TABLE 1.

Common epigenetic differences between normal and cancer tissues.

Cancer types	Epigenetic differences	Clinical significance	References
Glioma	DNA methylation	Radio-sensitive population possessed IDH mutations and low DNA methylation.	Molenaar et al., 2014, 2015; Baumert et al., 2016
Breast cancer	HAT	Radio-resistant population possessed low HAT.	Sharda et al., 2020
Breast cancer	HDAC	Radio-resistant population possessed high HDAC.	Sharda et al., 2020
Breast cancer	H3K27me3	Negatively correlated with radiosensitivity.	Healey et al., 2014; Nikolaev et al., 2020
Prostate cancer	H3K27me3	Negatively correlated with radiosensitivity.	Ngollo et al., 2017
Prostate cancer	EZH2	EZH2 is higher within the clinical failure population.	Varambally et al., 2002
Non-small cell lung cancer	EZH2	EZH2 overexpression associated with poor prognosis in Asian population, adenocarcinoma and stage I patient.	Wang et al., 2016