For example, single nucleotide polymorphisms, CYP2E1*7C, NC_000010.10:g.135340548A>G (rs2070672) and CYP2E1, NC_000010.10:g.135339244G>C (rs3813865), are significantly associated with high altitude polycythemia risk (Xu et al., 2015), with nasopharyngeal carcinoma risk in Cantonese (Jia et al., 2009), with poorer cancer-specific survival in head & neck cancer (Hakenewerth et al., 2013). Here, CYP2E1 is linked to cancer.