In spite of washing with PBS twice, extracellular treated RP53 was recovered from cell lysate only in K-Ras mutated cancer cell lines (*) but not in wild type K-Ras-cell lines including MDA-MB-468 (Breast cancer cell line; [12]), PC3 (Prostate cancer cell line; [13]) and MKN45 (gastric cancer cell line; [14]) (Figure 1A and B and Supplementary Figure 1A). Here, KRAS is linked to breast cancer.