ALB and cancer: In addition, it has been shown that oncogenic Ras mutations promote macropinocytic uptake of extracellular proteins such as serum albumin, which are catabolized in lysosomes and serve as an AA source to sustain cancer cells’ metabolic needs.[3, 4, 27] We observed that supplementing EBSS with 3% bovine serum albumin (BSA) partially restored pS6K levels in agreement with the mutated KRAS status of MDA‐MB‐231 cells (Figure 3c, and Figure S3a, Supporting Information),[28, 29] and resulted in a ≈60% reduction of collagen cleavage as compared to EBSS alone (Figure 3d).