Front is related to Rear. Rear is a synonym of Establish. 
Gene is a synonym of Factor. Factor is the opposite of Expand. Expand is related to Swell. Swell is related to Balloon. 
Front <--RelatedTo--> Rear <--Synonym--> Establish 
Gene <--Synonym--> Factor <--Antonym--> Expand <--RelatedTo--> Swell <--RelatedTo--> Balloon 