We can only speculate about the reason(s) for Meso64-TR3 being much more potent than Meso-TR3 on MUC16-expressing cancer cells but we believe that the high sensitivity of the full length mesothelin targeting moiety to elevated (56°C) and even to physiologically more relevant temperature conditions (37°C) might be a key discriminating factor for Meso-TR3's reduced functional properties. Here, MUC16 is linked to cancer.