Publisher Summary As normal cells progress to tumorigenicity, they must develop two
distinct new characteristics not possessed by the normal cells from which they arise: they
must become able to multiply without restraint and they must be able to create in vivo an
environment where this newly acquired growth potential can be realized. Normal cells are
antiangiogenic, because they secrete only low levels of inducers of angiogenesis and high
levels of molecules that inhibit neovascularization. These cells develop into successful …