CCN5 and breast cancer: CCN5 is found to be constitutively expressed in less aggressive human BC cells (i.e. MCF-7 and ZR-75-1), whereas its expression is minimally detected in moderately aggressive BC cell lines (i.e. SKBR-3) and it is completely undetected in the highly aggressive BC cell line (i.e. MDA-MB-231)21, 24.