In their article in the current issue of ONCOLOGY, Dr. Williams and colleagues define the relationships between genetic variation and patients’ response to radiation therapy. The article provides an abbreviated but excellent overview of models of clinical response utilizing genomic determinants, presented within the context of prognostic and predictive biomarkers. Genomic complexity is a characteristic common to many tumors, and can serve as an independent predictor of radioresistance and disease progression in some disease sites. Many other examples of genomic biomarkers are expertly discussed within the article. It is also worth noting that the first laboratory-based attempts to develop a predictive or prognostic biomarker of clinical radiosensitivity used the surviving fraction at 2 Gy (SF2) of cells harvested from tumor tissue or from normal tissue samples obtained by clinical biopsies.[3-5] Although effective, measuring the cellular clonogenicity of patient-derived material proved too laborious and impractical for routine clinical adoption. There is also a large body of literature describing the repair of radiation-induced DNA breaks as indicators of radiosensitivity. These types of cell-based radiosensitivity assays never gained widespread adoption. Those assays have given way to the more robust molecular approaches aimed at uncovering genomic signatures of toxicity and radiation response, as Dr. Williams et al discuss. In their article, they suggest that after 2 decades of rapid innovation in DNA-based technologies and sequence databases, genomic biomarkers of radiosensitivity have reached the point of clinical implementation, albeit not for routine use in most cases. The first genomic classifier panels of cellular radiosensitivity used small numbers of gene markers, and in vivo verification was not possible. Moreover, the function of the classifier genes and their role in assessing radiosensitivity was not always clear. These early limitations have now been addressed by the development of newer radiosensitivity signatures.
|Original language||English (US)|
|Number of pages||3|
|Journal||ONCOLOGY (United States)|
|State||Published - Jul 15 2017|
ASJC Scopus subject areas
- Cancer Research