSIONS: The deleted allele of rs3215400 shows an increased allele-specific expression and is significantly associated with an increased risk of capecitabine-induced HFS.