TNF and neoplasm: To get insight into TNFα has relevance to bevacizumab resistance in more detail in in vivo, we separated MDA-MB-231 cell lines resistant to bevacizumab (MDA-MB-231R) and injected MDA-MB-231R on one flank of mice with or without bevacizumab administration, then detected TNFα concentration in serum of tumor-bearing mice every week (n = 4).