The present invention relates to the inhibition of the function of SHP2 by both anti-SHP2 peptides and the chemical compound 4-(2-sulfaminoethyl)benzoic acid, SEBA, and SEBA derivatives binding to the phosphotyrosyl phosphatase domain of SHP2 thereby inhibiting the function of SHP2 both in vitro and in vivo. In addition, the inhibition of SHP2 may be useful as a treatment for human disease, and it has been shown that interfering with SHP2 function using the anti-SHP2 peptides and SEBA compounds reverses cell transformation and induces remission of preformed tumors in vivo demonstrating a possible treatment for cancer.