Abstract

Purpose

Estimating cancer risk associated with interplanetary space travel is complicated. Human exposure data to high atomic number, high-energy (HZE) radiation is lacking, so data from low linear energy transfer (low-LET) γ-ray radiation is used in risk models, with the assumption that HZE and γ-ray radiation have comparable biological effects. This assumption has been challenged by reports indicating that HZE radiation might produce more aggressive tumors. The goal of this research is to test whether high-LET HZE radiation induced tumors are more aggressive.

Materials and methods

Murine models of mammary and liver cancer were used to compare the impact of exposure to 0.2Gy of 300MeV/n silicon ions, 3 Gy of γ-rays or no radiation. Numerous measures of tumor aggressiveness were assessed.

Results

For the mammary cancer models, there was no significant change in the tumor latency or metastasis in silicon-irradiated mice compared to controls. For the liver cancer models, we observed an increase in tumor incidence but not tumor aggressiveness in irradiated mice.

Conclusion

Tumors in the HZE-irradiated mice were not more aggressive than those arising from exposure to low-LET γ-rays or spontaneously. Thus, enhanced aggressiveness does not appear to be a uniform characteristic of all tumors in HZE-irradiated animals.

中文翻译：

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在小鼠肝细胞癌和乳腺癌模型中，肿瘤侵袭性与辐射质量无关

 抽象的

 目的

估计与星际太空旅行相关的癌症风险很复杂。由于缺乏人体暴露于高原子序数、高能 (HZE) 辐射的数据，因此来自低线性能量转移 (low-LET) γ 射线辐射的数据被用于风险模型，并假设 HZE 和 γ 射线辐射具有可比的生物学效应。这一假设受到了报告的挑战，这些报告表明 HZE 辐射可能会产生更具侵袭性的肿瘤。本研究的目的是测试高 LET HZE 辐射诱发的肿瘤是否更具侵袭性。

 材料和方法

使用小鼠乳腺癌和肝癌模型来比较暴露于 0.2Gy 300MeV/n 硅离子、3 Gy γ 射线或无辐射的影响。评估了许多肿瘤侵袭性的指标。

 结果

对于乳腺癌模型，与对照组相比，硅照射小鼠的肿瘤潜伏期或转移没有显着变化。对于肝癌模型，我们观察到受辐射小鼠的肿瘤发病率增加，但肿瘤侵袭性没有增加。

 结论

HZE 照射小鼠的肿瘤并不比暴露于低 LET γ 射线或自发产生的肿瘤更具侵袭性。因此，增强的侵袭性似乎并不是 HZE 照射动物中所有肿瘤的一致特征。