The binding pattern of ch5E6 for high molecular weight endogenous forms was comparable to commercial anti-MUC16 mAb M11 (anti-CA125) in both cancers (Fig. 2, a-II and 2b-II, upper panel), which, however, failed to recognize the cleaved forms of MUC16 (Fig. 2, a-II and 2b-II, lower panel) advocating MUC16 cleavage as an important and universal event uncovered by mAb5E6. The gene discussed is MUC16; the disease is cancer.