We selected SYNCRIP and SNU13 as representative exogenous spliceosomal proteins because i) they were detected in TIS secretomes from drug-stressed cancer cells (Supplementrary Data 4, Sheets 2–3), ii) their levels increased in recipient cells after incubation with TIS (Fig. 4H), and iii) their depletion impaired DNA damage repair (Fig. 5E). Here, SNU13 is linked to cancer.