A similar study of individuals from homes of known radon concentration, where at least 20% were greater than 148 Bq·m−3, in Galicia, Spain, analysed 72 lung cancers and found no correlation between variation in radon exposure and either TP53 mutations or p53 expression, although the number of sequenced samples for mutation analysis was small (n = 4) with a relatively low radon concentration of between 11.1 and 51.8 Bq·m−3[71]. The gene discussed is TP53; the disease is lung carcinoma.