Abstract: The invention relates to an method for the detection of cancer cells of epithelium origin expressing the Ep-Cam antigen and identification of circulating micrometastatic cancer cells in peripheral blood tissues and other body fluids of patients suffering from cancer of epithelial origin, using a sample of total blood, body fluids or tissue, comprising the amplification of a cDNA molecule encoding the Ep-CAM antigen, which includes the following steps: (i) hybridizing mRNA isolated by any conventional technique, with a specific (reverse primer) oligonucleotide that hybridizes specifically to the nucleotide sequence of the Ep-CAM antigen; (ii) producing sequence specific single stranded DNA (complementary DNA) with or without 0.01 Mol DTT with the use of reverse transcriptase from mRNA extracted by any conventional technique; and (iii) detecting Ep-CAM and identifying circulating metastatic cancer cells.