During my translation work I often come across words that the author has put in italics, quotations marks, or in italics within quotation marks. And often the way they use them throughout the text is inconsistent.
As translators, we have to take a step back from the usage in the original document and remember the rules of our own brand of English. Mirroring the source is not an option. And we also have to smooth out all the inconsistencies.
Whether you put words, terms, titles, etc., into italics, quotations or in roman type will depend on the style manual you have been told to follow. And if you haven’t been given any specific instructions, it’ll depend on whether you use a British, American, Canadian, Australian, etc., guide for your work. You’ll find a long list of style guides (over 40) towards the bottom of my ‘Useful Links’ page.