The »East« is a persistent theme in the research on Kafka’s literature, but this East is confined to Europe. There are innumerable studies devoted to the tensions between the Jews of central and western Europe, reflecting also the contrast between the western use of the German language and the eastern use of »jargon« (i.e. Yiddish).
Given the context, I think that "Kafka‘s literature" means literature (books, studies, articles…) dealing with Kafka. Do you think that the apostrophe in "Kafka" is necessary? In my opinion, "Kafka‘s literature" means something like literature that Kafka liked or had in his library.