Fig. 5

Tumour resistance mechanisms against anti-angiogenic treatments. The upper image shows the various innate resistance mechanisms, which include a) presence of different targets, b) reduced apoptosis due to overproduction of Bcl2/Bcl-xl, and c) over expression of EZH2. In the lower image, the tumour responds initially in response to therapy by shrinking in size but undergoes acquired resistance which facilitates cancer re-growth. Some of the resistance mechanisms are a) initiation of alternative or complementary pathways, b) lysosomal sequestration of the drugs, c) SNPs and micro RNAs, d) recruitment of BMDCs, e) increased pericyte coverage of tumour vessels, f) EMT and g) establishment of new-pro-angiogenic pathways