SYNE1 and neoplasm: Unmatched PK is a challenge: prodrugs should be administrated when the plasma CPG2 level decreases to a very low level to reduce off-target activation; a rapid elimination of prodrugs (although a short residence time favors the safety) indicates that enough amounts of prodrugs and CPG2 should be transferred into the tumor in a short time, i.e., a narrow therapeutic time window.