ABSTRACT. Epidermal growth factor receptor (EGFR) is a transmembrane glycoprotein with tyrosine-kinase activity that plays an important role in multiple cellular functions. EGFR overexpression has been observed in several types of tumors and it is significantly associated with disease stage, survival, prognosis, and progression of cancer. The polymorphisms -216G>T, -191C>A, and (CA) n first intervening sequence 1803 EGFR polymorphisms and gastric cancer risk ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (1): 1802-1807 (2015) (IVS1) have been related to EGFR overexpression and have been studied in several types of cancer, but not in gastric cancer (GC). The aim of this study was to determine the association of these 3 polymorphisms and GC. Genomic DNA from 68 GC patients and 102 healthy blood donors were analyzed. Polymorphisms were identified by DNA-sequencing (-216G>T and -191C>A) and GeneScan (CA) n IVS1. The results showed that the distribution of the -216G>T and -191C>A genotypes differed between groups (P < 0.05). The odds ratio for the -216TT genotype was 4.59 (95% confidence interval = 1.55-13.54, P < 0.05) and 10.71 (95% confidence interval = 2.31-49.59, P < 0.05) for the -191AA genotype, both in a recessive model. The genotype and allele distributions of the (CA) n IVS1 repeat was similar in both groups. In conclusion, the -216TT and -191AA genotypes and GA haplotype of the EGFR gene were found to be associated with an increased risk of gastric cancer in a Mexican population.

ABSTRACT. Gastric cancer (GC), the third leading cause of cancerrelated deaths in Mexico and worldwide, can be classified into diffuse (DGC) or intestinal (IGC) types based on its histological characteristics. DGC is characterized by reduced expression of the cell adhesion protein E-cadherin, which is encoded by CDH1. The -472delA (rs5030625) and -160C>A (rs16260) polymorphisms in CDH1 induce a decrease in gene transcription; in fact, these mutated alleles have been associated with GC in some populations, with conflicting results. The aim of this study was to determine the association between the CDH1 -472delA and -160C>A polymorphisms and DGC and IGC in Mexican patients. The study was conducted in 24, 23, 48, and 93 individuals with DGC and IGC, without GC (control), and belonging to the general Mexican population (GMP), respectively. The genotypes were obtained by polymerase chain reaction -restriction fragment length polymorphism and the obtained data analyzed using Arlequin 3.1. The frequencies of the mutated allele (A) of -472delA were 0.326, 0.318, 0.284, and 0.296 in the DGC, IGC, control, and GMP groups, respectively, and those of the -160C>A polymorphism were 0.174, 0.318, 0.313, and 0.280, respectively. The genotype and allele frequencies of the two polymorphisms did not differ significantly (P > 0.05) among DGC, IGC, and control subjects. Therefore, we concluded that the CDH1 -472delA and -160C>A polymorphisms are not associated with DGC or IGC in patients from western Mexico.

Gastric cancer (GC) is the third most lethal type of cancer worldwide. Single nucleotide polymorphisms (SNPs) in regulatory sites or coding regions can modify the expression of genes involved in gastric carcinogenesis, as ERBB2 , which encodes for the tyrosine-kinase receptor HER-2. The aim of this work was to analyze the association of the polymorphisms: rs2643194, rs2517951, rs2643195, rs2934971, and rs1058808 with GC, as they have not yet been analyzed in GC patients, as well as to report their frequency in the general Mexican population (GMP). We studied genomic DNA from subjects with GC (n=74), gastric inflammatory diseases (GID, n=76 control subjects), and GMP (n=102). Genotypes were obtained by means of real-time PCR and DNA-sequencing. The risks for GC were estimated through odds ratio (OR) using the Cochran-Armitage trend test and multinomial logistic regression. Increased risk for GC was observed under the dominant inheritance model for the rs2643194 TT or CT genotypes with an OR of 2.75 (95%CI 1.12−6.75, P=0.023); the rs2934971 TT or GT genotypes with an OR of 2.41 (95%CI 1.01−5.76, P=0.043), and the rs1058808 GG or CG genotypes with an OR of 2.21 (95%CI 1.00−4.87, P=0.046). The SNPs rs2643194, rs2934971, and rs1058808 of the ERBB2 gene were associated with increased risk for GC.

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