Elisabeth del Río

Single nucleotide polymorphism in the 5′ tandem repeat sequences of thymidylate synthase gene predicts for response to fluorouracil‐based chemotherapy in advanced colorectal cancer patients

Thymidylate synthase (TS) is the primary target of 5‐fluorouracil (5‐FU). A VNTR polymorphism in the TS promoter region is associated with the efficacy of 5‐FU‐based chemotherapy in colorectal cancer. A common G>C SNP at the 12th nucleotide of the second repeat in the TS*3 alleles has been recently described. The combination of SNP and VNTR allows the definition of 3 TS alleles: *2, *3G and *3C. The aim of our study was to evaluate the predictive value of clinical response and survival of these new defined TS alleles. TS genotypes of 89 patients diagnosed with metastatic colorectal cancer and undergoing 5‐FU‐based chemotherapy were carried out. The clinical outcome was evaluated according to the genotype (high expression genotype: *2R/*3G; *3C/*3G; *3G/*3G; and low expression genotype: *2R/*2R; *2R/*3C; *3C/*3C. A higher overall response was observed in the group of patients with a low expression genotype (p = 0.035). The probability of achieving a clinical response of patients with a low expression‐related genotype was 2.9 higher than that of the other group (95% CI = 1.03–5.6, p = 0.04). The median time to progression was 12 months and 9 months in the low and high expression groups, respectively (p = 0.07, log rank test). Overall survival was significantly longer in the low expression group. In this group the median OS was not achieved at 50 months of follow‐up in contrast to the 20 months observed in the high expression group (p = 0.03). TS genotype was an independent predictor of progression‐free and overall survival in the Cox regression models after adjustment to the other clinical variables. The selection of patients who are likely to respond to 5‐FU therapy may be considerably improved if the TS genotype were to include both the VNTR and the SNP located within the promoter region of the gene.

Pharmacogenetics of the DNA repair pathways in advanced non-small cell lung cancer patients treated with platinum-based chemotherapy.

Genetic variants in DNA repair genes may play a role in the effectiveness of platinum-based chemotherapy in non-small cell lung cancer (NSCLC). We analyzed 17 SNPs in eight genes (ERCC1, ERCC2, ERCC3, ERCC4, ERCC5, XPA, XRCC1 and XRCC2) involved in DNA repair mechanisms and its association with outcome in NSCLC. This prospective study included patients with stages III and IV treated with platinum-based chemotherapy. All patients (n = 161) received cisplatin or carboplatin plus a third-generation drug. Additionally, stage IIIA and IIIB patients (n = 74) received concomitant or sequential radiotherapy. Germline polymorphisms were analyzed using the BioMark system in blood DNA samples. We found that in stage III patients, response was significantly associated with SNPs in ERCC1 and in ERCC3 genes, while radiotherapy-derived toxicity correlated with SNPs in the ERCC2 gene. In stage IV patients, response was associated with a genetic variant in the ERCC4 gene and survival with a SNP in the XRCC1 gene. The complexity of the DNA repair mechanisms along with the heterogeneity in the treatment of lung cancer could explain the role of multiple genes as putative biomarkers of patient outcome.

Allelic and genotypic associations of DRD2 TaqI A polymorphism with heroin dependence in Spanish subjects: a case control study

BackgroundConflicting associations with heroin dependence have been found involving the A1 allele of dopamine D2 receptor gene (DRD2) Taq I A polymorphism.MethodsWe compared two samples of unrelated Spanish individuals, all of European origin: 281 methadone-maintained heroin-dependent patients (207 males and 74 females) who frequently used non-opioid substances, and 145 control subjects (98 males and 47 females).ResultsThe A1-A1 genotype was detected in 7.1% of patients and 1.4% of controls (P = 0.011, odds ratio = 5.48, 95% CI 1.26–23.78). Although the A1 allele was not associated with heroin dependence in the entire sample, the frequency of A1 allele was higher in male patients than in male controls (24.4% vs. 16.3%, P = 0.024, odds ratio = 1.65, 95% CI 1.07–2.57). A logistic regression analysis showed an interaction between DRD2 alleles and gender (odds ratio = 1.77, 95% CI 1.15–2.70).ConclusionOur results indicate that, in Spanish individuals, genotypes of the DRD2 Taq I A polymorphism contribute to variations in the risk of heroin dependence, while single alleles contribute only in males.

Identification of the 185delAG BRCA1 mutation in a Spanish Gypsy population

Abstract The 185delAG BRCA1 deletion occurs with a high frequency in Ashkenazi Jews. We detected this mutation in two Spanish Gypsy women (the only Gypsy participants) in an extensive study of 90 high-risk families and 160 women with early-onset breast cancer. One of these Gypsy women belonged to a high-risk family and the other had had early-onset breast cancer. The mutation was also detected in 1 out of 25 Gypsy samples unrelated to breast cancer. All the samples with the mutation shared the marker alleles present in Jewish samples with 185delAG. This is the first report of this mutation in a non-Jewish well-defined ethnic population. According to these findings the carrier frequency of this mutation in Gypsy individuals could be several times higher than that of the general population, and this should be taken into consideration in genetic screening for cancer in Gypsy populations.

Immunoglobulin G fragment C receptor polymorphisms and KRAS mutations: Are they useful biomarkers of clinical outcome in advanced colorectal cancer treated with anti-EGFR-based therapy?

KRAS mutations have been identified as a strong predictor of resistance to anti‐epidermal growth factor receptor (EGFR) therapies. Besides inhibiting the EGFR pathway, anti‐EGFR monoclonal antibodies may exert antitumor effects through antibody‐dependent cell‐mediated cytotoxicity (ADCC). Through this mechanism, the antibody fragment C portion (Fcγ) interacts with Fc receptors (FcγRs) expressed by immune effectors cells. We investigated the association of FcγR polymorphisms and KRAS mutation with the clinical outcome of 104 refractory metastatic colorectal cancer (mCRC) patients treated with anti‐EGFR antibodies. FcγRIIa‐H131R and FcγRIIIa‐V158F polymorphisms were analyzed in genomic DNA using a 48.48 dynamic array on the BioMark system (Fluidigm, South Sanfrancisco, CA, USA). Tumor tissues from 96 cases were screened for KRAS mutations. KRAS mutation was associated with a lower response rate (RR) (P = 0.035) and a shorter progression‐free survival (PFS) (3 vs 7 months; P = 0.36). FcγRIIa‐H131R and FcγRIIIa‐V158F polymorphisms did not show statistically significant associations with response, PFS, or KRAS status. In the logistic regression analysis, KRAS status (P = 0.04) and skin toxicity (P = 0.03) were associated with RR. By multivariate analysis, the clinical risk classification (P = 0.006) and skin toxicity (P < 0.0001) were found to be independent risk factors for PFS. In conclusion, the FcγRIIa and FcγRIIIa polymorphisms are not useful as molecular markers for clinical outcome in mCRC patients. To date, the EORTC (European Organization for Research and Treatment of Cancer Classification), skin toxicity, and KRAS status are the only reliable biomarkers to identify patients that would benefit from anti‐EGFR therapy. (Cancer Sci 2010)

Autosomal recessive retinitis pigmentosa in Spain: evaluation of four genes and two loci involved in the disease

Autosomal recessive retinitis pigmentosa (ARRP) is a genetically heterogeneous form of retinal degeneration. The genes for the β‐subunit of rod phosphodiesterase (PDEB), rhodopsin (RHO), peripherin/RDS (RDS) and the rod outer segment membrane protein 1 (ROM1), as well as loci at 6p and 1q, have previously been reported as the cause of ARRP. In order to determine whether they are responsible for the disease in Spanish pedigrees, linkage and homozygosity studies using markers at these loci were carried out on 47 Spanish ARRP families. SSCP analysis was performed to search for mutations in the genes cosegregating with the disease in particular pedigrees. Three homozygous mutations in the PDEB gene were found, thus accounting for 6% of the cases. No other disease‐causing mutation was observed in the other genes analysed, nor was significant evidence found for the involvement of the loci at 6p or 1q. On the basis of these data, it is unlikely that these genes and loci account for a considerable proportion of ARRP cases.

Influence of thymidylate synthase and methylenetetrahydrofolate reductase gene polymorphisms on the disease-free survival of breast cancer patients receiving adjuvant 5-fluorouracil/methotrexate-based therapy.

This paper considers the influence of thymidylate synthase (TS) and methylenetetrahydrofolate reductase (MTHFR) polymorphisms on the disease-free survival of patients with breast cancer who were treated with adjuvant therapy containing 5-fluorouracil. Relevant clinical data were obtained from the clinical records of 93 patients included in the study. TS and MTHFR genotypes were determined by PCR–agarose gel electrophoresis (TS) and by means of real-time PCR on an ABI PRISM 7000 Sequence Detection System (MTHFR). The median age of 93 patients was 42 years (range 21–76). Fifty patients received CMF, 18 FAC and 25 FEC. The median follow-up of the series was 134 months, with 34 relapses (37%). Sixty patients had a low expression genotype of TS (64.5%) and 33 had a high expression genotype (35.5). No differences in disease-free survival were observed between the two groups (P=0.42). The MTHFR genotype of the 50 patients treated with a chemotherapy regime that included methotrexate was as follows: for C677T, 21 C/C, 21 C/T and eight T/T; for A1298C it was 22 A/A, 24 A/C and four C/C. No differences were found in disease-free survival as regards the MTHFR genotypes (P=0.1 and P=0.6, respectively). Nor were there differences in disease-free survival in the multivariate analyses that included the TS and MTHF genotypes and the relevant clinical variables (P=0.3 for TS, P=0.1 for C677T and P=0.6 for A1298C). This study shows that genotyping the TS or the MTHFR gene is of little value in the individual assessment of the use of adjuvant therapy in breast cancer patients.

Absence of large intragenic rearrangements in the DPYD gene in a large cohort of colorectal cancer patients treated with 5‐FU‐based chemotherapy

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT * Dihydropyrimidine dehydrogenase (DPD) is the enzyme responsible for the elimination of approximately 80% of the administered dose of 5-fluorouracil (5-FU). * Mutations in the DPD-coding gene have been shown to increase the risk of severe toxicity in 5-FU treated patients. * The IVS14+1G>A is the most common DPYD mutation. WHAT THIS STUDY ADDS * The intragenic rearrangements of DPYD using multiplex ligation-dependent probe amplification (MLPA) were studied for the first time in a large series of 234 colorectal cancer patients treated with 5-FU-containing chemotherapy. * No deletions or duplications of one or more DPYD exons were detected. The presence of the IVS14+1G>A mutation was also excluded. * These data show that neither the large genomic rearrangements in the DPYD gene nor the IVS14+1G>A mutation are responsible for the serious toxicity associated with a 5-FU containing regimen in this cohort of Spanish patients. AIMS To study the relationship between the toxicity associated with a 5-FU-based therapy and the presence of (i) the large intragenic rearrangements in the DPYD gene and (ii) the IVS14+1G>A mutation. METHODS We used the multiplex ligation-dependent probe amplification technique (MLPA) to study genomic DNA from 234 colorectal cancer patients treated with 5-FU-based chemotherapy. RESULTS We did not detect any deletion/duplication in the DPYD gene. The presence of the IVS14+1G>A mutation was also excluded. CONCLUSIONS Neither the large genomic rearrangements in the DPYD gene nor the IVS14+1G>A mutation play a significant role in the development of serious toxicity associated with a 5-FU containing regimen.

Pharmacogenetic analysis in the treatment of Hodgkin lymphoma

Abstract About 15–20% of patients with Hodgkin lymphoma (HL) treated with doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD) chemotherapy ± radiotherapy still die following relapse or progressive disease. The outcome might be influenced by gene polymorphisms influencing chemotherapy metabolism. We studied 126 patients with HL treated with the ABVD regimen. We analyzed glutathione S-transferases (GSTT1, GSTM1 and GSTP1), cytochromes P450 (CYP3A4 and CYP2D6), UGT1A1 and BLMH gene polymorphisms and their association with clinical and outcome variables. Patients with a GSTM1 genotype associated with extensive or ultrahigh activity had a probability of 93.8% to achieve a complete response, while the remainder of the patients had a probability of 82.3% (p = 0.04). This variable maintained its statistical significance in multivariate analysis (hazard ratio 3.7, 95% confidence interval 1–13, p = 0.05). Patients with an extensive or ultrahigh GSTM1 genotype had better prognostic factors than those with poor or intermediate genotypes (hemoglobin level, p = 0.003; serum albumin, p = 0.05; and International Prognostic Score, p = 0.038). Thus, in the treatment of HL, clinical determinants might be more relevant than the pharmacogenetic parameters analyzed to date.

Two contiguously located germline BRCA1 mutations in a Spanish early-onset breast cancer family

We identified two BRCA1 mutations in a high risk breast cancer family: the missense 1240 C > T (Thr > Ile) and the 1241delAC at codon 374, which results in a stop at codon 376. Both were contiguously located in the same BRCA1 gene, in a motif of 11 amino acids, which is highly conserved across human, canine and murine species. The presence of missense mutations in this motif in breast-cancer families suggests an important functional role for this protein region and a potential deleterious effect of the 1240C > T mutation.