PubMed's MeSH database does frequency search for mapping now?

OK, so here's a weird thing.

I searched induction therapy in the MeSH database (Pubmed) and it returned the MeSH term Neoadjuvant Therapy. Which is pretty close to what I was looking for, but the weird thing is, I can't figure out how it knew that. Induction therapy is not an entry term for Neoadjuvant Therapy, nor does the word induction appear anywhere in the scope note. The only thing that I can guess is that PubMed is now doing some kind of frequency search, the way that Ovid is so famous for, in order to return a MeSH result.