Confusion and prospects for carcinogenesis of gastric adenoma and dysplasia: What is the correct answer currently?

Table 1 The classifications of gastric adenoma of the Japanese Gastric Cancer Association and gastric superficial lesions of the WHO classification and the Vienna classification

Classification	Code	Diagnosis	Subtype	Subtype 2
JGCA[16]		Gastric adenoma	Intestinal type
			Gastric type	Pyloric gland type
				Foveolar type
WHO 2019[13]	8148/0	Glandular intraepithelial neoplasia, low grade
	8148/2	Glandular intraepithelial neoplasia, high grade
	8213/0	Serrated dysplasia, low grade
	8213/2	Serrated dysplasia, high grade	Intestinal-type dysplasia
			Foveolar-type (gastric type) dysplasia
			Gastric pit/crypt dysplasia
	8144/0	Intestinal-type adenoma, low grade
	8114/2	Intestinal-type adenoma, low grade	Sporadic intestinal-type gastric adenoma
			Syndromic intestinal-type gastric adenoma
	8210/0	Adenomatous polyp, low-grade dysplasia
	8210/2	Adenomatous polyp, high-grade dysplasia
Vienna[14]	3	Non-invasive low-grade neoplasia	Low-grade adenoma/dysplasia
	4	Non-invasive high-grade neoplasia
	4.1		High-grade adenoma/dysplasia
	4.2		Non-invasive carcinoma (carcinoma in situ)
	4.3		Suspicion of invasive carcinoma
	5	Invasive neoplasia
	5.1		Intramucosal carcinoma
	5.2		Submucosal carcinoma or beyond
Revised Vienna[15]	3	Mucosal low-grade neoplasia	Low-grade adenoma/dysplasia
	4	Mucosal high-grade neoplasia
	4.1		High-grade adenoma/dysplasia
	4.2		Non-invasive carcinoma (carcinoma in situ)
	4.3		Suspicious for invasive carcinoma
	4.4		Intramucosal carcinoma
	5	Submucosal invasion by carcinoma

JGCA: Japanese Gastric Cancer Association.

Table 2 Brief summary of The Cancer Genome Atlas classification

Type	Chromosomal instability	EBV	Microsatellite instability	Genomically stable
Percentage	50%	9%	21%	20%
Profile of patients		Male prevalence	Elderly age	Younger age
Location	GEJ, cardia	Corpus or fundus	Antrum	Distal location
Lauren type	Intestinal		Intestinal	Poorly cohesive
Other pathological feature	DNA aneuploidy	Carcinoma with lymphoid stroma
Prognosis			Favorable	Worst
Genetic features	TP53 mutation	Extensive DNA promoter methylation	MLH1 promoter hypermethylation	Low copy number alterations and mutational burden
	Amplification of TKR	CDKN2A promoter hypermethylation	High mutational burden	ARID1, RHOA, CDH1 mutations
		PIK3CA, ARID1A, BCOR mutations		CLDN18-ARHGAP26 fusion in 15%

TCGA: The Cancer Genome Atlas; EBV: Eptein-Barr virus; GEJ: Esophagogastric junction.