( ( ( ( ( ( Skin cancer ) ( is ( ( the ( ( most common ) ( malignant disease ) ) ) ( in ( the ( United ( States population ) ) ) ) ) ) ) , ) and ) ( ( ( excessive exposure ) ( to sunlight ) ) ( is ( ( a ( major cause ) ) ( of ( these cancers ) ) ) ) ) ) . )
(ROOT (S (S (NP (NN Skin) (NN cancer)) (VP (VBZ is) (NP (NP (DT the) (ADJP (RBS most) (JJ common)) (JJ malignant) (NN disease)) (PP (IN in) (NP (DT the) (NNP United) (NNPS States) (NN population)))))) (, ,) (CC and) (S (NP (NP (JJ excessive) (NN exposure)) (PP (TO to) (NP (NN sunlight)))) (VP (VBZ is) (NP (NP (DT a) (JJ major) (NN cause)) (PP (IN of) (NP (DT these) (NNS cancers)))))) (. .)))
Skin cancer is the most common malignant disease in the United States population, and excessive exposure to sunlight is a major cause of these cancers.
(ROOT (S (NP (NNP Sunlight)) (VP (VBZ is) (NP (NP (DT the) (VBG leading) (NN cause)) (PP (IN of) (NP (NN skin) (NN cancer))))) (. .)))