從低等的微生物到高等的動物細胞對於外界的刺激或傷害都會以一些特定的基因表現來調適或防衛;同樣也有些癌細胞對於輻射的抗性此一般正常細胞要強很多,這可能是因為這些癌細胞會表現出某些基因(或致癌基因)來調適或防衛輻射的傷害，而造成治療上的困擾。若能了解輻射線如何調節細胞內基因的表現，則有助於癌症的放射治療，或未來的基因療法，也是輻射在醫學上的實用性之一。在許多有關細菌應激反應{stress response)所誘發出的調節元(regulons)研究中，發現這類基因所表現的蛋白質多少與調適輻射致死效應有關;且在高等動物的細胞或組織中也顯示有些基因可以被輻射所誘發。本文將回顧一些調適的生物證據，並分析輻射所誘發出之基因的表現及它們在細胞保護作用中所扮演的角色,以及細胞如何感應輻射所引起的傷害;包括從細胞質中訊息的傳遞過程(signal transduction)，直到細胞核中一些特殊基因的活化。

　　　　　Prokaryotic or eukaryotic cells adjust themselves to a wide variety of either stimulation ordamages through regulating some specific gene expressions. Extensive studies of stress-inducedregulons in bacteria showed that some of these gene products are involved in the adaptation tolethal damages such as those by ionizing radiation. In mammalian cells, many genes are alsoinduced in response to radiation insult. During cancer radiotherapy, genes in cancer cells can beinduced, expressed and involved in the adaptive survival. In this review, the biological evidence forsuch adaptation and the possible roles of these radiation-induced genes may play are discussed.How these cells sense the radiation-induced damages, and how they transduce damaging signals tothe final destination of genome in order to activate the specific genes are also summarized.