Italic not working in XML?

Can anyone explain why all HTML tags are working/rendering in my XML but italic ?

Also, you can't put classes in xml right, I tried that it it didn't seem to recognized any classes开发者_高级运维.

Sorry getting familiar with XML

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XML has a CDATA function to pass characters used in the language.

There is a nice explanation to it here: http://www.w3schools.com/xmL/xml_cdata.asp