Dear JK,

The attached file is a recent published review that covers the answer to your question.

Effective Biomarkers and Radiation Treatment in Head and Neck Cancer

Thomas J. Ow, MD, MS; Casey E. Pitts, BA; Rafi Kabarriti, MD; Madhur K. Garg, MD, MB, BS

http://www.archivesofpathology.org/doi/pdf/10.5858/arpa.2014-0574-RA

Context.—Radiation is a key arm in the multidisciplinary treatment of patients with head and neck squamous cell carcinoma. During the past 2 decades, significant

changes in the way radiation therapy is planned and delivered have improved efficacy and decreased toxicity. Refined approaches in the application of radiation and chemoradiation have led to organ-sparing treatment regimens for laryngeal and pharyngeal cancers and have improved local and regional control rates in the postoperative, adjuvant setting. The molecular and genetic determinants of tumor cell response to radiation have been studied, and several potential biomarkers are

emerging that could further improve application and efficacy of radiation treatment in head and neck squamous cell carcinoma.

Objective.—To discuss the current understanding of potential biomarkers related to radiation response in head and neck squamous cell carcinoma.

Data Sources.—Existing published literature. 

Conclusions.—Several potential biomarkers are actively being studied as predictors and targets to improve the use and efficacy of radiation therapy to treat head and neck squamous cell carcinoma. Several promising candidates have been defined, and new markers are on the horizon.

(Arch Pathol Lab Med. 2015;139:1379–1388; doi:

10.5858/arpa.2014-0574-RA)

CONCLUSION

This review has highlighted several biomarkers that are actively being studied as predictors and targets to improve the use and efficacy of radiation therapy to treat HNSCC. Several promising candidates have been defined, and new markers are surely on the horizon. Biomarkers that lead to significant improvements in patient outcome will require rigorous validation and prospective testing.

Hoping this will be helpful,

Rafik

The most common DNA damage biomarker would be 8-OHdG. It is the first one to study and very useful. There are various ELISA kits available from GENOX for this test. It is very efficient and sensitive can even give you results in minute amount. However sample pretreatment is necessary. Hope this will help you.

Re: 8-OXOdG ... Not sure how useful (or appropriate) detection of 8-OXOdG is going to be for general surveillance of DNA double-strand break (DSB) repair by HR and NHEJ.

8-OXOdG is a measure of base-excision damage and the BER pathway has nothing to do with NHEJ or HR, which are DNA double-strand break repair pathways.  For general DSB repair competence, good old phospho-S139 H2A.X (i.e. gamma-H2A.X) is the gold standard for most IR dose experiments especially in vitro.  If you cells are cycling, BRCA1 or RAD51 foci formation are good markers of HR ability. Otherwise you need to do reporter assays for NHEJ and HR specifically.

We developed one such assay for HR, that relies on CRISPR-mediate homology directed repair, see: Pinder et al., 2015 NAR

Cheap, quick, fast.

Best,

Doc Dellaire

http://nar.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=26429972