We aimed to evaluate the inactivation of COX-2, HMLH1 and CDKN2A by promoter methylation and its relationship with the infection by different Helicobacter pylori strains in gastric cancer.
To investigate the expression of human telomerase reverse transcriptase gene (hTRT) in gastric cancer (GC) and its relevance with cell cycle regulators including P16INK4, cyclin and P53.
These results suggest that p16(INK4a) promoter hypermethylation is an early and frequent event in gastric carcinogenesis and may serve as a new prognostic biomarker for the risk of gastric cancers.
The present study demonstrated for the first time that gastric cancer patients with p16INK4a methylation specifically benefit from 5-FU-based adjuvant chemotherapy.
The overexpression of p16 seems to be a common event in the development of both intestinal and diffuse type of gastric cancer and it is likely that it may be driven by features of the neoplastic state.
The frequencies of LOH in two microsatellite sites, D9s171 and D9s1604, in p16 genome were associated with development of gastric cancer and no significant correlation was demonstrated between the LOH frequency and the cell differentiated types of tumor cells or clinical stages.
Relative expression of SNHG7 is upregulated in gastric cancer tissues and cells, and partially contributes to the development and progression of gastric cancer through regulation of p15 and p16 expressions.
p16(INK4a) and p14(ARF) genes are frequently inactivated by homozygous deletion and methylation of the 5'CpG islands in gastric cancer, which may play an important role in the carcinogenesis of gastric cancer.
Overall, 78% of GC cases harbored one clinically relevant GA or more, with the most frequent alterations being found in TP53 (50%), ARID1A (24%), KRAS (16%), CDH1 (15%), CDKN2A (14%), CCND1 (9.5%), ERBB2 (8.5%), PIK3CA (8.6%), MLL2 (6.9%), FGFR2 (6.0%), and MET (6.0%).
Our results demonstrate that STAT3, but not STAT5, is involved in GC cell growth and cell cycle progression through regulation of gene expression, such as Bcl-2, p16(ink4a) and p21(waf1/cip1).
On the other hand, the observed pattern of p16 (INK4A) hypermethylation suggests that this event is a good marker for the gastric cancer pathway in the Pará state population.