C6 and breast cancer: In the absence of sPLA2, the IC50 of c6-RAR prodrug in MT-3 breast cancer cell line was 110 μM, while the IC50 of c6-RAR prodrug decreased to 10 μm after adding sPLA2, indicating that the prodrug was hydrolyzed into c6-RAR and Lyso-O-SPG by sPLA2, in response to phospholipase [92].