The comet assay in clinical practice.
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.
Olive
P L
PL
Medical Biophysics Department, British Columbia Cancer Research Centre, Vancouver, Canada. polive@bccancer.bc.ca
Durand
R E
RE
Jackson
S M
SM
Le Riche
J C
JC
Luo
C
C
Ma
R
R
McLaren
D B
DB
Aquino-Parsons
C
C
Thomson
T A
TA
Trotter
T
T
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*