title: The comet assay in clinical practice.
abstract: The comet assay is a single-cell gel electrophoresis technique that measures DNA damage in individual cells. Since radiation produces 3-4 times more DNA damage in well-oxygenated cells compared with hypoxic cells, this assay can quantify the fraction of radiation-resistant hypoxic cells found in many solid tumours. This paper summarizes our results with 73 accessible metastatic tumours irradiated with palliative intent. Hypoxic fractions ranged from 0.0 to 0.67 with a mean of 0.15; 62% of these advanced tumours showed a hypoxic fraction > 0.05. Comparisons between two sequential aspirates in 33 tumours gave a slope of 0.92 (r2 = 0.88), suggesting that a single aspirate is generally representative of the tumour. A limitation, however, is that the hypoxic fraction could not be measured in clinical samples given a conventional dose of 2 Gy.
authors.affiliation: Medical Biophysics Department, British Columbia Cancer Research Centre, Vancouver, Canada. polive@bccancer.bc.ca
authors.forename: P L
authors.initials: PL
authors.lastname: Olive
authors.forename: R E
authors.initials: RE
authors.lastname: Durand
authors.forename: S M
authors.initials: SM
authors.lastname: Jackson
authors.forename: J C
authors.initials: JC
authors.lastname: Le Riche
authors.forename: C
authors.initials: C
authors.lastname: Luo
authors.forename: R
authors.initials: R
authors.lastname: Ma
authors.forename: D B
authors.initials: DB
authors.lastname: McLaren
authors.forename: C
authors.initials: C
authors.lastname: Aquino-Parsons
authors.forename: T A
authors.initials: TA
authors.lastname: Thomson
authors.forename: T
authors.initials: T
authors.lastname: Trotter
mesh_terms: D000818:Animals; D001707:Biopsy, Needle; D015687:Cell Hypoxia; D020552:Comet Assay; D004249:DNA Damage; D004586:Electrophoresis; D006801:Humans; D051379:Mice; D008809:Mice, Inbred C3H; D009369:Neoplasms / Q000235:genetics*