Scientists have discovered a mechanism that spurs the growth of two of every three breast cancers, according to a new study.
Two thirds of breast tumors feature the overproduction of a protein, called ER-alpha, that binds to the hormone estrogen . Researchers from the German Cancer Research Center report finding a gene that can be targeted to stop the overproduction.
Scientists have long studied the link between breast cancer and high levels of ER-alpha. Early-stage breast cancer cells produce too much of it,and this production is associated with faster cell division and can ultimately lead to tumor development , said Joerg Hoheisel, a scientist at the research center, located in Heidelberg.
"These molecules can interact with the estrogen hormone and, thus, even lead to cancer," Hoheisel said in a statement.
Hoheisel and his colleagues found that a tiny nucleic acid a building block of genes called miR-375 contributes to high levels of ER-alpha in cells. In healthy cells, an enzyme controls how much ER-alpha is made, keeping its levels in check. MiR-375 blocks production of this enzyme, and ER-alpha levels run amok, according to the study.
And to make things even worse, high ER-alpha levels trigger the production of more miR-375, creating a vicious cycle that boosts multiplication of cancer cells , the study said.
To see if this destructive cycle could be stopped, the researchers blocked miR-375, and found that they were able to slow the growth of breast cancer cells growing in lab.
More research must be done to see if miR-375 can be used as a target for breast cancer drugs, "but we hope to be able to use our results in the future for developing new strategies against tumors with too many estrogen receptors," Hoheisel said.
The study was published Nov. 23 in the journal Cancer Research.