Posted Thursday, March 8, 2012 --- 6:45 a.m.
BOSTON (AP) -- A new study could be very bad news for efforts to customize cancer treatment based on each person's genes.
Scientists have discovered big differences from place to place in the same tumor as to which genes are active or mutated. They also found differences in the genetics of the main tumor and places where the cancer has spread.
Study leader Dr. Charles Swanton of the Cancer Research UK London Research Institute says "we're finding that the deeper you go, the more you find."
This means the single biopsies that doctors rely on to choose drugs are probably not giving a true view of the cancer's biology. It also means that treating cancer won't be as simple as many had hoped.
Dr. Dan Longo says the research is a reality check for "overoptimism" about conquering cancer with new gene-targeting drugs.
The study is reported in Thursday's New England Journal of Medicine.
Copyright 2012 . The Associated Press.