( Researchers ( ( have ( learned ( that ( cancer ( is ( ( ( caused ( by changes ) ) ( -LRB- ( ( called ( ( mutations or ) alterations ) ) -RRB- ) ) ) ( in ( genes ( that ( control ( normal ( cell ( growth ( and ( cell death ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Researchers)) (VP (VBP have) (VP (VBN learned) (SBAR (IN that) (S (NP (NN cancer)) (VP (VBZ is) (VP (VBN caused) (PP (IN by) (NP (NNS changes))) (PRN (-LRB- -LRB-) (VP (VBN called) (NP (NNS mutations) (CC or) (NNS alterations))) (-RRB- -RRB-)) (PP (IN in) (NP (NP (NNS genes)) (SBAR (WHNP (WDT that)) (S (VP (VBP control) (NP (JJ normal) (NN cell) (NN growth) (CC and) (NN cell) (NN death))))))))))))) (. .)))
Researchers have learned that cancer is caused by changes (called mutations or alterations) in genes that control normal cell growth and cell death.
(ROOT (S (NP (NP (NNS Mutations)) (PP (IN in) (NP (NP (JJ regulatory) (NNS genes)) (SBAR (WHNP (WDT that)) (S (ADVP (RB normally)) (VP (VBP control) (NP (DT the) (NN cell) (NN cycle)))))))) (VP (VBP cause) (NP (NN cancer))) (. .)))