Final answer:
One of the main limitations of anti-angiogenesis therapy in cancer treatment is increased drug resistance, which may lead to enhanced tumor growth due to cancer cells overcoming the therapy's effects.
Step-by-step explanation:
Angiogenesis inhibitors are used in cancer treatment to prevent the formation of new blood vessels that supply nutrients and oxygen to tumors, which are essential for tumor growth. One of the limitations of anti-angiogenesis therapy is A) Increased drug resistance, as cancer cells may adapt to overcome the effects of these drugs. Tumors can also utilize alternative pathways to sustain angiogenesis or develop more aggressive phenotypes in response to the therapy. B) Enhanced tumor growth can sometimes occur paradoxically, due to the selection of more aggressive cancer cells or increased invasiveness induced by hypoxic conditions. On the other hand, C) Reduced metastasis and D) Improved immune response are generally considered potential benefits of anti-angiogenesis treatments rather than limitations. The therapy may reduce the likelihood of cancer spreading and can synergize with immunotherapy by improving the immune system's ability to fight cancer.