Avastin’s Failure in Breast Cancer: New Study May Explain Why It Happened
A newِ study mayِ explain whyِ theِ cancer drug Avastin hasn’tِ worked inِ the treatment ofِ breast cancer patients.
Although theِ drug stops tumor growth forِ a short time, itِ often leads toِ moreِ invasive tumors inِ the long run.
The reason forِ this revved-up invasiveness, researchers concluded fromِ experiments doneِ in mice, isِ that drugs likeِ Avastin increase theِ portion ofِ a tumor madeِ of breast cancer stem cells.
The seeds of a tumor
Avastin falls intoِ a category ofِ cancer drugs called antiangiogenic agents, whichِ aim toِ work byِ blocking theِ growth ofِ blood vessels thatِ supply tumors withِ vital nutrients andِ oxygen.
Wicha saidِ heِ andِ his colleagues suspected theِ causeِ of theِ new, aggressive growth, mightِ beِ cancer stem cells.
As expected, theِ tumors shrank andِ had fewerِ blood vessels feeding them.
Two sides of a drug
The newِ findings didn’tِ surprise Celeste Simon, a molecular biologist atِ the University ofِ Pennsylvania School ofِ Medicine whoِ studies theِ role ofِ the body’s lowِ oxygen environments toِ human health.
Stem cells really like to reside in a low oxygen area, Simon said.
What theِ study adds, Simon said, isِ evidence thatِ drugs likeِ Avastin increase theِ pool ofِ cancer stem cells living inِ these low-oxygen conditions.
The notion isِ that byِ making theِ tumor moreِ hypoxic, you’reِ actuallyِ selecting forِ the moreِ aggressive cells, sheِ said.
This andِ other papers underscore a growing idea inِ the therapeutic world that, likeِ allِ treatments, antiangiogenic drugs needِ to beِ very carefully evaluated inِ terms ofِ their full impact onِ human health.