Thus, food of aquatic origin is an important source of human exposure to methylmercury [280] and a low level of exposure to mercury can induce cancer cell proliferation by the estrogen receptor (ER), extracellular signal-regulated kinases 1/2 (ERK1/2), c-JUN NH(2)-terminal kinase (JNK), NADPH-oxidase, and nuclear factor erythroid 2-related factor 2 (NRF2) signaling, combined with anti-apoptotic and pro-survival signaling, the accumulation of DNA modifications, and the inhibition of DNA repair machinery [281]. The gene discussed is ESR1; the disease is cancer.