María-Encarnación Fernández-Contreras

Universidad Autónoma de Madrid, Madrid, Madrid, Spain

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Publications (5)14.39 Total impact

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    ABSTRACT: Experimental evidence has revealed that several thymidylate synthase (TS) DNA polymorphisms modulate gene expression, which, in turn is known to be down-regulated by oestrogen receptor subtypes. Consequently, this process might be influenced by female hormones. Based on these data, we investigated whether patient's gender and TS polymorphism exert an interactive effect on the clinical evolution of patients with advanced colorectal cancer (CRC) subjected to 5 fluorouracil (5FU)-based adjuvant chemotherapy. A retrospective study was carried out on paraffin-embedded sections from 81 CRC patients. A variable tandem repeat (VNTR) of 28 bp, a G/C single nucleotide polymorphism (SNP), and a deletion of 6 bp (ins1494del 6 bp) were studied. Genotyping methods were polymerase chain reaction (PCR) for VNTR, and PCR followed by restriction length fragment polymorphism (PCR-RFLP) for SNP and ins1494del 6 bp. The effect of TS genotype and gender on overall and progression-free survival was assessed in univariate and multivariate (Cox regression model) tests. In male patients, the study of combined TS genotypes showed that G&6+/6+ was an adverse marker for overall (P=0.04; median: not reached) and progression-free survival (P=0.03; median: 12 months, 95% CI: 0-32.4). In the multivariate analysis, the concurrence of G&6+/6+ combination and male patients resulted in a 5.5-fold increased risk of relapse or disease progression (95% CI: 1-32.1; likelihood test P=0.004; interaction P=0.06). TS genotype did not affect survival among women. The present study supports that the effect of TS polymorphisms on the clinical evolution of advanced CRC patients is significantly influenced by gender.
    Oncology Reports 05/2010; 23(5):1393-400. · 2.30 Impact Factor
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    ABSTRACT: In the present study we explored the effect of three polymorphisms of the TS gene on overall and progression- free survival of colorectal cancer (CRC) patients subjected to 5FU chemotherapy. A 28 bp variable number of tandem repeats (VNTR), a G/C single nucleotide polymorphism (SNP), and a deletion of 6 bp at position 1494 were studied. The possible combined effect of these DNA polymorphisms on the clinical outcome of patients was also evaluated. A retrospective study was carried out on paraffin-embedded sections from 113 patients diagnosed of advanced CRC. TS genotyping methods were polymerase chain reaction (PCR) for VNTR and PCR, followed by restriction length fragment polymorphism (PCR-RFLP) for SNP and ins/del 6 bp. To study the combined effect of TS polymorphisms, four categories were defined accordingly to the level of expression attributed to SNP and ins/del 6 bp genotypes: C&allele 6-, C&6+/6+, G&allele6- and G&6+/6+. VNTR and ins/del 6 bp genotypes varied with tumour anatomical site: 2R/2R genotype was rare in left-sided tumours (7.0% vs. 26.3% of right-sided and 24.1% of rectal cancers; P<0.01), where the variant allele 6- was very frequent (69.0%). Instead, most patients with right-sided tumours were wild-type homozygous 6+/6+ (63.9%) (P<0.01). Heterozygous 6+/6- genotype was more frequent among tumours classified as C (50.0%) and D (76.5%) Dukes stages (P=0.05). None of the studied polymorphisms alone affected overall or progression-free survival (PFS). C&6+/6+ and G&6+/6+ combined genotypes were respectively associated to the best and worst PFS (P=0.03 when compared with each other), while combinations carrying the allele 6- determined an intermediate evolution that might be indicative of a variable response to chemotherapy. The rate of Dukes B stage tumours was unexpectedly high (59.1%) among patients with the unfavourable G&6+/6+ combination. In our study the combination of high TS expression genotypes G&6+/6+ identifies a group of high risk within CRC patients treated with 5FU.
    International Journal of Oncology 01/2009; 34(1):219-29. · 2.66 Impact Factor
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    ABSTRACT: The presence of intratumoral lymphatic vessels (ILVs) and the expression of vascular endothelial growth factor-C (VEGF-C) in tumour cells have been studied as markers of lymphangiogenesis in order to evaluate their role in metastatic dissemination in laryngopharyngeal squamous cell carcinoma. A retrospective study was performed in 76 patients of N0 laryngopharyngeal carcinoma. with variable tumour size (T1-T4), histological grade, and location (supraglottic, glottic and hypopharyngeal). The presence of ILVs, as revealed by the expression of PA2.26 antigen and VEGF-C expression, were determined by immunohistochemistry (IHC). Low-grade and high-grade lymphangiogenesis were defined by qualitative and quantitative criteria. Multivariate analysis revealed low-grade ILV and VEGF-C expression to be associated respectively with 30.3- and 16.2-fold higher probabilities of cervical lymph node relapse (P = 0.005 and P = 0.032) and with 16.2- and 8.44-fold shorter disease-free survival (P = 0.009 and P = 0.045). Low-grade ILV and VEGF-C expression are independent predictive factors of cervical lymph node relapse and shortening of time to relapse in N0 laryngopharyngeal carcinoma.
    Annals of Surgical Oncology 02/2007; 14(1):248-57. · 4.12 Impact Factor
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    ABSTRACT: Several variables associated to thymidylate synthase (TS), the biological target of 5-fluorouracil (5FU) have been studied for their possible role as predictors of the clinical outcome and response to chemotherapy in colorectal cancer (CRC) patients. The level of protein expression and the number of variable tandem-repeats of a 28-bp sequence within the gene promoter have been proposed as predictive and/or prognostic factors with variable agreement, while consensus seems to be achieved with respect to the value of a single nucleotide polymorphism (SNP) described within this same region. More recently, an association between TS expression pattern and survival has been disclosed. Paraffin-embedded sections from 140 CRC patients were analyzed by immuno-histochemistry (Mab TS106) for TS levels and expression pattern. Also, VNTR and SNP were determined by polymerase-chain reaction (PCR) and restriction-length-fragment polymorphism (RFLP) in 123 and 112 patients, respectively. Cytoplasmic expression pattern tended to be associated to C SNP (p=0.06). Low TS expression levels, cytoplasmic expression pattern and C SNP arose as variables associated to longer progression-free survival (PFS) in patients treated with 5FU. Accordingly, patients having at least two favourable or unfavourable variables were classified respectively as 'low risk' and 'high risk', the former showing significantly longer PFS (p=0.0299). The possibility for designing a selection method for subsequent therapies is suggested on the basis of a probable combined effect of the above mentioned parameters but further studies in larger populations are needed to confirm these results.
    International Journal of Oncology 06/2006; 28(5):1303-10. · 2.66 Impact Factor
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    ABSTRACT: High intratumoral expression of thymidylate synthase (TS) has been reported as a factor of poor prognosis in patients with advanced colorectal cancer (CRC), but such association is unclear in some studies. Also, TS has been stated as a typical cytosolic enzyme, but nuclear location has been occasionally reported, and data on the clinical meaning of TS intracellular location are scarce. A retrospective study was performed in paraffin-embedded sections of primary tumor from 77 CRC patients treated with surgical resection and adjuvant 5-FU-based chemotherapy. TS levels and expression patterns were determined by immunohistochemistry (IHQ) using TS-106 antibody. Qualitative and quantitative variables were compared respectively by chi2 and Kruskal-Wallis tests; overall survival (OS) and disease-free survival (DFS) were analyzed with the Kaplan-Meier method and compared using the log-rank and Wilcoxon tests. TS was cytoplasmic in 27.1% of positive tumors and both, nuclear and cytoplasmic in 72.9%; specimens from seven patients (9.1%) lacked TS expression. TS levels were high in 21.6% of tumors with nuclear expression and low in 5.6%, whereas 68.4% of cytoplasmic ones showed low immunostaining intensity (p=0.02); cytoplasmic pattern was also associated to longer OS (p<0.009) and DFS (p=0.003). In patients with nuclear expression, low TS expression was associated to shorter OS (p<0.003) and DFS (p<0.04). These results indicate that, in our study, TS immunostaining patterns were related with OS and DFS, the best prognostic corresponding to cytoplasmic one, and, within the subset of patients with nuclear expression, low TS levels were associated to worse clinical outcome.
    International Journal of Oncology 11/2004; 25(4):877-85. · 2.66 Impact Factor