The present invention relates to compositions comprising peptides that may be variants, derivatives and structural equivalents of cupredoxins that inhibit the development of premalignant lesions in mammalian cells, tissues and animals. Specifically, these compositions may comprise azurin from Pseudomonas aeruginosa, and/or the 50-77 residue region of azurin (p28). The present invention further relates to compositions that may comprise cupredoxin(s), and/or variants, derivatives or structural equivalents of cupredoxins, that retain the ability to inhibit the development of premalignant lesions in mammalian cells, tissues or animals. These compositions may be peptides or pharmaceutical compositions, among others. The compositions of the invention may be used to prevent the development of premalignant lesions in mammalian cells, tissues and animals, and thus prevent cancer.