The EMT-related genes were LRPPRC, AGR2, CLDN4, CRIP1, DSP, ELF3, JUP, KRT8, KRT18, KRT19, FAM102A, TACSTD2, EPCAM, PEBP1, PSMD8, RAN, SNRPC, SPTAN1, EZR, DDR1, MLPH, and WDR34. In which, gene SNRPC, upregulated in CTC clusters, is a metastatic novel biomarker in breast cancer. This evidence concerns the gene AGR2 and breast cancer.