( ( The ( T cell ) ) ( ( ( ( is ( formed ( in ( the ( thymus gland ) ) ) ) ) and ) ( is ( ( ( ( a ( natural killer ) ) ( of ( foreign cells ) ) ) , ) ( including ( cancer cells ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NNP T) (NN cell)) (VP (VP (VBZ is) (VP (VBN formed) (PP (IN in) (NP (DT the) (JJ thymus) (NN gland))))) (CC and) (VP (VBZ is) (NP (NP (DT a) (JJ natural) (NN killer)) (PP (IN of) (NP (JJ foreign) (NNS cells))) (, ,) (PP (VBG including) (NP (NN cancer) (NNS cells)))))) (. .)))
The T cell is formed in the thymus gland and is a natural killer of foreign cells, including cancer  cells.
(ROOT (S (NP (DT The) (NNS thymus) (NN gland)) (VP (VBZ produces) (NP (NN t) (NNS cells))) (. .)))