Finally, reconstitution with the p66ShcA-S36A mutant further debilitated the lung-metastatic potential of p66ShcA-null mammary tumors (p66-CR (VC): 56% incidence; p66-CR (S36A): 31% incidence) (Fig. 3b), coincident with a 5-fold reduction in metastatic burden (Fig. 3c). Here, SHC1 is linked to breast cancer.