メディエイゴ

A drug that targets the cell surface receptors(1) that play an important role in many types of cancer(2) can bring about significant(3) tumour regression(4) in breast cancer(5) after only six weeks of use, a scientist told the 6th European Breast Cancer Conference (EBCC-6) today (Thursday 17 April).

Dr. Angel Rodriguez, from the Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, USA, said that the work demonstrated for the first time that the tyrosine kinase inhibitor(6) lapatinib(7) could decrease tumour-causing breast cancer stem cells(8) in the primary breast cancers(9) of women receiving neoadjuvant treatment(10) (treatment given before the primary surgery(11) for the disease). Dr. Rodriguez and colleagues studied 45 patients with locally advanced(12) breast cancer in which the gene(13) HER-2(14) was over-expressed(15). The patients received lapatinib for six weeks, followed by a combination of weekly trastuzumab(16) and three-weekly docetaxel(17), given over 12 weeks, before primary surgery. Biopsies(18) were performed at the time of diagnosis(19) and also after six weeks of lapatinib and cells(20) from the tumours were obtained(21) and analyzed.

“We saw significant tumour regression after six weeks of single agent lapatinib,” said Dr. Rodriguez. “Bi-dimensional(22) tumour measurements showed a median(23) decrease of minus(24) 60.8%. We had previously(25) showed that tumour-causing breast cancer stem cells were resistant to(26) conventional(27) preoperative(28) chemotherapy(29); indeed, residual(30) cancers that were exposed to(31) such chemotherapy showed an increase in tumour-causing cells and enhanced(32) tumour initiation(33) by the formation of mammospheres(34), small tumours that form when tumour-causing cells are cultured(35) in a test tube(36), which reflect the capacity of the cells to self-renew(37).