( ( ( ( ( ( Younger ( guinea pigs ) ) ( may ( develop ( ( skin ( ( tumors or ) leukemia ) ) ( -LRB- ( ( ( a cancer ) ( of ( the blood ) ) ) -RRB- ) ) ) ) ) ) , ) but ) ( ( ( most types ) ( of cancer ) ) ( ( ( are not ) ( common ( in ( guinea pigs ) ) ) ) ( until ( they ( are ( ( ( ( 4 to ) 5 ) years ) old ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (JJ Younger) (NN guinea) (NNS pigs)) (VP (MD may) (VP (VB develop) (NP (NP (NN skin) (NNS tumors) (CC or) (NN leukemia)) (PRN (-LRB- -LRB-) (NP (NP (DT a) (NN cancer)) (PP (IN of) (NP (DT the) (NN blood)))) (-RRB- -RRB-)))))) (, ,) (CC but) (S (NP (NP (JJS most) (NNS types)) (PP (IN of) (NP (NN cancer)))) (VP (VBP are) (RB not) (ADJP (JJ common) (PP (IN in) (NP (NN guinea) (NNS pigs)))) (SBAR (IN until) (S (NP (PRP they)) (VP (VBP are) (ADJP (NP (QP (CD 4) (TO to) (CD 5)) (NNS years)) (JJ old))))))) (. .)))
Younger guinea pigs may develop skin tumors or leukemia (a cancer of the blood), but most types of cancer are not common in guinea pigs until they are 4 to 5 years old.
(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)))))))) (. .)))