Estrogen-Receptor-Positive Cancers Associated with LAR Phosphatase.(protein tyrosine phosphatase)

2001 JAN 25 - (NewsRx.com) -- A new study conducted by researchers at the University of Rochester School of Medicine shows estrogen-receptor-positive tumors associate with the protein tyrosine phosphatase LAR.

Several signal transduction molecules have been identified on breast cancers in women, including the receptors for estrogen and progesterone, as well as the gene factor c-erbB2, according to C.M. Levea and colleagues. LAR is the latest of these signaling molecules to be identified based on preliminary research data, researchers report.

In the current study, Levea et al. examined the significance of LAR as a prediction indicator for breast cancer. Initial analysis of LAR in metastatic cell lines revealed enhanced expression of LAR.

"LAR expression was associated with metastatic potential in the well-characterized 13762NF rat mammary adenocarcinoma clones," Levea and colleagues reported. They also noted, "the metastatic MTLn3 and MTLn2 clones expressed sizable amounts of LAR."

In contrast, non-metastatic cells expressed very little LAR according to investigators.

Other signal transduction molecules were expressed at varying levels. C-erbB2 and epidermal growth factor receptors (EGFR) were at their highest in MTLn3, whereas they were weakly expressed in MTLn2.

"In human breast cancer specimens, LAR expression was strongly positive in 50% of metastatic cases but in only 21% of 'non-metastatic' cases," remarked ...