A method of treating a subject who has been diagnosed with cancer is described. The method includes characterizing the radiation-susceptibility of the subject by detecting a mutation in an NRF2 pathway protein in suitable sample obtained from the subject and treating the subject with radiation therapy if the subject is characterized as being radiation-susceptible, or treating the subject with radiation therapy and a radiosensitizing agent if the subject is characterized as being radioresistant. A method of determining if a subject has a history of tobacco smoking is also described that includes analyzing an NRF2 pathway protein to determine if a mutation is present in suitable sample obtained from the subject and characterizing the subject as having a history of tobacco smoking if a genetic fingerprint consistent with tobacco exposure is identified.
