Many tumor supressor genes are thought to reside on chromosome 3p because one copy of this region is frequently found to be deleted in several carcinomas. The gene encoding DLEC1 (deleted in lung and esophageal cancer protein 1), a 1,755 amino acid cytoplasmic protein, is located within a chromosomal region that is subject to abberations in many cancer cell lines and primary cancers. Reduced invasiveness and suppression of cell growth occurs when DLEC1 cDNA is introduced into a variety of cancer cell lines, suggesting that defects in the transcription of DLEC1 is a cause of lung, esophageal, and renal cancers. Evidence also suggests that methylation of the DLEC1 promoter may be associated with a poor prognosis in non-small cell lung carcinoma and nasopharyngeal carcinoma. With highest expression in kidney and prostate, there are three isoforms of DLEC1 that exist as a result of alternative splicing events.