Despite these limitations, we suggest that the RT-qPCR based analysis of CCNE2, DKFZp762E1312, EMP2, MAL2, PPIC, and SLC6A8 gene expression in the blood of patients with breast cancer or gynecologic malignancies is useful for the detection of circulating tumor cells, alone or combined with other markers such as hMAM or EpCAM. Interestingly, the DKFZp762E1312, EMP2, PPIC, and SLC6A8 transcripts, but not CCNE2 and MAL2 transcripts were detected in the blood of healthy females. This evidence concerns the gene SLC6A8 and breast cancer.