Identify whether the chemical compound that contains Calcium is carcinogenic.
calcium refers to element = 'ca'; label = '+' mean molecules are carcinogenic; label = '-' means molecules are non-carcinogenic;
SELECT T2.label AS flag_carcinogenic FROM atom AS T1 INNER JOIN molecule AS T2 ON T1.molecule_id = T2.molecule_id WHERE T1.element = 'ca'