TK1 and leukemia: The IP results with Mab-2 showed that 90% of the recombinant canine TK1 was able to bind to the beads at 4°C and 23°C (Figure 2F), while 40–60% of TK1 were bound to the beads when serum samples from dogs with leukemia, lymphoma and histiocytic sarcoma were analyzed (Figure 2F).