I would use an IIF() statement instead.
=IIF(Fields!Column1.Value <> "Specific Value", "Italic", "Normal")
Generally speaking a switch is a 'case' statement for multiple occurences and an IIF statement is a typical 'if, then, else' statement. The danger becomes that you can nest IIF statements like IIF(thing, 'set1', iif(thing2, 'set2', 'default')) but it would be easier to do a switch like Switch(thing, 'set1, thing2, 'set2', 'default'). The problem with switches is if an occurence of something happens of both one thing and another it assumes the first is true and just performs that. Thus you must account for proper order of something's occurence or it will assume the first instance. Generally when you have an instance of something and a default I use IIF. If there is a problem with a switch I will do a nested IIF generally or reorder the events of the Switch statement.
I hope that helps a little bit.