There have been dozens of researches showed that Cyclin F (CCNF) is aberrantly expressed or mutated in some cancer types, however, whether or how the alteration in CCNF contributes to the tumorigenesis and tumor progression is not yet known.[3] Studies have found that CCNF is in-frame fused in breast cancer[4] and CCNF has recurrently mutated in about 20% of Burkitt lymphoma,[5] which suggest that CCNF may play an operative role in cancers. Here, CCNF is linked to breast cancer.