Prognostic value of multiple reverse transcription-PCR tyrosinase testing for circulating neoplastic cells in malignant melanoma.
BACKGROUND
The reverse transcription-PCR tyrosinase assay (TYR test) cannot reliably detect malignant melanoma (MM) cells in blood as the cells often circulate at low concentrations. We evaluated the prognostic value of multiple TYR testing, the prognostic significance of individual positive TYR test results (TYR+) in asymptomatic melanoma patients, and whether statistical analysis could help in the interpretation of results of a test that measures phenomena that typically occur below its detection threshold.


METHODS
MM patients in stages I-IV (n = 150) underwent multiple testing with the TYR test during the course of their disease. TYR testing was performed as described by Smith et al. (Lancet 1991;38:1227-9). Statistical analyses were performed with the logistic function and t-test procedures.


RESULTS
The relationship between MM stage and the frequency of TYR+ was statistically significant (P = 0.011). Higher frequency of TYR+ in clinically asymptomatic patients after complete resection of the primary tumor was associated with an increased risk of recurrence of MM (prognostic sensitivity, 62%; specificity, 78%).


CONCLUSIONS
A single positive TYR test provides a warning for disease relapse, suggesting that multiple TYR testing might provide more reliable predictions of disease progression. Multiple testing and statistical analysis using a logistic function might allow for the interpretation of apparently inconsistent results of tests for very rare cells.
Szenajch
Jolanta
J
Department of Oncology, Military Institute of Medicine, Szaserów 128 Street, 00-909 Warsaw, Poland. jolaszen@wim.mil.pl
Jasiński
Bogdan
B
Synowiec
Agnieszka
A
Kulik
Jadwiga
J
Chomicka
Małgorzata
M
Struzyna
Jerzy
J
Nowecki
Zbigniew
Z
Rutkowski
Piotr
P
Ruka
Włodzimierz
W
Kupść
Witold
W
Siedlecki
Janusz A
JA
Wiktor-Jedrzejczak
Wiesław
W
D000328:Adult; D000368:Aged; D002460:Cell Line; D005134:Eye Neoplasms / Q000097:blood / Q000175:diagnosis / Q000473:pathology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008545:Melanoma / Q000097:blood / Q000175:diagnosis* / Q000473:pathology; D008875:Middle Aged; D014442:Monophenol Monooxygenase / Q000097:blood* / Q000235:genetics; D009367:Neoplasm Staging; D009360:Neoplastic Cells, Circulating; D011379:Prognosis; D012044:Regression Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012878:Skin Neoplasms / Q000097:blood / Q000175:diagnosis / Q000473:pathology
D014442:Monophenol Monooxygenase