The mixed-lineage leukemia 3 (MLL3) gene, which encodes an important component of a histone H3 lysine 4 methyltransferase complex named the ASC-2- and Mll3-containing complex (ASCOM), has been implicated as a tumor suppressor gene due to its frequent mutations in multiple types of human tumors as well as tumor induction upon targeted inactivation of the gene in mice.
By knocking out the PRIP gene in the tumor cell line, we demonstrated that PRIP deficiency led to inhibited tumor formation without affecting tumor cell proliferation.
The genetic locus NRC-1 within chromosome 3p12 mediates tumor suppression in renal cell carcinoma independently of histological type, tumor microenvironment, and VHL mutation.
Furthermore, the NRC-1 locus falls within a well-characterized homozygous deletion region of 5-7 Mb associated with a small cell lung carcinoma cell line, U2020, suggesting that a more general tumor suppressor gene may reside in this region.