RP1 and melanoma: IGFBP-rP1 is commonly regarded as a tumor suppressor in CRC,20 prostate cancer,15 breast cancer,16 lung cancer,17 melanoma,18 and thyroid cancer.19 Previous work from our laboratory suggested that IGFBP-rP1 expression in CRC tissue is correlated with a favorable prognosis.20 Although the prognosis relies heavily on tumor recurrence and distant metastasis after surgical resection, little was known about the function of IGFBP-rP1 in tumor cell motility.