Table 1.

Correlations between epigenetic clustering based on DNA methylation profiles in tissue specimens of non-cancerous gastric mucosa and clinicopathological parameters of the established gastric carcinomas

Clinicopathological parameters	Cluster A	Cluster B1	Cluster B2	P d
	(n = 20)	(n = 20)	(n = 69)
Patients
Age (years)
≥65	6	14	29	2.93×10−2
<65	14	6	40
Sex
Male	17	15	47	3.45×10−1
Female	3	5	22
H.pylori infectiona
Negative	9	6	22	5.71×10−1
Positive	11	14	45
Gastric carcinomas
Predominant histological classificationb				3.07×10−2
Differentiated	15	7	34
Undifferentiated	4	12	34
Mucin producing	1	1	1
Most aggressive histological classificationc				1.63×10−2
Differentiated	10	2	17
Undifferentiated	10	18	52
Mucin-producing	0	0	0
Tumor stage   pT1–pT2	7	1	19	4.57×10−2
pT3–pT4	13	19	50
Pathological tumor node metastasis stage				8.78×10−3
IA–IB	7	0	18
IIA–IIB	3	7	8
IIIA–IV	10	13	43

^aImmunohistochemical examination was performed for 107 patients from whom formalin-fixed and paraffin-embedded tissue specimens were available.

^bIf the tumor showed heterogeneity, findings in the predominant area were described.

^cIf the tumor showed heterogeneity, the most aggressive features of the tumor were described.

^dFisher’s exact test (P values of < 0.05 are underlined).