Evaluation of the use of tyrosinase-specific and melanA/MART-1-specific reverse transcriptase-coupled–polymerase chain reaction to detect melanoma cells in peripheral blood samples from 299 patients with malignant melanoma
Article first published online: 20 AUG 2003
British Journal of Dermatology
Volume 144, Issue 2, pages 279–287, February 2001
How to Cite
Brownbridge, G.G., Gold, J., Edward, M. and Mackie, R.M. (2001), Evaluation of the use of tyrosinase-specific and melanA/MART-1-specific reverse transcriptase-coupled–polymerase chain reaction to detect melanoma cells in peripheral blood samples from 299 patients with malignant melanoma. British Journal of Dermatology, 144: 279–287. doi: 10.1046/j.1365-2133.2001.04015.x
- Issue published online: 20 AUG 2003
- Article first published online: 20 AUG 2003
- Accepted for publication 21 September 2000
- malignant melanoma;
- polymerase chain reaction;
Background There is a current need for a reliable prognostic marker for melanoma patients, particularly those with stage 2 and stage 3 disease, so that adjuvant therapies can be directed appropriately.
Objectives To establish whether or not the use of tyrosinase-specific or melanA/MART-1-specific reverse transcriptase-coupled–polymerase chain reaction (RT–PCR) of peripheral blood cells detects preclinical disease progression in patients with malignant melanoma.
Methods Two hundred and ninety-nine patients with melanoma in clinical stages 1–4 were observed in this study. Samples were obtained sequentially from 153 of these patients at 4-week intervals over a period of up to 2 years and correlated with clinical evidence of disease activity. Tyrosinase and melanA/MART-1 amplicons were analysed by agarose gel electrophoresis and Southern blot hybridization subsequent to a single round of amplification.
Results We demonstrated a statistically significant increase in tyrosinase RT–PCR positivity with advancing stage of melanoma progression. The percentage tyrosinase positivity in 910 samples tested was: stage 1, 135 samples, 34% positive; stage 2, 196 samples, 51% positive; stage 3, 423 samples, 50% positive; and stage 4, 156 samples, 65% positive. The positivity rate for individual patients tested sequentially was higher if only one positive test was required to label a patient positive, at 42%, 65%, 82% and 81% for patients in stages 1–4, respectively. However, we did not find a clear pattern of conversion from negativity to positivity in patients who progressed during the study from stage 2 to stage 3 or stage 3 to stage 4, and found no clear evidence of increased positivity rates in the 6-week period following melanoma-related surgery in patients with stage 3 and 4 disease. The positivity rate for melanA/MART-1 was lower for both patients and samples, and no melanA/MART-1-positive sample was negative for tyrosinase.
Conclusions We conclude that the presence of circulating tyrosinase-positive cells as detected by this method appears to be a discontinuous rather than a continuous phenomenon, even in patients with stage 4 disease. For this reason the assay cannot be recommended as a method of sequentially monitoring individual patients in a clinical setting.