[Radiation induced tumors]. / Tumores radioinducidos.

Radiations at cellular level produce different effects, depending on type of radiation and irradiated tissue. The radiation-induced cancers are associated to non-letals genetics mutations, and to classify like radiation induced tumors is necessary that appear in the treatment volume, a long latency period (years), histolo-different to the primary lesion, enough doses quantitatively and that exists a greater incidence in the irradiated populations. The genetics mutations affect at tumoral suppressors gen(Gen RB I, p53, BRCA I, BRCA 2) and repressors gen (hMSH 2, hMLH I,...), they could be longer and multifocals mutations, and produce lack of cellular control and a greater predisposition to develop tumors and a probable risk of increment of radiosensitivity. We present some of the more representatives studies about radiation-induced tumors.

Lack of protection by carotenes against gamma-radiation damage in Phycomyces.

Carotenes could protect cells from radiation damage by chemically quenching the free radicals and the activated chemical species originated by the exposure. We tested this hypothesis with strains of the zygomycete Phycomyces blakesleeanus that contained different carotenes (phytoene, lycopene, beta-carotene) or different concentrations of beta-carotene. Pairs of strains were cultured together, exposed to a maximum of 73 Gy gamma-radiation from a Co source, and allowed to recover and grow further together on limited resources. Irradiation did not affect the relative abundance of each strain in the resulting spore crop. Thus, carotenes did not protect the fungal cells against gamma-radiation and did not influence their recovery from damage caused by the exposure.