Detection of p16 Hypermethylation in Gastric Carcinomas Using a Seminested Methylation-Specific PCR

Abstract

Aberrant DNA methylation of a CpG site is among the earliest and most frequent alterations in various tumors including gastric carcinoma. The aim of this study is to detect tumor-associated aberrant hypermethylation of the p16 gene from 60 gastric tumor and corresponding normal tissues using a seminested methylation-specific PCR (MSP). The results indicated that hypermethylation of the p16 gene could be detected in 80% (48/60) of the gastric tumor samples from the first PCR. However, the frequency increased significantly to 86.7% (52/60) of the gastric tumor samples after the second PCR. These results show that this technique increases the sensitivity of detecting p16 hypermethylation from tumor samples. Furthermore, the aberrant methylation of p16 was observed in all of the stages, confirming that this epigenetic alteration is an early event during gastric carcinogenesis. Clinicopathologic parameters such as age, sex, and histological differentiation of GC were not significantly associated with the methylation status.

Clinical Potential of DNA Methylation in Gastric Cancer: A Meta-Analysis

“…With methylation a dynamic event, protocols for sampling are also in need of clarification, both with respect to the region or site of sampling, and time of sampling. The distance of normal tissue from tumour [46], and time of sampling [21], [22] have all been documented to significantly influence methylation levels.…”

Abnormal Expression of p16INK4a, Cyclin D1, Cyclin‐Dependent Kinase 4 and Retinoblastoma Protein in Gastric Carcinomas

“…The reported prevalence of p16 loss in gastric carcinoma is 11-53% [4,[7][8][9][10][11][16][17][18][19]. Homozygous deletions and mutations of the p16 gene are rare, in the range from 0% to 13% [9,20] whereas hypermethylation in the gene promoter region accounts for inactivation in 18-87% of cases [16,21,22,19]. Gastric carcinoma tissues with p16 promoter methylation express significantly lower levels of p16 protein [8,20,22,23].…”

“…Homozygous deletions and mutations of the p16 gene are rare, in the range from 0% to 13% [9,20] whereas hypermethylation in the gene promoter region accounts for inactivation in 18-87% of cases [16,21,22,19]. Gastric carcinoma tissues with p16 promoter methylation express significantly lower levels of p16 protein [8,20,22,23]. As assessed by Northern blot analysis, gastric carcinoma cell lines reexpress p16 mRNA when treated with the demethylating agent 5-aza-2 0 -deoxycytidine [20].…”

DNA methylation markers in esophageal cancer

“…In fact, most blood DNA methylation markers are considered pan-cancer markers. For instance, SEPT9 shows methylation positivity in plasma samples from CRC, GC, EC, HCC, and cervical cancers ( Potter et al, 2014 ; Oussalah et al, 2018 ; Cao et al, 2020 ; Zhang et al, 2022 ; Bu et al, 2023 ), while P16 also serves as a common pan-cancer methylation marker ( Hibi et al, 2001 ; Zou et al, 2002 ; Hou et al, 2005 ; Lou-Qian et al, 2013 ). Therefore, detecting DNA methylation markers in EC blood samples often requires specific population screening or the use of tissue-origin algorithms to avoid false positive signals.…”