Functional characterization of the candidate tumor suppressor gene NPRL2/G21 located in 3p21.3C..     ///    " Initial analysis identified the NPRL2/G21 gene located in 3p21.3C, the lung cancer region, as a strong candidate tumor suppressor gene. "    ///    "We report inactivating mutations in a variety of tumors and cancer cell lines, growth suppression of tumor cells with tet-controlled NPRL2/G21 transgenes on plastic Petri dishes, and suppression of tumor formation in SCID mice. "    ///    "We speculate that the NPRL2/G21 nuclear protein may be involved in mismatch repair, cell cycle checkpoint signaling, and activation of apoptotic pathway(s). "    ///    At least two homozygous deletions of NPRL2/G21 were detected in 6 tumor biopsies from various locations and with microsatellite instability.     ///    "By sequence analysis, the main product of NPRL2/G21 encodes a soluble protein that has a bipartite nuclear localization signal, a protein-binding domain, similarity to the MutS core domain, and a newly identified nitrogen permease regulator 2 domain with unknown function. "    ///    Here we provide additional evidence of the tumor suppressor function of NPRL2/G21. 