The LCS6 polymorphism in the binding site of let-7 microRNA to the KRAS 3'-untranslated region: its role in the efficacy of anti-EGFR-based therapy in metastatic colorectal cancer patients.

OBJECTIVE: Although KRAS mutation status has been identified as a strong predictor of response to anti-epidermal growth factor receptor (EGFR) therapies, not all wild-type patients respond. The lethal-7 (let-7) family of microRNAs regulates KRAS activity. A functional polymorphism (rs61764370) has been described in the let-7 complementary site (LCS6). We hypothesized a possible association between this KRAS let-7 LCS6 polymorphism and the response to anti-EGFR treatments in KRAS and BRAF wild-type metastatic colorectal cancer patients (mCRC). MATERIALS AND METHODS: We studied the association of the KRAS let-7 LCS6 polymorphism with the response in 100 refractory mCRC patients treated with anti-EGFR antibodies. To assess the real effect of this polymorphism in relation to the treatment administered, we also studied this association in an independent cohort of patients treated exclusively with chemotherapy. The KRAS let-7 LCS6 polymorphism was genotyped using the BioMark system in blood and tumor DNA samples. The BRAF V600E mutation was analyzed in tumor samples. RESULTS: The KRAS let-7 LCS6 G-allele showed a statistically significant association with nonresponse to anti-EGFR-based treatment: 31.9% of patients with the T/T genotype presented a complete or a partial response versus no patients with T/G or G/G genotypes (P=0.004). No statistically significant differences were observed in the patients who received chemotherapy only. CONCLUSION: These data support the pharmacogenetic role of the KRAS let-7 LCS6 polymorphism in predicting the efficacy of anti-EGFR-based therapy in mCRC patients with the KRAS and the BRAF wild-type genotype.

Association of the CFTR gene with asthma and airway mucus hypersecretion.

INTRODUCTION: Asthma with airway mucus hypersecretion is an inadequately characterized variant of asthma. While several studies have reported that hypersecreting patients may carry genetic variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, many of those studies have been questioned for their numerous limitations and contradictory results. OBJECTIVES: (1) To determine the presence of genetic variants of the CFTR gene in patients with asthma with and without airway mucus hypersecretion. (2) To identify the clinical, inflammatory and functional characteristics of the asthma phenotype with airway mucus hypersecretion. METHOD: Comparative multicentre cross-sectional descriptive study that included 100 patients with asthma (39 hypersecretors and 61 non-hypersecretors). Asthmatic hypersecretion was defined as the presence of cough productive of sputum on most days for at least 3 months in 2 successive years. The patients were tested for fractional exhaled nitric oxide, spirometry, induced sputum cell count, total immunoglobulin E (IgE), peripheral blood eosinophil count, C-reactive protein, blood fibrinogen and blood albumin and underwent a skin prick test. Asthma control and quality of life were assessed by the Asthma Control Test and Mini Asthma Quality of Life questionnaires, respectively. Blood DNA samples were collected from the patients and next-generation sequencing using a MiSeq sequencer and the Illumina platform was used for the CFTR gene analysis. RESULTS: Genetic differences were observed in the c.1680-870T>A polymorphism of the CFTR gene, significantly more evident in hypersecretors than in non-hypersecretors: 78.94% vs. 59.32% in the majority allele and 21.05% vs. 40.67% in the minority allele (p = 0.036). Clinically, asthma hypersecretors compared to non-hypersecretors were older (57.4 years vs. 49.4 years; p = 0.004); had greater asthma severity (58.9% vs. 23.7%; p = 0.005); experienced greater airway obstruction (FEV1/FVC% 64.3 vs. 69.5; p = 0.041); had poorer asthma control (60% vs. 29%; p = 0.021); had lower IgE levels (126.4 IU/mL vs. 407.6 IU/mL; p = 0.003); and were less likely to have a positive prick test (37.5% vs. 68.85%; p = 0.011). CONCLUSION: The results suggest that patients with asthma and with mucus hypersecretion (1) may have a different phenotype and disease mechanism produced by an intronic polymorphism in the CFTR gene (NM_000492.3:c.1680-870T>A), and (2) may have a poorer clinical outcome characterized by severe disease and poorer asthma control with a non-allergic inflammatory phenotype.

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.

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.

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

BACKGROUND: Conflicting associations with heroin dependence have been found involving the A1 allele of dopamine D2 receptor gene (DRD2) TaqI A polymorphism. METHODS: We 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). RESULTS: The 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). CONCLUSION: Our results indicate that, in Spanish individuals, genotypes of the DRD2 TaqI A polymorphism contribute to variations in the risk of heroin dependence, while single alleles contribute only in males.

Association of CYP2D6 ultrarapid metabolizer genotype with deficient patient satisfaction regarding methadone maintenance treatment.

OBJECTIVE: The activity of cytochrome P-450 enzyme 2D6 (CYP2D6) could be related to heroin-dependent patient satisfaction with methadone maintenance treatment. We sought to compare satisfaction with the usual methadone treatment in patients who are ultrarapid, extensive or poor metabolizers, according to CYP2D6 genotyping. METHODS: Two hundred and five heroin-dependent patients filled out the Verona Service Satisfaction Scale for methadone maintenance treatment (VSSS-MT), before CYP2D6 genotyping. RESULTS: VSSS-MT overall scores were comparable in the poor metabolizer (N=9) and extensive metabolizer (N=185) groups, although they were higher in poor metabolizers and extensive metabolizers taken together than in the ultrarapid metabolizers (N=11) (p<0.003). Likewise, ultrarapid metabolizers scored higher than the rest of the sample on the VSSS-MT Basic Interventions subscale (p<001). Regarding this subscale, no poor metabolizers felt dissatisfied, and ultrarapid metabolizer males (N=7) reported lower satisfaction than ultrarapid metabolizer females (N=4) (p<0.022). Ultrarapid metabolizer genotype accounted for 4.2% of the variance on the VSSS-MT total scores, and 5.0% on the Basic Intervention scores. CONCLUSION: Heroin-dependent patients who are CYP2D6 ultrarapid metabolizers according to genotyping present deficient satisfaction with methadone maintenance treatment.

[Frequency of thiopurine S-methyltransferase alleles in different ethnic groups living in Spain]. / Frecuencia y distribución de las variantes alélicas del gen de la tiopurina S-metiltransferasa en distintos grupos étnicos españoles.

BACKGROUND AND OBJECTIVE: Thiopurine S-methyltransferase (TPMT) metabolizes thiopurine drugs regulating their cytotoxicity and clinical response. TPMT activity is inherited as an autosomal recessive trait and several mutations in the TPMT gene have been identified which correlate with a low activity phenotype. A variable number of tandem repeat within the TPMT promoter has been reported to modulate the levels of this enzyme activity. The allelic variants of the TPMT gene were analyzed in ethnic groups living in Spain. SUBJECTS AND METHOD: The frequency of 4 allelic variants of the TPMT gene as well as the genotype in the promoter region were analyzed in 138 Spanish blood donors, 95 gypsies and 51 Basque subjects. RESULTS: In the group of 138 blood donors, we identified: 13 carriers of a mutated TPMT allele (*3A, *3B, *3C), one homozygous TPMT*3B and a compound heterozygote (TPMT*3A/TPMT*3B). In the Basque group, 3 subjects were TPMT*3A carriers and one case was a TPMT*3B heterozygote. In the gypsy group one subject carried a TPMT*3A allele and 3 were compound heterozygotes TPMT*3A/TPMT*3B. The TMPT*3A was the most frequent mutant alelle. As for the polymorphic tandem repeat in the 5' flanking region of the TPMT gene, alleles with 4 or 5 repeats made up the vast majority (96%) of the chromosomes in the control group of Spanish subjects. This figure decreased to 75% in Basques and to 62% in gypsies, in whom 37% of the alleles contained more than 5 tandem repeats. CONCLUSIONS: The frequencies of the mutant TPMT alleles observed in the 3 groups are similar to those reported in Caucasian populations.

Methotrexate pharmacokinetic genetic variants are associated with outcome in rheumatoid arthritis patients.

BACKGROUND: Methotrexate (MTX) is the most used drug for the treatment of rheumatoid arthritis (RA) although outcome differs among patients. AIM: To evaluate whether polymorphisms in pharmacokinetic genes are associated with outcome in RA patients receiving MTX. PATIENTS & METHODS: We analyzed 28 SNPs in SLC19A1/RFC1, ABCB1, FPGS and GGH genes. RESULTS: We studied 194 RA patients receiving MTX monotherapy. Two FPGS SNPs, rs10987742 and rs10106, were associated with response (p = 0.033 and p = 0.041, respectively). The FPGS rs10106 variant was also associated with MTX survival (p = 0.005) and toxicity (p = 0.021). Three ABCB1 SNPs, rs868755, rs10280623 and rs1858923, were associated with toxicity (p = 0.025, p = 0.048 and p = 0.031, respectively). CONCLUSION: FPGS and ABCB1 genetic variants can influence the outcome in RA patients receiving MTX monotherapy.

A genetic polymorphism in the coding region of the gastric intrinsic factor gene (GIF) is associated with congenital intrinsic factor deficiency.

Congenital intrinsic factor (IF) deficiency is a disorder characterized by megaloblastic anemia due to the absence of gastric IF (GIF, GenBank NM_005142) and GIF antibodies, with probable autosomal recessive inheritance. Most of the reported patients are isolated cases without genetic studies of the parents or siblings. Complete exonic sequences were determined from the PCR products generated from genomic DNA of five affected individuals. All probands had the identical variant (g.68A>G) in the second position of the fifth codon in the coding sequence of the gene that introduces a restriction enzyme site for Msp I and predicts a change in the mature protein from glutamine(5) (CAG) to arginine(5) (CGG). Three subjects were homozygous for this base exchange and two subjects were heterozygous, one of which was apparently a compound heterozygote at positions 1 and 2 of the fifth codon ([g.67C>G] + [g.68A>G]). The other patient, heterozygous for position 2, had one heterozygous unaffected parent. Most parents were heterozygous for this base exchange, confirming the pattern of autosomal recessive inheritance for congenital IF deficiency. cDNA encoding GIF was mutated at base pair g.68 (A>G) and expressed in COS-7 cells. The apparent size, secretion rate, and sensitivity to pepsin hydrolysis of the expressed IF were similar to native IF. The allelic frequency of g.68A>G was 0.067 and 0.038 in two control populations. This sequence aberration is not the cause of the phenotype, but is associated with the genotype of congenital IF deficiency and could serve as a marker for inheritance of this disorder.

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.

Pharmacogenetic analysis in the treatment of Hodgkin lymphoma.

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.

Pharmacogenetic study in rectal cancer patients treated with preoperative chemoradiotherapy: polymorphisms in thymidylate synthase, epidermal growth factor receptor, GSTP1, and DNA repair genes.

PURPOSE: Several studies have been performed to evaluate the usefulness of neoadjuvant treatment using oxaliplatin and fluoropyrimidines for locally advanced rectal cancer. However, preoperative biomarkers of outcome are lacking. We studied the polymorphisms in thymidylate synthase, epidermal growth factor receptor, glutathione S-transferase pi 1 (GSTP1), and several DNA repair genes to evaluate their usefulness as pharmacogenetic markers in a cohort of 128 rectal cancer patients treated with preoperative chemoradiotherapy. METHODS AND MATERIALS: Blood samples were obtained from 128 patients with Stage II-III rectal cancer. DNA was extracted from the peripheral blood nucleated cells, and the genotypes were analyzed by polymerase chain reaction amplification and automated sequencing techniques or using a 48.48 dynamic array on the BioMark system. The germline polymorphisms studied were thymidylate synthase, (VNTR/5'UTR, 2R G>C single nucleotide polymorphism [SNP], 3R G>C SNP), epidermal growth factor receptor (Arg497Lys), GSTP1 (Ile105val), excision repair cross-complementing 1 (Asn118Asn, 8092C>A, 19716G>C), X-ray repair cross-complementing group 1 (XRCC1) (Arg194Trp, Arg280His, Arg399Gln), and xeroderma pigmentosum group D (Lys751Gln). The pathologic response, pathologic regression, progression-free survival, and overall survival were evaluated according to each genotype. RESULTS: The ∗3/∗3 thymidylate synthase genotype was associated with a greater response rate (pathologic complete remission and microfoci residual tumor, 59% in ∗3/∗3 vs. 35% in ∗2/∗2 and ∗2/∗3; p=.013). For the thymidylate synthase genotype, the median progression-free survival was 103 months for the ∗3/∗3 patients and 84 months for the ∗2/∗2 and ∗2/∗3 patients (p=.039). For XRCC1 Arg399Gln SNP, the median progression-free survival was 101 months for the G/G, 78 months for the G/A, and 31 months for the A/A patients (p=.048). CONCLUSIONS: The thymidylate synthase genotype and XRCC1 Arg399Gln polymorphism might help to identify Stage II-III rectal cancer patients with a better outcome after preoperative concomitant chemoradiotherapy.

Thymidylate synthase germline polymorphisms in rectal cancer patients treated with neoadjuvant chemoradiotherapy based on 5-fluorouracil.

PURPOSE: Chemoradiotherapy using 5-fluorouracil has shown to be effective treatment for rectal cancer. Thymidylate synthase (TS) is an important target enzyme for the fluoropyrimidines. However, the predictive role of TS levels in early stage rectal cancer is not yet well understood. We analyzed the value of TS gene polymorphisms as a predictive marker in patients with stage II and III rectal cancer treated with preoperative concomitant radiotherapy and fluoropyrimidine-based chemotherapy. METHODS AND MATERIALS: Between 1998 and 2007, blood samples were obtained from 51 patients with stage II/III rectal cancer. Forty patients were T2-3 (78%), 11 were T4 (22%), and 59% were N+. DNA was extracted from peripheral blood, and the genotypes were analyzed using PCR-restriction fragment length polymorphism and automated sequencing techniques. RESULTS: The *3/*3 thymidylate synthase genotype was associated with a higher response rate (pathological complete remission and microfoci residual tumor; 61 vs. 22% in *2/*2 and *2/*3; P = 0.013). In the multivariate analysis, the *3/*3 thymidylate synthase genotype was also an independent prognostic factor for better survival (P < 0.05). CONCLUSIONS: The thymidylate synthase genotype might help to identify patients with stage II/III rectal cancer who could benefit from pre- and postoperative fluorouracil-based chemotherapy.

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.

Characterization of variant alleles of cytochrome CYP2D6 in a Spanish population.

The CYP2D6 gene codes for a P450 monooxygenase which is involved in the biotransformation of a large number of commonly prescribed drugs. Adverse drug effects and therapeutic failure can be related to abnormal CYP2D6 activity. We investigated the allele and genotype frequencies of cytochrome P4502D6 in a Spanish population to predict the prevalence of ultra-rapid and poor metabolizer phenotypes in our population and to design a feasible CYP2D6 genotyping protocol. The study included 105 healthy unrelated Spanish Caucasian volunteers. CYP2D6 genotyping was performed by a combination of long-PCR, direct sequencing and allele-specific real-time PCR. The frequency of the wild-type CYP2D6*1 allele was 31%. The alleles coding for slightly (CYP2D6*2) or moderately (*9 and *10) reduced activity showed frequencies of 40.47, 2.38 and 1.90%, respectively. Frequencies of defective alleles *3, *4, *5 and *6 were 0.95, 13.8, 3.33 and 0.95%, respectively. The defective CYP2D6 alleles *7, *8, *12, *14, *15 and *21 were not found. Duplicated CYP2D6 alleles were detected at a frequency of 4.27%. Our protocol allows the identification of the four inactive CYP2D6 alleles (*3, *4, *5 and *6) and the detection of alleles with CYP2D6 *1, CYP2D6 *2 and CYP2D6*4 gene duplications. Testing for this reduced CYP2D6 allele set would facilitate its use in clinical practice by assisting in the development of individualized pharmacotherapy.

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.

Preclinical memory profile in Alzheimer patients with and without allele APOE-epsilon4.

To investigate the association between APOE-epsilon4 allele and memory phenotype in the preclinical stage of Alzheimer's disease (AD). We compared an extensive preclinical memory profile at the baseline evaluation of 2 AD genotype groups: APOE-epsilon4 allele carriers and patients with APOE-epsilon3 homozygosity. Baseline memory performance was carried out at least 2 years (interval of 27.7 +/- 4 months) before AD diagnosis was established, and analysis included different modalities of working memory (visuoperceptive, visuospatial, digit span and processing speed), of declarative memory (recent, verbal learning, prospective and semantic) and of nondeclarative memory (procedural, incidental and priming). We found no significant differences: memory performance was similar in both genotype groups. The presence of the APOE-epsilon4 allele does not seem to be sufficient to cause a distinctive preclinical memory phenotype in AD patients.

The prothrombin 20210A allele influences clinical manifestations of hemophilia A in patients with intron 22 inversion and without inhibitors.

BACKGROUND AND OBJECTIVES: The modulation of disease severity in hemophilia A (HA) patients may be related to the co-inheritance of mutations in genes with a known thrombotic effect such as factor V Leiden (FVL) and prothrombin. In the Spanish population, the prothrombin 20210A (PT20210A) allele is the most prevalent genetic risk factor for venous thromboembolism. DESIGN AND METHODS: We investigated the presence of both mutations in a cohort of 265 hemophiliac patients divided into two groups: I) 140 unrelated patients with moderate and mild HA and II) 125 unrelated patients with severe HA (83 carrying an inversion of intron 22). RESULTS: In group I, 4 patients had the FVL (2.8% vs. 2.98% controls) and 5 had the PT20210A (3.6% vs. 6.46% controls). In group II, two patients with inversion had the FVL (1.6%) and PT20210A was found in 10 patients (8%), five of them with inversion of intron 22 without inhibitors. One of these patients had the FVL and PT20210A mutations concomitantly. In the subgroup of patients with inversion who were carriers of the PT20210A, three parameters i.e. spontaneous bleeding (p=0.008), factor VIII utilization (p=0.016) and number of hemophilic arthropathies (p<0.0005) were significantly lower than in a subgroup of 11 age-matched non-PT20210A severe HA patients with inversion and without inhibitors. INTERPRETATION AND CONCLUSIONS: These results indicate that the inheritance of PT20210A could be a protective factor that mitigates the clinical severity of HA.