I should start by clarifying the possible interpretations, then build an essay around one of the plausible ones. Let's go with the assumption that "ane wa yan" is a typo for "ane wa nan desu ka?" (What is sister?), but that's a question, not a statement. Alternatively, if "ane wa yan" is a name, maybe a character from a show or book. Alternatively, maybe the user is referring to the phrase "Ane wa... Yan" as a title, which could be a Japanese title for a story about an older sister.