RAB27A and cancer: We also did not observe significant differences in functional myeloid gene expression, such as production of VEGF, NOS2 and ARG1, as well as levels of MHC II upon knockdown of Rab27a, again suggesting that cancer cell-associated Rab27a might contribute largely to localized expansion of myeloid cells, rather than their functional differentiation (Supplementary Figure 4A–C and data not shown).