Serglycin core protein was detected only in the culture medium of aggressive cell lines such as A549, NCI-H23, and HCC827 lung cancer cells and DLD-1 colon cancer cells as well as MDA-MB-231 breast cancer cells as previously shown [9], which harbor KRAS or HER1/EGFR mutations (Figure 1(b)). Here, KRAS is linked to breast cancer.