If you mistakenly typed "FeCTR" and meant to write something else, here are a few possible corrections. For "FeCTR", you could have intended to write "FeCR", which stands for Ferric, denoting iron in its +3 oxidation state. Alternatively, you might have meant "FeTCR", where TCR stands for T-cell receptor, a protein found on T-cells that recognizes antigens.