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Gemcitabine (2',2'-difluoro 2'deoxycytidine, dFdC) is an analog of cytosine with distinctive pharmacological properties and a wide antitumor-activity spectrum. The pharmacological characteristics of gemcitabine are unique because two main classes of genes are essential for its antitumor effects: membrane transporter protein-coding genes, whose products are responsible for drug intracellular uptake, as well as enzyme-coding genes, which catalyze its activation and inactivation. The study of the pharmacogenetics and pharmacoepigenetics of these two gene classes is greatly required to optimize the drug's therapeutic use in cancer. This review aims to provide an update of genetic and epigenetic bases that may account for interindividual variation in therapeutic outcome exhibited by gemcitabine.

Polymorphisms at the thiopurine S-methyltransferase coding gene (TPMT) determine enzyme activity and consequently, the development of toxicity secondary to thiopurines. Methods A total of 108 DNA samples from volunteer donors and 39 from patients with acute lymphoblastic leukemia (ALL) were analyzed. Genomic DNA from peripheral blood leukocytes was isolated by standard methods. TPMT gene fragments were amplified by PCR for exons 5, 7, and 10. Thereafter, these were analyzed by DHPLC for the most frequent mutant TPMT alleles. Results No elution profiles on DHPLC analysis, different from those previously reported, were documented. Frequency of functional allele polymorphisms was 17.6%, being the most frequent *3A (n = 13; 4.4%), followed by *3B (n = 5; 1.7%), *3C (n = 5; 1.7%), and *2 (n = 3; 1.0%). From 39 ALL patients, 22 were treated with thiopurines, and five from 10 with a functional polymorphism developed hematological toxicity (4 mild, 1 severe in a patient referred to our Hospital after developing pancytopenia while on treatment with thiopurine). Conclusions This is the first analysis of the polymorphisms at this gene in Mexican population. Since a direct relation has been documented within functional polymorphisms and enzyme activity, and DHPLC is a highly sensitive, rapid and efficient method, feasible to realize in any phase during the treatment of ALL patients, the routine typing of TPMT polymorphisms in the patients with ALL has been set in our Institution.

IntroductionRenin-angiotensin system (RAS) in brain cancer represents a scarcely explored field in neuro-oncology. Recently, some pre- and clinical studies have reported that RAS components play a relevant role in the development and behavior of gliomas. The angiotensinogen (AGT) rs5050 genetic variant has been identified as a crucial regulator of the transcription of AGT mRNA, which makes it a logical and promising target of research. The aim of this study was to determine the relationship between the AGT rs5050 genetic variant in blood with prognosis in astrocytoma.MethodsA prospective pilot study was performed on forty-eight astrocytoma patients, who received the standard-of-care treatment. Blood samples were taken prior to surgery and DNA was sequenced using Ion Torrent next-generation sequencing and analyzed by Ion Reporter software. Descriptive, bivariate, multivariate, and survival analyses were performed using SPSS v21, STATA 12 and GraphPad Prism 7.ResultsMedian follow-up was 41 months (range 1–48). Survival analysis showed a significant difference between the rs5050 genotypes (p = .05). We found lower survival rates in individuals with the GG-genotype of rs5050 AGT compared to patients with the TT- and TG-genotype (2 months vs. 11.5 months, respectively [p = .01]). In bivariate and multivariate analyses, GG-genotype was negatively associated with survival.ConclusionsIn patients with astrocytoma, AGT rs5050 GG-genotype was associated with poor prognosis. We propose this germline genetic variant as a complementary biomarker, which can be detected practically and safely in blood samples or saliva.

Background: The outcome of patients with primary extranodal diffuse large B-cell lymphoma (PE-DLBCL) varies according to the primary site involved. Primary gastrointestinal, breast, bone, craniofacial, and testicular DLBCL are rare extranodal manifestations of DLBCL. Objective: The objective of the study was to describe the clinical course of patients with PE-DLBCL disease in a referral cancer center. Results: From 637 patients, 51 (8.77%) were considered as having PE-DLBCL (25 gastrointestinal, 12 craniofacial, 6 breast, 5 bone, and 3 with primary testicular DLBCL). Complete remission was higher in all PE-DLBCL sites (100% in testicular, 92.6% craniofacial, 83.3% breast, 80% bone, and 80% gastrointestinal) compared with 73.3% in nodal DLBCL. Although 2 cases with breast PE-DLBC relapsed, they achieved a complete response with chemotherapy. The overall survival at 5 years was 100%, 80%, 78%, 58%, 58%, and 62% for patients with primary breast, primary bone, gastrointestinal, primary craniofacial, primary testicular, and nodal DLBCL, respectively. Conclusions: PE-DLBCLs constitute rare, primary sites of lymphoproliferative disorders in most cases, with localized disease and good prognosis. They require a combined chemoimmunotherapy with radiotherapy in most cases to improve local and systemic disease.