Despite the worldwide decline in the incidence of gastric cancer in recent years, this type of
cancer is the third with higher mortality. Modifications in the pattern of DNA methylation are
common in different types of cancer, including gastric cancer. In addition, changes in the
expression of proteins responsible for this epigenetic mechanism in tumors are associated with
changes in DNA methylation patterns. Therefore, understanding the gene machinery of the
DNA methylation during carcinogenesis is crucial for understanding the biological processes
involved in tumor development. In the present study, the relative mRNA expression of the
DNMT1, DNMT3A, DNMT3B, MeCP2 and MBD4 genes from 61 paired samples of gastric
tumors and adjacent non-neoplastic gastric tissues and 30 gastric tissue samples from
individuals without neoplasia. In the analysis between the different groups of samples, mRNA
of DNMT1 gene was significantly more expressed in gastric tumor and non-neoplastic adjacent
tissue when compared to gastric tissue of individual without neoplasia (p = 0.0196, p = 0.0466,
respectively). In addition, we observed that DNMT3A mRNA was significantly more expressed
in adjacent non-neoplastic gastric tissue compared to tumor tissue and non-neoplastic
individuals (p = .0.0076, p = 0.0029, respectively). The analysis with clinicopathological data
showed an association between DNMT3B mRNA expression with presence of lymph node
metastasis (p = 0.034) and gastric tumor stage III-IV (p = 0.048). When performing the gene
correlation, it was observed that MECP2 had a strong correlation between DNMT1 (0.666),
DNMT3B (0.685) and MBD4 (0.790) genes, another correlation was found between DNMT3B
and MBD4 (0.650). These results suggest that alterations in DNMT1 and DNMT3A gene mRNA
expression may be present in the early stages of gastric carcinogenesis, DNMT3B can be used
as a marker of prognosis.
|
