Published in Cancer Detection and Prevention 1996; 20(5).

Ultrasensitive detection of tumor cells in peripheral blood by RT-PCR

H Magdelenat¹, A Muller¹, F Martin¹, MG Denis², F Saporta¹, M Peter¹, O Delattre¹, P de Cremoux¹

The sensitive and specific detection of tumor cells in the peripheral blood (PB) and bone marrow (BM) of patients with primary solid tumors may have important clinical implications: marker of occult metastasis, detection of micrometastases, monitoring treatment efficacy. RT-PCR has been proposed for the detection of melanoma cells expressing tyrosinase mRNa, then for prostate cancer (PSA and PSM), hepatocarcinoma (alpha fetoprotein and albumin), neuroblastoma (tyrosine hydroxylase), breast cancer (cytokeratins). RT-PCR appeared more sensitive than cytological identification. We are currently evaluating: 1) The prognostic value of PB and BM Ewing tumor cells at diagnosis and after treatment. Tumor cells are characterized by specific variants of fusion transcripts resulting from chromosomal translocations. An intermediate evaluation indicates an association between the presence of cells in BM and metastatic disease. 2) The detection of circulating PSA-mRNA positive cells in stage T2 prostate cancer, with the aim of sparing radical prostatectomy in case of initial invasion. 3) The detection of circulating mammary cells in breast cancer, using a positive selection of epithelial cells and RT-PCR of MUC 1. Upon serial dilutions of tumour cells in blood, a sensitivity of 1 malignant per 1ml PB cells was achieved with Ewing's transcript RT-PCR and a sensitivity of I cell in 5m1 of blood was achieved with PSA and MUC 1 RT-PCR. Nucleotide sequencing of PCR products confirmed the specificity of these determinations. We conclude that RT-PCR of tumour or tissue specific markers is an ultrasensitive method for detecting circulating tumor cells in the blood of patients with primary solid tumors. The clinical impact of this detection is currently under investigation.

KEY WORDS: Circulating cells, micrometastasis, Ewing sarcoma, prostate cancer, breast cancer.

Paper presented at the International Symposium on the Impact of Cancer Biotechnology on Diagnostic and Prognostic Indicators; Nice, France; October 26 - 28, 1996; in the section on Metastasis.

http://www.cancerprev.org/Journal/Issues/20/5/103/558