( ( The ( National ( Cancer Institute ) ) ) ( ( says ( ( ( the ( ultraviolet portion ) ) ( of sunlight ) ) ( is ( ( the ( leading cause ) ) ( of ( skin cancer ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NNP National) (NNP Cancer) (NNP Institute)) (VP (VBZ says) (SBAR (S (NP (NP (DT the) (JJ ultraviolet) (NN portion)) (PP (IN of) (NP (NN sunlight)))) (VP (VBZ is) (NP (NP (DT the) (VBG leading) (NN cause)) (PP (IN of) (NP (NN skin) (NN cancer)))))))) (. .)))
The National Cancer Institute says the ultraviolet portion of sunlight is the leading cause of skin cancer.
(ROOT (S (NP (NNP Sunlight)) (VP (VBZ is) (NP (NP (DT the) (VBG leading) (NN cause)) (PP (IN of) (NP (NN skin) (NN cancer))))) (. .)))