“…The second branch is the inhibition of serine/threonine and tyrosine protein kinases that implies direct modulation of the key signal transduction pathways in cancer cells [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. This molecular mechanism is mainly realized by staurosporine and its derivatives.…”