Browsing by Author "Baez, Sergio"

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    Frequent epigenetic inactivation of chromosome 3p candidate tumor suppressor genes in gallbladder carcinoma
    (ELSEVIER IRELAND LTD, 2007) Riquelme, Erick; Tang, Moying; Baez, Sergio; Diaz, Alfonso; Pruyas, Martha; Wistuba, Ignacio I.; Corvalan, Alejandro
    Gallbladder carcinoma (GBC) is a highly malignant neoplasm that represents the leading cause of death for cancer in Chilean females. There is limited information about the molecular abnormalities involved in its pathogenesis. We have identified a number of molecular changes in GBC, including frequent allelic losses at chromosome 3p regions. Four distinct 3p sites (3p12, 3p14.2, 3p21.3 and 3p22-24) with frequent and early allelic losses in the sequential pathogenesis of this neoplasm have been detected. We investigated epigenetic and genetic abnormalities in GBC affecting 6 candidate tumor suppressor genes (TSG) located in chromosome 3p, including DUTT1 (3p12), FHIT(3p14.2), BLU, RASSF1A, SEMA3B and hMLH1 (3p21.3). DNA extracted from frozen tissue obtained from 50 surgical resected GBCs was examined for gene promoter methylation using MSP (methylation-specific PCR) technique after bisulfite treatment in all 6 genes. In addition, we performed PCR-based mutation examination using SSCP in FHIT and RASSF1A genes and loss of heterozygosity (LOH) analysis using microdissected tissue in a subset of tumors for the 3p21.3 region with 8 microsatellite markers. A very high frequency of GBC methylation was detected in SEMA3B (46/50, 92%) and FHIT (33/50, 66%), inter-mediate incidences in BLU (13/50, 26%) and DUTT1 (11/50, 22%) and very low frequencies in RASSF1A (4/50, 8%) and hMLH1 (2/50, 4%). Allelic loss at 3p21.3 was found in nearly half of the GBCs examined. We conclude that epigenetic inactivation by abnormal promoter methylation is a frequent event in chromosome 3p candidate TSGs in GBC pathogenesis, especially affecting genes SEMA3B (3p21.3) and FHIT (3p 14.2). (c) 2006 Elsevier Ireland Ltd. All rights reserved.
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    Mortality due to gallbladder cancer. Retrospective analysis in three Chilean hospitals
    (2010) Gabrielli, Mauricio; Hugo, Sebastian; Dominguez, Angelica; Baez, Sergio; Venturelli, Aliro; Puga, Maria; Diaz, Alfonso; Jarufe, Nicolas; Ferreccio, Catterina
    Background: Chile has the highest gallbladder cancer (GBC) death rate worldwide, affecting mainly Southern areas of the country. Aim: To compare the survival of GBC patients treated in hospitals located in areas with low and high risk for GBC. Material and Methods: Medical records of all patients with GBC admitted to one public hospital located in southern Chile, a public hospital and a private clinic, both located in Metropolitan Santiago, were reviewed. Cases were analyzed by age, sex, stage at diagnosis, ethnicity, socioeconomic status (SES) and rural residence. Survival was calculated using Kaplan Meier method. Results: A total of 598 cases (469 women), were analyzed. No differences in age or sex among hospitals were detected. At the moment of diagnosis, 75, 50 and 44% of cases from the hospital in southern Chile, the public hospital in Santiago and the private clinic in Santiago, were in stage IV respectively. Five years survival was lower in the public hospital in southern Chile than in the public hospital in Santiago (10.7 and 14.4% respectively, p <0.05) but not statistically different from the figure at the private clinic in Santiago (13.0%). However, when adjusting for stage at the moment of diagnosis, no difference in survival between the three hospitals, was found. The median days of survival were 1,559, 188, 70 and 69 for stages I, II, III and IV respectively. Conclusions: GBC mortality is high. The stage at the moment of diagnosis is only significant predictor of survival. (Rev Med Chile 2010; 138: 1357-1364).