Detection of germ-cell tumor cells in the peripheral blood by nested reverse transcription-polymerase chain reaction for alpha-fetoprotein-messenger RNA and beta human chorionic gonadotropin-messenger RNA

By establishing sensitive nested reverse transcription-PCRs for the detecti on of nRNA of alpha-fetoprotein (AFP) and beta human chorionic gonadotropin (beta bCG), we investigated the presence of circulating tumor cells in the peripheral blood of 119 patients with germ-cell tumor. A total of 336 bloo d samples obtained before and during therapy were examined with regard to c linical applicability. The overall ratio of positive PCR results was 26.5% and was independent of the serum concentration of and hCG/beta hCG. No corr elation of the positivity for AFP-mRNA to serum AFP level was found. In con tract, positive results in beta hCG-PCR a ere twice as frequent in patients with elevated serum hCG/beta bCG levels as in those with normal serum hCG/ beta hCG levels (P = 0.012). To develop a valid correlation to tumor stage, tumor histology, and serum level of tumor markers, a subgroup of 36 patien ts was evaluated before definite therapy. The subgroup revealed an overall ratio of 33.3% positive PCR results. The serum level of both of the markers did not correlate with the detection of corresponding mRNA in peripheral b lood samples. However, positive beta hCG-PCR results were found exclusively in patients with elevated serum hCG/beta hCG (6 of 18 versus 0 of 18; P = 0.019). Patients with stage IIC/III germ-cell tumor demonstrated nearly twi ce the frequently of positive PCR results as patients with stage I tumor [7 (41.2%) of 17 versus 4 (23.5%) of 17] in this subgroup. With regard to his tology, positive PCR results were found mostly in embryonal carcinoma.