Relationship between chromosome aberrations, micronuclei and cell kill in two human tumour cell lines of widely differing radiosensitivity.

The relationship between chromosome aberration frequency, micronucleus (MN) formation and cell kill was investigated in two human tumour cell lines, RT112, a radioresistant bladder carcinoma cell line, and HX142, a radiosensitive neuroblastoma cell line. As MN are generally accepted to result from acentric chromosome fragments that are lost at nuclear division and all unstable aberrations result in an acentric fragment, a 1:1 correlation between aberrations and MN might be expected. There was a good correlation between cell kill and aberration frequency in the two cell lines, however the relationship between cell kill and MN formation in the lines was very different. RT112 showed 0.22 aberrations and 0.21 MN per Gy whilst HX142 showed 0.61 aberrations and 0.078 MN per Gy. Possible reasons for the discrepancy observed in HX142 are discussed.