I don't think there is a way to search the signatures (Brian, is that a field that can be added for searching in the directory?).

Go to the search link at the top of each message-board page. Use melanoma as your search term and be sure to choose Search All Open Forums to maximize results. I looked quickly and found at least one -- screen name Michael Ballon. Perhaps you could get his e-mail address from his profile (search the directory using his screen name or member number) and write him.

All the best,
Leslie