Table 2.

Risk factors that induce epigenetic aberrations in various cancer types.

Risk Factor	Epigenetic Aberrations	Cancer Types	References
Smoke	DNA methylation	Lung cancer	[55,56,57,64,65,66] [68,69,70]
		Bladder cancers	[58,59]
		Prostate cancer	[60,62,63]
	Histone modification	Lung cancer	[72,73,74]
Alcohol	DNA methylation	Liver cancer	[77]
		Oral cancer	[82]
	Histone modification	Oral cancer	[77]
Betel nut	DNA methylation	Esophageal cancers	[88]
		Oral pre-cancerous lesions	[89]
	Histone modification	Esophageal squamous cell carcinoma	[90]
		Oral squamous cell carcinoma	[91]
		Oral cancer	[92]