The expression of SEL1L and TAN-1 in normal and neoplastic cells

We have previously reported on the isolation and chromosomal mapping of a n ovel human gene (SELIL), which shows sequence similarity to sel-1, an extra genic suppressor of C. elegans. sel-1 functions as a negative regulator of lin-12 activity, the latter being implicated in the control of diverse cell ular differentiation events. In the present study we compare the expression patterns of SELIL, and TAN-I, the human ortholog of lin-12 in normal and n eoplastic cells. We found that whereas both genes are expressed in fetal ti ssues at similar levels, they are differentially expressed in normal adult and neoplastic cells. In normal adult cells SELIL is generally present at v ery low levels; only in the cells of the pancreas does it show maximum expr ession, By contrast SELIL is generally well represented in most neoplastic cells but not in those of pancreatic and gastric carcinomas, where transcri ption is either downregulated or completely repressed. TAN-I on the other h and is well represented in almost all normal and neoplastic cells, with ver y few exceptions. Our observations suggest that SELIL is presumably implica ted in pancreatic and gastric carcinogenesis and that, along with TAN-I, it is very important for normal cell function. Alterations in the expression of SELIL may be used as a prognostic marker for gastric and pancreatic canc ers.