ITGB1 and neoplasm: Interestingly, CFPAC-1 endocytosis of ITGB1 was not affected by AP2M1 depletion or Pitstop2 treatment (Fig. 4i, j), validating the results of the plasma membrane proteomics and suggesting that integrin endocytosis is independent of clathrin in cell lines where AP2 loss did not enhance tumor growth.