Genetic screening analysis of patients with hereditary diffuse gastric cancer from northern and northeastern Brazil

Hereditary diffuse gastric cancer (HDGC) is a hereditary autosomal inherited syndrome associated with CDH1 germline mutations. In Brazil, gastrointestinal tumors are among the most prevalent tumor types and constitute a serious public health problem, especially in the northern and northeastern regions. This study aimed to investigate germline mutations, methylation pattern and genomic rearrangements in the CDH1 gene and quantitative changes in the DNA of HDGC patients in northern and northeastern Brazil. Twenty-seven DNA samples from the members of four families affected by HDGC were analyzed using array comparative genomic hybridization (aCGH), DNA sequencing and methylation pattern. No evidence of gain and loss events or any rearrangements were found in any of the samples tested using aCGH. No promoter region hypermethylation was observed either. Two of the four families presented different types of germline mutations. The 185G > T and 1018A > G germline mutations detected in this study have been described in Asian and European families, respectively. The ancestors of the two families carrying these mutations had originated from those continents. This is the first study to evaluate CDH1 gene germline mutations in Brazilian families with HDGC. In our study, 50% of the families showed no CDH1 gene alterations, and it is possible that in regions with a high incidence of gastric cancer, such as northern and northeastern Brazil, environmental factors might have induced the different genetic alterations analyzed in this study.