+---------------------SUBJ:V-N---------------------+    
      +------COMP:N-N(of)------+                         |    
      |        +--MOD_ATT:N-N--+                         |    
      |        |     +MOD_ATT:N+                         |    
      |        |     |         |                         |    
 Expression of H __NODE__ [__NODE__] in mammary gland occurs .
COMP:N-N(of) (expression,[__NODE__])
MOD_ATT:N-N ([__NODE__],H)
MOD_ATT:N-ADJ ([__NODE__],__NODE__)
SUBJ:V-N (occur,expression)