CCN1 and cancer: CCN1-Prom activities were also elevated in a series of single-oncogene transformed Fischer rat embryo cell (CREF) lines (CREF-src, CREF-raf, CREF-ras and CREF-HPV) [20, 31-33] as compared to the immortal non-transformed parental CREF cell line [34] and activity increased with the addition of tumor-promoting phorbol ester TPA (Fig. 1C), further supporting the elevated activity of tCCN1-Prom in cancer progression and metastases.