Radiation-induced bystander effects: What are they, and how relevant are they to human radiation exposures?

Benjamin Blyth, Pamela Sykes

    Research output: Contribution to journalReview articlepeer-review

    167 Citations (Scopus)


    The term radiation-induced bystander effect is used to describe radiation-induced biological changes that manifest in unirradiated cells remaining within an irradiated cell population. Despite their failure to fit into the framework of classical radiobiology, radiation-induced bystander effects have entered the mainstream and have become established in the radiobiology vocabulary as a bona fide radiation response. However, there is still no consensus on a precise definition of radiation-induced bystander effects, which currently encompasses a number of distinct signal-mediated effects. These effects are classified here into three classes: bystander effects, abscopal effects and cohort effects. In this review, the data have been evaluated to define, where possible, various features specific to radiation-induced bystander effects, including their timing, range, potency and dependence on dose, dose rate, radiation quality and cell type. The weight of evidence supporting these defining features is discussed in the context of bystander experimental systems that closely replicate realistic human exposure scenarios. Whether the manifestation of bystander effects in vivo is intrinsically limited to particular radiation exposure scenarios is considered. The conditions under which radiation-induced bystander effects are induced in vivo will ultimately determine their impact on radiation-induced carcinogenic risk.

    Original languageEnglish
    Pages (from-to)139-157
    Number of pages19
    JournalRadiation Research
    Issue number2
    Publication statusPublished - 2011


    Dive into the research topics of 'Radiation-induced bystander effects: What are they, and how relevant are they to human radiation exposures?'. Together they form a unique fingerprint.

    Cite this