In SituRepair by Human Malignant Cells of Radiation-Induced DNA Breaks

The rejoining of radiation-induced DNA breaks, characterized by 5′ termini, was measured by the polynucleotide kinase method. This method has potential clinical value because DNA damage can be measured for cells within solid tissue. Following irradiation of a human squamous-cell carcinoma, DNA rejoining occurred, but at a slower rate than observed for mammalian cells in culture. The results of the study indicate that cells within solid tumors, in situ, are able to repair at least some radiation-induced DNA damage. The importance of this type of repair to tumor response following therapeutic radiology is not known at present.