In the binding assay of [125I]PYK using A431 tumor cell membranes (Fig. 6), linear Scatchard plots indicated that [125I]PYK bound to a single population of binding sites with high affinity (Kd value; 51.3 ± 11.1 nM; Hill’s constant value; 1.02). The gene discussed is PHKA2; the disease is neoplasm.