( Still ( , ( ( cycling ( tumour cells ) ) ( ( were ( present ( in ( four ( of 13 ) ) ) ) ) ( -LRB- 31 ) ) ) ) )
(ROOT (S (ADVP (RB Still)) (, ,) (NP (NN cycling) (NN tumour) (NNS cells)) (VP (VBD were) (ADJP (JJ present) (PP (IN in) (NP (NP (CD four)) (PP (IN of) (NP (CD 13)))))) (NP (NNP -LRB-) (CD 31)))))
Still, cycling tumour cells were present in four of 13 (31
(ROOT (S (NP (NNS Cells)) (VP (VBP have) (NP (CD four) (NNS cycles))) (. .)))