Neoplastic transformation in vitro by low doses of ionizing radiation: role of adaptive response and bystander effects.
Mutat Res
; 597(1-2): 11-7, 2006 May 11.
Article
en En
| MEDLINE
| ID: mdl-16414089
ABSTRACT
The shape of the dose-response curve for cancer induction by low doses of ionizing radiation is of critical importance to the assessment of cancer risk at such doses. Epidemiologic analyses are limited by sensitivity to doses typically greater than 50-100 mGy for low LET radiation. Laboratory studies allow for the examination of lower doses using cancer-relevant endpoints. One such endpoint is neoplastic transformation in vitro. It is known that this endpoint is responsive to both adaptive response and bystander effects. The relative balance of these processes is likely to play an important role in determining the shape of the dose-response curve at low doses. A factor that may influence this balance is cell density at time of irradiation. The findings reported in this paper indicate that the transformation suppressive effect of low doses previously seen following irradiation of sub-confluent cultures, and attributed to an adaptive response, is reduced for irradiated confluent cultures. However, even under these conditions designed to optimize the role of bystander effects the data do not fit a linear no-threshold model and are still consistent with the notion of a threshold dose for neoplastic transformation in vitro by low LET radiation.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Transformación Celular Neoplásica
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
Mutat Res
Año:
2006
Tipo del documento:
Article
País de afiliación:
Estados Unidos