The structure and function of NKAIN2-a candidate tumor suppressor.

The deletion of chromosomal region 6q was commonly found in several types of human cancers, although the tumor suppressor genes (TSGs) located within this genomic region are not well established. Our recent work detected recurrent chromosomal truncation at the Na(+)/K(+) transporting ATPase interacting 2 (NKAIN2) gene in prostate cancer, which was also found to be truncated in leukemia and lymphoma, suggesting that NKAIN2 is potentially one of the TSGs located in the 6q commonly deleted region in human cancers. NKAIN2 gene consists of eight coding exons that span approximately 1 Mb of genomic DNA on chromosome 6q and there are four main splice variants. The function of this gene is not well investigated and the limited knowledge of this gene pointed to nervous system development. The chromosomal translocations in nervous development disorders usually lead to inactivation of this gene. In human tumors, both chromosomal deletion and translocation may also inactivate this gene and consequently contribute to tumorigenesis. Further genetic and cellular functional studies are required to establish its tumor suppressor role.