Compositions, methods, and combination therapies for the treatment of cancers, including lymphomas, leukemias, melanomas, lung cancer, and metastatic disease, are provided. Specifically, compositions comprising ligands to Pgrmc1 are disclosed for use in treating and inhibiting tumor growth and progression and inhibition of metastases. The compositions and methods using these ligands can be used alone or in combination with other reagents and cancer treatment modalities.