Saposin C pharmaceutical compositions and methods of treating cancer

A composition comprising:

• a polypeptide comprising the amino acid sequence of SEQ ID NO:
• 1 with zero to four amino acid insertions, substitutions, or deletions;
• a phosphatidylserine lipid;
• a buffer at pH 5.0 to 8.0;
• trehalose;
• and
• water,
• wherein the polypeptide is at a concentration of 0.4 to 5.0 mg/ml,
• wherein the molar ratio of the phosphatidylserine lipid to the polypeptide is in the range of 8:1 to 20:1, and
• wherein the phosphatidylserine lipid and the polypeptide are associated together in the form of vesicles suspended in the water.