( ( One-third ( of ( the patients ) ) ) ( ( are ( being ( treated ( for ( ( leukemia , ) ( the ( ( most common ) ( childhood cancer ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NN One-third)) (PP (IN of) (NP (DT the) (NNS patients)))) (VP (VBP are) (VP (VBG being) (VP (VBN treated) (PP (IN for) (NP (NP (NN leukemia)) (, ,) (NP (DT the) (ADJP (RBS most) (JJ common)) (NN childhood) (NN cancer))))))) (. .)))
One-third of the patients are being treated for leukemia, the most common childhood cancer.
(ROOT (S (NP (NNP Leukemia)) (VP (VBZ is) (NP (NP (DT the) (ADJP (RBS most) (JJ common)) (NN type)) (PP (IN of) (NP (NP (NN cancer)) (VP (VBN developed) (PP (IN in) (NP (NNS children)))))))) (. .)))