Yeah, I've noticed that (about Manga Updates). It's very clearly unfinished (and with the very obvious cliffhanger...), so it must be that either Manga Updates is wrong on this one (I hope so! they're occasionally wrong, so it's quite possible), or it was indeed canceled. If the latter, I wonder why it was licensed. Perhaps, it is just temporarily on-hold...Another possibility (though very unlikely) that "volume 1" refers to some different content than what we've got. In June's edition, the main story is just about half of the volume (the rest are unrelated - albeit quite interesting - short stories).
If anyone from June has any additional information on this title they could share (in particular, about the existence of the sequel), I'd really appreciate it.
The story itself is one of the more complex and original yaoi stories I've read recently. In its level of complexity and all the layers/nuances, it reminded me of "The Cornered Mouse Dreams of Cheese" by Setona Mizushiro. A pity the situation with the sequel is so unclear (to me, at least). There were no "Author's Notes" in the manga either - typically those would say if there's any continuation planned or not.